• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.79-86
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• 2012

This study was performed to investigate the physiochemical properties and anti-diabetic effect of yacon vinegar by two-step fermentation. Yacon was matured at room temperature for 20 days. The sugar content of yacon juice prepared from mature yacon was approximately $14^{\circ}Brix$. In the first stage, yacon wine was produced from the juice at $28^{\circ}C$ for 6 days. In the second stage, acetic acid fermentation was conducted at $30^{\circ}C$ and 200 rpm for 6 days to produce yacon vinegar with 4.75% acidity. The major free sugars of yacon vinegar were glucose and fructose at 2,072.12 mg% and 463.95 mg%, respectively. The acetic acid content was the highest of the major organic acids at 3,881.44 mg%. The total free amino acid content was 62.88 mg% with the main free amino acids being proline, ${\gamma}$-amino-n-butyric acid and ornithine. The major minerals of yacon vinegar were Ca, K and Mg. The in vivo anti-diabetic activity of yacon vinegar was investigated in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice. Diabetic mice were administered orally with 10% yacon juice and two yacon vinegars (5% and 10%) at a dose of 7 mL/kg body weight once per day for 4 weeks. Five% yacon vinegar improved the fasting blood glucose levels and glucose tolerance test significantly compared to the diabetic control group (p<0.05). Yacon vinegar increased the pancreatic C-peptide concentration in a dose-dependent manner. These results show that 5% yacon vinegar has a more potent effect on ameliorating hyperglycemia than 10% yacon juice.