Effect of Edible Starch Coating Enrichmed with Pennyroyal (Mentha pulegium)Essential Oil on Shelf life of Rainbow Trout Fillet

Nowadays, the tendency to use food packaging with antimicrobial activity of natural origin has increased. The use of edible and biodegradable films has been considered as an appropriate alternative to non-degradable plastic coatings.

In this study, the effect of coating with wheat starch and Pennyroyal (Mentha pulegium essential oil was investigated on microbial and physicochemical characteristics of rainbow trout fillet in cold conditions.

For this purpose, different treatments under the influence of starch, starch and Pennyroyal essential oil (1%), starch and Pennyroyal essential oil (2%) were prepared and physicochemical and microbial changes were evaluated at specified intervals (0, 4, 8, 12 and 16 days).

In the microbial test, the count of total bacterial and other bacteria by starch and starch + 1% and 2%, the essential oil was decreased in different days, also the difference between the control group and other treatments was significant (p < /em>≥0.05). The highest effect of pH reduction belonged to starch + 1% and 2% essential oil in different studied days. The level of pH was not different among different treatments on day 0 of storage. However, there was a significant difference between the control group and treatments on the fourth, eighth, twelfth, and sixteenth days of storage (p < /em>≥0.05). The results of the oxidative test showed that on the 16th day of storage, the lowest level of TBA was related to the treatment with starch + 2% essential oil and the highest value was related to the control group. In fact, the application of the coating layer delayed the oxidation process.

This study demonstrated antioxidant and antibacterial properties of the composition of edible starch and pennyroyal essential oil on the increased shelf-life of Rainbow trout fillet.