Effects of Edible Coating Containing Nano-emulsion of Aloe vera and Eugenol on the Physicochemical Properties of Shrimp during Cold Storage

article as doi: 10.1002/jsfa.9581

Journal of the Science of Food and Agriculture

Shahrzad Sharifimehr, Nafiseh Soltanizadeh*, Sayed Amir Hossein Goli
Department of Food Science and Technology, College of Agriculture, Isfahan University of Technology, Isfahan, 8415683111, Iran

The beneficial advantages of edible nano-emulsion coatings over typical coatings have made them suitable for coating foods with a high lipid content. The results of the present study revealed that the combination of Aloe vera gel powder and eugenol is suitable for use as an
edible coating. In general, nano-emulsions containing 20 g/L of Aloe vera’s gel powder and 30 ml/L of eugenol exhibited the lowest pH as well as the highest antioxidant activity and viscosity, all of which make this nano-emulsion a promising choice for food coating. The most important problem with this coating, however, is its opacity and the mild red color that might change food color and detract from its consumer appeal. Seafood, especially shrimp, contains such nutrient compounds as proteins and long chain fatty acids, which are susceptible to environmental agents. A novel technology to preserve the quality of seafood, such as shrimp, is coating it with edible
compounds. The present study showed that Aloe vera and eugenol nano-emulsions might have profound and desirable effects on retarding lipid oxidation. It was also shown that these nanoemulsions are capable of improving other qualitative parameters of seafood during their cold
storage. More specifically, it was found that they can decrease drip loss, color changes, and textural disintegration and deterioration but increase stored food pH during cold storage. Based on the results obtained, a direct relationship was established between the improvements gained in shrimp quality and the concentrations of eugenol and Aloe vera used in nano-emulsions. The best results of 67% reduction in drip loss and 48% decrease in cooking loss were obtained in the presence of 20 g/L of Aloe vera and 30 ml/L of eugenol. In addition, the amount of malondialdehyde reduced from 1.17 mg/kg in uncoated shrimp to 0.59 mg/kg in coated samples when 20 g/L of Aloe vera and 30 ml/L of eugenol were used. The nano-emulsion prepared in this study may, therefore, be recommended as a desirable coating not only to gain considerable improvements in shrimp quality but also to retard oxidative reactions in shrimp during its 7 days cold storage. It should be noted that the natural compounds such as eugenol and Aloe vera can affect the sensory properties of shrimp. Hence, the effect of these compounds on sensory properties of coated shrimps alongside with their antimicrobial properties must be considered in
the next study.