PSVII-21 - Impact of low voltage electrical stimulation applied to longissimus thoracis et lumborum and semitendinosus on meat quality and palatability

Abstract: Low voltage electrical stimulation (LVES, 20-120V) is safer and more cost-effective than high voltage electrical stimulation (HVES). Despite some studies showing positive effects of LVES on meat quality, no studies have evaluated the effects of LVES on meat flavour profile. The objective of this study was to examine the effects of LVES applied directly to the longissimus thoracis et lumborum (LTL) and semitendinosus (ST) muscles on meat quality and flavour profile. Thirty-two steers (689.2±29.66 kg live weight) were used. After carcass splitting and randomizing by carcass side, the LTL and ST of one carcass side were stimulated individually with 45 V_RMS at 49.83±2.32 min post-mortem using a commercial stimulator. The other carcass side remained unstimulated. The LTL and ST pH were measured at 45 min, 3 h, 3 d and 6 d. At 3 d post-mortem, LT objective color (Minolta L^*, a^*, b^*, hue, chroma) was measured and one steak from LT and ST were collected for cooking losses and shear force analyses. The remaining muscle was weighed, vacuum-packaged, aged until 6d post-mortem and, subsequently, unpackaged and re-weighed to calculate purge losses. One steak from each muscle was placed in a retail display and objective color at 0 and 4d (6 and 10d post-mortem) and drip losses were assessed. Cooking losses and shear force of 6 and 12-d aged steaks from each muscle were measured. Trained panelists evaluated sensory attributes of frozen-thawed 6-d aged longissimus lumborum (LL) and ST steaks. There were stimulation×ageing time interactions for pH in both muscles, as LVES reduced the pH at 3 h but did not affect pH at 3 and 6d post-mortem (P< 0.001 Fig. 1). The LVES did not significantly affect the LT color values at 3 d post-mortem (P>0.05, data not shown) or in retail display(P>0.1, Table 1). In the ST, however, there were stimulation×ageing time interactions for a^*, b^* and chroma measured in retail display, with stimulation increasing all these values at 0 d, whereas there was no effect on a^* and chroma and a lesser increase in b^* after 4 d (P< 0.001, Table 1). Regardless of ageing time, LVES increased ST L^* (P< 0.05) and hue (P< 0.001) in retail display (Table 1). The LVES did not affect LT and ST drip losses (P>0.1, Table 1), shear force, descriptive sensory attributes and LT purge losses (P>0.1), but increased ST purge losses (P< 0.05) (data not shown). The LVES increased burnt aroma (P< 0.05) and umami (P< 0.01) and salty (P=0.075) tastes and decreased bitter taste (P< 0.01) and green-hay flavour (P< 0.05) in the LL, but did not affect ST flavour (P>0.1) (Table 2). Overall, LVES had muscle-specific effects with improvements in ST retail color and LL flavour profile.