348 Dietary almond skin to lambs: effect on meat oxidative stability.

Abstract This study aimed to investigate the effects of feeding lambs diets containing two levels of almond skin on meat oxidative stability. Thirty Pinzirita × Valle del Belice male lambs (2 months old, body weight 12.7 ± 2.07 kg) were randomly assigned to 3 groups and fed ad libitum for 56 days with: a conventional diet (CON) or diets containing 14% (A14) or 28% (A28) dried almond skin as replacement of corn. Fatty acid profile and hydrophilic antioxidant capacity were assessed in fresh meat, while color and lipid oxidation were evaluated over 7 days of refrigerated storage. Data were statistically analyzed using a mixed model. No differences in the content of saturated, monounsaturated, and polyunsaturated fatty acids were observed among the treatments (P >0.05). The dietary treatment did not influence the stability of meat colour and metmyoglobin development (P >0.05). Whereas, colour parameters and metmyoglobin development were affected during storage time (P< 0.001), showing a typical browning pattern. Regarding the hydrophilic antioxidant capacity, ferrous ion chelating activity (FICA) and DPPH assays showed no differences (P >0.05); while Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and Folin-Ciocalteu assays were significantly affected in the hydrophilic meat fraction (P< 0.05). In both Folin and FRAP assays – which measure the reducing ability of the extract – were observed smaller values in almond treatments compared to the control. Conversely, the TEAC assay, which assesses radical scavenging ability, showed increased values in the almond groups compared to the control treatment. Dietary treatment and the interaction between dietary treatment and time of storage did not affect the content of secondary lipid oxidation products, analysed with TBARS assay (P >0.05). Whereas, TBARS values increased along 7 days of refrigerated storage (P< 0.001). The inclusion of both levels of almond skin as a substitute of corn in the lamb diet did not worsen the fatty acid profile nor the colour parameters of the meat. The meat antioxidant capacity assays revealed an increase in radical scavenging capacity, while the reducing ability decreased. No differences on lipid oxidation values were observed between the treatments. In the light of the above, the almond skin could substitute corn in lambs’ diet without detrimental effects on FA profile, color stability and lipid oxidation of meat. Further analyses will be conducted to better understand the differences in antioxidant capacity and to evaluate the content of lipophilic antioxidants. This work was supported by the National Recovery and Resilience Plan (NRRP), NextGenerationEU; Project code PE00000003, CUP E63C22002060006, Project title “ON Foods - Research and innovation network on food and nutrition Sustainability, Safety and Security – Working ON Foods”.