Poultry meat preservation with citric acid obtained from the fermentation of wheat straw by Aspergillus niger

Abstract

Wheat straw is a highly abundant waste material that can be utilized as a carbon source in various fermentation processes. This study aimed to generate citric acid using Aspergillus niger from wheat straw and to evaluate its preservative potential in fresh poultry meat samples. Wheat straw samples were dried, pulverized, and chemically pretreated. The obtained wheat straw slurry (100 g L-1) was saccharified at 50 °C using cellulases obtained from Trichoderma viride. The hydrolyzed substrate was then subjected to fermentation by Aspergillus niger at 35 °C, 180 rpm, and pH=5 for 7 days. The citric acid generated was determined via the HPLC technique. Poultry meat was obtained and treated by soaking in different concentrations (1, 2, and 3%) of citric acid (n=4). The treated samples were then stored in sterile plastic bags for 14 days at 4 °C. Total Bacterial Count (TBC), Total Coliform Count (TCC), TVB-N, and TBARS were determined as storage progressed, and pH, TTA, and sensory evaluation were carried out. The highest citric acid obtained was 14.15 g L-1 which resulted in a percent yield of 26.18%. Treatment of meat with 3% citric acid had the lowest TBC and TCC of 2.55 and 0.34 Log10 CFU g-1 after 7 days of storage respectively. There were significant differences in the TBC and TCC observed within the treatments (P<0.05) as observed. T-VBN and TBARS reduction during storage was most evident in meat samples treated with 3% citric acid, retaining acceptability of 31.22 mg 100 g-1 and 0.74 mg kg-1, respectively at day 10. The 2% citric acid treatment had the best sensory attributes (16) on day 7. Findings from this study show that treatment with 2% citric acid and above showed promising results in extending the shelf-life of fresh poultry meat samples.