Impact of aging methods and frozen storage on beef quality attributes from different finishing diets

Doctoral thesis abstract

Abstract

Aging and freezing practices play a fundamental role in meat palatability. This work studied the effects of preservation methods (PM) on meat quality attributes, from steers finished on pasture (P: n=15) or grain (G: n=15). 60 striploins (longissimus thoracis et lumborum, LTL) from British breed steers younger than 30 months were used. The PM assessed dry aging in a bag (DAb) and wet aging (WA) for 40 d and then frozen storage (Fr): (DAb+Fr) and (WA+Fr) for 180 d. Additionally, aging methods (AM) included combinations of both for a total period of 40 d without subsequent freezing: DAb for 20 d + WA for 20 d (DW) and WA for 20 d + DAb for 20 d (WD). Lightness (L*) meat from G-finished steers was lighter than that on P-finished (P<0.01). Considering PM, DAb+Fr samples had the lowest L*, a* and b* values (P<0.01) compared to DAb, WA and WA. This difference was also observed in higher counts of Psychrotrophic bacteria (PSY) and Enterobacteriaceae (ENT) than WA+Fr, DAb and WA (P<0.01). Regarding AM, WD presented higher counts of PSY and total bacteria (TBC) (P<0.05) than the other three treatments (DAb, WA and DW). Greater concentrations of polyunsaturated fatty acid (PUFA, PUFA n6), and conjugated linoleic acid (CLA) (P<0.01) were observed in all AM from P-finished and in WD from G-finished steers, while saturated (SFA) and monounsaturated (MUFA) were greater in DW and WD from G-finished steers (P<0.05). Sensory analyses reported acceptable ratings for all PM, with DAb presenting higher aldehyde concentrations associated with intense meat flavors preferred in some premium markets. WA could satisfy consumer demand for tenderness and juiciness. Both offer valuable strategies for producing high-quality meat for domestic and export markets. Different aging methods followed by a freezing period could be used to export meat with quality attributes that consumers require.