To analyze the sensory characteristics of meat samples with a crude fat content between 23.8% and 48.6% taken from 34 Japanese Black steers, we grilled the meat and subjected it to analytical sensory evaluation. We also measured the amounts of moisture, protein, nucleic acid and glutamic acid. An increase in crude fat content increased the tenderness, juiciness, and fattiness in the meat quality evaluation. An increase in crude fat content reduced the crude protein and moisture contents; it also slightly reduced the nucleic acid and glutamic acid contents, although when the reductions in these umami components were assessed relative to the moisture content they changed little. Increasing the fat content up to a certain point greatly enhanced the umami intensity and beef flavor intensity in the meat quality evaluation and raised the overall evaluation score; the peak of the appropriate crude fat content for these purposes was about 36%.

The enzymes responsible for the conversion of N(alpha)-[(benzyloxy)carbonyl]-D-lysine (N(alpha)-Z-D-lysine) to N(alpha)-Z-D-aminoadipic acid (N(alpha)-Z-D-AAA) by Rhodococcus sp. AIU Z-35-1 were identified. N(alpha)-Z-D-Lysine was first converted to N(alpha)-Z-D-aminoadipic delta-semialdehyde (N(alpha)-Z-D-AASA) by D-specific amino acid deaminase, whereas N(alpha)-Z-L-lysine was converted to N(alpha)-Z-L-AASA by L-specific amino acid oxidase. The resulting N(alpha)-Z-D-AASA was then converted to N(alpha)-Z-D-AAA by the same aldehyde dehydrogenase that is responsible for N(alpha)-Z-L-AASA oxidation. The product amount of the D-specific amino acid deaminase reached the maximum at one day of cultivation in the L-lysine medium. The aldehyde dehydrogenase reached the maximum at three days of cultivation.

No abstract

No abstract

No abstract