Food Preservation: Use of Silk Fibroin as an Edible Coating on Bananas

Silk fibroin, the main structural protein of silk, is a biomaterial that has been extensively studied in textile, biomedical, and electronic applications.Due to its hydrophobic nature and its ability to assemble into antiparallel, beta-pleated sheets, the strength, flexibility, and conformability of fibroin have also led to its use as a coating to prolong produce.This study investigates whether the application of a 1% weight/volume aqueous silk fibroin suspension to bananas would prolong their shelf life; additionally, it attempts to determine whether increasing the beta-sheet content of the protein via water annealing (exposure of fibroin to water vapor in a vacuum at constant temperature) would be more effective than coating alone.Measured parameters of fruit spoilage assessed daily in the study were: visible signs of ripening, weight loss, maintenance of turgor, and mold/yeast growth.After the 8-day ripening period, bananas coated in fibroin and stored ambiently at room temperature exhibited less visible signs of spoilage, lost less weight, maintained more firmness/turgor, and grew fewer molds and yeast than did the control cohort.The effect of all measured parameters was slightly more pronounced in the group of bananas that were coated and annealed.Considering that one-third of the food produced in this country is never eaten, this research holds the promise of safely and effectively enhancing food preservation methods, with the hope of far-reaching societal impacts.