Potential Utilization of Green Tea Leaves and Fenugreek Seeds Extracts as Natural Preservatives for Pacific White Shrimp during Refrigerated Storage

Ethanolic extracts of green tea leaves (GTE) and fenugreek seeds (FSE) were screened for their antibacterial activity against four food pathogenic strains using disc diffusion method. The two extracts revealed antimicrobial activity against selected bacterial strains. GTE showed the highest antibacterial activity to Escherichia coli and Staphylococcus aureus at a concentration of 1% with inhibition zone equal to 29.45 ± 0.64 mm and 25.68 ± 1.2 mm, respectively. In addition, the effect of GTE and FSE combined with chitosan coating on the shelf life of Pacific white shrimp (PWS) (Litopenaeus vannamei) during refrigerated storage have been studied. Our results indicated that using GTE or FSE during the refrigerated storage of PWS led to significantly decreased Total Volatile Bases Nitrogen, Thiobarbituric acid reacting substances, total bacterial count, and pH. The sensory properties of PWS have improved considerably in the samples treated GTE or FSE. These findings suggested that the application of chitosan coating combined with GTE or FSE to PWS is advisable to achieve better quality during refrigerated storage.