Natural coatings from cephalothorax and exoskeletons of crab (Callinectes sapidus) and shrimp (Litopenaeus vannamei) and its application on a non-climacteric fruit, raspberry (Rubus idaeus) to extend its shelf life

Abstract

The use of natural polymers such as chitin and chitosan obtained from crustacean residues (shrimp and/or crab cephalothorax) present benefits when used as edible coatings to preserve and increase the useful life of some fruits. In this study, physicochemical and sensory techniques were used to evaluate the shelf life of raspberries (Rubus idaeus) coated with these polymers. Lots of raspberries were coated with a chitin-chitosan (Q-Qn) biofilm from cephalothorax and exoskeletons of crab and shrimp in a ratio (50:50), using control lots with Sigma-Aldrich chitosan at a concentration of 1.5% in mass (Qn 1.5%). Additionally, there were batches of uncoated fruits (blank). All batches were kept for a period of 21 days of storage at temperatures of 5, 25, and 35°C. Among the results are that the experimental coating under study Q-Qn obtained from cephalothorax and exoskeletons of crab and shrimp presented antifungal activity when used on raspberries, avoiding the development of fungi in all batches to which it was applied. The sensory evaluation carried out on the jams obtained from the coatings determined that consumers preferred the jam made with raspberries coated with commercial chitosan (Qn 1.5%). Additionally, the sensory evaluation did not detect an aftertaste of shrimp or crab in the jam made with raspberries coated with chitin-chitosan (Q-Qn). This makes it possible to implement the experimental coating using different concentrations in the application of biofilms to raspberries, as well as in making changes in the preparation of jams in order to obtain greater acceptance of their sensory attributes.