Agave fructans as prebiotics.

Abstract

Mexico is considered the origin center and biodiversity of the Agave genus, since a large number of Agave species are found in its territory. These plants present a crassulacean acid metabolism (CAM) and their principal photosynthetic products are fructans. Fructans are polymers of fructose generally linked to a moiety of a terminal glucose. Due to the βconfiguration of the anomeric C2 in their fructose monomers, fructans are resistant to hydrolysis by the human digestive enzymes and can be fermented by colonic microflora producing short chain fatty acids Correspondence/Reprint request: Dr. Mercedes G. Lopez, Unidad de Biotecnologia e Ingenieria Genetica de Plantas, CINVESTAV-IPN Unidad Irapuato, A.P. 629, Irapuato, Gto., 36500, Mexico E-mail: mlopez@ira.cinvestav.mx Mercedes G. Lopez & Judith E. Urias-Silvas 2 (SCFA). Fructans posses numerous nutraceutical properties, being one of them their prebiotic effect. A prebiotic is a selectively fermented ingredient that allows specific changes, both in composition and/or activity in the gastrointestinal microflora, which confers benefits upon host well-being and health. Fructans affect physiological and biochemical processes in humans and animals, resulting in better health and reducing the risk of many diseases, stimulating the immune system of the body, decreasing the levels of pathogenic bacteria in the intestine, relieving constipation, decreasing the risk of osteoporosis by increasing mineral absorption, reducing the risk of atherosclerosis by lowering the synthesis of triglycerides and fatty acids in the liver and decreasing their level in the serum. These fructans also modulate the hormonal level of insulin and glucagon, thereby regulating carbohydrate and lipid metabolism by lowering the blood glucose levels. Inulin and oligofructose also reduce the incidence of colon cancer. All these properties have been attributed principally to commercial fructans which posses mainly β(2-1) linkages. In the case of Agave and Dasylirion fructans, these posses a molecular structure compose of a complex mixture of fructans containing principally β(2-1) linkages, but also some β(2-6) and highly branch, and a neo-type feature, these types of fructans have just been denominated agavins. Agavins stimulated the growth of Bifidobacterium breve and Lactobacillus casei more efficiently than most commercial inulins.