Increasing omega-3 levels through dietary co-extruded flaxseed supplementation negatively affects pork palatability

The potential for omega-3 fatty acids to improve human health has increased the demand for omega-3 enriched products. Flaxseed, due to its high α-linolenic acid content, has gained attention as a dietary ingredient for swine. However, the high oil content may cause feed handling and oxidative stability problems. Co-extruding flaxseed with field peas alleviates these problems, possibly due to the antioxidant capacity of peas and increased nutrient digestibility of the co-extruded product. The hypothesis of the present experiment was that feeding flax when co-extruded with peas and in combination with barley/ wheat based diets would alleviate potential problems with oxidative stability and fat softness, in both barrows and gilts. To clarify the impact of feeding co-extruded flaxseed on carcass quality and pork palatability, 96 pigs (48 barrows and 48 gilts) were fed three different levels of flaxseed (0%, 5% and 10% of dietary intake) for 76 days. Carcass quality and meat quality characteristics of pure loin muscle and ground pork (20% fat) were evaluated.

Fat hardness and belly firmness decreased (P < 0.001) with increasing co-extruded flaxseed. Pigs fed co-extruded flaxseed levels had higher lean yield (P = 0.045) and total lean content (P = 0.034). Loin from barrows had higher fat content compared to gilts (P < 0.001). Co-extruded flaxseed supplementation increased (P < 0.001) omega-3 content in loin and ground pork. Pork flavour intensity and off-flavour intensity scores lowered (P < 0.001) with increasing levels of co-extruded flaxseed, being more accentuated (P = 0.023) in reheated pork chops from barrows. Diet affected all texture and flavor sensory characteristics (P < 0.05) as tissue levels of omega-3 fatty acids increased, likely as a result of increased lipid oxidation. On the other hand, feeding coextruded flaxseed to increase omega-3 fatty acid content in trimmed loin muscle did not result in levels sufficient to meet label requirements and had limited effects on palatability.

Flax co-extruded with peas did not provide sufficient antioxidant capacity to alleviate texture and flavor problems in high fat products with elevated polyunsaturated fatty acids content. Consequently, further studies should take into consideration that pork is typically marketed with some level of seam and/or trim fat.