Shrimp is known as a rich source of nutrients but it has a limited shelf life because of its severe perishability. In this study the effect of shrimp coating with edible nanoemulsion containing different concentrations of eugenol and Aloe vera on physicochemical properties of shrimp during cold storage and deep fat frying was evaluated. Hereupon, the mixtures containing 0%, 1% and 2% Aloe vera, 0%, 1.5% and 3% eugenol and Tween 80 as an emulsifier were prepared and treated with ultrasound at frequency of 20 kHz and power of 300 W during 30 min to produce nanoemulsion. Then experiments were continued in three parts. First, the properties of nanoemulsions such as pH, particle size, viscosity, color, turbidity and antioxidant activity were evaluated. Then, shrimps were coated with nanoemulsions and some physicochemical properties including pH, drip loss, cooking loss, color, texture and Thiobarbitoric acid index of shrimp in 1, 3, 5 and 7 days after storage at 4?C were investigated. At last coated shrimps were fried at 160?C for 6 min and cooking loss, fat absorption, texture, color, peroxide and Thiobarbitoric acid index were studied at first, second and third months of storage at -18?C. The results of this study showed that production of nanoemulsions from eugenol and Aloe vera caused significance increase in antioxidant activity of both compounds (p 0.05). Also by increasing Aloe vera concentration, pH and lightness of nanoemulsion decreased significantly while redness, yellowness, turbidity and antioxidant activity considerably increased (p 0.05). On the other hand, by increasing eugenol concentration in nanoemulsion, viscosity, antioxidant activity, turbidity and yellowness increased remarkably (p 0.05) and particle size, lightness and redness decreased (p 0.05). After coating of shrimp with the nanoemulsions, it specified that drip loss of coated shrimps decreased severely during storage at 4?C. Also changing in pH, oxidation, color and texture were much slower in coated shrimps than that of uncoated (p 0.05). Overall, the best results were related to the coated samples with nanoemulsion containing 3% eugenol and 2% Aloe vera . Besides, the application of coating for fried shrimps caused significance reduction in lightness and fat absorption during frying. Also, the rate of peroxide and TBA value increase slowed down during frozen storage (p 0.05). These coating increased a* and b* as well as all texture parameters (p 0.05).Altogether, according to the results, the best nanoemulsion coating was containing 3% eugenol and 2% Aloe vera which improved shrimp properties during cold storage, frying and frozen storage.
