Abstract
This study was conducted to find the suitable storage conditions for immature black soybeans (Glycine max Merr. 'Tamba kuro') served as a vegetable snack. Immature black soybeans with pods and stems were packaged in a polyethylene bag with and without perforation (Perforated Polyethylene Bag, PPB and Non-perforated Polyethylene Bag, NPB), and in a laminated film (“Canz” film) bag with and without 100% Nitrogen (Laminated film + N2 Bag, LNB and Laminated film Bag, LB), which has a high gas-barrier property. The black soybeans packaged in these plastic bags were stored at 1 °C for 21 days or at 20 °C for 7 days. The gas concentrations in the bags stored at 1 °C showed higher levels of carbon dioxide in LB and LNB than in NPB, and lower levels of oxygen in LNB than in LB during storage for 7 days. The black soybean quality, which was evaluated by the color of pods, stems and seeds, and the taste of seeds, was maintained well in all bags during the storage at 1 °C for 7 days. After storage at 1 °C for 14 days, the green color of pods and stems faded in PPB and NPB, and the color on the seed surface turned to deep purple in LB, where as the quality was maintained relatively well in LNB. Starch content in the seeds had a tendency to decrease slightly in all bags during storage at 1 °C. Especially. the decreasing tendency was more conspicuous in PPB and NPB than in LB and LNB. Sucrose content in the seeds stored in PPB and NPB tended to increase as days of storage at 1 °C increased. Amino acid contents were found to be higher in seeds stored for 7 days at 1 °C than 20 °C in each bag. And it was observed that alanine was accumulated markedly in seeds packaged in LB and LNB during the storage at 1 °C for 7 days.
