CHITOSAN AND CLAYMINERALS COATING’S EFFECT ON MELON MINIMALLY PROCESSED’S QUALITY

Minimally processed fruits are a growing follow-up in the plant food industry. Perishability, susceptibility to contamination by microorganisms, and physico-chemical changes that affect quality are a concern on these products. Strategies to prolong the post-harvest life of fruits include the application of edible, biodegradable and sustainable coatings. The aim of this study was to evaluate the effect of the coating of chitosan (1.5%) and bentonite (0.2%) on the physico-chemical changes and the growth of psychrotrophic bacteria in minimally processed melon (MMP). Two groups of samples, MMP with coating (MMP-R) and MMP without coating (MMP-C) were analyzed on different storage days at 6°C. Both groups presented significant score (p<0.05) of psychrotrophic as of the third day, however, MMP-C had increasing proliferation until day 7 and MMP-R remained stable until the seventh day. As for the physical-chemical parameters, a significant decrease in acidity was observed in the MMP-C group, with a subsequent increase on day 7. In the MMP-R group, the acidity showed no significant change until day 5, but on the last day of storage a significant increase of this parameter was evidenced. In the fruits of the MMP-C group, the reduction of TSS was progressive and significant (p <0.05) throughout the storage period, while in the treated fruits, maintenance was observed from day 3. There was also a significant reduction in pH on days 3 and 7 on MMP-C and on days 1 and 7 on MMP-R. In MMP-C an inverse correlation (r =-08515) and significant (p=0.0017) was observed between the psychrotrophs and the TSS. As microbiological growth increased, the TSS content decreased significantly. It is concluded that the clayminerals coating controlled the microbial growth and minimized the reduction of TSS in the minimally processed melon, resulting in a longer storage time for the coated fruit.