Application of nanoemulsions (w/o) with active compounds of cactus pear fruit in starch films to improve antioxidant activity and incorporate antibacterial property

Abstract

AbstractIn order to improve the quality of food and extend its shelf life, preservation methods have been developed. Edible films have aroused potential interest in food preservation due to their ability to maintain quality product attributes. The objective of this research was to incorporate nanoencapsulated compounds of cactus pear “xoconostle” (Opuntia oligacantha C.F. Först) into “chayotextle” (Sechium edule Sw.) starch films. For the formulation of the starch films, different concentrations of nanoemulsion (0, 0.2, 0.4, 0.6, and 0.8%) were used. Phenols, flavonoids, antioxidant activities (ABTS [2,2‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulphonate)] and DPPH [2,2‐diphenyl‐1‐picrylhydrazyl]), antibacterial properties, and mechanical properties (tensile strength, Young's modulus, and elongation percentage) of the films were analyzed. The results showed significant differences (p < .05) between the formulations. In phenols and antioxidant properties, DPPH had a significant increase (p < .5) during storage. In contrast, in flavonoids and antioxidant (ABTS) activities, a decrease was observed. Inhibition was observed with gram‐negative bacteria (Escherichia coli and Salmonella typhimurium). No significant (p > .05) changes were found in traction resistance in up to 30 days of storage. In Young's modulus and elongation percentage, significant differences were found (p < .05). The addition of nanoencapsulated compounds of cactus pear produces active films of starch with antioxidant and antibacterial properties.Practical ApplicationCurrently, it is very important for consumers that food conservation be achieved using natural products. Films based on polymers of natural origin could be used as food packaging technologies. Particularly, the starch of indigenous origin like the “chayotextle” (chayote tuber) has been demonstrated to be suitable for the elaboration of films. The addition of oils and bioactive extracts from fruits and plants to films improves the conservative properties of foods. These natural additives have bioactive compounds with antioxidant and antibacterial properties. One source of these compounds is the cactus pear Opuntia oligacantha C.F. Först (xoconostle). Bioactive compounds are unstable especially when they are exposed to environmental factors. Hence, encapsulation systems have been designed for their protection and controlled release as nanoemulsions. The films with the addition of nanoemulsions have shown an improvement in antioxidant activity and have incorporated antibacterial activity in contrast to the control film. Consequently, these films can better preserve foods for more time without using synthetic products.