Galactomannans from Neltuma spp. as Emerging Functional Dietary Fibre for Human Nutrition: Extraction Technologies...

Galactomannans are reserve polysaccharides widely distributed in legume seeds and recognized for their technological and physiological properties. Their structure, consisting of a β-(1→4)-linked mannose backbone with α-(1→6)-galactose side chains, determines their solubility, viscosity, and functional behavior. In recent years, galactomannans have gained increasing attention as functional dietary fibre due to their potential effects on glycemic regulation, cholesterol reduction, gut microbiota modulation, and short-chain fatty acid production. This review critically analyzes the current knowledge on galactomannans derived from Neltuma spp., a group of underutilized leguminous species native to arid and semi-arid regions of Latin America, particularly the Gran Chaco ecosystem. This review aims to describe the structural characteristics of sources of galactomannans from seeds, extraction and purification technologies, and their potential nutritional implications of Neltuma spp.-derived galactomannans, highlighting their role as sustainable ingredients for human nutrition. Conventional extraction methods, including aqueous and alkaline extraction, are compared with biotechnological approaches such as enzymatic pretreatments, ultrasound-assisted extraction, and membrane technologies, highlighting their effects on yield, purity, and structural preservation. Evidence suggests that Neltuma spp. seeds represent a promising alternative source of food-grade galactomannans with potential applications as sustainable hydrocolloids and functional ingredients. However, studies regarding their digestibility, microbiota interactions, and clinical effects remain limited. The valorization of Neltuma spp. may contribute to the diversification of dietary fibre sources while supporting sustainable bioeconomy strategies and regional food innovation in Latin America.