Green modification techniques: Sustainable approaches to induce novel physicochemical and technofunctional attributes in legume starches

Abstract

Background: Starch is the major component of legume seeds. Hitherto, legume starches have been incorporated into the formulation of numerous food products to improve nutritional and quality attributes. However, in order to widen such applications, modifications of legume starches through chemical and physical approaches are inevitable. Scope and approach: Given the upsurged consumer awareness toward the probable detrimental impacts of using chemical reactants during food processing, various green modification approaches (i.e. conventional/novel thermal techniques plus non-thermal methods) have been investigated to replace the use of chemicals. Such techniques could induce intentional/inadvertent alterations in major components of legume-based products, particularly starch. Therefore, the focus of present review was to provide insights into the changes in legume starch upon various green modification techniques. Key findings and conclusions: Unlike chemical approaches, green modification techniques barely affect the stereochemistry of the starch molecules. From the structural point of view, during conventional thermal processes (e.g., heat-moisture treatments, annealing, steaming), the major changes are limited to the rearrangement of starch molecules inside the granule, while novel thermal methods (e.g., microwave, ohmic heating) might cause granular disintegration and drastic morphological alterations. Moreover, non-thermal processing methods (e.g., high-pressure processing, sonication, pulsed electric field) could provoke moderate changes in both morphology and internal structure of starch granules. Furthermore, green modification methods are potent tools in customizing nutritional attributes of starch by enhancing/diminishing its digestibility.