Effect of edible quinoa protein-chitosan based films on refrigerated strawberry ( Fragaria    × ananassa  ) quality

Background: Strawberries are non-climacteric fruits with a low respiration rate, but are subject to serious fungal deterioration during postharvest handling. The edible coatings based on chitosan (CH), quinoa protein-chitosan (Q/CH) and quinoa protein-chitosan-sunflower oil (Q/CH/SO) may provide a solution to this problem. Thus, in this work CH, Q/CH and Q/CH/SO were elaborated and applied to fresh strawberries, and its effect on the strawberries shelf life during storage for 15 d was evaluated by mold and yeast count, fungal decay, carbon dioxide rate, physicochemical properties, and sensory evaluation.
Results: On all analysis days, the strawberries coated with the film-forming CH, Q/CH and Q/CH/SO solutions presented a significant lower amount of mold and yeast growth than the uncoated strawberries. Coated strawberries with Q/CH/SO decreased the CO₂ emission rate by 60% compared to the uncoated strawberries. The color of the strawberries was not influenced by the films. There was no significant difference between the different coating groups and the uncoated group in the physicochemical parameters. Sensory analysis showed that the coating application retained the total sensorial quality.
Conclusions: Fresh strawberries coated with CH, Q/CH/SO and Q/CH edible films had longer shelf lives than uncoated fruits.