Potential industrial and nutritional applications of shrimp by-products: a review

ABSTRACT

Asia is the largest producer of shrimp, accounting for 70% of the global cultured production. The market for shrimp has a high demand and the by-products from shrimp processing make up 40–60% of the whole shrimp. The main by-products include the head, viscera, shell, pelopods, tail, cephalothorax, and exoskeleton. The trends of the future and hurdles of shrimp by-product utilization have been outlined. These by-products are a good source of protein and have anti-inflammatory, anti-fungal, and anti-oxidant properties. They also enhance the immune system and have bioactive compounds that encourage their use for anti-cancerous, anti-hypertensive, and various other diseases. The waste produced can yield valuable by-products, including astaxanthin, oil, carotenoids, fortified products, nutrient-enriched chitin, protein, flavor enhancers, and composite flour. The yield of astaxanthin is 59.97 µg/g along with carotenoid is 68.26 µg/ml dw, chitosan (87%), protein (47.8%), oil extracted (88.9%) from shrimp by-products, and shrimp head is a rich source of protein (66%) and chitin (6%). These by-products can help meet the growing demand of an increasing population. The abundance of healthy ingredients found in shrimp makes it a valuable resource for scientists, entrepreneurs, and industrialists to develop new products. Additionally, utilizing shrimp waste can help reduce the burden on the earth and decrease environmental pollution.

KEYWORDS:

• Shrimp waste
• bioactive compounds
• industrial applications
• environmental sustainability
• shrimp waste-based products
• nutritional benefits

Introduction

The seafood industry is a significant component of the worldwide food sector, encompassing a diverse range of marine animals such as gastropods, cephalopods, and crustaceans, including crabs, krill, and shrimp. Seafood is considered to be a highly nutritious food source, providing a significant amount of both micro and macro nutrients that are essential for maintaining a healthy diet. Additionally, seafood plays a crucial role in ensuring food security for populations around the world. The reported global production of aquaculture and fisheries in 2020 was 2.14 billion metric tons. Nevertheless, the COVID-19 restrictions, the catches of lobsters, tuna, shrimp, and cephalopods persisted at their peak levels in comparison to the capture fisheries in the year 2020.^[1,2]

Crustaceans represent the most significant seafood sector, and prawns and shrimps are the second most commonly exported species. Shrimp and its derivatives are utilized in various forms and are experiencing a growing demand in developed nations. According to a report by IMARC, the market value of shrimp was recorded at 62.8 billion US dollars in 2021. It is projected to increase to 84.2 billion US dollars in 2027, with a compound annual growth rate of 4.8% during the period of 2022–2027.^[3] The shrimp cultivation is a significant contributor to the economic advancement and sustenance of developing nations, particularly in coastal regions where non-agricultural land can be utilized for aquaculture and the promotion of sustainable economic growth.^[4]

Asia stands as the largest shrimp producer, with a share (70%) of the global cultured shrimp market. The shrimp processing yields by-products that constitute a significant proportion, range (40–60%), of the entire shrimp. The shrimp head, comprises 40 to 48% of the whole shrimp, is the primary component that is discarded if not utilized appropriately.^[5,6] A significant amount of shrimp residues is discarded without any useful treatment during the shrimp processing. According to Silva and his colleagues, shrimp residues hold significant potential for utilization in the food industry to recover bioactive compounds and add value.^[7] Deep-sea shrimp are known to contain high levels of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These shrimps are a rich source of fatty acids, minerals, amino acids, and proteins that have neutral effects on cholesterol levels, with no increase in bad cholesterol but a potential increase in good cholesterol.^[8] The shrimp by-products are gaining popularity due to their nutrients and industrial potential leading sustainability as presented in Table 1.

Table 1. The major objectives obtained from shrimp by-products with key highlights.

Specific objectives	Key highlights	References
Deproteinization and demineralization optimization process for chitin extraction from shrimp by-products	Chitin obtained by process had ash, and protein residual content with degree of N-acetylation greater than 93% and purity (98%)	^[Citation9]
Extracting lipid and astaxanthin products for potentially exploring sustainable approach	Investigating fish oil as alternative option to vegetable oil for astaxanthin recovery from shrimp by-products. The extracts were high in omega-6 fatty acids	^[Citation10]
Evaluate astaxanthin and lipid extraction from shrimp by-products using organic mixtures and comprehensive analysis of fatty acids and lipids	The yield of lipid (2–8.69 dry wt%) for wet shrimp by-products and 1–4% from freeze dried. Astaxanthin yield range (57–88 mg/g) from wet and 119-218mg/g from dry by-products. Lipid rich in phospholipids and omega-3 fatty acids	^[Citation11]
Exploring nephroprotective and antidiabetic effects of astaxanthin extracted from the shrimp waste in alloxan diabetic animals The main objectives of this research were to explore the antidiabetic and nephroprotective effects of astaxanthin extracted from the shrimp waste in alloxan diabetic animals, it is one of the beta-cytotoxic substances that is commonly used for the induction of diabetes in animal models	When used in the treatment of diabetes, shrimp astaxanthin may be able to reduce oxidative damage and avoid pathological alterations in diabetic rats	^[Citation12]
Develop and characterize shrimp muscle protein antioxidant edible films incorporating carotenoids from various sources, namely, a lipid extracts rich in astaxanthin obtained from shrimp waste, a tomato extracts rich in lycopene from tomato peel waste, and commercial β-carotene	Develop and assess shrimp muscle protein antioxidant edible films using carotenoids from several sources, such as commercial β-carotene, a tomato extracts rich in lycopene from tomato peel waste, and a lipid extract rich in astaxanthin from shrimp waste	^[Citation13]
Development of shrimp flour from shrimp residues for product development as alternative ingredient	The protein content was for shrimp flavored biscuits (20.52%) and 40.13% for spiced shrimp flour. It is considered as promising ingredient in the food industry	^[Citation14]
Investigating antioxidant activity, functional properties and bioactive potential of peptidic fraction from shrimp by treatment with alcalase	The carotenoproteins peptidic fraction is a good source of peptides and natural antioxidants with functionalities	^[Citation15]
Improving antibacterial and antioxidant activities of shrimp waste hydrolyzates conjugation with GlcN. The main objective is to valorize shrimp by-products such as carpace and cooking juice	Protein hydrolyzates generated from shrimp by-products may be heated to 100°C in the presence of GlcN and utilized as antibacterial and antioxidant components for various applications.	^[Citation16]
Determination of cholesterol content of shrimp flour and sensory evaluation of pastry and soup made from flour	The flour has potential for utilizing as crucial ingredient for new product development	^[Citation17]
Using different hydrolysis condition and proteases for taste sensor, salt content and bioactivity	The sensitivity and dose dependence of taste sensor to peptides and amino acids	^[Citation18]
Ecofriendly extraction solvent specifically vegetable oil such as olive, flaxseed and sunflower oil for astaxanthin recovery and encapsulated the extracted astaxanthin	The astaxanthin yield is 235 ± 4.07 μg astaxanthin/g by-products. The efficiency of encapsulated astaxanthin has potential applications in food industries	^[Citation19]
Recovery of protein from shrimp by-products	The by-products presented protein (58.5%) on dry basis. The yield of protein concentrated was 47.8% on dry basis. It can be considered as potential ingredient for food formulations	^[Citation20]
Investigating optimal aqueous enzymatic extraction (AEE) of oil from shrimp by-products and fatty acid composition of oil	The aqueous enzymatic extraction (AEE) of oil from shrimp by-products including flavor protease, alkaline protease, compound protease, and neutral protease. The oil extraction yield was 88.9%	^[Citation21]
Extracting EPA and DHA rich oil from shrimp by-products	The oil rich in omega-3 polyunsaturated fatty acids such as EPA (7.8%) and DHA (8%)	^[Citation22]
Characterize and produce hydrolyzate from shrimp waste by commercial enzyme system. Functional properties of shrimp head protein hydrolyzate and raw shrimp head investigated	Enzymatic hydrolysis showed increase in FAA (17.22%) and protein which has biochemical and functional properties	^[Citation23]
Influence of adding ethanol as a co-solvent to the scCO2 on the extraction yields of lipids and astaxanthin, as well as the amount of astaxanthin, DHA and EPA fatty acids and in the extract made from the waste of freeze-dried redspotted shrimp	The maximum recovery of astaxanthin (65.2%) and lipids content (93.8%).	^[Citation24]
Evaluate the use of subcritical water (sCW) to obtain amino acids and protein from shrimp shell in the hydrolyzates, and purify chitin	Protein (34.2 mg/g) from shrimp shell was obtained by sCW processing at 260°C/50 bar/40 min, highest yield of protein (34.2 mg/g) was obtained by sCW processing at 260°C/50 bar/40 min The highest yield of chitin obtained was 26.39% by sCW at 260°C/50 bar/40 min	^[Citation25]
Direct utilization of shrimp shells for reusable and rechargeable catalysts. Developing sustainable methods for selective transfer hydrogenation reactions	Result indicated anchoring of DMPZ-Tz played a very important role for achieving performance without catalysts and catalysts synthesis for utilizing homogenous counterparts	^[Citation26]

The shrimp by-products are rich in both micro-nutrients and bio-active components, which are very helpful for the human body and open new opportunities for the food and nutraceutical sectors to develop new products through fortification and enrichment. This could further reduce food insecurity issues around the world.^[27] This comprehensive review focuses on the potential industrial and nutritional applications of shrimp by-products. Different body parts of shrimps, health benefits, and industrial applications are reviewed, which would be crucial for industrialists, scientists, and nutritionists to exploit shrimp by-products for developing new products that are nutrient-enriched and healthy that everyone can afford. The unique sensorial characteristics of shrimp by-products also favor their utilization for the development of new products. A large number of products developed from shrimp’s by-products and few are displayed in Figure 1, such as fortified biscuits, bread, peach drink tea, acid curd cheese, extruded snacks, yogurt, margarine, shrimp powder, and laundry detergents, are discussed in detail. The principal design of this review is to motivate other researchers to an exploration of unidentified opportunities from other crustacean by-products and fisheries.

Figure 1. Industrial applications of shrimp by-products.

Valuable parts of shrimp waste

Shrimp processing produces a huge amount of waste, including head, tails, viscera, cephalothorax, and exoskeleton presented in Figure 2, which is usually discarded without further processing. Due to the importance of valuable waste, the processing industry can exploit it further for the development of diverse value-added products.

Figure 2. Valuable parts of shrimp waste.

Head

The global production and consumption of shrimp is on the rise, resulting in a corresponding increase (50%) in shrimp waste, which includes heads, tails, and shells.^[28] The head is comprised of different potentially important components such as carotenoids,^[29] chitin,^[30] protein,^[31] protein hydrolyzate, chitosan, and minerals.^[32] It has been reported that Penaeus semisulcatus head is a rich source of protein (66%) and chitin (6%) when measured on a dry basis, making it a highly valuable food source.^[33] Shrimp head contains 10 different types of endogenous proteases, including myofibril-bound serine proteinase, chymotrypsin, cathepsin B, pepsin, a serine protease, trypsin, metalloprotease, cathepsin L, collagenase, and calpain.^[34] According to a study conducted by Liu and his team, shrimp heads are a rich source of polyunsaturated fatty acids (PUFA), essential amino acids, crude protein, micro and macro minerals. Additionally, the ratio of sodium to potassium in shrimp head is mostly below 1.5, which makes them a good option for human consumption.^[27]

Viscera

The process of shrimp cooking results in the emission of a pleasant aroma, which is attributed to the pyrazines produced by the shells and viscera. The presence of thiazolines and thiazoles was detected by analysis performed of volatile compounds in the roasted whole shrimp, which were found to contribute to both the roasted and rich aromas. The shrimp shell and viscera are known to possess significant aroma characteristics that greatly impact the overall aroma perception of shrimp dishes, as reported in this study.^[35] Carotenoprotein, a significant bioactive compound, is obtained from shrimp by-products through the utilization of the protease enzyme. The hydrolyzate exhibits a lipid (9.4%) and protein content (79.6%). The hydrolyzate is rich in essential amino acids (465 mg/g), and its nutrient value is notably high, rendering it advantageous for human consumption. Carotenoprotein exhibits anti-hypertensive and scavenging properties, rendering it useful in the food industry.^[36]

The image depicted in Figure 2 portrays the shrimp viscera, and Litopenaeus vannamei viscera has undergone purification to obtain heparin-like glycosaminoglycan. This compound is known for its potent anti-coagulant and anti-thrombin, and is also abundant in glucuronic acid.^[37] The giant catfish viscera are considered valuable enzymes source, particularly Alcalase, and trypsin, which are comparable to commercial sources. These enzymes have been found to be useful in the extraction of carotenoids, making them an economical option for enzyme sourcing.^[38]

Shrimp shell, pleopods, and tail

The crustacean’s exoskeletons are composed of chitin (15–40%), calcium carbonate (20–50%), and protein (20–40%). The desiccated exoskeletons hold significant worth, with a value ranging from 100 to 120 US dollars per tonne.^[39] The shrimp shells, as depicted in Figure 2, represent a crucial component of these organisms, possessing considerable commercial value across various industries. The SS is composed of several significant constituents, including astaxanthin,^[40] chitin,^[41] and protein.^[42] These components are particularly abundant in chitosan and chitin, which possess significant anti-bacterial properties. As such, chitosan has been employed as an effective agent against various pathogens in humans, food, and water. The utilization of this technology exhibits extensive potential in the domains of water treatment and food preservation. Chitosan and chitin of high quality were obtained through the processes of demineralization, deproteinization, and deacetylation.^[43]

According to recent research, the SS exhibits anti-oxidant properties and contains the highest concentrations of EPA and DHA.^[44] Chitosan, chito-oligomers, and chitin are derived from SSs.^[45] The comparative analysis of shrimp appendages and shells did not yield evidence to support the superiority of the former over the latter. The color, extractability, and deacetylation of chitosan and chitin derived from Penaeus. monodon shells were found to be comparable to those obtained from Macrobrachium rosenbergii.^[46] Compared to chitosan isolated from SSs, standard chitosan exhibits lower levels of deacetylation and higher levels of protein, chitin, and minerals. The utilization of these wastes in both the food and non-food industries has been identified as a potential necessity.^[47]

Cephalothorax (CT) and exoskeleton

Crustaceans, particularly shrimp, contain a variety of beneficial components such as astaxanthin, peptides, chitin, carotenoids, and protein, although some parts are not suitable for consumption. Chitin (30%) extracted from Penaeus vannamei cephalothorax.^[48,49] The shrimp cephalothoraxes and heads contain pigmented oil that is rich in beneficial nutrients such as omega-3 fatty acids, unsaturated fatty acids, mono and diesters of free fatty acids (FFA), astaxanthin, palmitic acid, and oleic acid.^[50] Figure 2 presents the cephalothorax, which has multiple uses and beneficial effects. Lipids are extracted from lipid-containing solid residues of cephalothorax that contains elevated levels of FFA, monoester, and diester astaxanthin, canthaxanthin, and carotenoids, which may be utilized in the production of value-added goods. Carotenoids have the highest yield of 8.6–8.8 milligrams per gram of lipid, and lipid constitutes 10–11 grams per 100 grams. The amplitude of ultrasonics is directly proportional to the lipids. The ultrasound-assisted technique is more effective than the typical solvent extraction method for extracting lipids from solid residues.^[51]

The most effective method for extracting lipids while preserving their quality involves combining ultrasound-assisted extraction with vacuum-microwave treatment from the cephalothorax. This treatment reduces the hydrolysis and oxidation of lipids, allowing for the retention of important components such as astaxanthin and omega-3 fatty acids. Incorporating treatments into the lipid extraction process can help to mitigate the negative impact on lipid quality.^[52] The high-pressure technology applied to extend shrimp shelf life by inhibiting enzymes and microorganisms. This process results in minimal reductions of omega-3 fatty acids, while the bioactive compounds remain stable. From an industrial perspective, the shelf life of refrigerated shrimp is limited due to the occurrence of melanosis and microbial activity. The thermal treatment of shrimp has been found to affect the presence of significant compounds, including fatty acids and bioactive compounds, primarily located in the cephalothorax region. This treatment has been implemented as a means of improving the shelf life of shrimp, as reported by Gómez-Estaca and his team.^[53] The aforementioned compounds, characterized by superior quality, are obtained through environmentally-friendly extraction techniques from shrimp by-products of substantial quantities. It is anticipated that these compounds can exhibit innovative potential in the fields of pharmaceuticals and nutraceuticals.^[48]

Health-promoting benefits

Shrimp-derived protein hydrolyzates are considered to be a valuable protein source due to their advantageous anti-oxidant properties.^[54] Protein hydrolyzate (PH) exhibits remarkable characteristics such as superior oil retention capacity, interfacial discreteness, and solubility. According to Ketnawa and her colleagues, enzymatic processing of boiled shrimp which are noncommercial renders to be useful for valorization, obtaining anti-depressants compounds, hypoglycemic agents, astaxanthin, and soluble peptides/proteins that have potential applications as functional foods.^[38] The utilization of PH and discard hydrolyzates derived from SS has been found to possess the capacity to chelate metal ions, particularly ferrous ions, exhibit radical scavenging activity, and demonstrate a power reduction. The bleaching of beta-carotene in an oil-in-water emulsion has been impeded by certain inhibitors. Additionally, cupric ions have been found to induce peroxidation of low-density lipoprotein cholesterol, commonly known as bad cholesterol, as well as peroxyl. Furthermore, hydroxyl radicals have been observed to be efficiently induced the scission of DNA strands. According to Ambigaipalan and Shahidi’s findings, PH fractions exhibit the most significant angiotensin I-converting enzyme (ACE) inhibitory activity.^[55]

The utilization of marine PH as a source of naturally occurring bioactive peptides with ACE inhibitory activity has garnered significant attention due to its immense potential. In several industries, ACE inhibitor peptides are commonly employed as safe and natural ingredients.^[56] The hydrolyzate enzyme derived from Pandalus borealis by-products, possessing a high molecular weight, is employed for hypertension prevention and oxidative stress management.^[57] According to Widyastuti et al., chito-oligosaccharides exhibit significant anti-fungal properties through biotransformation using actinomycetes against Malassezia globosa. These findings suggest that such chito-oligosaccharides may represent a promising avenue for the development of high value products.^[58] Chito-oligomers exhibit anti-microbial properties that are employed in combating pathogenic microorganisms present in the foregut. These oligomers are also utilized as feed additives to improve gut health. According to Varun et al., there is potential for them to serve as a substitute for antibiotics in animal feed.^[45] The prodigiosin possesses extensive medical applications in various domains such as cosmetics, food colorants, and candles.^[59]

The natural preservative constituents in the pharmaceutical industry are sulfated glycosaminoglycans (SGSS), as reported in Table 2.^[63] The carotenoid family encompasses astaxanthin derived from marine sources, which exhibits anti-oxidant properties and has been found to possess anti-diabetic effects. Figure 3 illustrates the advantageous impacts of shrimp by-products. According to Qamar et al., the addition of astaxanthin to semen improved the freeze-thaw quality of dog sperm.^[67] According to Sila et al., astaxanthin derived from shell exhibits noteworthy efficacy in mitigating the effects of diabetes in rats. This compound has been found to be effective in combating oxidative stress, preventing damage to kidney cells, inhibiting hyperglycemia, and averting pathological changes.^[12] Similarly, authors have reported that the utilization of a preventive administration of astaxanthin and fish oil supplementation is aimed at modifying the enzymatic anti-oxidant system of the dental pulp tissue by means of oxidative stress.^[68] The utilization of shrimp waste oil and its pigments has been observed to have significant impacts on the anti-oxidant potential, particularly in the context of medical and food applications. According to Sadighara, Hariri, and Kazemi, carotenoids play a significant role in safeguarding against oxidative damage.^[69]

Figure 3. Nutritional benefits of shrimp by-products.

Table 2. Nutritional and medicinal applications from shrimp by-products.

Source	Raw materials	Product	Yield	Medicinal applications	References
Shrimp (Pandalus borealis)	SS, tvarog at 0.25%	Acid Curd cheese (ACC)	Favorable addition of astaxanthin lipid preparation (ALP) to ACC was 0.5%	ACC with ALP has excessive anti-oxidant activity	^[Citation60]
Shrimp head powder (SHP)	SHP, Acetylcholinesterase, 2, 2-diphenyl-1-picrylhydrazyl	Prodigiosin (PG)	The maximum yield of PG level is 6310 mg per liter	SHP is a cost-effective bioproduction of PG, for practical application in anti-Alzheimer drugs, and anti-nitric oxide	^[Citation59]
Shrimp processing by-products	By-products	Shrimp oil	The oil extracted is 88.9%	During shrimp processing, aqueous enzymatic oil is extracted which has high economic value, and health benefits	^[Citation21]
Shrimp (P. merguiensis)	Shells, Pseudomonas aeruginosa bacteria	Chitosan	The highest yield of Chitosan is 87%	It has vast applications in medicine and beneficial effects on health	^[Citation61,Citation62]
Pink shrimp (Parapeneus longirostris)	SS	SGSS	The net yield of SGSS was 7%	SGSS had anti-oxidant and anti-hypertensive properties used as functional food ingredients	^[Citation63]
By-products of six shrimp species	Carapace, head, shell, and tail	Carotenoids,astaxanthin	Yield of total carotenoid is 68.26 µg/ml, and astaxanthin is 59.97 µg/g dw	It is a powerful anti-oxidant which have vast practical application in both food and non-food applications	^[Citation64]
Pink shrimp (P. longirostris)	Heads, SS, CT, appendix, and Sephadex G-25	ACE inhibitor peptides	NA	Develop such products which have anti-hypertensive effects and used them as nutraceutical ingredients	^[Citation56]
Shrimp (Fenneropenaeus chinensis)	Shell, protamex, papain, trypsin, alcalase, and, deionized water	Hydrolysates	NA	It is a potential inhibitor of α- amylase used in food for the prevention of diabetes	^[Citation65]
Raw frozen shrimp	SS, ACE, trypsin, α-chymotrypsin, pepsin	Bioactive peptides	NA	Potential applications of PH as a supplement, functional, nutraceutical, and blood pressure lowering	^[Citation55]
Shrimp (Penaeus vannamei Boone)	SS	Astaxanthin	The maximum extraction yield is 72.0 µg per gram	It is used as natural anti-oxidants in the pharmaceutical and food industries	^[Citation66]

The utilization of Artichoke stem’s by-product powder (ASP) and shrimp by-product powder (SBP) has been found to be effectively decreased the levels of low-density lipoproteins, commonly known as bad cholesterol, as well as triglycerides and their concentration. The intervention resulted in a reduction in blood glucose levels, a decrease in cholesterol levels, and an improvement in serum liver enzyme activity and anti-oxidant enzyme activity when compared to the positive control group. The utilization of ASP as a source of inulin and SBP as a source of chitin has been proposed for the development of nutraceutical formulations in functional food products. These sources are considered rich in natural dietary fiber, which can potentially enhance the nutritional value of such products. This approach may have implications for the prevention of various diseases, including obesity and its associated health risks.^[70] The application of shrimp head as a cost-effective and readily available source for the identification, biosynthesis, and isolation of active anti-diabetic compounds has been explored. Paenibacillus sp. utilizes fermentation to convert shrimp heads into natural α-glucosidase inhibitors (AGIs), which have been identified as a potential therapy for diabetes. This approach presents a highly economical means of acquiring AGIs, which have demonstrated utility in the management of type 2 diabetes. According to Nguyen and Wang, there are significant active compounds, including adenine and nicotinic acid, whose inhibition is characterized by a high degree of specificity.^[71]

The polysaccharide known as heparan sulfate, characterized by a high degree of sulfation, is isolated from the heterogeneous cephalothorax of Penaeus brasiliensis. This compound exhibits a greater capacity for inhibiting the infection of dengue type 2 virus and the Japanese encephalitis virus. It exhibits superior efficacy compared to heparin against these viral agents. The shrimp heads are utilized in clinical applications due to their comparatively lower anti-coagulant activity in comparison to heparin.^[72] The utilization of shrimp head meal in layer rations can result in improved quality of meat and eggs due to its high protein content, as well as its enrichment in chitin and fiber. According to Yeasmin et al., the proportion of shrimp head meal is 25%.^[73]

The consumption of shrimp cephalothorax has been found to affect the maturation of goldfish gonads and growth. According to Gowsalya and Kumar, the incorporation of head meal at a rate (15%) is essential for the maturation of goldfish gonads and growth.^[74] The utilization of a cost-effective and well-balanced ration is crucial in ensuring optimal shrimp growth, as the cumulative feed intake is directly correlated with the overall shrimp dietary intake. This necessitates the incorporation of expensive feed into the diet. There exists an inverse relationship between the mortality rate and feed cost in relation to the consumption of head meal diets. According to a recent study conducted by SS Islam, Paul, and Islam, the optimal proportion of soybean meal in the ration of head meal is 25% for achieving optimal growth performance in layer pullets.^[75] The mitigation of white spot disease in shrimp is achieved through the utilization of mangrove flour in conjunction with shrimp skin, a by-product, as a dietary supplement. Incorporating chitosan flour and mangrove flour into shrimp feed has been found to enhance the shrimp’s resistance to the white spot syndrome virus.^[76]

Chitosan is obtained through the process of deacetylation from chitin, a significant constituent of marine shells. This is attributed to its remarkable anti-microbial properties and its ability to dissolve effectively in water. Chitosan derivatives are utilized to enhance various properties such as water solubility, mechanical strength, anti-microbial activity, and biocompatibility via chemical reactions and physical integration. According to Ding et al.,^[61] this substance exhibits potential for medicinal applications, including wound dressing, drug delivery, and implantation of medical devices. These findings suggest promising prospects for its future use in clinical settings. The estimated prevalence of shellfish allergies among the adult populace of the United States is around 2%.^[61] The clinical management of shellfish allergy is hindered by limited knowledge of shellfish allergens and a dearth of dependable diagnostic assays. The identification of immunoreactive proteins present in food and their resistance to digestive processes are crucial aspects in the advancement of novel polyclonal antibodies aimed at enhancing the efficacy of allergen detection techniques in food products.^[77]

Anti-oxidant activity

In the processing industry, the shrimp head is used to obtain beneficial bioactive peptides. This process generates PH from Metapenaeus dobsoni, which has been found to have the highest anti-oxidant activity.^[78] According to a study’s findings, pigmented oil extracted from shrimp residues is known for its high anti-oxidant activity, stability, and affordability.^[7] Parapenaeus longirostris is a source of astaxanthin and carotenoids that possess bioactive properties and function as antioxidants. Astaxanthin has the potential to inhibit lipid peroxidation, which can stimulate the system of antioxidant cells and modulate the inflammatory process in stressed cells. According to Messina et al., utilizing the shrimp by-products is crucial in obtaining astaxanthin.^[79]

According to a study by Sangsuriyawong, Limpawattana, and Siriwan, astaxanthin can be loaded with liposomes at a concentration of 70% at 2% (w/v) of phosphatidylcholine (PC). These results in higher cellular uptake and entrapment efficiency compared to PC (23%). Additionally, the study found that this method maintains astaxanthin’s potent anti-oxidant activity. SS-derived astaxanthin possesses cytotoxic, anti-oxidant, and anti-tyrosinase properties. It exhibits tyrosinase inhibition and possesses potent anti-oxidant activity.^[80] Astaxanthin from SS has properties of cytotoxicity, anti-oxidant, and anti-tyrosinase. It has tyrosinase inhibition and activities of a potent anti-oxidant. Astaxanthin is a non-cytotoxic cell found in the fibroblast of the human dermis. It is commonly used as an ingredient in functional foods and skin health products due to its safety and effectiveness.^[81]

Anti-cancer activity

Astaxanthin is a marine-based ketocarotenoid that possesses anti-inflammatory and oxidative stress-reducing properties. It has been found to inhibit the growth of breast cancer cells and tumors, as well as reduce the rate of proliferation. Moreover, the use of astaxanthin treatment has been found to be effective in reducing breast cancer cells as well as multiple types of cancer.^[82] Chitosan and chitin extracted from Penaeus monodon have been found to possess anti-cancer properties against human ovarian cancer cells. However, it is worth noting that chitin exhibited lower anti-cancer activity than chitosan. According to a study by Srinivasan, Velayutham, and Ravichandran, the extracted chitosan and chitin characterized by using XRD, SEM, and FTIR and the results showed that the chitosan has demonstrated noteworthy properties in combating the cell line PA-1 of human ovarian cancer, making it a promising candidate for the pharmaceutical industry and revealed useful information to expand chitosan biological applications.^[41]

According to a study conducted by Priya, Vijayakumar, and Janani, chitosan can be utilized as a reducing agent in an environmentally friendly method to produce biogenic silver nanoparticles (AgNPs). These AgNPs have been found to possess anti-cancer properties against human hepatocellular carcinoma HepG2 cells.^[83] The carapace and cooking juice of shrimp are protein sources that are typically discarded by the crustacean industry. Protein hydrolyzate is a versatile substance that possesses both anti-bacterial and anti-oxidant properties, making it useful for a wide range of applications. The anti-oxidant activities of hydrolyzates can be enhanced by conjugation through glucosamine at high temperatures, which results in a reduction of amino acids. However, it is important to note that this process may also lead to an increase in product browning.^[16]

Bioactive peptides found in shrimp waste are high-quality proteins that have been characterized as having anti-cancer properties. These peptides can be used as a therapy for chronic diseases with high mortality rates, such as cancer. They are a natural and cost-effective alternative to traditional drugs and have abundant beneficial effects on the body. Peptides are being used as a replacement for expensive drugs in the treatment of cancer, a disease that can be fatal. Peptides are utilized as functional ingredients in food to promote good health. Astaxanthin is a lipophilic compound that possesses potent biological properties such as anti-diabetic, anti-viral, and anti-cancer effects.^[84,85]

Immune boosting

Immunopathology, which refers to the self-inflicted harm caused by the inflammatory response, is attributed to the oxidation of molecules that are triggered by the immune system. The field of immunopathology pertains to age-related ailments that hasten the aging process. In order to prevent immunopathology, dietary antioxidants like astaxanthin and carotenoids, as well as endogenous antioxidant enzymes, are commonly employed. Astaxanthin is a potent antioxidant that exhibits the potential in mitigating age-related ailments. According to Dhinaut et al., the immunomodulatory effects of astaxanthin, an antioxidant, have been observed to stimulate the immune system while simultaneously mitigating the negative impacts of aging on immunopathology.^[86] Astaxanthin is the primary carotenoid pigment that possesses potent anti-oxidant characteristics and exerts advantageous impacts on the immune system of humans, as presented in Table 2. The compound possessing bioactivity exhibits noteworthy utility in several industries such as cosmetics, food, and pharmaceuticals.^[64]

Astaxanthin is a noteworthy antioxidant, whereas a diet that is rich in fat induces oxidative stress. The fish growth that was fed a high-fat diet was observed to have improved upon the administration of dietary astaxanthin supplementation. Additionally, a decrease in the hepatosomatic index was noted. The inclusion of astaxanthin in high-fat diets for fish resulted in a reduction of oxidative stress as evidenced by decreased levels of malondialdehyde and increased activity of superoxide dismutase.^[87] Chitin, the second most prevalent polymer after cellulose, is highly resistant to degradation and insoluble. According to Subramanian et al., the secondary products derived from biopolymers are utilized as drug delivery agents and immune system enhancers in fish.^[88]

The substitution of fish meal has a negative impact on the diet of clostridium autoethanogenum protein (CAP) with regards to transcription, immune indexes of serum, intestine histology, and Litopenaeus vannamei growth. The significant inclusion of CAP has exhibited adverse effects on nutrient utilization and protein synthesis by modulating ribosomal pathways, pancreatic secretion, protein absorption, and digestion, and disrupting lysosomal pathways and metabolic processes through phagosomes. Furthermore, the immune system’s function and shrimp growth performance have been impacted by CAP’s influence on immune system pathways. The intestinal histology of fish fed with a diet containing approximately 560 grams per kg of fish meal and 30% CAP substitute showed adverse effects on growth without any other noticeable effects.^[89]

Fertility enhancement

Worldwide, the approximate percentage of infertile couples is 15.^[90] The shrimp by-products play an important role in maintaining the nutrients that enrich diets for every individual, and abundant health benefits are presented in Figure 3. Mostly, astaxanthin has positive effects on sperm fertility.^[91] It has multiple benefits in humans, as previously discussed, and sperm functioning is ameliorated by astaxanthin, which is utilized for males to decrease idiopathic infertility.^[92] It reduces oxidative stress and is the strongest antioxidant that potentially protects fertility against the toxicity of heavy metals, especially cadmium, which decreases fertility, damages the testis, reduces viability, and increases CatSper1 gene expression. Sperm count is significantly increased by astaxanthin.^[93]

Potential industrial applications

The implementation of quality control measures for the storage and processing of food and non-food products is of paramount significance for several industries. Figure 4 illustrates a variety of food and non-food applications for products derived from shrimp by-products. The management of the substantial waste produced in fish processing is a global concern, and the by-products generated in shrimp processing are utilized for the production of various bio-based commodities. Shrimp waste is a highly valuable source of commercially significant biomolecules, including chitosan, protein, astaxanthin-rich oil, and chitin. The use of these biomolecules is particularly noteworthy due to the superior quality of astaxanthin obtained, which is a potent antioxidant with diverse industrial applications. Additionally, the natural colorant properties of astaxanthin make it a desirable ingredient in food formulations. Overall, shrimp waste represents the optimal yield of astaxanthin is 30 mg per kg of dry shell.^[94]

Figure 4. Potential industrial products from shrimp by-products.

The exoskeleton and cephalothorax are sources of protein that can be employed to produce highly nutritious functional foods. The head and SS contain protein (47.8%) a total of 16 amino acids, and protein concentrate derived from these sources has the potential to be utilized as an ingredient in the food industry.^[20] The protein yield (22.25%) is used for the extraction of chitin, and oil from Solenocera choprai has important omega-3 fatty acids and PUFA.^[94] Shrimp head powder (SHP) is a highly nutritious source of protease. The residual SHP is commonly used to extract chitin, which is known for its excellent adsorption capacity. The majority of chitin is obtained from the fermented SHP and SHP, which is particularly effective as an adsorbent for dyes. There is no significant difference in quality between the chitin obtained from fermented SHP and SHP as both types of chitins have their own unique potential. Chitinous materials derived from fermented SHP and SHP have demonstrated effective adsorption and dyeing capabilities, making them a promising option for water treatment applications.^[95]

The appropriate yield of chitosan is 225 grams per kg, and that of chitin is 156 grams per kg of dry shell. Shrimp waste is used as a source of chitosan, protein, and chitin that can be potentially used as feed-stock in bio-refinery processes.^[94] Chitin can contribute to reducing environmental pollution and the use of chemical reagents in agriculturally based industries.^[96] This is due to its green route and potential for promoting sustainability. The utilization of these wastes can reduce the burden on the environment and minimize negative impacts by utilizing natural resources, as noted in this study.^[97] The physicochemical properties of the chitosan are affected by heating process. The conventional procedure yielded chitosan (12.7%) of high molecular weight and the microwave extraction procedure yielded chitosan (11.8%) of medium molecular weight. The results demonstrated that chitosan extracted by conventional method has best anti-bacterial activity against the target bacteria.^[98]

Food applications

Astaxanthin is primarily obtained from crustaceans by-products.^[99] The cognitive dysfunction protection offered by the compound is superior when administered at the same dose, in powder form as compared to the astaxanthin extract. According to Taksima, Chonpathompikunlert, and Sroyraya, astaxanthin powder is considered the optimal product for safeguarding functional food against brain disorders and for use in AD therapy.^[100] The carapace contains β-carotene and vitamin E, both of which are recognized as antioxidants in the human diet. However, the antioxidant capacity of these compounds is comparatively lower than that of the astaxanthin pigment. The carapace flour of Litopenaeus vannamei contains various components including crude fiber, fat, protein, ash, and moisture. The utilization of this substance as a provider of antioxidants has been observed in both the food and cosmetic sectors.^[101]

The incorporation of this substance into food products is commonly practiced to enhance their nutritional value owing to its significant content of omega-3 fatty acids. The spouted bed method has been employed to obtain high-quality powdered products.^[5] Astaxanthin is utilized as a nutrient supplement in fortified foods and as a coloring agent in innumerable applications.^[102] The aforementioned factor holds significant value in enhancing the well-being of the human population. The implementation of high-pressure processing techniques is essential for achieving improved yields and enhanced product quality within a shorter time frame. According to Irna et al., Penaeus monodon exhibits a higher concentration of carotenoids and astaxanthin with maximum yield compared to the other five species.^[64] The lipid content in the body carapace and head is considerable that can be harnessed for the creation of value-added products that are rich in PUFA. These fatty acids have demonstrated commercial potential in the food industry.^[103]

Products utilizing an extract of encapsulated lipid to impart color exhibited comparable results to those using synthetic colorants. Enzymatic hydrolysis has been employed for the retrieval of valuable components.^[99] The resultant hydrolyzate has been utilized to enhance the anti-oxidant properties and supplement protein content, thereby maximizing the nutritional value of food products in the industry.^[104] Chitosan, a dietary fiber with multifarious physiological, technological, and functional characteristics, is utilized to enhance the quality of food. Chitosan due to its fat-absorbing ability is commonly ingested as a health supplement in the form of capsules and tablets. The product portfolio diversification of shrimp industry utilizing its waste for economic resilience and environmental sustainability. The chitosan extracted from shrimp waste could be used as food emulsion stabilizer. Research findings indicated that the stabilizer developed by shrimp shell possessed appropriate emulsion stabilizing properties.^[105]

Additionally, it is employed in the enhancement of shrimp-derived extruded snacks, which have gained popularity among individuals seeking a protein-rich regimen. The incorporation of chitosan (1%) in Acetes-based extruded snacks is aimed at enhancing their functional properties and fiber content.^[106] The percentage of chitosan used in this context is a critical factor. The approximate inclusion level of Acetes is 150 grams per kg. The inclusion of shrimp powder in extruded snacks has been found to enhance their mineral and protein content. These snacks have been identified as possessing optimal sensory properties and are commonly utilized as functional foods.^[107]

Bakery

The composition of fatty acids in oil derived from shrimp processing was determined and reported 11 distinct fatty acids.^[21] The utilization of microencapsulated shrimp oil (MSO) has been observed to enhance the bread loaf volume and impart desirable redness and yellowness to both the crust and crumb of the bread upon fortification (3%).^[108] Table 3 displays some potential industrial food applications of shrimp waste. The bakery industry places significant importance on the utilization of flavored biscuits and spiced flour derived from shrimp exoskeletons. These products possess the potential to serve as a source of nutrient-rich substances, as perceived by consumers.^[14] The sensory and quality properties are affected by the inclusion of MSO in the biscuit. The incorporation of MSO (6%) in biscuits has been reported to enhance their nutritive value. This incorporation did not have any adverse effects on the sensorial and quality properties of the biscuits. To ensure the stability of oxidation during storage, the biscuits were kept in the dark, thereby retarding lipid oxidation.^[109]

Table 3. Potential industrial food applications of shrimp waste.

Source	Pretreatment	Product	Practical applications	References
Blackening tiger (Penaeus monodon)	The temperature at 0°C when transport, SHP washed, drained, packed, and frozen at −18°C before processing, these were grounded using the food grinder	Seafood broths or soups, shrimp flavor seasoning	Utilizing shrimp waste in seafood-based products, and improving the product’s shelf life	^[Citation28]
Arctic sweet shrimp	Enzymolysis is done at 30°C to 60°C for 1 hour then astaxanthin was extracted	Astaxanthin	Develop value-added products for commercialization	^[Citation40]
Pacific white shrimp (Litopenaeus vannamei)	Shrimp lipid extracted from CT, and liposomes is prepared for fortification	Fortified peach tea drink	Application in fortification of a drink that is free of cholesterol	^[Citation112]
Litopenaeus vannamei	Waste pressed through a mesh sieve (2 mm), and solid waste used for the production of chitin then stored at −20°C	Chitin, SS meal, chitosan products, and hydrolyzate	Hydrolysate is used in feed supplements as valuable and as an attractant of aquaculture feed	^[Citation113]
Litopenaeus vannamei	Shrimp carapace has extraction times between 120 to 240 minutes, and then dry by sun drying after washing, and blended mesh of 80–100 size	Carapace flour, pigment astaxanthin	Pigmented astaxanthin is used in the food industry as an anti-oxidant, coloring agent and in the cosmetic industry	^[Citation101]
Atlantic shrimp (Pandalus borealis)	Shrimp waste thawed at 21°C, and kept at −20°C	Astaxanthin enriched products	Development of astaxanthin-enriched products	^[Citation102]
White leg shrimp (Litopenaeus vannamei)	CT dry 24 hours in an oven at 105°C, grounded, and blended at 4°C for 2 min, 9500 rpm of speed	Astaxanthin, carotenoids, canthaxanthin	High carotenoids content and good fatty acids utilized in the food industry as coloring pigmentation	^[Citation114]
Litopenaeus vannamei	CT grounded and blended at 4°C for 2 min of 9500 rpm speed	Oil, carotenoids, and lipids	Nitrogen flushing during ultrasonication increased the oxidative stability of lipids	^[Citation52]
Litopenaeus vannamei	Fresh CT and exoskeleton sanitized at 5 ppm of chlorinated water then packed in bags, and frozen at −18°C	Shrimp protein concentrate	Potential ingredient in food formulations, and protein-enriched products	^[Citation20]
Litopenaeus vannamei	Exoskeleton placed with ice flakes in boxes, washed to remove blood and viscera residues, and dry at 65°C	Spiced flour and flavored biscuits with shrimp	Enrichment of protein in food application, and development of novel products	^[Citation14]
Pink shrimp (Farfantepenaeus subtilis)	Waste was stored at −4°C during transport, and washed then grounded by the grinder, and homogenized paste kept at −20°C	Powder, oil enriched with bioactive compounds	Enriched vegetable oil with astaxanthin is used in food applications	^[Citation5]
Paste shrimp (Acetes spp.)	Fresh Acetes were transported with icing, washed it then blanched, and dry for 6 hours at 50°C in air dry then powdered through a .5 mm mesh sieve, packed in bags, and kept at 25°C	Extruded snacks	Acetes are rich in protein and used for fortification and enrichment of foods	^[Citation107]
Shrimp (Acetes spp)	Acetes transported in ice packed, washed, blanched, and dried approx. for 6 hours at 55°C, and in powdered form packed in bags	Fortified snacks with chitosan	Fortification has increased the functional properties of food for developing snacks products	^[Citation106]
Litopenaeus Vannamei	Mix ingredients, and kneaded to form the dough, Baked in a baking oven for 20 min at 205°C	Fortified biscuit with MSO	The nutritive value of biscuits improved by the incorporation of MSO	^[Citation109]
Farfantepenaeus subtilis	CT froze at −18°C and thawed when used	Hydrolysate, animal feed	Hydrolysate is used for protein supplementation as an anti-oxidant component in food	^[Citation104]
Litopenaeus vannamei	Hepatopancreas transported with ice bags and used within 1 month which frozen at −18°C	Bread fortified with MSO	MSO is used to fortify the items of bakery and nutrient-dense products	^[Citation108]
Litopenaeus vannamei	Shells were placed in ice bags, and transported in 2 hours,1 kg of each packed into bags and 2 months frozen at −20°C	Yogurt fortified with astaxanthin	Fortified yogurt in the dairy industry for developing fortified products	^[Citation115]
Shrimp (Penaeus semisulcatus)	Trypsin was added to waste for 120 min heated at 37°C, and hydrolyzate centrifuged	Oil fortified by its pigment’s products are margarine, ice cream, and cheese	Functional ingredients such as omega-3 and PUFA, and good nutritional value	^[Citation69]
Litopenaeus vannamei	CT packed in isothermal boxes, transported at 0°C, and loss in weight is due to adherence of flour with mil	Pastry, soup, pastries, savory fries, and flour	Flour of shrimp CT for developing novel products	^[Citation17]

The feasibility of incorporating Litopenaeus vannamei cephalothorax into flour has been demonstrated, with a notable high content of protein, minerals, and cholesterol. The favorable reception of soup and pastry suggests that cephalothorax in flour form holds promise for the creation of novel products and is utilized in diverse products owing to its nutrient-rich composition.^[17] The pigments obtained are used to inhibit bacterial growth in biofilms. The carapace and head contain a significant quantity of bioactive carotenoids. Carotenoid pigments exhibit anti-bacterial activity against both gram-positive and gram-negative bacteria, as well as anti-microbial activity against pathogenic microorganisms. Carotenoids exhibit anti-biofilm properties and demonstrate efficacy against bacterial biofilms.^[29]

The color changes phenomenon in crustaceans can be attributed to the liberation of two significant polar pigments, namely drosopterin and riboflavin, by astaxanthin. The concentration of drosopterin is impacted by thermal treatment. Verhaeghe and his colleagues have suggested that to ensure the production of high-quality shrimp products, it is recommended to subject them to heating temperatures below 80°C.^[110] A novel fluorescent tag with intelligent features has been designed utilizing a filter membrane. The membrane exhibits remarkable responsiveness toward biogenic amines, thereby enabling real-time monitoring of seafood freshness visually. The fluorescent tag-based shrimp freshness monitor has potential practical applications in quality control. According to Liu and his team, owing to the reversible conformation changes of fluorescein, low-cost conformational fluorescent tags have been developed that can be recycled, rendering them a significant tool for monitoring food safety and freshness.^[111]

Dairy

Dairy and related products are commonly manufactured and consumed as daily foods worldwide due to their high nutritional, functional, and nutraceutical benefits. Shrimp waste contains a range of beneficial compounds that represent potentially functional ingredients in the dairy industry (Table 3). Shrimp shell (SS) paves a new way for functional foods to be used to enhance the flavor of cheese for taste, which is becoming very popular among consumers with the use of astaxanthin.^[60] Oil from shrimp waste is a natural component in food applications such as cheese, margarine and ice cream.^[69] The skim milk is fortified with shrimp oil, and the nanoliposomes are very effective for shrimp oil. In this way, the skim milk that is fortified has good stability for a period of 15 days at 4°C, and it also maintains the stability of shrimp oil, which has the highest amount of essential fatty acids for a complete diet. A large number of products can be fortified in this way, which enhances the dairy industry.^[116]

In a research, authors reported moderate clotting activity from crustaceans for the new development of cheese products and their ripening. The proteins from Pleoticus muelleri are used as milk clotting agents for cheesemaking and offer huge potential for use in dairy biotechnology.^[117] The encapsulation with potential use as a functional ingredient in yogurt can extend the stability of astaxanthin, and the complex of coacervate with alginate chitosan beads provides astaxanthin with sufficient protection over an extended storage life. Astaxanthin beads in the yogurt have an application as a functional food for consumers.^[115]

The lipid extracts are effectively encapsulated in round molecules, which are in multiple droplet forms. The freeze-drying is used to stabilize the microcapsules, whose properties are good: low water activity, hygroscopicity, improved stability of astaxanthin, water solubility, food coloring, and intense red color. When extracts of shrimp lipid were encapsulated in yogurt by complex coacervation, their sensory properties and coloring capacity improved effectively while reducing their odor characteristics compared to lipid extracts that were not encapsulated in yogurt. Encapsulated gellified fish provided a uniform, attractive color but no improvement in sensory properties. The intense lipid red color from cephalothorax and the encapsulated lipid color are uniform, which is attractive for consumers and has potential applications in food owing to its coloring.^[118] Chitosan from shell has huge potential as a coagulant in the dairy industry for the removal of pollutants such as chemical oxygen demand, turbidity, and ultraviolet at a wavelength of 254 nm by a dose of 73.34 mg per liter at pH 5.00 from dairy effluent, and it is an eco-friendly, low-cost coagulant that is a chemically enhanced basic treatment for wastewater in dairy.^[119]

Beverage

The beverage industry has the potential for developing new drinks according to consumer needs and demands that provide hydration and a source of nutrients. Lower-cholesterol lipids are encapsulated in liposomes by a combination of glycerol and pectin stabilizers. The fortified drink with liposomes (3%), increases the amount of astaxanthin and PUFA.^[112] The cephalothorax and exoskeleton of Litopenaeus vannamei at pH 8 have the highest emulsifying, oil, and water retention capacities and greatest solubility.^[20] Protein hydrolyzate has good stability and emulsion properties, and they are used as potential emulsifying agents in the food industry.^[38,65]

Shrimp oil loaded with chitosan nanoparticles to protect it from rancidity and oxidation with almost no remarkable loss of astaxanthin or PUFA. The oil-loaded with chitosan nanoparticles is readily dispersed in water and stable thermodynamically, making it advantageous for fortification in the food industry, especially beverages. It is a cost-effective technique as chitosan is abundantly available at inexpensive rate.^[120] The best anti-microbial agent for controlling spoilage microorganisms is chitosan, which is used in the beverage industry, especially in the wine sector. Although chitosan can damage bacteria and yeast in fermentation, it is used in fermented beverages as a good anti-microbial.^[121] The encapsulated astaxanthin is potentially used as a functional ingredient in the food industry.^[99]

Non-food applications

The employment of shrimp by-products for non-food and industrial purposes is attributed to their appropriateness in the production of a diverse array of eco-friendly and cost-effective commodities, subject to individual accessibility and affordability. The utilization of shrimp by-products exhibits regional variability, thereby presenting an opportunity to alleviate poverty, augment earnings, and enhance product excellence, particularly for individuals residing in developing nations and employed predominantly in the aquaculture and shrimp processing sectors. Astaxanthin exhibits anti-oxidant activity and possesses diverse properties, rendering it suitable for employment in industrial domains.^[66] The composite film is a crucial component in food packaging and has extensive practical utility as an anti-oxidant, protective, anti-bacterial, and food preservation film. Additionally, it serves as a protective measure against bacterial food spoilage. It was found that chitosan-gelatin films exhibit lower water vapors permeability when compared to film composites of chitosan. The practical applications of these composite films have been outlined in Table 4.^[122]

Table 4. Potential industrial non-food applications of shrimp waste.

Source	Raw materials	Pretreatment	Product	Practical applications	References
Shrimp (Litopenaeus vannamei)	Shrimps, free astaxanthin standard, chitosan, gelatin	Shrimps packed in bags of ice and stored at −20°C	Bio-functional composite film	Used as a potential application for anti-oxidant and anti-microbial in many packaging materials to increase the shelf life of foods	^[Citation122]
Shrimp (Pandalus borealis)	Carapace, shell, CT,	Chitin is extracted from the shell by deproteinization and demineralization at room temperature. shells dried at 80°C for 16 h and chitosan get by chemical deacetylation from chitin	PUR chitosan foam	The chitosan improves the sorption and physiological properties of PUR foam. It has the benefit of reducing microplastics in the water environment	^[Citation123]
SS	Shell, anhydrous methanol, rapeseed oil	Shell incompletely carbonized for 2 h, loaded with KF by impregnation, dry at 120°C for 12 h	Biodiesel	Novel environmentally friendly approach, which is used as a petroleum-based substitute due to the non-toxic of biodiesel	^[Citation124]
Fishery processing by-products	Fishery processing by-products, shells	The activity of pH is 9, and the temperature at 70 to 80°C	Laundry detergents	Applied as a detergent additive	^[Citation125]

The degradation of bioplastic is facilitated by a plethora of microorganisms, predominantly fungi, and bacteria. The composite material is comprised of SS and cassava peel as fillers. The objective of this study is to develop a bioplastic-based packaging solution suitable for both packaging and direct consumption of food. The bio-plastic intended for immediate consumption is composed of chitosan (5% weight). This material is deemed safe for human consumption due to its favorable mineral content and absence of heavy metals. The development of bag packaging involves the incorporation of a suitable chitosan composition (7% weight). This particular composition exhibits superior mechanical properties compared to other compositions and is commercially viable as a plastic material due to its high elongation and tensile strength values.^[126]

SS is used to improve the properties of starch foam, which is modified by SS and egg shell. Calcium carbonate at the commercial level is used for the effects of modification for comparing. The baking process is used to prepare the starch foams, and the high protein in SS and calcium carbonate agglomerations on the formation of steam bubbles in the baking process have huge impacts that increase starch foam density and reduce the impact strength of izod at higher fillers. Starch foam, along with egg shell, has low density, izod has high impact strength, and the cell size is narrow. Egg shell acts like a nucleating agent, which has less protein. SS and egg shell both have maximum weight loss in starch foam, which is moderately reduced by adding bio-fillers because the organic components thermal stability of both is low.^[127] The organic compound chitosan is the second-largest polymer after cellulose and is widely used for medicinal values, agricultural fields, and biomedical purposes. It is also used as a care product for primary health as well as in food supplementation. The natural alternative source of chitin is shrimp, which is being used in sectors of biotechnology for diverse benefits.^[128] The weight of chitosan (1.5%) with polyurethane (PUR) foam, has the highest oil and water absorption properties and is very important for the industry of sustainable development.^[123]

Nutraceuticals

The contemporary era has witnessed a surge in the demand for food production enriched with nutraceuticals on a global scale. Shrimp waste, possessing functional properties to combat diverse ailments, has emerged as a viable source for meeting this demand.^[129] The lipid content of Litopenaeus vannamei’s cephalothorax was subjected to saponin treatment resulting in the removal of cholesterol. The resultant product was a crude shrimp lipid enriched with PUFA, specifically EPA and DHA, while simultaneously reducing cholesterol levels. The extraction of shrimp lipid from cephalothorax is a crucial process. The nutraceutical industry has shown a keen interest in shrimp lipids due to the presence of astaxanthin, DHA, and EPA. These compounds can be utilized to develop new products that are low in cholesterol and high in PUFA. Saponin treatment can be employed to reduce cholesterol levels in these products.^[130]

Núñez-Gastélum and his team examined that oil is a nutraceutical product that exhibits advantageous properties.^[50] For instance, the nutraceutical properties of fortified whole wheat crackers containing shrimp oil were investigated. The crackers exhibit a popular and crunchy texture and are enriched with essential fatty acids in sufficient amounts. The incorporation of mixed tea seed oil and shrimp oil microcapsules in whole wheat crackers is found to have a beneficial effect on health.^[131] The utilization of peptides derived from SS in functional foods has been found to contain advantageous compounds for anti-hypertensive purposes. This innovative approach has garnered attention within the nutraceutical industry.^[132] The employment of SS as a natural preservative in the pharmaceutical sector and as a scavenging agent against anti-oxidant activity has been documented.^[63]

In this regard, the impact of dietary supplementation with powdered biofloc on the growth performance and nonspecific immune response of shrimps was accessed. The authors observed that supplementation of biofloc in the diet enhanced the innate immunity of shrimps. The optimal proportion of biofloc (4%) in the dietary supplement, confers resistance to disease in shrimps. This indicates that the dietary supplement is utilized to enhance the shrimps’ innate immunity, promote growth performance, and bolster disease resistance. Biofloc has emerged as a practical and viable alternative to dietary supplements. The potential use of biofloc as a dietary supplement depends on biofloc method, beneficial microorganisms, and organic compounds quantity.^[133] Chitosan, which has capacities for fat and water binding, is extracted. The chitosan, which is commercially produced from shrimp of coastal origin, is lower than the chitosan from deep-sea origin, which has applications in food. Deep-sea chitosan is of good quality due to its structural and commercial properties, which have applications in medicine, and because it is an anti-cholesterolemic agent.^[97]

Marine hydrolyzates and proteins offer huge potential as a novel way of using peptides that have an anti-hypertensive effect and developing products that have functional and nutraceutical benefits.^[56] It is good for valine and leucine, which are nutritious essential amino acids of the rate-limiting system and have applications in food as anti-oxidants and nutraceutical products.^[65] The shrimp by-products are ingredients with bioactive such as astaxanthin for developing natural new nutraceutical products that will be the healthiest foods for consumers.^[27] Most marine organisms have chitinase-producing ability from microbial strains, and a novel Achromobacter xylosoxidans marine strain uses chitin to produce chitinase, which degrades the by-products, major amino acids in shellfish waste such as isoleucine, threonine, lysine, aspartic acid, arginine, methionine, and alanine, and products that have vast applications as supplements in the aquaculture industry, which ultimately reduces pollution.^[88]

The war in any country affected its energy and food systems at national and international levels. There is need to develop such systems which leads to sustainable growth of the economy. International Energy Agency has warned to lower mandates of biofuel, which could result in rising demand of petroleum and supply concerns. There is a need to adopt approaches for the crisis implication for biofuel and food markets and plan sustainable approaches to alleviate concerns faces.^[134] Bio-waste materials have been utilized for many times. There are lots of tools based on environmental, economics, and energy impacts have been utilized. Bioproducts and biofuels via biorefineries, can offer environmental benefits compare to fossil counterparts, provided conditions are maintained. These conditions can be assessed by tools based on exergy, emergy, energy, and life cycle assessment or combination of these to improve systems.^[135]

Conclusions and future prospects

The abundance of food processing waste and the growing demand for eco-friendly and organic substitutes to traditional synthetic supplements make it imperative to explore innovative applications of food by-products. The utilization of shrimp-processing by-products as non-synthetic food additives is a promising avenue under the current “clean-label” trends, as evidenced by several positive outcomes and leads toward sustainability. The present review has displayed the copious information available on the constituents of shrimp by-products and their extensive potential as versatile, multi-purpose additives in the development of novel food products and nutraceuticals. The potential co-existence of nutrients, fibers and bioactive components, which may confer both techno-functional, chemo-protective and health-related benefits simultaneously. It is recommended to conduct a reassessment to determine if additional biotransformation processes could be employed to produce purified nutraceutical, techno-functional ingredient with high value. Furthermore, the optimization of synergistic behavior can be executed. This includes a thorough analysis of the cost effectiveness as well as the sensory acceptability of the end products. More research is needed for exploring the medicinal, nutraceuticals and industrial benefits of shrimp and waste products. Further studies on other crustacean such as woodlice, lobsters, crabs, krill, and prawns based and along with the waste of these crustacean expected in the future for revealing their importance to design novel value-added products leading toward sustainability.

Abbreviations

International market analysis research and consulting: IMARC, Eicosapentaenoic acid: EPA, Docosahexaenoic acid: DHA, Polyunsaturated fatty acids: PUFA, Shrimp Shell: SS, Angiotensin I-converting enzyme: ACE, Sulfated glycosaminoglycans: SGSS, Artichoke stem’s by-product powder: ASP, Shrimp by-product powder: SBP, Phosphatidylcholine: PC, Polyurethane (PUR) foam, Free fatty acids: FFA, Microencapsulated shrimp oil: MSO, α-glucosidase inhibitors: AGIs, Acid curd cheese: ACC, Free amino acids: FAA, Prodigiosin: PG

Acknowledgement

The authors are thankful to The University of Lahore.

Disclosure statement

No potential conflict of interest was reported by the author(s).