Enhancing the functionality of chitosan- and alginate-based active edible coatings/films for the preservation of fruits and vegetables: A review

A number of studies have established the potential of chitosan and alginate-based edible film/coatings for preserving the quality attributes of fruits and vegetables. Findings demonstrate that these films/coatings act as a barrier on the surface of fruits and vegetables which causes higher moisture and water retention, create favourable micro-environments by optimizing the concentration of gases and delays ripening. Sincere efforts are being further made to improve the efficiency of edible films using functional additives such as phenolics, essential oils (EOs) and nano-forms. These additives have unlocked a new dimension for enhancing functional properties of alginate/chitosan-based films. These functional compounds are now emerging as an important component of edible films/coatings for prolonging shelf-life of fruits and vegetables. The present review comprehensively elaborates recent studies on functional additives and their mechanism of action. Here we also establish their proficiency in extending quality and shelf-life of various fruits including guava, pear, blueberries and vegetables like cucumber, capsicum and mushroom. Principles behind antimicrobial and antioxidant activities of additives in preventing the food spoilage are also reviewed. Competency of phenolics, EOs and nano-forms in extending the shelf-life without affecting the nutritional properties and safety aspects of the fruits and vegetables still require further attention. (C) 2020 Published by Elsevier B.V.