Effect of including chia in the diet of Pampa Rocha pigs raised outdoors on drip loss and oxidative stability of meat

Abstract

Chia seeds (Salvia hispanica L.) are a rich source of polyphenols and flavonoids, with antioxidant properties, and omega-3 fatty acids, vitamins and minerals. These  compounds included in pigs' diet enriches the meat, improves its nutritional profile and  protects it against post-mortem lipid oxidation and it is an opportunity to add value to local pigs meat. Then, in this study it was evaluated the effect of  chia seeds  included in the finishing diet of Pampa Rocha pigs raised outdoors on pasture, on lipid oxidation and drip loss, in two muscles, Longissimus thoracis (LT) and Psoas major (PM), fresh (F) and stored (S) 7 days, at 1-2°C under vacuum. Three diets (8 pigs/diet) were used: a diet without chia, with 5%, and with 10% of chia. After sacrifice, the muscles were removed and drip loss was determined (difference between initial/final weight, 24 hours, 4°C), expressed as percentage. Lipid oxidation was determined by the thiobarbituric acid reactive substances, expressed as mgMDA/kg meat. Data were analysed by ANOVA GLM, with diet, muscle and process as fixed effects, and post hoc Tukey-Kramer test (p< 0.05). Chia did not affect lipid oxidation (p>0.05), but PM showed a higher MDA than LT and S presented higher MDA than F (p<0.05). In spite of the fact that chia is a high fatty acid source it is likely that polyphenol could play a protective role on the lipid oxidation. No effect of diet on drip loss was observed but  PM had less loss of water than LT. Storage provoked less drip loss than fresh ones, probably it was residual water. Taking into account lipid oxidation and drip loss, inclusion of chia did not negatively affect meat quality. Storage and muscle were more important factors to affect lipid oxidation and drip loss.