| چکیده انگلیسی مقاله |
Background and Objectives: Edible coatings prepared from whey protein concentrate and glycerol were evaluated for their ability to maintain quality and improve shelf-life of fresh-cut melon stored at 5ºC. Materials and Methods: Coatings were prepared containing different quantities (5, 7.5 and 10 gr) of whey protein concentrate and used to coat fresh-cut melon slices. Uncoated fresh-cuts melon slices were served as control. For comparative purposes, a sample of melon slices was treated with a 1% calcium chloride (CaCl2) solution usually used in producing fruit slices. Shelf-life of all the samples was assessed based on weight loss, color changes (l*, a*, b* and a/b*(, flesh firmness, titratable acidity (TA), total soluble solids (TSS), and sensory properties. Results: As compared to the control and CaCl2 samples, the whey protein concentrate coating brought about a decrease in weight loss of the fresh-cut melon slices. No statistically significant differences in TSS and TA were observed between the coated sample and controls after 4 weeks storage at 4±1ºC, but the coated and CaCl2-treated melon slices were significantly (p< 0.05) firmer than the control slices. The difference in firmness between the coated and CaCl2-treated melon slices was not significant. The data also showed that, based on the L*a*b* color measuring system, the coated fresh-cuts of melon showed higher L* and a*, and lower b* and a/b*, values compared to uncoated control slices. With regard to sensory properties of the melon samples, the panelists rated whey protein-coated fresh-cut fruit higher than the uncoated samples, although samples with different contents of the coating were not significantly different at the end of the storage period (P>0.05). The results also showed that the coated fruit samples received the highest score with regard to flavor, gloss, and overall acceptability. In addition, the whey protein-coated samples showed a significant decrease in gloss compared to control and CaCl2–treated samples. Increasing the level of whey protein in the coated samples led to increases in elasticity modulus, tensile strength, and elongation. Conclusion: Edible whey protein-based coating can be used as a new, effective method in cold storage of fresh-cut fruits. Keywords: Fresh-cut melon, Coating, Whey protein concentrate, Shelf-life |