Effect of immersion in low-pH solution on physicochemical properties of high-pH venison.

The color of venison observed at a high-pH is not preferred by consumers. However, the physicochemical properties of venison soaked in a low-pH solution to lower its high-pH are unknown. We investigated the effect of immersion in a low-pH solution on the physicochemical properties of a high-pH venison. The pH of M. longissimus thoracis from seven female wild deer (Cervus nippon) was measured and divided into normal-pH venison and high-pH venison groups. The a* and b* values for high-pH venison were lower than those for normal-pH venison before storage. There was no significant difference in the pH between high-pH venison immersed in a pH 4 solution and normal-pH venison stored. The drip loss of immersed high-pH venison was significantly lower than that of normal-pH venison and high-pH venison. Cooking loss and total loss were the lowest for normal-pH venison and the highest for immersed high-pH venison. The maximum load between normal-pH venison, high-pH venison, and immersed high-pH venison did not differ significantly. Our work showed that meat color became favorable by immersing high-pH venison in a solution of pH 4, followed by heating.

Evaluation of colorimetric pH strips for wild animal meat using image analysis.

Colorimetric pH strips (MColorpHast™) are very convenient to use, but the decision of pH is based on an individual's color perception and is, therefore, subjective. We developed a pH calculation program for the image of coloring strips on CIE1976 (L*a*b* color space), which slightly underestimated human judgment as the color of pH darker. This image analysis and three individuals' judgments were used for evaluating the strip's features for various qualities of meat from wild animals, and the results were compared with the assessments based on potentiometric pH. In both methods, dipping the strips in distilled water just before use improved the regression coefficient compared with that mentioned in the manual. The image analysis showed higher correlation than human judgments but slightly underestimate pH by a maximum of 0.13 unit from the regression line of the potentiometric pH. In addition, the image analysis revealed meat pigment changed pH higher on the color scale in the lower meat pH region. The strips must be used according to the manual, but dipping is effective when the meat surface is dry, and keeping the strips from touching the meat drip is important in lower pH region because the pigment affects the color of pH.