Estudo dos amidos de gengibre (Zingiber officinale) e inhame branco (Dioscorea sp) modificados fisicamente e adicionados do prebiótico lactulose

Abstract

Starch is one of the most important, inexpensive and abundant carbohydrates available in nature. Composed of a mixture of two polysaccharides, amylose and amylopectin. Ginger (Zingiber officinale), a rhizome, and white yam (Dioscorea sp), a tuber, are considered unconventional sources of starch and have been increasingly studied in an attempt to find different characteristics without changing the structure of the starch. The physicochemical composition, color characteristics, thermal, structural and paste properties of these starches were investigated and compared with those of the most widely used cornstarch worldwide. Corn starch showed higher thermal stability, while non-conventional starch had higher lipid and protein content. Ginger starch had higher gelatinization temperatures and relative crystallinity compared to corn and yam starches. Larger pellet sizes, and greater tendency to yellow, were found for ginger and yam starch which had the highest peak viscosity. Physical modification is a way of structurally altering starches without the use of chemicals. It offers the potential to modify their functionality at low cost and in an environmentally sound manner. The thermal, morphological and structural properties of ginger and white yam starches were studied after these starches passed through the ball mill at three different times (20, 30 and 40 min). The thermal stability of ground starches increased as milling time increased. The enthalpy and temperatures of the starch gelatinization process decreased after grinding, as well as the relative crystallinity of the samples. The granules had their sizes decreased and cracks were observed. Prebiotics, which are the carbohydrates that help the development of probiotic microorganisms primarily in the intestinal colon, are widely used with improvements in health. Among them, lactulose, which is a disaccharide formed from fructose and galactose, is a common food ingredient as it has several interesting characteristics for both the food industry and the health benefits. Lactulose was added to ginger and yam starches by two methods: homogenization in water and ball mill. The thermal, morphological, structural properties and quantification of disaccharide by high performance liquid chromatography on starches were investigated. The stability and thermal degradation of the added starches of the prebiotic were altered, as well as the gelatinization properties and relative crystallization, especially in the samples that passed the abrasive grinding. In the obtained micro images it can be observed that there was the interaction between starch and lactulose, especially in the milling. Through HPLC analysis it was possible to observe that the prebiotic was present near the starches, mainly in the highest concentrations worked