Methodology for Extraction of Soluble Non-Starch Polysaccharides and Viscosity Determination of Aqueous Extracts from Wheat and Barley

Abstract

Cereal grains contain various amounts of non-starch polysaccharides (NSP), which are composed predominantly of arabinoxylans, b-glucans and cellulose. The detrimental effect of soluble NSP is mainly associated with the viscous nature of these polysaccharides and their physiological effects on the digestive medium. Our study had in view to investigate the influence of some extraction conditions on the viscosity of wheat and barley aqueous extracts. Water extract viscosities (WEV) appeared to be related to the particle size, the extraction time and temperature, and to the time elapsed after isolation of the extract. The experiments revealed as optimum conditions for obtaining the soluble NSP extract from wheat and barley and for WEV determination: granulation of 0.5 mm size, extraction temperature 40°C, extraction time 60 min, and viscosity measurements immediately after extract isolation. Keywords IntroductionPolysaccharides are widespread biopolymers, which quantitatively represent the most important group of nutrients in botanical feed. Carbohydrates constitute a diverse nutrient category ranging from sugars easily digested by the monogastric animals in the small intestine to dietary fibre fermented by microbes in the large intestine [1].Dietary fibre (DF) is now defined as food material, particularly plant material, that is not hydrolysed by enzymes secreted by the human digestive tract but that may be digested by microflora in the gut.The types of plant material that are included within the definitions of DF may be divided into two forms, based on their water solubility.• Insoluble dietary fibre (IDF) which includes celluloses, some hemicelluloses and lignin; • Soluble dietary fibre (SDF) which includes b-glucans, pectins, gums, mucilages and some hemicelluloses.The IDF and SDF compounds, apart from lignin, are known collectively as nonstarch polysaccharides (NSP), which was one of the earlier definitions of DF.In animal nutrition, as ''non-starch-polysaccharides'' are summarized polysaccharides, which cannot be degraded by endogenous enzymes and therefore reach the colon almost indigested. Individual NSP groups have different chemical and physical characteristics that result in various effects on physiology of intestine and on organism in general.Non-starch polysaccharides are principally non-a-glucan polysaccharides of the plant cell wall. They are a heterogeneous group of polysaccharides with varying degrees of water solubility, size, and structure.Non-starch polysaccharides, according to Ebihara and Kiriyama [2], and Englyst and Hudson [3], refer to all carbohydrate fractions and types of dietary fibre, with the exception of lignin, either soluble or insoluble. Included are pectic substances, hemicelluloses, celluloses and gums (guar) and mucilages [4,5].Cellulose, hemicellulose and pectic substances are known as plant cell wall NSP since they comprised 80-90 % of the plant cell wall [5]. Resistant starch, theoretically, falls outside the NSP concept, but practically it depends on the method used...

Functional and health-endorsing properties of wheat and barley cell wall’s non-starch polysaccharides

“…The viscosity, biological, and physiochemical properties of these polysaccharides are oblige of their beneficial physiological effects in the small and large intestine. [38,72] Generally, cell walls of cereal grains (2-8%) contain arabinoxylans, (1, 3; 1, 4)-β-glucans, arabinogalactan, and pectins. [35,72,73] Whereas, literature revealed that among cereals, barley and oats are rich in mixed linked β-glucans, while wheat, rye, and triticale contain arabinoxylans (Pentosans).…”

“…[38,72] Generally, cell walls of cereal grains (2-8%) contain arabinoxylans, (1, 3; 1, 4)-β-glucans, arabinogalactan, and pectins. [35,72,73] Whereas, literature revealed that among cereals, barley and oats are rich in mixed linked β-glucans, while wheat, rye, and triticale contain arabinoxylans (Pentosans). [74] They are not digested by human's small intestinal enzymes and so contribute to total dietary fiber intake.…”

Investigation of the effects of fermented wheat bran extract containing beta‐glucanase on beta‐glucan of cereals used in animal feed

“…This viscosity reduction in all may results from the degradation of soluble nonstarch polysaccharides by endogenous enzymes (Lee & Ronalds, 1972). Both arabinoxylans and betaglucans are the main sources of the flour dispersion viscosity and cleavage of them by endogenous xylanases (Capriţa & Capriţa, 2012;Caprita et al, 2011), and beta-glucanases will reduce the viscosity (Lai, Slade, & Fincher, 1993). Soluble proteins and soluble starch may also contribute to the dispersions viscosity and their hydrolysis respectively by native proteolytic enzymes (Kawamura & Yonezawa, 1982) and beta-amylases (Hara-Nishimura & Nishimura, 1987) of flour would take part in viscosity reduction.…”

“…Measurement of water extract viscosity in cereals is an indirect means of estimation of their soluble nonstarch polysaccharide content such as beta‐glucan (Caprita et al., 2011; Gamel et al., 2014).…”

Isolamento de polissacarí­deos não amiláceos da banana (musa cavendishii L. variedade Nanicão) e seu potencial uso como ingrediente funcional.

“…PNAs ou também chamados de polímeros não amido, são os principais componentes da parede celular de várias plantas, frutas, vegetais, grãos e cereais (CAPRITA;CAPRITA;CRETESCU, 2013;CUMMINGS et al, 1997a). Segundo Bailey (1973) Os polissacarídeos não amiláceos presentes na banana madura podem ser considerados como compostos bioativos que podem ser extraídos ou purificados das bananas ainda em estágios avançados de maturação (ANDERSON et al, 2009;CUMMINGS et al, 1997b;SCOTT;DUNCAN;FLINT, 2008;SLAVIN;SLAVIN;GREEN, 2007).…”