To evaluate the effects of meat-aging treatment using the chilled room of a domestic refrigerator (R-XG6700H, Hitachi Global Life Solutions, Inc.), we compared the number of viable bacteria and concentration of taste components in, as well as palatability of, beef and pork loin, aged using a refrigerated (refrigerated aging) or a chilled room on vacuum mode (about 0.8 atm) at superchilling temperature of around －1 ℃ (chilled aging). The growth rate of viable bacteria in the case of chilled aging was 62.3 % lower in beef and 55.0 % lower in pork than in the case of refrigerated aging. The rate of increase in the total free amino acid content in beef was lower in the case of chilled aging compared to that in refrigerated aging; however, the suppression rate was lower than that for the number of viable bacteria. In contrast, the rate of increase in the total free amino acid content in pork did not change significantly in the case of chilled aging compared to that in refrigerated aging. Furthermore, the results of sensory evaluation showed that umami of pork and beef were significantly stronger in chilled aging for 7 days than in refrigerated aging for 3 or 4 days. These results indicate that beef and pork meats using the chilled room of a domestic refrigerator at superchilling temperature of around －1 ℃ for 7 days increases the content of total free amino acids in meat and improves its palatability compared with meats using a refrigerated room of a domestic refrigerator for 3 or 4 days.
