Emerging technologies for isolation of natural hydrocolloids from mucilaginous seeds

Many mucilaginous seeds around the world have been introduced for use as accessible, cost-effective, and natural sources of hydrocolloids. These hydrocolloids are used as thickening, gel-forming, foam-, and emulsion-stabilizing agents in a wide range of foods and pharmaceuticals. Due to the strong bonds between the mucilage layers and their hard seed cores, often a severe mechanical stress is required for quick and efficient separation of mucilage layers from their seed cores. The conventional method for isolating/extracting hydrocolloids from mucilaginous seeds includes a hydration process, followed by applying severe mechanical shear stress by high-speed mixers or with rotating blade stirrers. Therefore, a heterogeneous mixture of crushed seeds and mucilage may be produced. Several stages of time-consuming and energy-intensive centrifugation or filtration are required to separate the crushed seeds and impurities, followed by drying and grinding. Application of mechanical shear stress often leads to high levels of seed damage, resulting in crushed seed cores, which, on the one hand, makes the use of centrifugal force inevitable, and on the other hand, results in the entry of a large number of impurities from the crushed seeds into the isolated hydrocolloids. To address this issue, in the recent years, some attempts have been made to use emerging technologies and new approaches for isolation of seed gums aiming at improving the extraction process of seed mucilage. This chapter aims to review the conventional and emerging isolation methodologies and provide an overview of the current state of hydrocolloid isolation technique