USE OF CHITOSAN AND CHITOSAN-CASEINATE COATING TO PROLONG SHELF LIFE OF MINIMALLY PROCESSED APPLES

The effect of biopolymer coatings (1% chitosan, 2% chitosan, caseinate/chitosan blend at ratio 2/1) in combination with anti-browning agent (1% citric acid, 1% l-ascorbic acid agents, 1% Ca[Cl.sub.2]) on the shelf life of minimally processed apples was studied. The experimental works were divided in two phases: in the first phase, the coating composition has been selected on the bases of microstructural analysis of the coatings on the fruit surface (SEM), respiration rate, water resistance, and color. In the second phase of the study, the shelf life of packed minimally processed apples coated with the selected coating was studied during storage at 5[degrees]C. The uncoated sample dipped in anti-browning solution was used as control. The following quality attributes were monitored after 1, 3, 7, 11 and 14 days: pH, hardness, relative humidity (RH %) and color. All coatings effectively reduced respiration rate of minimally processed apples but only caseinate/chitosan one was not significantly different from the control sample in terms of color attributes (p