Correlations of mature beef palatability with optical probing of raw meat

Abstract

Organoleptically tested samples of longissimus dorsi (LD) and semitendinosus (ST) muscles from 20 beef carcasses covering a wide chronological age were tested with probes for connective tissue fluorescence (365 nm excitation) and for muscle reflectance (400–800 nm). In LD, the number of fluorescence peaks cm −1 was correlated with toughness ( r = 0·73, P ≤ 0·0005), whereas the half-width of peaks was the best single predictor for ST ( r = 0·66, P < 0·005). Measurements on initial penetration of samples were more useful for predicting meat toughness than those made as the probe was withdrawn. With the reflectance probe, negative correlations of reflectance with taste intensity were detected (for example, r = − 0·63, P ≤ 0·005 at 420 nm in ST), but stronger correlations of taste with the fluorescence signal were detected (for example, r = 83, P ≤ 0·0005 for peaks cm −1 measured coaxially). Correlations of the fluorescence signal with taste may have been fortuitous, because taste was correlated with toughness ( r = 61, P ≤ 0·005). However, ST juiciness was correlated with the height of the largest fluorescence peak in a transect ( r = 0·78, P ≤ 0·0005 for coaxial measurements damped at 10 Hz) although no significant correlation of ST juiciness with toughness was detected ( r = 0·06). These results demonstrate the UV probe to be a fairly robust predictor of toughness from connective tissue, working as well on a wide age range of carcasses as it does on a narrow age range. Further development may enable the empirical prediction of taste, juiciness and hardness.