MIKUŠ, Ľ., VALÍK, Ľ., DODOK, L.: Usage of hydrocolloids in cereal technology. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 5, pp. 325-334 Hydrocolloids are high-molecular-weight polymer substances soluble in water which create viscous colloidal solutions. They are mainly used to infl uence functional properties of food (structure, texture, etc.), improving their properties during production (bigger dough volume, better dough manipulation -better adhesion), increasing stability, maintaining taste fi rmness in frozen products and prolonging durability of cereal products in food industry. Hydrocolloids are characteristic for their thickening eff ect and are used for their emulsifying and steadiness properties. The aim of this review is to provide useful information about hydrocolloids including chemical structure, origin, common and recommended usage in food industry, proper application in the cereal technology and future scientifi c heading of these hydrocolloids.hydrocolloids, colloidal solution, thickening, toughening Food hydrocolloids are biopolymers with high molecular weight, containing a hydrophile string, o en with colloidal properties (ability to fi rmly bind large amount of water, up to one hundred times of its weight), which are used as ingredients in food industry to adjust the microstructure, texture, taste and to prolong shelf-life. Their properties are aff ected by size of molecules, directions and association of molecules, concentration, size of particles, dispersion degree and others.The name "hydrocolloid" includes many polysaccharides obtained from plants, seaweed, microorganisms, as well as modifi ed biopolymers created by chemical or enzyme adaptation of starch and cellulose (Renard, 1996;Rollet, 1995).Food industry observed an increased application of these biopolymers in the last years. Although they are used at concentrations less than 1 % they have considerable eff ect on texture and sensorial properties in food products.Hydrocolloids have neutral taste and aroma, which enables them free access to food insertion. Hydrocolloids are used as sugar, fat and gluten substitutes, stabilizers (emulsions, foams), crystallizing inhibitors, thickening agents, gelatinization substances and they also modify starch gelatinization (Chenlo, 2009;Rosell, 2001). Natural hydrocolloid gums are a good source of soluble dietary fi bre (up to 85 % of dry mass). Their energy value is minimal to none, therefore are hydrocolloids used as fat replacing ingredients. Soluble dietary fi bre also reduces the concentration of cholesterol and improves gastrointestinal functions and glucose tolerance (Sozer, 2009).Hydrocolloid usage in cereal technologies depends on their properties to densify liquids (viscosity increase), water holding capacity, hydration rate and eff ect of temperature on hydration (for most hydrocolloids viscosity drops with rising temperature) (Příhoda, 2003).From health point of view, hydrocolloids are used in dough and bread systems to block fat absorption during the baking p...

New wheat-rye bread fortified with cereal dietary fibre, β-glucan hydrogel, and sourdough starter culture was designed in this study. The impact of these additives on nutritional composition and antioxidant properties was investigated. Functional bread with extruded wheat bran (10.0 %), cereal β-glucan hydrogel (12.5 %), and lactobacilli starter culture was compared with traditional wheat-rye bread (control). The contents of basic nutrients (protein, fat, etc.), dietary fibre, biologically active compounds (polyphenols and flavonoids), qualitative and quantitative analysis of simple saccharides and phenolic acids (by HPLC) were analysed in both bread types. Antioxidant activity, measured by two spectrophotometric methods (2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid); ABTS and di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (2,2-diphenyl-1-picrylhydrasyl); DPPH, was also evaluated. The effect of the addition of the above ingredients, as compared with traditionally prepared bread, was examined in the postprandial study, in which glucose and insulin levels were determined. In comparison with the control bread, higher amounts of dietary fibre, flavonoid content, and antioxidant activity were attained in the designed bread. Consumption of the designed bread led to reduced glucose levels in healthy males (n = 10) 120 min after the ingestion of the functional bread compared with the control (p < 0.048). No statistically significant change in the insulin response in the volunteers was observed after consumption of the designed bread compared with the control.

The brewer¢s yeast was used for preparation of concentrate with content of β-glucan. Hot water extraction (100°C, 5 hours) and subsequently an alkaline extraction of sediment using 1 M NaOH at 90

No abstract

2013