Effect of protein addition in properties of gels produced with jackfruit (Artocarpus integrifolia) seed starch: rheological and texture properties

Starches and proteins are two major types of biopolymer components in many foods. The interactions of protein with starches greatly influence the matrix structure and properties of starch-based food systems. In this study, the physical–chemical properties and the effect of the commercial whey protein concentrate in the texture and rheological properties of jackfruit starch gels were evaluated. The experimental design was completely randomized, using a 4 × 4 complete factorial scheme, with four levels of starch (3, 6, 9 and 12%) and four levels of protein (0, 2, 4 and 6%). In higher concentrations of starch the addition of proteins delayed the beginning of gelatinization, led to an increase in G′ and G″ and decrease in the tan (δ) values, characterizing the gel as strong, e.g., the gel network became more structured. However, in the treatment with 6% starch the addition of protein led to a decrease in gel strength. For gels with 9% starch the increase in protein concentration, led a slight increase in the hardness and cohesiveness, characterizing a more rigid and cohesive gel. Overall, gels with 3 and 6% of starch showed characteristic behavior of a weak gel and with 9 and 12% of strong gel.