The purpose of this study was to investigate the quality and antioxidant properties of three fermented sweet potato cultivars (Shinyulmi, Hogammi, and Shinjami) using lactic acid bacteria. During the fermentation, the pH was lowered and the titratable acidity increased. The viable cell counts of lactic acid bacteria increased 8.44-9.62 log CFU/g. Organic acid content (especially lactic acid) of sweet potatoes increased by fermentation. Also, γ-Aminobutyric acid increased more than 8.6 times by fermentation in all samples. The total polyphenol and flavonoid contents of sweet potato, showed insignificant changes in all samples by fermentation. ABTS radical scavenging activity of all samples slightly decreased by fermentation, but not significantly. DPPH radical scavenging activity decreased slightly by fermentation except Shinyulmi. However, when compared with the varieties, Shinjami showed the highest activity. The reducing power of Shinjami decreased slightly by fermentation, but activity was the highest among all samples. Based on these results, most of the chemical properties and functionality of fermented sweet potato are retained after fermentation, although some antioxidant activity decreases. We suggest that three fermented sweet potato cultivars (Shinyulmi, Hogammi, and Shinjami) using lactic acid bacteria can be used in various applications because of their effective functional properties.

This study compared the quality and drying characteristics of dried king oyster mushroom (Pleurotus eryngii), shiitake mushroom (Lentinus edodes GNA01) and maitake mushroom (Grifola frondosa) slices obtained by sundrying, hot-air drying (40, 50, 60 ), low-temperature vacuum drying (20, 25, 30 ), heat-pump dehumidifying drying (30, 40, 50 ), and freeze drying. The quality changes investigted included color, browning degree, hardness, general components, -glucan. Color changes in king oyster mushroom during freeze drying were β less than that between control (raw) and treated mushrooms. Compared with other drying methods, low-temperature vacuum drying of shiitake mushroom resulted in less color changes. Browning degree differed significantly between the different drying methods. As temperature increased, low-temperature vacuum drying resulted in decreased browning while heat-pump dehumidifying drying resulted in increased browning. In king oyster mushroom, hardness increased with temperature under hot-air drying, low-temperature vacuum drying and heat-pump dehumidifying drying. In shiitake mushroom, hardness increased with increasing temperature under hot-air drying and heat-pump dehumidifying drying. β-glucan content after drying was found to be between 28.29 and 39.39% in king oyster mushroom, 23.05 and 29.48% in shiitake mushroom and 16.10 and 24.51% in maitake mushroom.