Effects of whey protein isolate based coating enriched with Zingiber officinale and Matricaria recutita essential oils on the quality of refrigerated rainbow trout

The present study aimed to investigate the effect of whey protein isolate (WPI) coating enriched with essential oils (ginger and chamomile) on rainbow trout fillets during storage at 4°C. Samples were analyzed at 0, 3, 6, 9, 12, and 15 days for microbiological (total aerobic mesophilic bacteria, psychrotrophic bacteria, lactic acid bacteria, Pseudomonas), chemical analyses (pH, thiobarbituric acid reactive substances-TBARS, total volatile base nitrogen-TVB-N, peroxide value [PV]) and sensory quality (odor, taste, tissue, appearance). Bacterial growth was inhibited in samples with high concentrations of essential oils due to its antimicrobial activity. During the storage period, TVB-N, TBARS, and PVs content gradually increased in all groups, and significant differences were found between the groups (p <.05). In conclusion, the addition of of ginger and chamomile essential oils to WPI coatings showed a positive effect on the rainbow trout shelf-life. Practical applications: Whey protein is a by-product of the cheese-making industry and is already known as an excellent barrier to oxygen, aroma, and oil and can be used as a coating material for improving the oxygen barrier property of food packaging. The use of an essential oil in fresh fish preservation may be considered an alternative “natural” additive, extending the shelf life of the product. Our study has clearly shown that addition of ginger and camolime essential oil and whey protein isolate coating in fish resulted in longer shelf life, and this method could be commercially used. © 2016 Wiley Periodicals, Inc.