APPLICATION OF EDIBLE STARCH-BASED COATING INCLUDING GLYCEROL PLUS OLEUM NIGELLA ON ARILS FROM LONG-STORED WHOLE POMEGRANATE FRUITS

Abstract

ABSTRACT Two concentrations of cold-pressed seed oil at a 300 and 600 ppm of Nigella sativa incorporated into starch-based edible coating were applied onto pomegranate arils. Arils were individually treated with a solution of only starch coating (starch + glycerol, 2:1, v/v), 300 ppm oil + starch coating (starch + glycerol, 2:1, v/v and N. sativa oil, 300 ppm) and 600 ppm oil + starch coating (starch + glycerol, 2:1, v/v, N. sativa oil, 600 ppm). The untreated arils were used as the control group. All treatment groups were then stored at 4C for 12 days. The following parameters were examined on arils: softening, weight loss, total soluble solids (TSS) content, pH, titratable acidity (TA), L* value, chroma value, vitamin C content, anthocyanin content, browning index, microbial growth and organoleptic quality. Treatments with 300 and 600 ppm oil + starch coating greatly reduced softening of pomegranate arils, weight loss and % of browning index, loss of vitamin C, loss of anthocyanin content and delayed microbial decay. Results indicated that 300 ppm oil + starch coating significantly reduced weight loss, browning decay rates, the highest overall arils quality scores at the end of storage. Edible starch-based coating including N. sativa oil appeared to be a good mixture for maintaining the quality of fruits during storage. PRACTICAL APPLICATION Several techniques have been used for preserving fruits by reducing their quality changes and quantity losses during storage, through a better understanding of the respiration process in fresh fruits. Edible coatings on fresh fruit can provide an alternative for modified atmosphere storage by reducing quality changes and quantity losses through modification and control of the internal atmosphere of the individual fruits. The present study demonstrated that Nigella sativa incorporated into starch-based edible coating was applied onto pomegranate arils, which could preserve the quality. N. sativa oil can also be used as a preservative in the fresh-cut processing industry.