Active coating film based on gelatin/trans-cinnamic acid for cold preservation of peach fruits (Prunus persica L. Bastch)

Abstract

The environmental risks associated with petroleum-based and nonbiodegradable packaging materials have prompted a current emphasis on emergence of biopolymer packaging materials. The study examined the effects of different concentrations of trans-cinnamic acid (0.065 mg, 0.125 mg, and 0.25 mg) which are equivalent to 0.0065%, 0.0125%, and 0.025% based on weight of gelatin on the sensory assets and quality of Mit Ghamr peach fruits coated with trans-cinnamic acid/gelatin coating films (Cinn@Gel) that were kept for 20 day at 3.5±1 °C during two seasons. The minimal inhibitory concentration of trans-cinnamic acid incorporated into gelatin film (Cinn(0.125)@Gel) was 0.125 mg. FTIR and XRD were used to characterize the produced films. The lowest water vapor permeability (WVP) (0.29 ± 0.01 g.mm.m−2.kPa−1.day−1) and highest oxygen permeability (OP) (0.367 ± 88 × 10−3 cc.m/m2.day.atm) are related to Cinn(0.25)@Gel film. Cinn(0.25)@Gel had the highest antioxidant activity (12.01 ± 1.6%) compared with gelatin control film (5.15 ± 6%). Equilibrium moisture content data were consistent with GAB sorption isotherm model. Sensory characteristics showed no perceptible sign of decay to fruits coated with Cinn(0.125)@Gel until day 15 of the cold storage period compared to uncoated and gelatin coated fruits. It verified the least significant value of decay percentage up to 20 days of cold storage. Similarly, Cinn(0.125)@Gel coated fruits exhibited a remarkable delay in softening, decrease of weight loss (%), a decrease of total acidity (%), and an increase of total soluble solids (%) compared to the other treatments. The results revealed that Cinn(0.125)@Gel coating could keep quality, prolong shelf life and insert superior sensory characteristics (appearance, odour, texture, taste and overall acceptability) compared to other treatments up to 20 days under cold storage of peach fruits.