Poultry meat accounts for 49% of India’s total meat production, with consumption exceeding 5.8 million metric tons in 2024-25 (BAHS, 2025). The increase in global demand for convenient, nutritious and functional food has driven substantial innovation within food industry, particularly in the development of meat products (Toldrá and Reig, 2011). Chicken nuggets have become popular for their palatability, convenience, affordability and versality due to quick preparation, low cost and extended shelf life when frozen (Abd-El-Aziz et al., 2021). The rising demand for chicken nuggets reflects consumer preferences for quality, taste and health benefits (Pakseresht et al., 2022). To address this, our study incorporated finger millet to chicken nuggets to enhance these attributes and meet consumer expectation.
       
Finger millet, commonly referred to as ragi, is an important small-grained cereal extensively grown across Asia and Africa. India is among the leading producers of finger millet, contributing nearly 2.2 million tons annually and the crop is well suited to adverse agro-climatic environments. (https://www.icrisat.org/crops/finger-millet/overview). Owing to its rich nutritional composition, particularly its high levels of calcium, iron and dietary fibre, finger millet has gained attention as a valuable ingredient for food fortification aimed at combating micronutrient deficiencies (Amadou et al., 2013). In addition, its substantial fibre content supports digestive health, while the presence of antioxidant compounds may help alleviate oxidative stress and inflammatory conditions (Chethan and Malleshi, 2007).
       
The incorporation of finger millet flour into meat products like chicken nuggets presents a novel strategy to improve their nutritional quality by enhancing fiber and mineral content along with functional benefits (Kaur et al., 2024). Finger millet also offers functional properties such as water-holding and emulsifying capacity, which can improve the texture and juiciness of meat products to enhance sensory and textural properties (Rathod and Annapure, 2017). The unique taste, color and high fiber content of finger millet may alter the flavor and appearance of the final product, making formulation optimization and consumer testing crucial for consumer acceptance (Shobana, 2013). Moreover, antioxidants present in finger millet may enhance product shelf life by reducing lipid oxidation (Rathod and Annapure, 2017). However, finger millet flour have  moderate moisture content ranging upto 13%  which can also promote microbial growth, potentially reducing the shelf life of chicken nuggets (Devi et al., 2014). Therefore, it is essential to evaluate the shelf life and storage stability of finger millet-based chicken nuggets under different storage conditions to ensure their safety and quality over time. Herein, we evaluated shelf life quality of chicken nuggets incorporated with finger millet (Ragi flour) at refrigerated storage (4±1°C).

Formulation of chicken nuggets
 
Fresh boneless chicken meat obtained from 6-week-old broilers was purchased from a nearby retail meat outlet and transported hygienically to the laboratory of the Department of Livestock Products Technology, College of Veterinary Science, andUAT, Kumarganj, Ayodhya (U.P.), in polyethylene pouches. Visible skin, excess fat, tendons and connective tissues were carefully removed prior to processing. The cleaned meat was then packed in high-density polyethylene (HDPE; density 0.93-0.97 g/cm³) bags and stored at -18±1°C overnight. Before use in product preparation, the frozen meat was thawed under suitable conditions.     
       
After thawing at room temperature, the deboned chicken meat was cut into small cubes of approximately 3 cm and minced through a 6 mm plate using a meat mincer (Ramon AK, Model P-22). Chicken nuggets were prepared according to a standardized formulation consisting of lean meat, salt, spices, condiments and preservatives, as presented in Table 1. During emulsification in a bowl chopper, minced meat was initially blended with salt, sodium nitrite and sodium tripolyphosphate for nearly 30 seconds. Ice flakes were then incorporated and chopping was continued for about 1.5 minutes. Subsequently, vegetable oil was added gradually while chopping proceeded for an additional 2 minutes. Thereafter, condiments and spice mixtures were incorporated, followed by further chopping for another 2 minutes. Finger millet flour was added at a level of 6% to the meat emulsion and chopping was continued until a uniform emulsion was obtained. The control formulation was prepared using the same procedure and ingredient composition, excluding the addition of finger millet flour, as shown in Table 1.


       
The prepared meat emulsions were separately transferred into stainless steel moulds measuring 14 cm × 7 cm × 3 cm to obtain uniformly shaped nuggets. The moulded products were steam cooked for 35 minutes, ensuring that the internal core temperature reached 75±2 °C. After cooking, the nuggets were allowed to cool to room temperature and subsequently cut into uniform pieces measuring approximately 4 × 1.5 × 1.5 cm. The nugget samples were aerobically packaged in HDPE pouches and stored under refrigerated conditions (4±1°C) for shelf-life evaluation. Analyses were carried out at 4-day intervals up to 20 days of storage (0, 4, 8, 12, 16 and 20 days), with an additional assessment on the 22^nd day. Changes in sensory characteristics, physico-chemical properties (pH, thiobarbituric acid value and peroxide value), as well as microbiological quality were evaluated during storage. The entire experiment was conducted in five independent trials, with three samples analyzed in each replication.
 
Analytical procedures
 
pH of chicken nuggets was measured using a digital pH meter as suggested by Troutt et al. (1992). Moisture content of the nuggets was determined as per procedures of AOAC (1990). The Thiobarbituric (TBA) value of chicken nuggets was determined with slight modifications in the technique described by Strange et al. (1977). The peroxide value of the product during storage studies was determined using the standard procedure of AOAC (1990).
 
Sensory evaluation
 
Sensory evaluation was carried out by a semi-trained panel of ten faculty members from the College of Veterinary and Animal Sciences, Kumarganj, Ayodhya, using an 8-point descriptive scale (Keeton 1983). The nuggets were assessed for appearance, flavour, juiciness, texture and overall acceptability after checking for any undesirable colour or off-flavour. Samples were served warm to evaluate their sensory quality during storage.
 
Microbiological quality
 
Microbiological evaluation of the chicken nuggets was carried out by determining total plate count, psychrophilic count and coliform count following the methods prescribed by APHA (1992). Plate count agar for total plate count and psychrophilic count and Voilet Red Bile Agar (VRBA) for coliform count were procured from Hi-media Laboratories Pvt. Ltd., Mumbai for the enumeration of microbes. The plates for total plate count and psychrotrophic counts were incubated at 37±1°C for 48 h and 4±1°C for 10-14 days, respectively, after making appropriate dilutions. The plates for coliform count were incubated at 37±1°C for 48 h. The  plates showing 30-300 colonies were counted and the number of colonies was multiplied by the reciprocal of respective dilutions and expressed as log10 cfu/g of sample. Coliform colonies were identified based on characteristic red or purple colonies on VRBA medium.
 
Statistical analysis
 
The data generated during the study were analyzed using the Analysis of Variance (ANOVA) employing version 24.0 of the SPSS software (Snedecor and Cochran, 1994).

Physico-chemical properties
 
The results presented in Table 2 and 3 highlights the impact of refrigerated storage on the physico-chemical characteristics and moisture content of chicken nuggets over a 22-day period. The evaluation included both control nuggets and those with 6% finger millet, focusing on key parameters such as pH, TBA (Thiobarbituric Acid) values, peroxide values and moisture content.




       
The pH values for both control and finger millet enriched chicken nuggets exhibited a gradual increase throughout the storage period. The control nuggets showed a rise in pH from 6.20 on day 0 to 6.39 on day 22, while the finger millet enriched chicken nuggets displayed a slightly lower increase from 6.15 to 6.37 during the same period. This stabilization is likely attributable to the antioxidant and antimicrobial properties of finger millet, which could slow down the enzymatic and microbial processes responsible for pH changes (Devi et al., 2008). The storage period means reflected a similar upward trend, indicating consistent pH increases over time across both treatments. The production of bacteria and the breakdown of lactic acid may be the cause of the increase in pH of chicken nuggets kept at refrigeration temperature (Jay, 1996). Gamit et al., (2020) also reported gradual increase in pH of chicken cutlets with 5%finger millet during refrigerated storage. Similarly, another study showed significant increase in pH during refrigeration storage of chicken extended with finger millet (ragi) flour (Naveena et al., 2006).
       
The 6% finger millet enriched chicken nuggets, however, consistently exhibited lower TBA values, starting at 0.16 mg/kg on day 0 and reaching 1.039 mg/kg by day 22. This reduction in TBA values highlights the antioxidative effects of finger millet, which appears to effectively delay the oxidation of lipids, thereby preserving the sensory quality of the nuggets. The treatment mean values for finger millet enriched chicken nuggets were consistently lower than the control, reinforcing the role of finger millet in minimizing oxidative damage. The current study findings are consistent with those of Naveena et al., (2006) and Das et al., (2015), who also found a highly significant (P<0.05) difference between treatments and storage times of chicken patties formulated with finger millet flour.
       
Similarly, peroxide value is a useful method to determine the early stages of fat oxidation. The finger millet enriched chicken nuggets exhibited a slower rise, with values increasing from 4.71 meq peroxide/kg fat to 22.74 meq peroxide/kg fat over the same period. The lower peroxide values for finger millet enriched chicken nuggets further emphasize the antioxidative potential of finger millet, which likely inhibits the formation of hydroperoxides, delaying the onset of rancidity (Devi, 2014). The treatment and storage period means reflected this trend, with control nuggets experiencing significantly higher oxidative deterioration compared to finger millet enriched chicken nuggets. Das et al., (2015) reported highly significant difference between storage period, but non-significant difference in between treatments of chicken patties formulated with finger millet flour.
       
The moisture content of the nuggets also declined progressively during storage, which is a typical phenomenon in refrigerated meat products due to evaporation and structural changes in the protein matrix (Pathera et al., 2016). The finger millet enriched chicken nuggets retained higher moisture levels, starting at 60.78% on day 0 and decreasing to 57.132% on day 22. The superior moisture retention in finger millet enriched chicken nuggets can be attributed to the water-binding properties of finger millet, which contains fiber and carbohydrates that help trap water within the product matrix (Munshi and Dashora, 2024). This enhanced moisture retention likely contributes to better texture and juiciness in ragi-enriched nuggets, which is an important factor for maintaining sensory appeal during extended storage. However, Chatli et al., (2015) reported significantly higher moisture content in control than the treatments in emu meat nuggests formulated with finger millet. Biswas et al., (2011) reported significant decrease in moisture content of duck patties with increase in the storage period.
       
Overall, the results indicate that incorporating 6% finger millet into chicken nuggets has multiple benefits during refrigerated storage. Finger millet significantly stabilizes pH levels, reduces lipid oxidation as evidenced by lower TBA and peroxide values and enhances moisture retention. These improvements contribute to better quality preservation, extended shelf life and improved sensory attributes of the product.
 
Sensory quality
 
The data presented in Table 4 highlights the sensory evaluation of chicken nuggets during refrigerated storage over a period of 22 days. Sensory attributes assessed are appearance, flavor, juiciness, texture and overall palatability, with values reported for both control and 6% finger millet incorporated nuggets.


       
Appearance is an essential sensory attribute as it directly influences the visual appeal and consumer acceptance of food products. The results show that the control nuggets experienced a gradual decline in appearance during the 22-day storage period which can be attributed to factors such as surface dehydration, discoloration or the development of storage-related defects over time. In contrast, the 6% finger millet enriched chicken nuggets consistently scored higher than the control for appearance across all storage periods. The initial score was 7.67 on day 0, which dropped to 6.38 on day 22. The higher appearance scores for the finger millet enriched chicken nuggets suggest that the incorporation of finger millet may have contributed to better retention of color or surface integrity during storage. This could be due to the antioxidant properties of finger millet, which might have delayed oxidative changes leading to discoloration. The treatment mean for 6% finger millet (7.10) was higher than the control (6.85), highlighting its superior performance in maintaining appearance. According to Zargar et al., (2014), the appearance score of sausages was significantly impacted by both the treatments and the lengthening of the storage period (4±1°C). Thomas et al., (2010) also noted a similar decreasing pattern for hurdle-treated sausage kept at 4±1°C and Naveena et al., (2006) noted a downward trend in the cooked chicken patties’ appearance score over time while being stored in the refrigerator (4±1°C).
       
Flavor, a critical determinant of consumer satisfaction, showed a consistent downward trend for both control and 6% finger millet enriched chicken nuggets during storage. For the control nuggets, the flavor score decreased which can be linked to lipid oxidation, protein degradation, or microbial activity, which are common in meat products during prolonged storage. The 6% finger millet enriched chicken nuggets exhibited higher flavour scores throughout the storage period, starting at 7.29 on day 0 and reducing to 6.24 by day 22. The higher scores for finger millet enriched chicken nuggets may be due to the antioxidant properties of finger millet, which could have slowed lipid oxidation and maintained flavor integrity. The treatment mean for 6% finger millet (6.91) was significantly higher than the control (6.53), indicating a notable improvement in flavor preservation with finger millet incorporation. However, by day 22, the flavor differences between the treatments narrowed, suggesting that the protective effects of finger millet diminished with extended storage. According to Naveena et al., (2006), the score decreased during storage, reaching its lowest value on the twenty-first day. Additionally, he said that flavor was not greatly impacted by the treatment. Microbial growth and fat oxidation may be the cause of the dramatic drop in flavor score at the end of storage.
       
Juiciness is a vital attribute influencing the texture and overall mouthfeel of chicken nuggets. For the control nuggets, the juiciness score steadily decreased which can be attributed to moisture loss during storage, which is common in refrigerated meat products. The 6% finger millet enriched chicken nuggets, however, consistently scored higher for juiciness throughout the storage period. The initial score was 7.45, which decreased to 6.38 by day 22. The higher juiciness scores for finger millet enriched chicken nuggets can be linked to the water-binding properties of finger millet, which may have helped retain moisture during storage. The treatment mean for 6% finger millet (6.99) was substantially higher than the control (6.63), further emphasizing the positive impact of finger millet on juiciness retention. Sakunde (2007) reported similar results, claiming that the juiciness of chicken patties is influenced by the reduction of fat and moisture.
       
Texture reflects the structural integrity and chewiness of the nuggets, both of which significantly impact sensory acceptability. The control nuggets exhibited a consistent decline in texture scores which is likely due to protein and fat degradation, as well as moisture loss, which affects the structural cohesiveness of the nuggets. The 6%  finger millet enriched chicken nuggets maintained higher texture scores throughout storage, starting at 7.71 on day 0 and ending at 6.29 on day 22. The improved texture scores for finger millet enriched chicken nuggets may result from the binding and structural stabilizing properties of finger millet, which likely helped maintain the cohesiveness and firmness of the nuggets over time. The treatment mean for 6% finger millet (7.07) was significantly higher than the control (6.63), indicating that finger millet effectively mitigated the negative effects of storage on texture.
       
Overall palatability integrates all sensory attributes (appearance, flavor, juiciness and texture) to reflect the general appeal of the product. For the control nuggets, the overall palatability score decreased from 7.48 on day 0 to 6.25 on day 22. This decline mirrors the cumulative impact of storage-related changes in the individual sensory attributes. The 6% finger millet enriched chicken nuggets consistently outperformed the control in terms of overall palatability, with scores decreasing from 7.66 on day 0 to 6.29 on day 22. The higher scores for finger millet enriched chicken nuggets reflect their superior performance across all sensory parameters, likely due to the positive effects of finger millet in preserving quality during storage. Naveena et al., (2006) reported nearly identical results, noting a non-significant difference between the control and finger millet patties and a significant drop in score over the course of a 21-day refrigerated storage period. Sakunde (2007) reported lower scores for all the sensory attributed, although the chicken nuggets incorporated with different levels of finger millet was acceptable upto 9% finger millet.
       
The storage period means for all attributes (appearance, flavor, juiciness, texture and overall palatability) showed a declining trend over time, reflecting the cumulative impact of storage-related changes. The initial storage period means were highest on day 0 (e.g., 7.54 for appearance, 7.08 for flavor) and lowest on day 22 (e.g., 6.32 for appearance, 6.20 for flavor).
       
For all attributes, the treatment means for 6% finger millet enriched chicken nuggets were consistently higher than the control, confirming the beneficial effects of finger millet on sensory quality. These findings suggest that incorporating finger millet not only enhances initial sensory attributes but also slows the rate of quality degradation during storage.
 
Microbiological quality
 
Storage related changes in microbial quality of chicken nuggets with and without finger millet flour pertaining to the total plate count, psychrophilic count and coliform count during refrigeration storage are presented in Table 5.


       
Total plate count (TPC), which measures the overall microbial load, a steady increase was observed in both treatments throughout the storage period. Control nuggets showed a rise from 4.31 log cfu/g on day 0 to 6.35 log cfu/g on day 22, reflecting the natural progression of microbial growth in meat products during refrigeration. However, the finger millet enriched chicken nuggets exhibited slightly lower TPC values at each interval, increasing from 4.13 log cfu/g on day 0 to 6.25 log cfu/g on day 22. The slower microbial growth in the finger millet enriched chicken nuggets indicates antimicrobial properties due to its bioactive compounds such as phenolics and antioxidants, which inhibit the growth of spoilage-causing bacteria. The storage period mean for TPC showed a gradual increase, with the finger millet enriched chicken nuggets consistently maintaining lower microbial counts compared to the control, highlighting the shelf-life-enhancing potential of finger millet. The results partially agree those of Naveena et al., (2006), who found that aerobic plate counts significantly increased over a 21-day storage period while remaining within the spoilage limit. Earlier studies have also reported that the total plate count of the control and treatment of different chicken based products increased significantly over the course of the storage period (Zargar et al., 2014; Das et al., 2015; Gamit et al., 2020).
       
The Psychrophilic Count, which measures cold-tolerant microorganisms, followed a similar pattern of growth. In control nuggets, psychrophilic bacteria were not detected (ND) on day 0 but began to appear by day 4, with a count of 2.71 log cfu/g and steadily increased to 4.56 log cfu/g by day 22. In contrast, the finger millet enriched chicken exhibited delayed and slower growth, with psychrophilic counts of 2.31 log cfu/g on day 4, rising to 4.33 log cfu/g on day 22. The storage period mean for psychrophilic bacteria increased steadily over time but remained lower in ragi-enriched nuggets, reflecting their improved microbial stability during storage. The findings of the present study are in close agreement with Zargar et al., (2014) who also not detected the psychrophilic bacteria on the day zero, however thereafter the count followed significant (p<0.05) increasing trend with progress in storage period. Increase in psychrophilic count during storage of finger millet extended chicken patties was also reported by Naveena et al., (2006).
       
The coliform count, an indicator of hygiene and potential contamination, revealed no detection (ND) in either product during the initial storage period (up to day 12). By day 16, however, coliform bacteria began to appear in both treatments. In, control nuggets showed a count of 1.80 log cfu/g on day 16, which increased to 2.75 log cfu/g by day 22, indicating a gradual rise in contamination or microbial activity during prolonged storage. In comparison, the finger millet enriched chicken nuggets exhibited slightly lower coliform counts, with 1.60 log cfu/g on day 16, rising to 2.64 log cfu/g on day 22. The lower coliform counts in finger millet enriched chicken nuggets suggest that finger millet may help to mitigate contamination risks, likely due to its antimicrobial components. The storage period means for coliform count confirmed the trend of delayed and reduced contamination in finger millet enriched chicken nuggets, highlighting its potential role in maintaining better hygiene standards during storage. Similarly, Kumar and Tanwar (2011) who detected coliform count on 10^th day onwards in control chicken nuggets (without clove powder) whereas on 15 days onwards in clove powder treated chicken nuggets. Whereas Thomas et al., (2010) noted occasional and interrupted occurrence of coliform in hurdle treated pork sausages in all the treatments and a definite pattern was not observed.
       
The incorporation of finger millet into chicken nuggets represents a sustainable and innovative approach to meat product development. The broader implications of these findings highlight the potential of finger millet as a functional ingredient in meat product development. Its ability to enhance sensory quality, improve functional properties makes it a valuable addition to processed meat formulations. Additionally, its high nutritional content, including dietary fiber, calcium and iron, addresses consumer demand for healthier, nutrient-rich foods.

This study highlights the potential of finger millet (ragi) flour as a functional ingredient for developing healthier and value-added chicken nuggets. Incorporation of 6% finger millet improved oxidative stability, sensory quality, moisture retention and microbial quality during refrigerated storage. The findings support the utilization of nutrient-rich millets in meat products, thereby enhancing shelf life, consumer acceptability and nutritional value.

The authors are grateful to College of Veterinary Science, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya (U.P.) for providing facilities to complete this research.
 
Declarations
 
Funding
 
The research work was supported by College of Veterinary Science, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya (U.P.).
 
Authors’ contributions
 
All the authors contributed to the conceptualization, methodology, formal analysis and writing of original draft. All authors have read and agreed to the published version of the manuscript.

Authors declare there is no conflict of interest.