Inca Peanut Seed Albumin Promotes the Retrogradation of Corn Starch

While starch and protein are two major biopolymer components that usually coexist in foods, how protein influences starch retrogradation, and subsequently the food matrix structure and properties, is complex and dependent on factors such as protein and starch types. Herein, the effect of the addition of Inca peanut seed albumin (IPA, ≤10%) on the retrogradation of native corn starch (NCS) upon aging for ≤7 days was investigated. Dynamic rheological results show that the addition of IPA significantly promoted the short-term (1 day) retrogradation of NCS as reflected by the increased storage modulus and smaller loss tangent. Differential scanning calorimetry results indicate that IPA increased the retrogradation enthalpy, especially with a high content (≥5%) of IPA (P < 0.05). In addition, with a higher level of IPA, the hardness increased after storage for 1 or 7 days. The ratio of the band intensities at 1047 and 1022 cm^-1and the relative crystallinity of the NCS/IPA mixture also increased after storage, especially with a high content (≥5%) of IPA. Scanning electron microscopy results show that the addition of IPA increased the surface roughness and porosity of the starch gel after storage. This work shows that the addition of IPA as a plant protein could be a promising way to modify the properties of starch-based foods by inducing retrogradation while enhancing the nutritional and functional properties of foods.