Organic Pea Starches – II. Investigation of Physicochemical and Techno‐Functional Properties

Abstract

The physicochemical and technofunctional properties of several pea starches harvested in consecutive years are studied. All samples are cultivated in the same geographical locations. Despite limited variation of amylose content that is found (mean amylose content of 32.1 ± 1.4% and a range from 29.2% to 35.7%), the varieties demonstrate significant differences in their functional properties. During gelatinization, all starches exhibit comparable onset temperatures (To) within the range of 60.8–63.7 °C. However, the conclusion temperature (Tc) displays a considerably broader spectrum, spanning from 73.5 to 80.0 °C. Furthermore, noticeable systematic differences between the samples from 2020 to 2021 are observed. In terms of the hot paste viscosity, two main shear viscosity curves are identified. These are independent of the harvesting period and could be associated with differences in average molar masses examined previously. Pea varieties with comparable low starch molar masses (<25 × 106 g∙mol−1) show a stronger shear thinning behavior. The starches also exhibit substantial variations in mechanical gel strength and gel elasticity. The gel strengths range from 5.5 to 17.0 N. Increasing firmness of gels appears to correspond to reduced elasticities. For comparison, native corn starch, potato starch, and wrinkled pea starch are considered.