Effect of pH modulation on the physicochemical characteristics of chicken bone extract

Abstract

This study investigated the effect of brown rice-vinegar-induced changes in pH on the physicochemical properties (ash, moisture, protein, fat, collagen, chondroitin sulfate, sugar, and mineral content, color, salinity, and pH) of chicken bone extract. The following treatments were employed: control (purified water, 62%; chicken bones, 30.47%; chicken feet, 6.88%; garlic, 0.58%; pH 7), T1 (purified water, 62%; chicken bones, 30.47%; chicken feet, 6.88%; garlic, 0.58%; organic brown rice vinegar, 0.01%; pH 6), T2 (purified water, 62%; chicken bones, 30.47%; chicken feet, 6.88%; garlic, 0.58%; organic brown rice vinegar, 0.02%; pH 5), and T3 (purified water, 62%; chicken bones, 30.47%; chicken feet, 6.88%; garlic, 0.58%; organic brown rice vinegar, 0.23%; pH 4). Protein, ash, and chondroitin sulfate contents and the brightness tended to increase, while the yellowness and redness, sugar content, salinity, and pH tended to decrease when the percentage of brown rice vinegar was increased. The collagen content was significantly higher in the control and T3 groups. Further, the Ca content tended to increase, while K, Mg, N, and P contents tended to decrease with increasing percentage of brown rice vinegar. The Ca/P ratio improved as the percentage of brown rice vinegar increased. At a concentration of 0.02%, brown rice vinegar effectively improved the overall quality of chicken bone extract in terms of the investigated physicochemical properties (minerals being the exception). Therefore, use of 0.02% brown rice vinegar during the preparation of chicken bone extract would result in the most ideal physicochemical properties.