Gel-forming Ability Research Articles

Matrix polysaccharides of oat coleoptile cell walls

Separation of component polysaccharides in extractable fractions of the noncellulosic matrix of Avena sativa coleoptile cell walls shows that the principal classes of polymers present are glucuronoarabinoxylans (GAX) and iodine-negative hemicellulosic β-glucans. Rhamnogalacturonan is a minor component. GAX contains about 5–10% glucuronic acid and its 4- O-methyl ether, arabinose in amount almost equal to xylose, and a small amount of galactose; some subfractions contained appreciable amounts of glucose and galacturonic acid but these may derive from separate, contaminating polysaccharides. From the sedimentation and diffusion coefficients and intrinsic viscosities of one subfraction each of the GAX and of the hemicellulosic glucan that had been purified to apparent homogeneity by criteria of sedimentation and borate electrophoresis, MWs of about 200 000 were calculated by two methods. The viscosity characteristics and gel-forming ability of the hemicellulosic glucan give evidence of appreciable molecular interactions which suggest that this polymer is an important structural component of the cell wall.

Complex formation of gel-forming bacterial (1→3)-β- D-glucans (curdlan-type polysaccharides) with dyes in aqueous solution

The complex formation of Polysaccharide 13140 ( 1) or 13127 ( 2) [curdlan-type polysaccharides: gel-forming bacterial (1→3)-β- D-glucans] with dyes in aqueous solution was investigated. The (1→3)-β- D-glucans reacted specifically with Aniline Blue (water soluble) ( 3) to form stable color complexes. The rate of interaction between 1 or 2 and 3 in aqueous solutions was shown to be proportional to both concentration and gel-forming ability of 1 and 2. This complex formation is to be applied to the quantitative analysis and the determination of gel-forming ability of curdlan-type polysaccharides.

TECHNOLOGICAL ASPECTS OF HIGH QUALITY RAW MATERIAL OBTAINING FOR PECTIN PRODUCTION


 The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.

Tenderness and Juiciness of Freeze-Dried Chicken Meat as Related to Maturity of Birds

ALTHOUGH freeze-dried chicken has highly acceptable flavor, color and storage stability, a dry and tough texture often remains after rehydration. This deficiency in texture has been attributed to the loss of water holding capacity by the muscle proteins, and protein denaturation during drying was suggested as the cause of this loss (Brooks, 1958).According to Hamm and Deatherage (1960), the decreased ability of meat proteins to rehydrate was usually due to the formation of an excessive amount of electrostatic and hydrogen bonds between actin and myosin in the myofibrillar filaments.Connell (1957) suggested that increases in toughness and a loss of gel-forming ability in dehydrated fish might be due to increased crosslinking of protein chains. He proposed that this could also cause dryness, due to poor water-binding capacity.Gawronski et al. (1964) concluded that sulfhydryl/disulfide exchange had an important role in post-rigor tenderization. Kahn and van den Berg (1965) recently …