No abstract

The objective was to evaluate the sensory categorisation of beef by Japanese consumers, based on Meat Standards Australia methodology. Various cuts of beef, with a wide range of quality (from Australian and Japanese cattle) and three cooking methods (grill, yakiniku, shabu shabu), were evaluated by 1620 Japanese consumers in Tokyo and Osaka. Consumers rated each sample for four sensory attributes (tenderness, juiciness, flavor and overall satisfaction), then selected one of four grades (unsatisfactory/2-star, good everyday/3-star, better than everyday/4-star, and premium quality/5-star), based on the quality of the beef within each cooking method. Meat quality scores, denoted as MQ4 scores (weighted combination of the four sensory attributes) were calculated from the Japanese consumer test results, to describe the Japanese consumer rating of beef. The distribution of the Japanese consumer MQ4 scores showed a clear distinction between grades, with the majority of scores being included within the boundaries of each grade. The MQ4 score allocated approximately 64% of the samples to their correct consumer grades. The MQ4 score showed potential to be used as a tool in developing and monitoring a consumer-focused grading system that is able to predict Japanese consumer satisfaction of individual beef cuts prepared by different cooking methods.

Messenger RNA (mRNA) expression of calpain-1 (µ-calpain), -2 (m-calpain), -3 (p94), small subunit (calpain-4; 28 kDa), and three types of calpastatin (CSTN) isoform were investigated for 10 skeletal muscles of Holstein cattle by real-time and/or semi-quantitative reverse transcription polymerase chain reaction. Noticeably, effect of muscle type was observed on 28 kDa expression (P < 0.001) with a tendency of higher 28 kDa expression in myosin heavy chain (MyHC)-2x-rich muscles compared to MyHC-slow-rich muscles. The CSTN-I and -III expression in Longissimus thoracis (LT) showed the lowest value among the muscles tested. Moreover, 28 kDa/CSTN-I ratio was higher in the diaphragm (DP), psoas major (PM), and LT than those in the lingual muscles (TN), masseter (MS) and pectoralis (PP) (P < 0.05). Calpain-1/CSTN I, calpain-2/CSTN I in LT and PM were higher than that in TN (P < 0.05). Calpain-3/CSTN-I and -III in LT and/or PM showed higher values than that in TN (P < 0.05). These results indicated that the calpain and CSTN expressions are regulated by muscle type, suggesting especially by muscle fiber type. Calpains/CSTN-I ratios, especially 28 kDa/CSTN-I, may account for higher extent of post mortem proteolysis previously observed in LT and PM muscles.

This paper presents a comparison of Japanese and Australian consumer sensory responses to beef, based on Meat Standards Australia methodology. Japanese and Australian consumers evaluated paired beef samples according to four sensory traits, and the weighted results were combined to produce a Meat Quality score (MQ4). The consumers also categorized the beef samples to one of four grades (unsatisfactory, good everyday, better than everyday and premium). The proportion of samples assigned to each grade was similar for Japanese and Australian consumers for yakiniku and shabu shabu cooking methods; however, Japanese consumers assigned lower scores to the grill samples. In terms of the MQ4 boundary scores between grades, these were very similar for both Japanese and Australian consumers across all cooking methods. In terms of the weightings for the four sensory traits, juiciness was more important for Japanese consumers than Australian for grill and shabu shabu cooking methods. Flavor had the highest weighting for both consumer groups. This study showed that a beef description system based on the MQ4 score, with some adjustments to the weightings and cut-off values, could be useful in describing the eating quality of beef for the Japanese consumer.

No abstract