Maintenance of pomegranate arils quality by zinc enrichment, a comparison between zinc sulfate and nano zinc oxide

Abstract

Pomegranate arils are very perishable which restricts the distribution and supply chains of arils. Zinc treatment not only may fortify arils, but also has the capability of preventing the growth of pathogens. This study was performed to compare two different forms of zinc including nano zinc oxide (nZnO) and zinc sulfate (ZnSO4), each one in four concentrations of 0 %, 0.4 %, 0.6 % and 0.8 %. Zinc enrichment was evaluated by atomic absorption. Zinc enriched arils were stored in polypropylene-packed containers weighing approximately 50 g at 5 °C and 90–95 % relative humidity. Sampling was done at 5 d intervals during 30 d of storage. Zinc content in arils treated with 0.8 % ZnSO4 was 37.5 times more than the control, which can be a very effective way to meet body nutritional needs. Zinc treatment had an effect on all measured indices. The highest amount of total soluble solids (TSS), titratable acidity (TA), total phenolic content (TPC), antioxidant activity and anthocyanin content, and the lowest weight loss (WL) were found in the arils treated with 0.8 % ZnSO4. Overall, 0.8 % ZnSO4 followed by 0.8 % nZnO treatments were the most beneficial treatments to increase the shelf life and to maintain arils qualitative characteristics.