Effects of aging and dietary supplementation with polyphenols from Pinus taeda hydrolysed lignin on quality parameters, fatty acid profile and oxidative stability of beef

Context: The inclusion of Pinus taeda hydrolysed lignin (PTHL) in beef diets could improve quality and stability of meat, but effects could vary through the aging period (AP). Aim: The aim was to evaluate the effects of the PTHL inclusion in the diet of finishing beef cattle on meat quality, fatty acid composition and oxidative stability at Days 1, 8, 11 and 15 of aging. Methods: Forty Limousin bulls (340 ± 42 kg) were fed ad libitum on a total mixed ration (TMR). The control group received exclusively TMR for 120 days, while the experimental group received the same TMR as the control group but supplemented with PTHL (Oxifenol, I-Green, Padua, Italy; 35 g/day per head at 1-90 days and 70 g/day per head at 91-120 days). Key results: Diet did not influence the chemical composition, pH, cooking loss, Warner-Bratzler shear force and hydroperoxide content. The Warner-Bratzler shear force (P < 0.001) decreased, while lightness (P < 0.01) and hydroperoxides (P < 0.001) increased through the aging period. Thiobarbituric acid reactive substances were similar for both diets at 1 and 15 days. However, thiobarbituric acid reactive substances at 8 and 11 days were higher for control than for the PTHL diet (P = 0.023 for interaction). Protein carbonyls were higher for control than for the PTHL diet at 8 days (P = 0.003 for interaction), but similar for both diets for the other dates. Saturated, monounsaturated and polyunsaturated fatty acids varied through the AP with PTHL diet, while no changes were observed with control diet (P < 0.01 for interactions). At 11 days, the n-6: n-3 ratio passed from being the minimum value with the PTHL diet to be the maximum with control diet (P < 0.01 for interaction). Conclusions: The effects of PTHL inclusion in bull finishing diets depends on the AP but, generally, may result in beef with meat with beneficial effects on human health. Implications: Including PTHL in the diet of finishing bulls can be useful to improve meat quality, favouring the use of natural waste substances deriving from vegetal production.