Augmenting the Oxidative Stability of Chicken Nuggets by incorporating cumin and Black cumin as natural preservatives

ABSTRACT

The present research investigated the effectiveness of cumin and black cumin extracts as natural antioxidants in uncooked chicken nuggets stored at refrigeration temperature (4°C) for 12 days and compared the results with a control treatment. Seven treatments were formulated, including a control group (Tc), T1 (0.5% cumin), T2 (1% cumin), T3 (1.5% cumin), T4 (0.5% black cumin), T5 (1% black cumin), and T6 (1.5% black cumin). The product was evaluated for several physicochemical parameters on days 0, 3, 6, 9, and 12 of storage. The data was analyzed using a two-way factorial design under a completely randomized (CRD) design. Results showed that both treatments and storage significantly impacted all physicochemical properties, including DPPH, TPC, pH, POV, and TBARS (p < 0.05). The values of TBARS significantly decreased with the increase in the concentration of cumin extract whereas TBARS increases during the storage period. Moreover, the interaction effect (Treatment*storage days) did not significantly affect any of the physicochemical parameters (p > 0.05). Sensory evaluation showed that T3 (1.5% cumin) was the most pleasant and preferred treatment. Conclusively, both cumin and black cumin have good antioxidant properties and can be used as natural antioxidants to increase the shelf life of food products.

KEYWORDS:

• Cumin
• antioxidant potential
• chicken nuggets
• oxidative stability
• physicochemical properties

Introduction

Chicken meat is an integral part of global cuisine and is commonly used in daily meals. Its widespread popularity, especially in developing nations, reflects a growing demand for delicious flavor and essential nutritional benefits. As a perishable item, meat satisfies taste buds and provides crucial amino acids required for human growth and development^[1]. Consumers are more concerned about the nutritional quality of meat products. Besides high protein, it provides other micronutrients such as fatty acids, minerals, and vitamins.^[2] It is a good protein source, so it is highly recommended to consume daily.^[3] Due to perishability, meat and meat products are more susceptible to quality deterioration through oxidation or microbial growth.^[4] Meat is deemed sanitary upon slaughter and serves as a favorable environment for microbial proliferation when the skin is removed.^[5]

During the storage of meat products, quality characteristics may depreciate due to microbial growth and oxidation in [email protected] lipid oxidation in meat and meat products, specific changes occur, resulting in nutritional loss of the meat product and causing loss of flavor. Oxidation of lipids is a complicated process and usually depends upon certain factors that include the availability of oxygen, the chemical structure of meat, water, and storage temperature. In meat and meat products, oxidation of lipids results in the creation of several compounds that have an adverse outcome on the quality features of the product. Hence, several changes occur, resulting in the loss of the meat and meat products’ color, flavor, nutritional, and texture attributes. The usage of antioxidants can inhibit the oxidation of lipids in meat and meat products, and in this way, the meat product shelf life can be increased.^[4] The physical and chemical structure of meat, due to its high perishability, makes it more susceptible to oxidation. The oxidative stability of meat depends upon substances prone to oxidation like proteins, pigments, polyunsaturated fatty acids (PUFA), and cholesterol.^[2] Lipid deterioration can cause off-flavors when handling and storing meat and meat products. Aldehyde, ketones, and organic acids are produced during oxidation and are associated with certain cardiovascular and carcinogenesis diseases.^[6]

Antioxidants can effectively suppress lipid peroxidation by degrading peroxides, preventing chain inhibition, and binding metal ions, which act as catalysts to activate chain reactions.^[7] Many amalgams possess antioxidant activity, but only a tiny proportion of these compounds are used in food and food products.^[8] Antioxidants are classified into two basic types: natural and synthetic. Several synthetic antioxidants are found which are used in different meat products to increase the shelf life of these products. When added to food products, antioxidants improve shelf-life by inhibiting free radicals produced during oxidation. Some typical synthetic antioxidants used by meat processors to preserve meat include butylated hydroxytoluene (BHT), propyl gallate (PG), and butylated hydroxyanisole (BHA).^[9] However, when used in a high dose, BHT may cause internal and external hemorrhage. Similarly, BHA causes lesion formations in rats. Both BHT/BHA have been shown to produce toxins and carcinogens.^[10]

The National Research Council Food Additive Committee report states that BHA and BHT are commonly used synthetic antioxidants in food. However, they may become ineffective at higher concentrations and even act as pro-oxidants. The use of both BHT and BHA in food products is limited due to their potential to cause serious health problems. These synthetic antioxidants are also expensive and have carcinogenic effects, further restricting their usage in foods.^[11] The increasing concern over synthetic antioxidants’ potential toxicity and continuous customer worry have heightened interest in using natural antioxidants to prolong the shelf life of food products.^[10] Natural antioxidants are derived from plant sources. Herbs and spices contain higher antioxidant potential because of specific components like polyphenols, lignins, flavonoids, and terpenoids.^[8] Spices include fruit (red chili, cumin, and black pepper), leaves (rosemary, oregano, and mint), stem (cinnamon, coriander), bulb (onion, garlic), and other plant parts.^[12]

Plant-derived antioxidants may be divided into phenolic chemicals, vitamins, and carotenoids. In addition to being the most abundant plant components with antioxidant activity, several phenolic compounds also have antibacterial and antifungal properties and significant influence on the tastes and textures of food items. Phenolic substances have a wide range of structures, ranging from simple molecules (such as ferulic acid, vanillin, gallic acid, and caffeic acid) to polyphenols such as tannins and flavonoids.^[13]

Cuminum cyminum L. also known as cumin, is an annual plant that belongs to the family Apiaceae.^[14] Cumin oil is recognized for its antioxidant qualities, which help to mitigate oxidation. A substantial proportion of the cumin’s volatile oil consists of cymene, terpenoids, and cumin aldehyde. Cuminaldehyde serves as the principal component found in cumin seeds.^[15] Black cumin, also known as Nigella sativa L. belongs to the Ranunculaceae family. Thymoquinone, thymol, and thymohydroquinone are the active ingredients of black cumin oil.^[16]

This research aimed to discover the potential of cumin and black cumin as natural preservatives for meat and demonstrate how they can improve the oxidative stability of chicken meat nuggets. Unlike previous studies, this research thoroughly examined the impact of these spices on the quality of chicken meat nuggets, including physicochemical, biochemical, and sensorial properties. In addition to the previously observed improvements in oxidative stability, these detailed findings provide new insights into using cumin and black cumin as meat preservatives.

Materials and methods

Preparation of cumin and black cumin extract

Superior quality cumin (Cuminum cyminum L.) and black cumin (Nigella sativa L.) were purchased from the local market of Faisalabad, Pakistan. Cumin and black cumin seeds were cleaned and washed using tap water and dried using a fan. Then, seeds were ground with the help of a grinder to obtain a fine powder.

The solvent extraction technique, as described by Fadel et al.^[17] was used for the extraction of cumin and black cumin. 200 g each of cumin and black cumin powder was taken in six conical flasks. Three different concentrations (50%, 70%, and 90%) of ethanol were used for the extraction of cumin and black cumin, as shown in Table 1. These samples were constantly shaken in an orbital shaker for 47–48 h with 3–4 h intervals. After shaking the sample for 48 h, the extract was filtered using filter paper. Next, the sample was separated from the solvent by condensing it in a rotatory evaporator under vacuum. When the volume of samples remains ~1 mL, the distillation process was stopped. Extract samples were shaded from light and kept in the freezer in sealed vials until further use.

Table 1. Treatment plan for ethanolic extraction of cumin and black cumin extracts.

Cumin		Black cumin
Treatments	Description	Treatments	Description
T1	E:W (50:50)	T4	E:W (50:50)
T2	E:W (70:30)	T5	E:W (70:30)
T3	E:W (90:10)	T6	E:W (90:10)

E = Ethanol, W = Water.

The antioxidant activity of three different concentrations of ethanolic extracts of cumin and black cumin was measured by DPPH-free radical scavenging activity and total phenolic content (TPC).

1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical activity

Free radical scavenging activity of cumin & black cumin ethanolic extracts was calculated using the method described by El-Ghorab et al.^[18] using a spectrophotometer at 517 nm. 1 mL of ethanolic extracts of cumin and black cumin from each treatment were added in different tubes. Then, 1 mL of DPPH solution was added. Test tubes containing the solution were shaken vigorously and then allowed to stand for 30 min in a dark place at room temperature. A spectrophotometer measured absorbance at 517 nm. Inhibition of free radicals by DPPH in percent (%) was calculated as:

DPPH inhibition (%) = $\frac{100\times \left(\mathit{Ablack}-\mathit{A}\mathit{sample}\right)}{\mathit{A}\mathit{black}}$

Where DPPH inhibition (%) = percent inhibition

Total phenolic contents (TPC)

The total phenolic contents were determined by the (FC) Folin-Ciocalteu reagent method, as explained by Ozsoy et al.^[19] 0.1 mL aliquot of the extract was mixed with 0.1 ml of Folin-Ciocalteu reagent (threefold times diluted with distilled water) and allowed to stand for 3 min. After 3 min, 0.3 ml of sodium carbonate (2%) solution was added. The mixture was allowed to react for another two hours. After the given time, a spectrophotometer was used to measure the absorbance of the sample at 760 nm. Gallic acid was used as the standard for the calibration curve. TPC was expressed in mg Gallic acid equivalents (GAE) per gram of fresh sample (mg/g). One of three ethanol concentrations that give the maximum extraction yield was selected for further study.

Product development

Procurement of chicken meat

The chicken meat was procured from the local market just after being slaughtered. After that, chicken meat was deboned, and visible fat was trimmed and chilled in a refrigerator at 4°C. Chicken nuggets were made using chicken treated with varying concentrations (0.5%, 1%, and 1.5%) of cumin and black cumin extracted using a solvent mixture of ethanol and water (90:10 ratio). Seven different treatments were formulated, as given in Table 2.

Table 2. Treatment plan for development of chicken nuggets using cumin and black cumin.

Treatment No.	Cumin extract %	Black cumin extract %
T0	-	-
T1	0.5	-
T2	1	-
T3	1.5	-
T4	-	0.5
T5	-	1
T6	-	1.5

Preparation of nuggets

The raw materials for the recipe were purchased from the market and then weighed according to the recipe. After weighing, the ingredients were cleaned with fresh and clean water. The chicken meat was minced using an electric mixer to prepare high-textured chicken nuggets. Chicken nuggets were prepared as the method described by Perlo et al..^[20] First of all, chicken meat was minced using a meat mincer. After mincing, minced meat was mixed with onion paste using a meat mixer for 5–10 min, followed by all the remaining ingredients (garlic paste, black pepper, salt) to have a uniform blend. After thoroughly mixing all the ingredients, the mixture was spread in a thin layer (10 mm thickness) and shaped into discs of 30 mm diameter (10 ± 1 g/piece) in the Meat Science and Technology Laboratory (NIFSAT, UAF). When chicken nuggets were prepared treated with varying concentrations (0.5%, 1%, and 1.5%) of cumin and black cumin extracted using a solvent mixture of ethanol and water (90:10 ratio), these nuggets were put in plain flour followed by bread crumbs. Heat the oil to 180°C for frying in a deep fryer. Frying of chicken nuggets was done till a golden brown color appeared.

Physicochemical analysis of chicken nuggets

pH analysis

The pH was calculated by the method of Hossain et al..^[21] For calculating the pH of the sample, the pH meter was calibrated using standard buffers of pH 4, 7, and 10. After that, chicken nugget sample was minced using a meat mincer, and then homogenization was carried out in 100 mL of distilled water using a homogenizer for 25–30 s. The homogenized sample was transferred to another flask. The electrode of the pH meter was dipped into the sample, and the pH value was measured.

Color (CTn) determination

The color value (CTn) was calculated by using a hand tristimulus colorimeter (Color Test Meter II) according to the method of El-Gasim and Al-Wesali.^[22] By using standards, calibration of the colorimeter was done (54 CTn for dark and 151 CTn for light). Color values were calculated by placing the sample under the photocell.

Texture analysis

Textural analyses of samples were recorded using a texture analyzer according to the procedure of Carlos et al..^[23] A compression test (force in kg) was performed to determine the texture analysis of a fresh sample at regular storage intervals. The texture profile was performed using pre-test speed (2 mm/s), post test speed (5 mm/s) and test speed was adjusted at 1 mm/s with deformation of 3 mm.

Biochemical analysis of chicken meat

Peroxide value (POV)

Peroxide values were calculated using the method reported by Sallam et al.^[24] A 5 g sample was taken in a 250 ml glass stoppered flask. To melt the fat in a sample, the flask containing the sample was heated for 3 min at 60°C in a water bath. Stirring was done and the addition of 30 mL of acetic acid-chloroform solution in a 3:2 ratio was also done for the homogenization of the sample and also for dissolving the fat content. The sample was filtered using filter paper to remove the meat particles. Before transferring the filtrate to a burette, 0.5 mL saturated KI solution was added to the filtrate. The filtrate was titrated against sodium thiosulfate standard solution at 25 g/L. The starch solution was used as an indicator. Peroxide value was determined by the formula below and expressed in milli-equivalent per kg of the sample.

POV (meq/kg) = $\frac{\mathit{S}\times \mathit{N}}{W}\times 100$

where S is volume of titration used (mL), N is normality of the sodium thiosulfate solution and W is weight of the sample (kg).

Thiobarbituric acid reactive substances assay (TBARS)

The chicken meat sample’s oxidative stability was calculated according to the method of Schmedes and Holmer.^[25] 10 g minced chicken (fresh) was dispersed in 25 mL acid solution (200 g/L of TCA in 135 g/L phosphoric acid solution), and homogenization was done for 25–30 s. Filtration was done by using filter paper, and 2 mL of filtrate was taken in a test tube. 2 mL of TBA solution (3 g/L) was added to the test tube. The test tubes were incubated in a dark place for 20–22 h at room temperature. Using a UV-VIS spectrophotometer, absorbance was measured at 532 nm.

Total phenolic contents (TPC)

The total phenolic contents of chicken meat samples were determined by the (FC) Folin-Ciocalteu reagent method, as mentioned above.

Sensory evaluation

Chicken nuggets prepared using different concentrations (0.5%, 1%, and 1.5%) of cumin and black cumin extracts and control samples were fried and then subjected to sensorial evaluation for up to 12 days. The evaluation was done by different panelists from NIFSAT for quality attributes like taste, color, texture, flavor, and overall acceptability. The marks were noted in the performa using a hedonic scale (9-points) after every 3 days according to the treatment plan to evaluate the liking and disliking of the panelists.

Statistical analysis

Statistical analysis was conducted on raw data gathered to measure the significance level and comparison of means as described by Montgomery.^[26] Statistical analysis was done by using statistix 8.1 (Germany). A two-way, complete, randomized design was used to determine the level of significance.

Results and discussion

Antioxidant activity of extracts

Antioxidants are compounds that prevent the production of free radicals in lipids due to oxidation. In this study, the antioxidant activity of cumin and black cumin extracts obtained by using different ethanol concentrations was measured by DPPH scavenging activity and total phenolic contents (TPC), and the optimal solvent concentration was used for further study.

1, 1-diphenyl-2-picrylhdrazyl (DPPH) free radical activity

The antioxidant activity of cumin and black cumin extracts was treated with DPPH solution, and their inhibition percentage was studied against DPPH solution. The mean values for DPPH (%) of cumin and black cumin extracts at different concentrations of ethanol are given in Table 3. The maximum reading of cumin for DPPH radical was found to be 64.39% ± 0.29 at 90% ethanolic concentration when compared with 50% and 70% concentration. The DPPH values for 50% and 70% concentrations of ethanolic extracts of cumin were found to be 40.10% ± 0.46 and 48.82% ± 0.38, respectively. For black cumin extracts, the maximum reading of black cumin for inhibition of DPPH radical was found to be 63.74% ± 0.34 at 90% ethanolic concentration when compared with 50% and 70% concentration. The DPPH values for 50% and 70% concentrations of ethanolic extract of black cumin were 39.91% ± 0.18 and 47.26% ± 0.34. The results revealed that cumin showed higher DPPH inhibition than black cumin. These results were similar to those obtained from the study of Thippeswamy and Naidu,^[14] who found that cumin showed higher antioxidant potential than black cumin. The results showed that the antioxidant activities of cumin varieties were found to be Bitter cumin > Cumin > Black cumin.

Table 3. DPPH (%) and TPC (mg GAE/100g sample) values of Cumin and Black cumin during extraction.

Treatments	DPPH (%)		TPC (mg GAE/100g sample)
	Cumin	Black cumin	Cumin	Black cumin
Ethanol 50%	40.10 ± 0.46^C	39.91 ± 0.18^C	41.78 ± 0.42^C	41.05 ± 0.28^C
Ethanol 70%	48.82 ± 0.38^B	47.26 ± 0.34^B	47.19 ± 0.20^B	46.79 ± 0.26^B
Ethanol 90%	64.39 ± 0.29 ^A	63.74 ± 0.34 ^A	64.44 ± 0.35 ^A	62.12 ± 0.33 ^A

Total phenolic content (TPC) determination

Total phenolics are the compounds present in plants that act as direct indicators of antioxidant activity. Using Folin’s reagent, total phenolic contents were measured at three different concentrations (50%, 70%, and 90%) of ethanolic extracts of cumin and black cumin. It is the most commonly used procedure for the determination of total phenolics. Mean values for TPC of cumin and black cumin extracts are depicted in Table 3. The results are represented as mg of Gallic acid equivalent (GAE) per 100 grams of fresh sample. The maximum reading of cumin for TPC was 64.44 ± 0.35 mg GAE/100g extract at 90% ethanolic concentration compared to 50% and 70% concentration. The TPC values for 50% and 70% concentrations of ethanolic extract of cumin were found to be 41.78 ± 0.42 and 47.19 ± 0.20 mg GAE/100g extract, respectively. For black cumin extracts, the maximum reading for TPC was found to be 62.12 ± 0.33 mg GAE/100g extract at 90% ethanolic concentration compared to 50% and 70% concentration. The TPC values for 50% and 70% concentration of ethanolic extract of black cumin were found to be 41.05 ± 0.28 and 46.79 ± 0.26 mg GAE/100g extract. Thippeswamy and Naidu^[14] observed the TPC of methanolic cumin extracts to be 9 mg/g dry weight. Shan et al.^[27] revealed a total phenolic content of 2.3 mg/g dry weight for 80% methanolic extract of cumin. The variations may be due to the use of different solvents and concentrations of solvents used. Statistical results obtained from both methods (TPC and DPPH) concluded that the best extraction of antioxidants in cumin and black cumin was found using 90% ethanol compared to 70% and 50% concentrations. Thus, extracts from 90% ethanolic concentration were selected for further studies.

Physicochemical analysis of chicken nuggets

pH analysis

The pH of chicken nuggets is essential as it determines the product’s shelf life. The findings of study showed that the pH of treatments increased significantly (p < 0.05) as the concentration of cumin and black cumin increased. While during storage days, the similar trend observed which shown highly significant results (p < 0.05) as depicted in Table 4. It is observed from the results that the pH value of chicken nuggets increased as the percentage of cumin and black cumin increased as compare to control treatment. The pH of control treatment was 5.16 ± 0.02 to 6.03 ± 0.00 till the end of the study. While T1 (0.5% cumin) and T4 (0.5% black cumin), having the most negligible concentration of natural antioxidants, showed increased pH values for chicken nuggets as compared to the control treatment.

Table 4. Mean values for pH of chicken nuggets stored at 4^°C.

Treatment	Day
	0	3	6	9	12
Tc (Control)	5.16 ± 0.02^G	5.69 ± 0.01^G	5.80 ± 0.00^G	5.93 ± 0.02^G	6.03 ± 0.00^G
T1 Cumin 0.5%	5.46 ± 0.04^E	5.81 ± 0.02^E	5.90 ± 0.05^E	6.01 ± 0.04^E	6.12 ± 0.02^E
T2 Cumin 1%	5.81 ± 0.01^C	6.03 ± 0.05^C	6.12 ± 0.02^C	6.22 ± 0.03^C	6.42 ± 0.03^C
T3 Cumin 1.5%	6.01 ± 0.03^A	6.21 ± 0.01^A	6.23 ± 0.02^A	6.32 ± 0.00^A	6.48 ± 0.02^A
T4 Black cumin 0.5%	5.51 ± 0.04^F	5.67 ± 0.03^F	5.78 ± 0.02^F	6.02 ± 0.04^F	6.21 ± 0.00^F
T5 Black cumin 1%	5.71 ± 0.02^D	5.89 ± 0.01^D	5.91 ± 0.01^D	6.16± 0.03^D	6.32 ± 0.01^D
T6 Black cumin 1.5%	5.82 ± 0.02^B	5.93 ± 0.04^B	5.98 ± 0.02^B	6.21 ± 0.05^B	6.40 ± 0.01^B

T3 (1.5% cumin) showed the highest pH value, which was 6.48 ± 0.02 as compared to the control treatment, which was found to be 6.03 ± 0.00 on the 12^th day, while T6 (1.5% black cumin) showed a slightly lower pH (6.4 ± 0.01) as compared to T3 and T2. Differences in the pH values were due to different cumin and black cumin concentrations. The pH gradually increased with an increase in storage days (Table 4). Results revealed that adding cumin to chicken nuggets as a natural antioxidant has more effect on pH values than black cumin.

According to Madane et al.,^[28] the pH value of chicken nuggets during storage period significantly (p < 0.05) increased with the addition of Dragon fruit peel including control group which was closely corelated to current study findings. Cumin samples showed a higher increase in pH values than black cumin. These findings are closely related to the finding of Abdel-Hamid,^[29] who revealed that pH values tend to increase over storage time in meat products with the addition of natural antioxidants and also in a control sample in which no antioxidant was used. The present results are also according to the findings of Moon,^[30] who observed that pH values varied significantly at refrigerated meat storage. Aslam et al.^[31] studied the effect of bioactive peptides on the antioxidant potential of broiler meat which indicated that the pH of chicken nuggets gradually increased with storage time. The results showed the similar trend as observed in current study.

Color analysis (CTn values)

A vital quality attribute in sensory evaluation is the color of the product. It is regarded as the first perception that the consumer perceives. Based on the product’s color, the consumer can evaluate the food product. The results of current study indicated that the treatments as well as storage days shown highly significant (p < 0.05) effect on color values of nuggets stored at a refrigerated temperature of 4°C while Treatment*Days interaction was non-significant (p > 0.05) as depicted in Table 5. Color values of control treatment stored at a refrigerated temperature range from 103.07±1.65 to 96.63 ± 0.49 CTn.

Table 5. Mean values for color (CTn) value of chicken nuggets at 4^°C.

Treatment	Days
	0	3	6	9	12
Tc (Control)	103.07 ± 1.65^F	100.89 ±0.97^F	98.78 ± 0.46^F	97.77 ± 0.23^F	96.63 ± 0.49^F
T1 Cumin 0.5%	105.92 ± 1.72^E	104.39 ±0.21^E	102.73 ±0.22^E	101.09 ± 0.26^E	98.26 ± 0.67^E
T2 Cumin 1%	107.33 ± 0.52^D	105.82 ± 0.66^D	104.29 ± 0.41^D	102.83 ± 0.17^D	100.65 ± 0.25^D
T3 Cumin 1.5%	109.61 ± 0.43^B	107.92 ± 0.49^B	106.36 ± 0.39^B	104.89 ± 0.44^B	103.02 ± 0.38^B
T4 Black cumin 0.5%	107.81 ± 0.81^C	106.67 ± 0.36^C	105.82 ± 0.21^C	104.18 ± 0.12^C	102.64 ± 0.31^C
T5 Black cumin 1%	110.29 ± 0.56^B	108.51 ± 0.72^B	106.21 ± 0.36^B	104.82 ± 0.23^B	103.07 ± 0.26^B
T6 Black cumin 1.5%	112.66 ± 1.07^A	109.70 ± 0.31^A	107.96 ± 0.18^A	107.10 ± 0.20^A	106.01 ± 0.33^A

At 0 day, color values of chicken nuggets in various treatments differ from 103.07 ± 1.65 to 112.66 ± 1.07 CTn, and at the end of the study (12^th day), values were decreased from 96.63 ± 0.49 to 106.01 ± 0.33 CTn. All the treatments have a significant effect on the CTn values of chicken nuggets. Among the cumin treatments, T3 has the highest values for color (103.02 ± 0.38 CTn) due to the higher concentration of cumin extract (1.5%). At the start of the study, the value was 109.61 ± 0.43; on the 12^th day, the value was 103.02 ± 0.38 CTn. Other treatments also significantly affect the color values of chicken nuggets but in lower quantities. When used at different levels, black cumin also significantly affects the CTn values of chicken nuggets. The best treatment was found to be T6, followed by T5 and T4. At the start of the study, the value for T6 was 112.66 ± 1.07 CTn, and at 12-day analysis, the value was 106.01 ± 0.33 CTn. The decrease in CTn values was due to the storage conditions. Color values for T5 range from 110.29 ± 0.56 to 103.07 ± 0.26 CTn. The study revealed higher color values with increased levels of cumin and black cumin. However, storage studies showed a darker color. During storage, the color scores degraded from 0 days to the 12^th day. The degradation of color in chicken nuggets might be due to pigments or non-enzymatic browning. The results are closely related to the results of Wu,^[32] who conducted an experiment and reported that the addition of antioxidants used for storing meat products decreases color values because the addition of antioxidants releases moisture from the product’s surface. Luciano^[33] also reported that adding antioxidants maintained the color attribute of lamb minced meat, improving its shelf stability.

Texture analysis

One of the essential sensorial quality attributes in the selection process is texture. The results of this study revealed that both the treatment and storage time showed highly significant (p < 0.05) effect on texture value of chicken nuggets stored at refrigerated temperature (4°C) while the interaction effect of treatments and days was nonsignificant (p > 0.05) as given in Table 6.

Table 6. Mean values for texture analysis (force in kg) of chicken nuggets stored at 4^°C.

Treatment	Days
	0	3	6	9	12
Tc (Control)	4.92 ± 0.06^A	5.45 ± 0.18^A	7.71 ± 0.15^A	9.23 ± 0.23^A	12.38 ± 0.05^A
T1 Cumin 0.5%	3.82 ± 0.06^C	4.80 ± 0.02^C	7.05 ± 0.05^C	8.97 ± 0.01^C	12.02 ± 0.07^C
T2 Cumin 1%	3.51 ± 0.05^E	4.46 ± 0.04^E	6.52 ± 0.11^E	8.04 ± 0.04^E	11.28 ± 0.04^E
T3 Cumin 1.5%	3.14 ± 0.08^G	4.20 ±0 .01^G	5.76 ±0.03^G	6.87 ± 0.10^G	10.06 ± 0.05^G
T4 Black cumin 0.5%	3.94 ± 0.02^B	5.17 ± 0.02^B	7.35 ± 0.05^B	9.07 ± 0.02^B	12.21 ± 0.11^B
T5 Black cumin 1%	3.75 ± 0.04^D	4.89 ± 0.01^D	6.81 ± 0.15^D	8.47 ±0.04^D	11.48 ± 0.19^D
T6 Black cumin 1.5%	3.44 ± 0.05^F	4.60 ± 0.03^F	6.01 ± 0.05^F	7.08 ± 0.12^F	10.80 ± 0.65^F

At 0 to 12-day texture analysis, the T_c value changes from 4.92 ± 0.06 to 12.38 ± 0.05 force in kg. As the storage time increased, the value for texture analysis also increased. It is also observed from the results that all the treatments in which natural antioxidants were added in different concentrations revealed lower shear force than the control group. The lowest values for texture were found in T3 and T6, in which the levels of antioxidants used were higher than all the other treatments. At 0 days, the value was 3.14 ± 0.08 for T3, and at the end of the study, the value was increased up to 10.06 ± 0.05. Similarly, the value for T6 at 0 days was found to be 3.44 ± 0.05; at the end of the study, it was found to be 10.8 ± 0.65. The results showed that cumin and black cumin both showed a decrease in texture values as the level of antioxidants was increased in the treatments.

T1 and T4 slightly decreased texture values compared to the control treatment. At 0 days, the value was found to be 3.82 ± 0.06; at the end of the study, the value was 12.02 ± 0.07 for T1. The treatment T1, T2, and T3 (12.02 ± 0.07, 11.28 ± 0.04, and 10.06 ± 0.05) showed low texture values as compared to T4, T5, and T6 (12.21 ± 0.11, 11.48 ± 0.19, and 10.8 ± 0.65) at the end of the study. Cumin showed minimum texture values as compared to black cumin. All treatments have low texture values compared to the control treatment in which no antioxidant was added. These results are familiar with the findings of Moran,^[34] who observed that the addition of natural preservatives in all treatments showed low force when compared with the control group.

Biochemical analysis of chicken meat

Peroxide value (POV)

Peroxide value (POV) indicates rancidity. Free radicals are produced as oxidation continues, producing ketonic and aldehyde bodies, which result in an odd flavor. The findings of this study indicated that both the storage time and treatments showed highly significant (p < 0.05) effect on peroxide value of chicken nuggets when stored at 4°C while the interaction effect of treatments and days are nonsignificant (p > 0.05) which were given in undefined 7.

Table 7 shows that treatments with natural antioxidants (cumin and black cumin) resulted in lower POV values with storage days compared to the control group with no antioxidants. The results of the treatments revealed that POV values increased with time, with maximum POV values recorded on the 12th day. The statistical analysis showed that POV values for Tc (no antioxidant added) changed from 5.41 ± 0.05 to 9.23 ± 0.05 meq/kg at the end of the study. While treatments T1 (0.5% cumin) and T4 (0.5% black cumin) did not reveal any significant change compared to the control group due to the lower level of antioxidants. Similarly, T2 (1% cumin) and T5 (1% black cumin) showed a slightly lower mean when compared with the control group at the end of the study.

Table 7. Mean values for peroxide value POV (meq/kg) of chicken nuggets stored at 4°C.

Treatment	Day
	0	3	6	9	12
Tc (Control)	5.41 ± 0.05^A	6.61 ± 0.03^A	7.78 ± 0.09^A	8.55 ± 0.02^A	9.23 ± 0.05^A
T1 Cumin 0.5%	4.95 ± 0.02^B	5.95 ± 0.05^B	7.00 ± 0.02^B	7.86 ± 0.05^B	9.18 ± 0.04^B
T2 Cumin 1%	4.12 ± 0.01^E	5.43 ± 0.06^D	6.46 ± 0.03^D	7.33 ± 0.08^D	8.94 ± 0.06^E
T3 Cumin 1.5%	3.82 ± 0.00^G	4.73 ± 0.03^F	5.50 ± 0.05^F	6.41 ± 0.01^F	7.18 ± 0.02^G
T4 Black cumin 0.5%	4.37 ± 0.04^C	5.61 ± 0.08^C	6.77 ± 0.03^C	7.55 ± 0.02^C	9.20 ± 0.05^C
T5 Black cumin 1%	4.23 ± 0.02^D	5.47 ± 0.05^CD	6.73 ± 0.02^CD	7.44 ± 0.05^CD	9.04 ± 0.01^D
T6 Black cumin 1.5%	3.92 ± 0.01^F	4.89 ± 0.01^E	5.75 ± 0.04^E	6.78 ± 0.08^E	7.33 ± 0.02^F

Treatments T3 (1.5% cumin) and T6 (1.5% black cumin) showed minimum POV values (3.82 ± 0.00 and 3.92 ± 0.01 meq/kg) due to higher concentrations of cumin and black cumin used. However, cumin showed the lowest POV values compared to black cumin on the 12th day of the study. There were no significant changes in POV values of treatments T1 (0.5% cumin) and T4 (0.5% black cumin) due to lower concentrations of antioxidants (cumin and black cumin) used as compared to the control treatment. It was evident from the results that both cumin and black cumin have a significant role in lowering the POV values of chicken nuggets at refrigerated temperatures.

These results were similar to those obtained from the study of Thippeswamy and Naidu,^[14] who found that cumin showed higher antioxidant potential than black cumin. Ghasemi et al.^[35] studied the physicochemical characteristics of chicken nuggets treaded with plant essential oils and described that peroxide values were significantly (p < 0.05) increased during storage time which is similar with the current study findings.

Thiobarbituric acid reactive substances (TBARS) value

Thiobarbituric acid reactive substances (TBARS) value is commonly used as an indicator of the oxidation of lipids in meat Raharjo and Sofos.^[36] The treatments and storage time had highly significant (p < 0.05) effect on TBRAS of nuggets while the treatments and day interaction had nonsignificant effect (p > 0.05) of chicken nuggets stored at 4°C as given in Table 8. The results showed that the thiobarbituric acid reactive substances (TBRAS) value of chicken nuggets during the control treatment (Tc) was maximum (0.69 ± 0.03) and minimum (0.29 ± 0.01) on the 12th and initial day of the storage study, respectively. The TBRAS values of chicken nuggets treated with cumin 0.5% (T1) were 0.24 ± 0.00, 0.25 ± 0.01, 0.31 ± 0.00, 0.49 ± 0.02, and 0.58 ± 0.01 during the storage period of 0, 3, 6, 9, and 12 days, respectively. The maximum value of TBRAS was 0.50 ± 0.03, and the minimum was 0.22 ± 0.01 on the 12th day and initial day of storage in the treatment T2 (chicken nugget with Cumin 1%), respectively. On the other hand, in treatment T3 (chicken nugget with Cumin 1.5%), the TBRAS values were recorded as 0.39 ± 0.01, 0.28 ± 0.01, 0.21 ± 0.01, 0.12 ± 0.03, and 0.11 ± 0.005 at 12, 9, 6, 3, and 0 days of storage, respectively.

Table 8. Mean values for Thiobarbituric acid (TBA) µmol./c of chicken nuggets stored at 4^°C.

Treatment	Day
	0	3	6	9	12
Tc (Control)	0.29 ± 0.01^A	0.36 ± 0.02^A	0.44 ± 0.00^A	0.54 ± 0.01^A	0.69 ± 0.03^A
T1 Cumin 0.5%	0.24 ± 0.00^A	0.25 ± 0.01^AB	0.31 ± 0.00^C	0.49 ± 0.02^B	0.58 ± 0.01^B
T2 Cumin 1%	0.22 ± 0.01^AB	0.18 ± 0.02^D	0.28 ± 0.01^E	0.40 ± 0.01^D	0.50 ± 0.03^E
T3 Cumin 1.5%	0.11 ± 0.005^C	0.12 ± 0.03^E	0.21 ± 0.01^G	0.28 ± 0.01^E	0.39 ± 0.01^G
T4 Black cumin 0.5%	0.22 ± 0.0^AB	0.27 ± 0.00^B	0.33 ± 0.02^B	0.52 ± 0.01^A	0.66 ± 0.02^B
T5 Black cumin 1%	0.18 ± 0.01^B	0.21 ± 0.008^C	0.31 ± 0.00^D	0.47 ± 0.01^C	0.56 ± 0.01^D
T6 Black cumin 1.5%	0.12 ± 0.00^C	0.15 ± 0.02^DE	0.25 ± 0.01^F	0.35 ± 0.03^D	0.45 ± 0.01^F

The TBRAS value of chicken nuggets treated with 0.5% black cumin (T4) was maximum (0.66 ± 0.02) at 12 days of storage and minimum (0.22 ± 0.01) at the initial day of storage. At 3, 6, and 9 days of storage, the TBRAS value of T4 was 0.27 ± 0.00, 0.33 ± 0.02, and 0.52 ± 0.01, respectively. Similarly, for T5 (chicken nuggets with 1% black cumin), TBRAS values were 0.18 ± 0.01, 0.21 ± 0.008, 0.31 ± 0.00, 0.47 ± 0.01, and 0.56 ± 0.01 at 0, 3, 6, 9, and 12 days of storage while the TBRAS value of T6 was 0.12 ± 0.00 and 0.45 ± 0.01 at the initial day and 12th day of storage. The chicken nuggets treated with 1.5% black cumin showed the TBRAS values at 3, 6, and 9-day storage were 0.15 ± 0.02, 0.25 ± 0.01, and 0.35 ± 0.03, respectively. These results were similar to those obtained from the study of Thippeswamy and Naidu,^[14] who found that cumin showed higher antioxidant potential than black cumin. In meat and meat products, 0.75 mg MDA/kg is the standard value and an index of oxidation of lipids.^[37] In meat products, 0.5 to 2.0 mg MDA/kg is the range of TBA values, where the rancid flavor is initially detected.^[38] Madane et al.^[28] investigated that the TBARS values of chicken nuggets incorporated with Dragon fruit peel was significantly increased from day 1st to till 20th day of storage time. These results strongly supported the current study findings. Ghasemi et al.^[35] also studied that the TBARS value was significantly (p < 0.05) increased during storage period of chicken nuggets incorporated with plant essential oil. These findings showed similar trend as observed in this study.

Total phenolic contents (TPC)

Table 9 shows mean values for total phenolics (TPC) of chicken meat in mg GAE/100g of the sample during storage of 12 days. The statistical results showed that all the treatments showed significant differences in total phenolic content (TPC). The statistical results showed that the treatment and storage time had significant (p < 0.05) effect while treatment and days interaction had nonsignificant effect (p > 0.05) on TPC of nuggets (Table 9). The level of cumin and black cumin in the treatments directly impacted the total phenolic contents (TPC). The TPC values reached their maximum on the initial day and decreased gradually with storage days in all treatments. The control samples showed a decrease in TPC values from 45.17 ± 0.08 to 42.84 ± 0.10 mg GAE/100g during the study. At the same time, T3 (1.5% cumin) and T6 (1.5% black cumin) showed the highest TPC values on the initial day, with 56.9 ± 0.03 and 53.63 ± 0.07 mg GAE/100g chicken meat, respectively. On the 12th day, T3 and T6 still had the highest values, with 53.92 ± 0.03 and 52.01 ± 0.03 mg GAE/100g meat, respectively. These treatments were found to be the best. T1 (0.5% cumin) and T4 (0.5% black cumin) showed the slightest increase in TPC on the initial day, with 48.59 ± 0.02 and 46.89 ± 0.05 mg GAE/100g meat, respectively, as compared to the control group. T2 (1% cumin) and T5 (1% black cumin) showed a rise in TPC values compared to the control sample, but the values were lower than those of T3 and T6. Additionally, it was noted that cumin showed more excellent antioxidant activity than black cumin. These results were similar to those obtained from the study of Thippeswamy and Naidu [14], who found that cumin possessed higher antioxidant potential than black cumin. Another study was conducted by Le [39], who observed that chicken meat possessed 51.24 mg GAE TPC per dry weight of meat sample by measuring the phenolic contents and estimating the antioxidant potential. TPC values were maximum at 1st day of storage and gradually decreased with successive storage of chicken nuggets treated with essential plant oils as described by Ghasemi et al..^[35,39] These findings showed significantly decreasing (p < 0.05) trend of TPC values of chicken nuggets during storge which closely corelated with current study results. [38]

Table 9. Mean values for Total phenolic content TPC (mg GAE/100g) of chicken nuggets stored at 4°C.

Treatments	Day
	1	3	6	9	12
Tc (Control)	45.17 ± 0.08^G	44.86 ± 0.01^G	44.44 ± 0.03^G	43.78 ± 0.08^G	42.84 ± 0.10^G
T1 Cumin 0.5%	48.59 ± 0.02^E	48.17 ± 0.06^E	47.88 ±0.06^E	47.28 ± 0.01^E	46.84 ± 0.11^E
T2 Cumin 1%	53.41 ± 0.05^C	52.88 ± 0.09^C	52.41 ± 0.12^C	51.93 ± 0.05^C	51.38 ± 0.04^C
T3 Cumin 1.5%	56.9 ± 0.03^A	55.88 ± 0.12^A	55.11 ± 0.06^A	54.51 ± 0.02^A	53.92 ± 0.03^A
T4 Black cumin 0.5%	46.89 ± 0.05^F	46.37 ± 0.13^F	46.06 ± 0.09^F	45.75 ± 0.11^F	45.27 ± 0.01^F
T5 Black cumin 1%	49.51 ± 0.04^D	49.10 ± 0.07^D	48.63 ± 0.01^D	48.28 ± 0.08^D	47.94 ± 0.06^D
T6 Black cumin 1.5%	53.63 ± 0.07^B	53.10 ± 0.02^B	53.54 ± 0.03^B	52.43 ± 0.05^B	52.01 ± 0.03^B

Sensory evaluation of chicken nuggets

In any product development, sensory evaluation is an essential tool. Acceptance of any food product depends upon the consumer’s satisfaction, acceptance, and awareness of the flavor, texture, color, taste, and overall acceptability. The quality of food products can be observed through physical, chemical, and microbiological tests; however, these tests cannot deliver evidence, such as whether the consumer will accept or reject the product. In this study, a 9-point hedonic scale was used to measure the degree of acceptance. The panelists assessed five sensory aspects: color, flavor, taste, texture, and overall acceptability. The sensory panelists were experts in evaluating the quality of various food items, especially meat products. The results showed that all parameters were significantly affected by the treatments (as shown in Figure 1) and that the treatments had a significant impact over the storage period, as shown in Figure 2.

Figure 1. Effect of different treatments on sensorial properties of chicken nuggets.

Figure 2. Effect of storage in different treatments on sensorial properties of chicken nuggets.

Conclusion

It is concluded that both black cumin and cumin extracts have been found to be potent antioxidants that can effectively minimize the formation of free radicals in refrigerated chicken nuggets. The most impactful treatments involved utilizing black cumin extracts and a 1.5% concentration of cumin. These natural extracts can significantly improve the quality of meat products. Throughout the storage period, the pH and total phenolic contents with a concentration of 1.5% cumin were notably elevated. Moreover, the peroxide value and TBARS were dramatically reduced compared to the other samples. The T3 treatment achieved the highest score in overall acceptance compared to the other treatments. Further study must be done using higher concentrations of cumin and black cumin to explore the potential of these spices..

Acknowledgement

The authors are highly obliged to Library Department of University of Agriculture Faisalabad, Government College University Faisalabad and IT department of Higher Commission of Pakistan for access to journals, books and other valuable database.

Disclosure statement

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