Impact of adding sorghum dried distillers’ grains on the quality properties of emulsified chicken sausages

ABSTRACT

Recently, the market for emulsified chicken sausages (ECS), which are poultry meat products, has been growing owing to their excellent nutritional and eating qualities and because of their consumption is not forbidden by any cultural and religious laws. Sorghum dried distillers’ grains (SDDGs), a byproduct of the brewing of Taiwan’s famous sorghum wine (kaoliang liquor), are rich in nutrients; however, due to a lack of suitable processing applications, they pose serious waste problems. This study aimed to assess the quality of ECS formulated by replacing corn starch with SDDGs at levels of 0, 20, 40, 60, 80%, and 100%. ECS containing SDDGs showed substantially higher water-holding capacity (WHC) (7.83 to 15.49%), hardness (224.17 to 340.00 gf/mm²), cohesiveness (0.10 to 0.15), and lower L* (57.75 to 52.47), a* (4.95 to 3.83), b* (13.61 to 10.77), and pH values (6.04 to 5.71) compared to those of control ECS (5.35%, 185.67 gf/mm², 0.08 and 63.03, 5.08, 14.90, 6.22) (p < .05); however, they did not affect springiness. Additionally, control ECS exhibited the lowest water loss (6.16%), fat loss (2.80%), water-holding capacity (WHC) (5.35%), cooking loss (8.96%), hardness (185.67 gf/mm²), cohesiveness (0.08), gumminess (20.12 gf), and chewiness (0.33 mJ), which substantially increased with increasing SDDGs levels; however, the L*, a*, b*, and pH values decreased. According to our results, we confirm the ECS could be prepared using SDDGs, offering potential and effectively improve the diversity of poultry meat products, establish appropriate processing and application of dried distillers’ grains, and reduce waste and environmental problems caused by alcohol brewing.

KEYWORDS:

• Emulsified chicken sausages
• poultry meat
• sorghum dried distillers’ grain
• quality

Introduction

Meat and meat products offer a high quantity and quality of proteins, are an excellent source of essential nutrients (vitamins and minerals), and have satiating characteristics.^[1–3] Due to increased poultry production, many food processing industries are focusing their business operations and development on innovating and developing new poultry products.^[4] The emulsification technique has been used to manufacture meat products, which are more popular than other processed meats because they are convenient to consume in a variety of foods.^[5] Common emulsified meat products include sausages, which are the most common and popular processed meat products in the commercial market and are consumed in many countries and diverse cultures worldwide.^[6] Influenced by various climates, religions, eating habits, ingredient availability, and processing and preservation methods worldwide, sausages have become diverse meat products.^[7] Moreover, owing to their low manufacturing costs and simple technology, sausages are currently one of the most commonly produced and consumed meat products.^[4]

The use of raw materials is the most important factor to consider when preparing sausages. The demand for meat products is constantly changing because of a growing focus on diet and health, changes in lifestyle, and preferences for convenient food options by consumers. Pork, beef, and chicken are the most commonly used ingredients in sausages. Among these, poultry meat, particularly chicken, is the best choice for sausages because it contains higher amounts of proteins and lower amounts of fat and cholesterol than red meat (beef and pork).^[8] In modern society, the consumption of ready-to-eat (RTE) foods has become a habitual trend owing to the increasing demands of work and busy lifestyles. Chicken sausage is a popular RTE food product among consumers.

Owing to their convenience and availability, poultry meat products are generally less expensive to manufacture than comparable red meat (beef and pork) products, which has contributed to the substantial increase in their consumption worldwide.^[9] In particular, chicken is readily available owing to its high yield and affordability. Therefore, the market demand for poultry sausages has been growing not only because of their good nutritional and eating qualities but also because the consumption of poultry meat is not forbidden by most cultural and religious laws.^[4,10] In addition, as mentioned above, as consumers continue to deepen their awareness of healthy diets, their consumption needs are shifting toward healthy and nutritious foods with additional health-promoting functions. Therefore, consumers require healthier and more functional meat products,^[9] which has also contributed to the increasing demand for functionally emulsified chicken sausages (ECS) in developed countries.

Meat plays an important role in the human diet. The demand for healthy, safe, and high-quality foods by consumers is increasing,^[11] and accordingly, concerns about the safety of synthetic additives are increasing. Therefore, many studies have reported the application of natural materials in meat industry.^{[1,2,6,8,9,11]}

Sorghum is one of the most important but least utilized staple crops in Asia, Africa, and America.^[12] Additionally, sorghum grains has a lower cost of production in comparison to corn.^[13,14] Sorghum grain is a rich in nutrients and phenolic compounds. The phenolic compounds in sorghum are unique and more abundant and diverse than other common cereal grains.^[15] Therefore, sorghum grain has been used to develop variety of food and beverages. Besides its use as a food, sorghum is used to produce alcoholic liquor.

Distillers grains, a byproduct of ethanol brewing, hold high nutritional value because of the removal of starch during the fermentation process.^[16,17] Sorghum dried distillers grains (SDDGs) are a byproduct generated after brewing a famous Taiwanese alcoholic liquor, kaoliang liquor.^[18] Some studies reported the higher concentration of protein, fiber,^[13,16] and lower lipid content^[13] of SDDGs when comparing the maize distiller dried grains.^[14] However, SDDGs are often wasted in large quantities due to a lack of suitable applications; therefore, the practical application of distillers’ grains has become a priority^[18] and many distillers’ grain-based foods, such as biscuits, have been developed over the past years. However, their application in the field of poultry, such as in ECS, has not been well explored.

In summary, SDDGs have high nutritional value and processing properties^[18]; however, due to the lack of detailed studies on poultry meat products, there are no reports on the effects of SDDGs as additives on the quality properties of ECS. Therefore, the present study aimed to investigate the effects (cooking loss, emulsion stability, water-holding capacity (WHC), color, pH value, texture profile analysis, and emulsion stability) of substituting corn starch in raw materials at different concentrations (20%, 40%, 60%, 80%, and 100%) during ECS production.

Materials and methods

Materials

The chicken breast meat (Taiwan Farm Industry Co., Ltd.), sugar (Taiwan Sugar Corporation), salt (Taiyen Biotech Co., Ltd), corn starch (Buildmore Enterprise Co., Ltd.), pig casings (obtained from the local market in Pingtung County, Taiwan), and SDDGs (obtained from the Pingtung Brewery of Taiwan Tobacco and Alcohol Company, Taiwan) used in this study were all stored at 7°C in a refrigerator until further processing.

Preparation of SDDGs

The samples were first placed in a DKN 612 oven (Yamoto Company, Tokyo, Japan) and dried at 45°C for 10 h. After drying, the SDDGs were ground using an RT-N08 grinder mill (Rong Tsong, Taichung, Taiwan) and sieved through a 550 μm sieve (30 mesh; Retsch GmbH, Haan, Germany). The sieved SDDGs powder was stored in a sealed container and stored at 7°C. The moisture, crude protein, crude fat, crude fiber, ash content, and total carbohydrate contents of SDDGs were 8.0%, 13.8%, 5.3%, 17.7%, 5.0%, and 50.2% (wet weight basis), respectively (data not shown).

ECS manufacturing

The raw materials were weighed according to the formulas presented in Table 1. First, a DH802S meat grinder (grinding plate with 4 mm diameter holes’ Taiwan Ding Han Machinery Co., Ltd.) was used to obtain a homogeneous mixture. The samples were minced using a CB-7 meat grinder (K.S.H., Kinn Shang Hoo Iron Works, Kaohsiung, Taiwan) for 15 min. The minced meat was filled (EM-30; Mainca, Barcelona, Spain) into pork intestine casing and shaped into ECS (length = 15 cm, diameter = 3 cm, weight = 125 ± 2 g), which was then steamed at 100°C for 15 min in a CK-485 steamer (Chuan Kuel, Changhua,Taiwan). Finally, the ECS was stored in a sealed bag at −18°C for further analysis (no more than 48 hours). The ECS were placed at room temperature (about 30°C) for 3 hours to thaw before experiment.

Table 1. Ingredients used to produce sorghum distillers’ grain ECS.

Ingredient	Treatments
	S-0	S-20	S-40	S-60	S-80	S-100
chicken breast	1000.0	1000.0	1000.0	1000.0	1000.0	1000.0
Ice water	64.1	64.1	64.1	64.1	64.1	64.1
Sugar	64.1	64.1	64.1	64.1	64.1	64.1
Salt	21.4	21.4	21.4	21.4	21.4	21.4
Corn starch	58.3	46.6	35.0	23.3	11.7	0.0
SDDGs	0	11.7	23.3	35.0	46.6	58.3

0% SDDGs (S-0); 20% SDDGs (S-20); 40% SDDGs (S-40); 60% SDDGs (S-60); 80% SDDGs (S-80); 100% SDDGs (S-100).

ECS, emulsified chicken sausages; SDDGs, Sorghum dried distillers’ grains.

Cooking loss analysis

Distilled water (20 mL) was boiled in a crucible (W) on an HP-303D heating plate (NewLab, Taipei, Taiwan). Next, 2 g of (X) ECS was added and heated for 5 min. The liquid was dried in the crucible at 105°C to constant weight (W1). The cooking loss was calculated using the following formula:

(1) $\mathrm{C}\mathrm{o}\mathrm{o}\mathrm{k}\mathrm{i}\mathrm{n}\mathrm{g}\mathrm{l}\mathrm{o}\mathrm{s}\mathrm{s}=\left(\left(\mathrm{W}1-\mathrm{W}\right)/\mathrm{X}\right)\times 100$(1)

All analyses performed in the present study were performed in triplicate.

Emulsified stability and water-holding capacity (WHC) analysis

The emulsified stability and WHC were analyzed according to Chou.^[18] Samples (20 g) were suspended in a beaker sealed with aluminum foil and heated at 75°C for 30 min (BH-230D water bath, Yida Company, New Taipei City, Taiwan) and then cooled. he beaker was weighed and placed in a DV453 dryer at 60°C (Channel model, New Taipei City, Taiwan) to remove moisture. The dried beaker was weighed again, and the following formula was used to calculate the emulsified stability:

(2) $\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{L}\mathrm{o}\mathrm{s}\mathrm{s}\mathrm{\%}=\left(\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}/\mathrm{S}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\right)\times 100$(2)

(3) $\mathrm{F}\mathrm{a}\mathrm{t}\mathrm{L}\mathrm{o}\mathrm{s}\mathrm{s}\mathrm{\%}=\left(\mathrm{O}\mathrm{i}\mathrm{l}\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}/\mathrm{S}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\right)\times 100$(3)

(4) $\mathrm{W}\mathrm{H}\mathrm{C}\mathrm{\%}=\left(\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{e}\mathrm{n}\mathrm{t}-\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{L}\mathrm{o}\mathrm{s}\mathrm{s}\mathrm{\%}\right)/\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{e}\mathrm{n}\mathrm{t}\times 100$(4)

Analysis was performed in triplicate.

Color analysis

We used the Color Quest XE system procured from Hunter Associates Laboratory (Reston, VA, USA) to determine the color properties of the ECS (1 cm in thickness and 3 cm in diameter). The test results revealed the following color properties of the samples: L-value (“100” represents full brightness, and “0” represents full darkness); a-value (“＋” represents red, “0” represents gray, and “－” represents green); and b-value (“＋” represents yellow, “0” represents gray, and “－” represents blue). Three measurements were performed for each set of samples. Each analysis was performed in triplicate.

pH Value

Five grams of ECS was mixed with 45 mL of distilled water for 5 min, and after standing for 30 min, a PL 700PV(s) pH tester (Great Tide Instrument Co., Ltd., Taipei, Taiwan) was used for pH measurement. Each analysis was performed in triplicate.

Texture profile analysis

Based on a previously described method,^[19] we used the EZ Test-500N texture analyzer (TAXTZ-5, Shimadzu Co., Kyoto, Japan) to measure the ECS textural properties. We conducted two compression-testing sessions for a given sample (length = 2 cm, diameter = 3 cm). The specifications of the tests were a 60 mm/min compression speed, a rounded probe (diameter = 10 mm), and a compression height equal to 50% of the sample’s height. Each analysis was performed in triplicate.

Statistical analysis

The experiments were carried out in triplicate. Data were statistically analyzed using the SAS software (SAS Institute, Cary, NC, USA). The mean values in the various groups were compared using Duncan’s multiple range test. The differences were considered to be statistically significant at p < .05.

Results and discussion

Cooking loss

The ECS produced in this study showed cooking losses ranging from 8.64% to 25.71% (Table 2). When the levels of SDDGs were between 40% and 100% (S-40, S-60, S-80, and S-100), the cooking loss rate of the ECS significantly increased and was significantly higher than that of S-0 (control ECS, 8.96%) and S-20 (20% SDDGs, 8.46%) (p < .05). This result is likely attributed to the pH. Limam and Mohamed (2019) have demonstrated that the cooking losses for chicken sausages supplemented with chia seeds range from 14.25 to 24.54% and that cooking loss in meats depends on their final pH (5.72–6.54), and this range was similar to the range of cooking loss and pH values obtained in the present study. In addition, the cooking loss in the ECS may be due to the effect of SDDGs on water binding, which affects water loss during cooking. Similarly, Canti et al. (2021) combined jack beans (Canavalia ensiformis L.) and soy protein isolate as a binder to prepare chicken sausages and measured a cooking loss of 26.54%, noting that cooking loss was affected by water loss during cooking, which is influenced by water-binding proteins.^[8] Therefore, in this study, as the SDDG level increased, the lower protein content in the raw material resulted in less water retention and increased water release, which increased cooking losses.

Table 2. Analysis results of ECS cooking loss at different SDDGs levels.

Experimental group	Cooking loss (%)
S-0	8.96 ± 0.51^e
S-20	8.46 ± 0.44^e
S-40	10.72 ± 1.57^d
S-60	12.48 ± 1.21^c
S-80	20.23 ± 0.82^b
S-100	25.71 ± 0.27^a

0% SDDGs (S-0); 20% SDDGs (S-20); 40% SDDGs (S-40); 60% SDDGs (S-60); 80% SDDGs (S-80); 100% SDDGs (S-100).

Means in the same column with different superscripts are significantly different (p < .05).

ECS, emulsified chicken sausages; SDDGs, Sorghum dried distillers’ grains.

Emulsification stability and WHC

The various ECS produced in this study (Table 3) showed that the water loss ranged between 5.84% and 17.87% with increasing levels of SDDGs and water loss tended to increase, whereas S-20 (20% SDDGs, 5.84%) and S-40 (40% SDDGs, 7.22%) exhibited the lowest water loss; however, the results were not statistically significant (p > .05). Consistent with our results, Baek et al. (2016) have shown that water loss ranges from 1.93% to 13.5% for emulsified pork sausages prepared with canola and flaxseed oils added to the raw material.^[20] Similarly, Park and Kim (2016) have also shown that emulsified pork sausages prepared with the addition of black rice flour exhibit a water loss between 8% and 17%.^[6]

Table 3. Analysis results of ECS emulsification stability and WHC at different SDDGs levels.

Experimental group	Water loss (%)	Fat loss (%)	WHC (%)
S-0	6.16 ± 0.35^e	2.80 ± 0.16^de	5.35 ± 1.07^d
S-20	5.84 ± 0.30^e	2.62 ± 0.14^e	7.82 ± 3.06^cd
S-40	7.22 ± 1.04^e	3.49 ± 0.54^e	9.21 ± 1.94^bcd
S-60	9.47 ± 1.91^c	4.52 ± 0.84^c	13.13 ± 4.32^abc
S-80	13.73 ± 0.50^b	6.54 ± 0.33^b	14.29 ± 5.04^ab
S-100	17.87 ± 0.38^a	7.85 ± 0.12^a	15.49 ± 1.62^a

0% SDDGs (S-0); 20% SDDGs (S-20); 40% SDDGs (S-40); 60% SDDGs (S-60); 80% SDDGs (S-80); 100% SDDGs (S-100).

Means in the same column with different superscripts are significantly different (p < .05).

ECS, emulsified chicken sausages; SDDGs, Sorghum dried distillers’ grains.

In the present study, we observed a fat loss of 2.62–7.85% (Table 3). When SDDGs was used to prepare the ECS, the fat loss was significantly different compared to that of S-0 (control ECS, 2.80%) but not S-20 (20% SDDGs, 2.62%) and S-40 (40% SDDGs, 3.49%) (p < .05). Moreover, fat loss increased as SDDGs levels increased, Park and Kim (2016) and Baek et al. (2016) suggested that fat loss in emulsified pork sausages ranges from 6% to 12% with the addition of black rice flour and from 1.93% to 4.82% with the addition of rapeseed oil and flaxseed oil.^[6,20] These previous findings are consistent with the results of our study, which may be due to the presence of crude fiber in SDDGs (17.7%, data not shown). In a previous study, Gorachiya et al. (2022) reported that chicken sausage fortified with fiber exhibits fat loss ranging from 6.37% to 6.64%.^[21] Therefore, the findings of this study suggest that SDDGs improve the emulsion stability of emulsified meat products such as chicken sausages.

The WHC of the ECS prepared with different SDDGs levels ranged from 7.82% to 15.49% (Table 3). The addition of SDDGs was positively correlated with WHC; at SDDGs levels of less than 20% (S-20), ECS exhibited the lowest WHC (7.82%), whereas there was no significant difference (p > .05) between the 20% and 40% SDDGs (S-20 and S-40). Consistent with our results, Munsu et al. (2021) reported that the WHC of ECS supplemented with seaweed ranges from 1.60% to 8.86%^[1] and Limam and Mohamed (2019) demonstrated that the WHC for ECS supplemented with chia seeds ranges from 17.73 to 18.70.^[9]

The WHC of meat protein gels is significantly different at approximately pH 6,^[22] which is similar to the pH of the ECS obtained in the present study. Moreover, proteins are denatured during ECS production, gradually forming a network that absorbs water. However, at higher SDDGs levels, the interaction between ingredients, especially non-meat ingredients, may have a significant effect on WHC.^[23] In addition, the fiber component is closely related to the water retention of chicken sausages,^[1] suggesting that the crude fiber contained in the SDDGs in this study (17.7%, data not shown) may also affect the WHC. Zaini et al. (2021) further explained that this effect may be attributed to the occurrence of fiber hydration, where water molecules enter the pore space in the fiber particles during ECS fabrication^[24] leading to an increase in WHC, which is consistent with the trend observed in the present study.

Color

In the present study, the L* values for experimental ECS were 52.47–57.75 (Table 4). Nurul et al. (2010) reported an L* value range of 39.72–45.92 for commercial sausages.^[25] Peña-Saldarriaga et al. (2020) also reported an L* value of 67.42–69.42 for chicken sausages formulated with chicken fatty byproducts.^[4] Marapana et al. (2018) demonstrated that the L* value of chicken sausages with different casings ranges from 60.73 to 62.48.^[7] Yadav et al. (2020) also indicated that chicken sausages mixed with wheat bran combined with dried apple and carrot pomace have L* values ranging from 52.02–59.60.^[2] Furthermore, Zaini et al. (2021) reported an L* value range of 49.72–60.32 for chicken sausages supplemented with banana peel flour.^[24] Therefore, the results of our study are consistent with those previously reported.

Table 4. Analysis results of ECS color at different SDDGs levels.

Experimental group	L*	a*	b*
S-0	63.03 ± 0.01^a	5.08 ± 0.04^a	14.90 ± 0.01^a
S-20	57.75 ± 0.08^b	4.95 ± 0.11^b	13.61 ± 0.03^b
S-40	56.40 ± 0.04^c	4.71 ± 0.05^c	12.51 ± 0.04^c
S-60	54.21 ± 0.09^d	4.50 ± 0.04^d	11.88 ± 0.08^d
S-80	51.48 ± 0.10^e	4.36 ± 0.04^e	11.09 ± 0.01^e
S-100	52.47 ± 0.09^f	3.83 ± 0.05^f	10.77 ± 0.03^f

0% SDDGs (S-0); 20% SDDGs (S-20); 40% SDDGs (S-40); 60% SDDGs (S-60); 80% SDDGs (S-80); 100% SDDGs (S-100).

Means in the same column with different superscripts are significantly different (p < .05)

ECS, emulsified chicken sausages; SDDGs, Sorghum dried distillers’ grains.

At different SDDGs levels, the L* value of the ECS in each experimental group was significantly lower than that of S-0 (control ECS, 63.03), and the addition of SDDGs was negatively correlated with the L* value. Similar trends were reported by Zaini et al. (2021),^[24] Lee et al. (2017),^[26] and Jin et al. (2017).^[11] Moreover, Jin et al. (2017) reported that control chicken sausages exhibit the highest L* values,^[11] which is similar to the trend reported in our study.

The a* and b* values were 3.83–4.95 and 10.77–13.61, respectively (Table 4). These values were significantly lower for experimental ECS than for S-0 (control ECS, 5.08 and 14.90) (P < .0.5). Yadav et al. (2020) have revealed that the a* value range of chicken sausages mixed with wheat bran combined with dried apple and carrot pomace is 6.09–7.44.^[2] Jin et al. (2017) and Jin et al. (2016) reported a* value ranges for pork sausages of 5.68–7.43 and 2.66–4.05,^[11,19] respectively. Moreover, Park and Kim (2016) demonstrated that emulsified pork sausages containing black rice flour have a* values ranging from 5.58 to 6.58.^[6] Ham et al. (2017) also revealed an a* value ranging from 5.0–5.33 for pork sausages.^[27] In addition, Jin et al. (2017) and Ham et al. (2017) reported that the control chicken sausages have a higher a* value than the experimental ones.^[11,27] Therefore, our results are similar to previously reported ones.

In the present study, the SDDGs levels appeared to be negatively correlated with the b* value of ECS. Jin et al. (2016) reported a b* value range of 10.44–11.43 for sausages.^[19] Zaini et al. (2021) also reported a b* value range of 9.25–13.40 for chicken sausages supplemented with banana peel flour.^[24] Munsu et al. (2021) reported that the b* value for chicken sausages supplemented with seaweed ranges from 10.82–13.66.^[1] Therefore, the results of the present study are consistent with previous studies,

In the present study, all SDDGs -supplemented experimental ECS exhibited significantly lower L*, a*, and b* values than S-0 ECS (63.03, 5.08, and 14.90, respectively). Similar trends were reported by Ham et al. (2017) and Park and Kim (2016).^[6,27] This result may be because the color of the SDDGs affects the color change of the ECS during the process.^[6]

pH

Table 5 shows the various ECS produced in this study, with pH values ranging between 5.71 and 6.04. We observed that with increasing levels of SDDGs, pH tended to decrease. Jin et al. (2016) reported that the pH of emulsified pork sausages ranges between 6.14 and 6.50.^[19] Lee et al. (2017) also reported a pH range of 6.25–6.33 for chicken breakfast sausages supplemented with isolated soy proteins and wheat sprouts.^[26] Jin et al. (2014) reported a pH range of 6.03–6.30 for emulsified pork sausage containing red beet powder.^[23] Similarly, Limam and Mohamed (2019) demonstrated that the pH of chicken sausage supplemented with chia seeds ranges from 5.72 to 6.54 and suggested that the cooking losses of the meat depended on the final pH (5.72–6.54).^[9] These previously reported pH ranges are similar to the pH range obtained in the present study (Table 5).

Table 5. Analysis results of ECS pH at different SDDGs levels.

Experimental group	pH
S-0	6.22 ± 0.01^a
S-20	6.04 ± 0.02^b
S-40	5.94 ± 0.01^c
S-60	5.92 ± 0.01^c
S-80	5.75 ± 0.02^d
S-100	5.71 ± 0.03^e

0% SDDGs (S-0); 20% SDDGs (S-20); 40% SDDGs (S-40); 60% SDDGs (S-60); 80% SDDGs (S-80); 100% SDDGs (S-100).

Means in the same column with different superscripts are significantly different (p < .05).

ECS, emulsified chicken sausages; SDDGs, Sorghum dried distillers’ grains.

In the present study, when SDDGs were used to prepare the ECS, the pH value of S-0 (control ECS, 6.22) was significantly higher than that of each experimental ECS group (p < .05), and the SDDGs level was negatively correlated with the pH of the ECS. Consistent with our results, Jin et al. (2017) and Ham et al. (2017) also reported a pH range of 5.68–6.05 and 5.96–6.00 for chicken sausages,^[11,27] respectively, and indicated that the control chicken sausage corresponded to a higher pH. Moreover, the decrease in the ECS pH may be due to the production of lactic acid by lactic acid bacteria,^[28] and the pH value of meat products can be influenced by the ingredients, meat composition, and additives.^[23,29]

Texture profile analysis

The results of the analysis of the effects of different levels of the SDDGs on the textural properties of the ECS produced in this study are presented in Table 6. When the SDDGs were used to prepare the ECS, the hardness, cohesiveness, gumminess, and chewiness properties were significantly higher than those of S-0 (control ECS, 185.67 gf/mm², 0.08, 20.12 gf and 0.33 mJ; p < .05).

Table 6. Analysis results of ECS texture at different SDDGs levels.

Experimental group	Hardness (gf/mm^2)	Springiness	Cohesiveness	Gumminess (gf)	Chewiness(mJ)
S-0	185.67 ± 3.06^d	0.04 ± 0.00^a	0.08 ± 0.01^c	20.12 ± 1.36^b	0.33 ± 0.04^d
S-20	224.17 ± 12.49^c	0.04 ± 0.00^a	0.10 ± 0.03^ab	21.83 ± 6.42^b	0.38 ± 0.05^d
S-40	253.00 ± 19.93^b	0.05 ± 0.01^a	0.13 ± 0.03^b	23.49 ± 5.44^b	0.38 ± 0.01^d
S-60	287.00 ± 33.96^b	0.04 ± 0.02^a	0.14 ± 0.02^a	39.79 ± 0.78^a	0.84 ± 0.05^c
S-80	277.00 ± 15.31^b	0.05 ± 0.36^a	0.16 ± 0.04^a	43.48 ± 3.52^a	1.63 ± 0.03^a
S-100	340.00 ± 13.12^a	0.06 ± 0.02^a	0.15 ± 0.04^a	52.44 ± 5.03^a	1.44 ± 0.01^b

0% SDDGs (S-0); 20% SDDGs (S-20); 40% SDDGs (S-40); 60% SDDGs (S-60); 80% SDDGs (S-80); 100% SDDGs (S-100).

Means in the same column with different superscripts are significantly different (p < .05).

ECS, emulsified chicken sausages; SDDGs, Sorghum dried distillers’ grains.

Table 6 shows that the hardness of various ECS in this study was between 224.17 and 340.00 gf/mm²; with increasing levels of SDDGs, the hardness value tended to increase. Seo et al. (2016) indicated that the hardness value of sausages ranges between 300 and 350 gf/mm^2[3]. Lee et al. (2017) also reported a hardness value range of 290–322 gf/mm² for chicken breakfast sausages supplemented with isolated soy proteins and wheat sprouts.^[26] Yadav et al. (2020) demonstrated that the hardness value of chicken sausages mixed with wheat bran combined with dried apple and carrot pomace is 27.48–53.60 N.^[2] The results of this study are consistent with those previously reported. Moreover, Gorachiya et al. (2022) reported that the hardness of chicken sausages fortified with fiber exhibited hardness values ranging from 17.22 to 22.07 N.^[21] Previous studies also reported that the hardness of chicken sausages increases with the increase in fiber content in raw materials^[2,21] and is higher than that of the control chicken sausages. Similar results were obtained in the present study, which may explain why the SDDGs contained crude fiber (17.7%, data not shown).

Table 6 shows that the springiness of various ECS in this study was between 0.04 to 0.06; springiness was not affected by the level of the SDDGs (p > .05). The interaction between protein and water is affected by water availability and pH, which in turn affects the formation of the protein gel matrix, as well as the springiness of the ECS.^[22] The optimal pH for gelation is approximately pH 7.0–7.5, which is close to the pH range of the experimental ECS obtained in the present study (5.71–6.22, Table 5).

Cohesiveness analysis indicated that the cohesiveness of the various ECS produced in this study (Table 6) ranged from 0.10–0.16. The cohesiveness of each experimental ECS (S-20, S-40, S-60, S-80, and S-100) was significantly higher than that of S-0 (control ECS, 0.04) (p < .05). Peña-Saldarriaga et al. (2020) examined the cohesiveness of chicken sausage formulated with chicken fatty byproducts and reported a cohesiveness value of 0.18,^[4] whereas Chou et al. (2022) demonstrated that the cohesiveness of kamaboko prepared with sorghum dried distiller grains ranges from 0.11–0.43.^[30] Similarly, Baek et al. (2016) have shown that the cohesiveness of emulsified pork sausages prepared with canola and flaxseed oils ranges from 0.24 to 0.45.^[20] Therefore, the results obtained in this study were similar to those previously reported.

Suryananingrum et al. (2015) reported that meat cohesiveness is affected by interactions between proteins and water.^[22] In the present study, higher SDDGs levels led to higher ECS cohesiveness, and some results were statistically significant (p < .05). This effect may be attributed to the enhanced formation of cross-linked myosin heavy chain components by slightly reducing the myosin heavy chain content through polymerization^[30]Therefore, in this study, the SDDGs levels significantly affected ECS cohesiveness.

The gumminess of various ECS (Table 6) produced in this study ranged from 21.83–52.44 gf. The gumminess of each experimental ECS (S-20, S-40, S-60, S-80, and S-100) was significantly higher than that of S-0 (control ECS: 20.12 gf). Song et al. (2017) have found that the gumminess of emulsified sausages increases with an increase in the proportion of Monascus powder. Furthermore, Uzzaman et al. (2018) indicated that the stickiness (range:0.10–0.55 kgf) of red tilapia mince gel (Oreochromis sp.) is altered by the addition of chitosan,^[31] a trend similar to the one identified in the present study.

Table 6 shows that the chewiness of various ECS in this study ranged between 0.38 and 1.44 gf; with increasing SDDGs levels, chewiness value tended to increase. In the study by Li et al. (2017), the chewiness of emulsified pork sausages was measured at 1.32–1.42 N, increasing with the increase of wheat flour. Similar trends have been reported by Jin et al. (2017).^[11] The emulsified pork sausages supplemented with Gleditsia sinensis Lam. extract exhibit chewiness ranging between 1.86 and 1.99 N. Munsu et al. (2021) also reported that the hardness and chewiness increase with the addition of seaweed in the formulation.^[1] These results indicate that the meat gel texture may be closely related to the gel formed by the ingredients in the raw materials.^[31]

Conclusion

In this study, the effects of different SDDGs at levels of 0, 20, 40, 60, 80%, and 100% on the quality properties of ECS were evaluated. Cooking loss, emulsification stability, and WHC of the ECS tended to increase with increasing SDDGs. However, the lowest L*, a*, and b* values and pH were observed at the highest SDDGs level (100%). In terms of texture profile analysis, higher levels of hardness, cohesiveness, gumminess, and chewiness were observed at higher SDDGs levels; however, some of these results were not significant. The present study suggests that the use of SDDGs to replace starch in formulations can significantly affect ECS quality, depending on the amount of SDDGs added. Thus, SDDGs may be used as appropriate natural ingredients in meat processing (e.g., ECS). According to our results, SDGs can be used to replace starch in the manufacture of meat derived products and affect the qualities. As quality is critical for the acceptability of meat products and sausages, the optimization of SDDGs and their application in emulsified meat products warrants further research. Furthermore, the application of SDDGs can effectively reduce the waste of distillers’ grains and the environmental problems derived from alcohol brewing.

Author contributions

Conceptualization, C.F.C.; data curation, Y.C.H.; formal analysis, Y.C.H.; project administration, C.F.C.; supervision, C.F.C.; validation, C.F.C.; writing the original draft, C.F.C.; and writing the review and editing, C.F.C.

Acknowledgments

The authors would like to acknowledge the master’s degree Program in Safety and Health Science, Chang Jung Christian University, Taiwan, for their support and use of the experimental facilities.

Disclosure statement

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

Additional information

Funding

This work was supported by Chang Jung Christian University (R.O.C.).