To evaluate peanut sprouts as a functional food material, the quality characteristics and antioxidant activities of soybean yoghurt with different percentages (0.5, 1.0, 2.0, and 3.0%) of peanut sprout powder (PSP) contents were investigated. The pH of soybean yogurt with PSP decreased in a time- and dose-dependent manner during fermentation, whereas the titratable acidity increased under the same conditions. The Hunter L value (lightness) decreased while the b value (yellowness) and a value (redness) increased as the PSP concentration in soybean yogurt increased. Prior to fermentation, the sugar content of the soybean yogurt increased as the PSP level increased, but the contents decreased as fermentation progressed. Meanwhile, the viscosity of the soybean yogurt increased during fermentation, and the lactic acid bacteria population was higher than that of the control. The sensory properties, including the flavor, color, taste, and overall acceptability, of the soybean yogurt containing 0.5 and 1% PSP, respectively, were higher than those of other tested yoghurts (with 0, 2.0, and 3.0% PSP contents). The antioxidant activity of the soybean yogurt significantly increased at the PSP concentrations of over 1.0%. These results suggest that the addition of PSP has beneficial effects on the quality and functionality of soybean yogurt, and that the addition of 1.0% PSP is the most suitable for manufacturing soybean yogurt.

This study developed a high-utility type of vinegar from Rubus coreanus by optimizing its fermentation conditions. In the alcohol fermentation process, the optimal conditions for the maximization of the alcohol contents were an initial sugar concentration of 15 °Brix, a temperature of 30℃ and 4 days. The optimal conditions for the acetic acid fermentation were 9 days of fermentation at 30℃ and 200 rpm, with 6% alcohol and 2% initial acidity. The sucrose, fructose, and glucose contents were 952.90, 491.01, and 386.62 mg%, respectively. The free organic acids were acetic, malic, succinic, malonic, oxalic, and lactic acids. The total free amino acid content was 104.33 μg/mL, with alanine, glutamic acid, γ-amino-N-butyric acid, and o-phospho-ethanolamine as the major amino acids. The K, Na, and Mg contents were 1,686.10, 172.50, and 69.33 ppm, respectively. The total phenolic and anthocyanin contents were 25.19 and 80.71 mg/100 mL, respectively. The DPPH- and ABTS.+ radical scavenging activities were approximately 65 and 94%, respectively. Moreover, the vinegar’s β-carotene bleaching activity and reducing power showed that it had strong anti-oxidant properties. These results show that Rubus coreanus vinegar has anti-oxidant properties and may be used as functional food.