Quality and Physiology of Postharvest Dioscorea persimilis Tubers Affected by Storage Conditions

Objective  Effects of storage conditions on the quality and physiology of postharvest Dioscorea persimilis tubers were studied.

Methods  Tubers of a local D. persimilis variety from Ninghua, Fujian were wrapped with soil to retain moisture and stored at 10 ℃, 5 ℃ or ambient temperature for 150d. Bud-sprouting, dehydration rate, and contents of protein, starch, amino acids, soluble sugars, sucrose, total phenols, polysaccharides, and allantoin of the tubers were measured. In addition, malondialdehyde (MDA), OH-inhibition capacity (OHIC), activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and polyphenol oxidase (PPO) as well as amylase, neutral invertase (NI), acid invertase (AI), and sucrose phosphate synthase (SPS) were monitored. Using these measurements as indicators, effects of the various storage conditions on tuber quality were evaluated.

Results  Storage at 10 ℃ performed most effectively in suppressing sprouting and maintaining stable quality and balanced antioxidants of the tubers. Although 5 ℃ also inhibited sprouting, the temperature caused chill injury with sweetening, aggravated membrane lipid peroxidation, and browning on the tubers. And ambient temperature encouraged the tubers to sprout and accelerate metabolism, leading to decline in nutritional quality with decreased starch and protein contents.

Conclusion  The soil-coated tubers at 10 ℃ for medium-to-long-term storage appeared to be most effective in prolonging shelf life of the harvest.