| Summary: | 碩士 === 國立宜蘭大學 === 生物資源學院碩士在職專班 === 107 === USDA prime grade beef chuck eye roll derived from Holstein was dry aged with traditional method, dry aged in bags and wet aged in vacuum package for 7, 14 and 21 days respectively and then analyzed for physical, microbial and sensory differences. Higher aging and trim losses were found in beef dry aged traditionally and aged in dry aging bags. Aged beef was more tender compared with frozen beef without aging (control). In regard of hardness of the beef, wet-aged beef was less hard than bag dry-aged beef, while the latter was less hard than traditionally dry-aged beef. Significant differences in total plate count and total fungi count were observed between each sample and the control (P<0.05). Total plate and fungi count of samples dry aged traditionally were all significantly lower than the control (P<0.05). There were no significant differences with respect to total plate and fungi count among beef aged in bag for 21, 14 and 7 days, but they were all significantly higher than beef aged traditionally and the control (P<0.05). Beef wet aged for 14 days had lower total plate count than wet aged for 21 days (P<0.05), but higher than wet aged for 7 days (P<0.05). Nevertheless, total plate and fungi count on samples of wet aged beef, regardless of days, were all significantly higher than the control (P<0.05), while those aged for 21 and 14 days have significant higher total plate and fungi count than all other samples (P<0.05). No significant differences were found in cooking loss, pH, and water activity. As for sensory preferences, regardless of aroma, tenderness, juiciness, flavor, and overall acceptability, beef dry aged in bag for 14 days received the highest score among all the samples analyzed. Overall, beef palatability is improved through all three types of aging methods adopted in this study.
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