Shelf-life extension and quality retention in fresh-cut carrots coated with pectin

Fresh-cut carrot slices were treated with 2% calcium chloride, 2% calcium propionate, 0.01% chlorine, 0.5% hydrogen peroxide, chitosan (0.5 and 1%), 5% sesame oil emulsion, 0.5% ascorbic acid and a mixture of 0.5% ascorbic acid and 0.03% EDTA, low methoxyl pectin (0.75 and 1.5%), methyl cellulose, and polyvinyl alcohol (2 and 4%). Samples coated with polyvinyl alcohol or pectin could be stored at 8 degrees C for 12 days, compared to other treatments, where the samples could be stored only for 5-7 days. However, pectin, because of its GRAS status and efficacy was selected for coating the fresh-cut carrots for shelf-life and biochemical characterization studies. An increase of about eight to twelve times in the concentration of phenolic acids was seen in control samples stored for eight and 12 days. About three- to seven-fold increase in the total flavonoid concentration was seen in control samples, compared to pectin-treated samples during their storage for eight and twelve days. Among the flavonoids, accumulation of apigenin, hesperetin, myricetin and narenginin was higher, compared to other flavonoids in control samples. Fresh and pectin-coated samples were closely placed in the biplot for phenolic acids and flavonoids, indicating comparable concentrations of phenolic acids and flavonoids in fresh as well as pectin-coated carrots. An increase of about three and seven times in the concentration of phenolic acids and flavonoids, respectively was observed in control samples, compared to pectin-treated samples on the twelfth day of storage. This could be directly co-related with white blush formation and bitterness in control samples, resulting in low acceptability for such samples. Industrial relevance: Low shelf-life of fresh-cut carrots during storage is largely attributed to white blush and deterioration in sensory attributes. This study revealed that coating of fresh-cut carrot slices with low methoxyl pectin helped in extending their shelf-life up to 12 days during refrigerated storage. Compared to control, carrot slices coated with 0.75% pectin showed nearly three-fold lower accumulation of phenolic acids, responsible for white blush formation and seven-fold lower flavonoid content, responsible for astringency and bitterness in fresh-cut carrot slices during storage for12 days. Therefore, pectin coating of fresh-cut carrots for enhancing their shelf-life holds promise for commercial applications.