Pea starch amylose-lipid complexes for plant-based foods

Abstract: The protein isolation process from pulse sources like peas often generates starch as a waste by-product. Pea starch typically displays a high amylose content causing it to form brittle and unworkable gels. By creating amylose-lipid complexes the properties of amylose can be changed, resulting in more usable products for food systems. Pea Starch (PS) containing 30% amylose was evaluated for its ability to form amylose-lipid complexes with stearic acid (SA).

Preliminary research showed that during DSC, Texture Profile Analysis (TPA) and rheological analysis, of the PS complexation with 2.0% w/w (dry basis starch) SA improved the textural properties of the products. DSC analysis indicated that amylose lipid complexes were formed and decreased the onset of gelatinization of the amylose. TPA of the pea starch-stearic acid (PS-SA) complex increased the level of cohesiveness, chewiness, and resilience. These parameters further suggest that SA interacts with amylose, decreasing its brittleness properties. However, complexation also increased the absolute hardness of the gel, but this can be attributed to the solid properties of SA, and not the amylose forming more firm gels. Rheological analysis by oscillatory strain sweep from 0.01-700% strain showed the PS complexation with SA significantly decreased the storage modulus (G’) compared to the PS alone. This was reflected in the stress-strain curve where the PS-SA complex had a 50% decrease in the shear stress value at the yield point. However, the yield point for the PS sample was slightly greater than the complexed sample, but it was observed that the PS sample displayed several peaks when reaching higher strain rates indicating multiple structural yielding or breakage events at different strains. The PS-SA sample, on the other hand, displayed smoother, plastic profiles. Overall, the PS-SA complex demonstrated that amylose lipid complexation may be a useful tool in modifying starch behavior for food systems.