Fresh-cut fruit and vegetable coatings by transglutaminase-crosslinked whey protein/pectin edible films

Fresh cut apples, potatoes and carrots were coated by a blended whey protein/pectin film, prepared in the presence of transglutaminase, and several properties of the coated and uncoated fruit and vegetable samples were analyzed during their storage. The linear increase in apple weight loss observed during storage was significantly reduced after 10 days when the samples were coated by whey or soy protein isolate films (about 20 and 40%, respectively) but mostly (about 80%) by whey protein film grafted with pectin and transglutaminase. In addition, the latter film was able to totally prevent the weight loss of potato and carrot samples at least until the 6th day of sample storage. Coating by the crosslinked blended film prevented microbial growth in all samples analyzed, also preserving their phenolic content and carotenoid in carrots. Finally, a marked reduction of both hardness and chewiness, detected after ten days of storage in all the uncoated samples by a texture profile analysis, was shown to be effectively counteracted by coating, whereas no significant differences in the acceptability scores of the coated samples after storage, were recorded by a sensory panel with respect to all samples tested before storage.