Research Of SO₂ Injury Threshold On Red Globe Table Grapes

Taken red globe table grapes as the material, we studied on the threshold of SO2 fumigation in different environments and the best concentration and way to keep the grape fresh. While, we also identified the pathogenic bacteria easy to make the grape bad. Combined with SO2 intermittent fumigation, we found the best temperature for grapes’ storage. All that made us know more about both low SO2 damage and residual, which provide theoretical basis for the preservation of red globe table grapes.(1) It was verified further that mature grapes shoud be used to store and preserve other than immature or secondary ones by studying on the freezing point, soluble solid content (SSC) and firmness of different kinds of grapes.(2) The SO2 damage threshold were different under different environment s,such as temperature, concentration and time. Excessive SO2 increased relative conductivity and malondialdehyde content, destroyed the integrity of the cell membrane, decreased chlorophyll in stem and anthocyanin in skin strengthened the activity of polyphenol oxidase, stem turned brown and white spot appeared on the skin surface.(3) By studied the dynamic of SO2 absorption of Red grape, it was deduced that SO2 mainly through stem brush into the fruit and fruit, fruit stalk and fruit brush were especially vulnerable to the SO2 bleaching damage. In addition, effects were diversity of different packings and it was better in weightlessness rate, skin bleaching index and sound rate when the packing was 10 kg.(4) It was determined that the best concentration of SO2 fumigation and fumigation methods for Red grape was that the first time fumigation 500 μl/L×1.0 h, every 15 days, 300 μl/L × 0.5 h fumigation processing by detecting the content of soluble solid content (SSC), titratable acid, vitamin C and SO2 residue.(5) The pathogens were identified after postharvest and Rhizopus nigricans, Aspergillus niger, Botrytis Cinerea and Penicillum sp p were respectively determined. Also, effect was better for lower rates of pathogens carrier in flesh, brush, pedicel and disease incidence.