Effect of chitosan coatings with and without Stevia rebaudiana and modified atmosphere packaging on quality of cold stored fresh-cut apples

Abstract

In this study, it was aimed to investigate the changes in polyphenoloxidase (PPO) activity, antioxidant properties and microbiological quality of fresh-cut apple slices coated with chitosan and stevia combinations under MAP (polypropylene-PP, 30 μm) storage at +1 °C for 3 days. The apples were cube-shaped and divided into three samples: i-Control (C, without coating), ii-Chitosan (CH, dipped into film mixture consisting of 0.75% chitosan, 1.5% glycerol and 2% ascorbic acid) and iii-Chitosan-Stevia combination (CHS, same CH film contains 2.5% stevia extract). PPO activity and microbiological (total yeast& mold-TYM and total psychrophilic aerobic bacteria-TPAB, total mesophilic aerobic bacteria-TMAB), total phenolic, antioxidant capacity, O2-CO2% and pH analyzes were performed. Results showed that PPO activity, O2-CO2% and pH values were lower, antioxidant substances were higher than C sample. At the end of the storage, CHS samples showed high PPO activity and antioxidant capacity values compared to CH. TMAB was found in C sample but it was under detectable limit (<2) during storage in CH and CHS samples; TPAB was found under detectable limit (<2) in all samples. Additionally, the chitosan and stevia have reduced the TYM counts. As conclusion; CH and CHS edible films are effective applications for reducing PPO activity and microbial load.