Effects of Mulberry Fruit Extract on the Microbiological Quality of Chia Seed Flour-enriched Chicken Nuggets during Refrigerated Storage

Abstract

Growing consumer preference for safe, minimally processed and naturally preserved food products has encouraged researchers and the meat industry to explore alternative preservation strategies. The incorporation of natural antioxidants and antimicrobial agents into meat products has emerged as a promising approach to control microbial growth, retard oxidative deterioration and improve product shelf life while meeting consumer demand for clean-label foods. This study was conducted to evaluate the antimicrobial potential of mulberry fruit extract (MFE) in chia seed-enriched chicken meat nuggets. The microbiological quality of the developed functional chicken meat nuggets was assessed through total plate count (TPC), yeast and mould (Y&M) count, and coliform count during refrigerated storage (4 ± 1°C) for 16 days. Four experimental treatments were formulated: a control (T1), nuggets incorporated with 10% chia seed flour (T2), nuggets containing 10% chia seed flour supplemented with 0.5% mulberry fruit extract (MFE) (T3), and nuggets containing 10% chia seed flour supplemented with 80 ppm butylated hydroxytoluene (BHT) (T4). On day 0, microbial loads were comparable among treatments, ranging from approximately 2.27 to 2.58 log CFU/g. However, by day 16, T1 and T2 exhibited higher TPC values (3.99 and 3.97 log CFU/g, respectively), whereas T3 and T4 showed significantly (P ≤ 0.05) lower counts (3.73 and 3.90 log CFU/g, respectively), indicating improved microbial stability. Yeast and mould were not detected in any treatment up to day 8 of storage. However, by day 16, T1 recorded the highest Y&M count (2.18 log CFU/g), while T3 maintained a significantly (P ≤ 0.05) lower count (1.60 log CFU/g), suggesting the antimicrobial efficacy of MFE. Coliforms were absent in all samples throughout the storage period, likely due to high-temperature processing during cooking and adherence to good hygienic practices. Overall, the incorporation of MFE, particularly in combination with chia seed flour, significantly enhanced the microbial stability of chicken meat nuggets during refrigerated storage. These findings highlight the potential of natural ingredients such as MFE as effective alternatives to synthetic preservatives and support the development of clean-label meat products.