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Alkali Extraction (alkali + extraction)
Selected AbstractsUltrasonic assisted alkali extraction of protein from defatted rice bran and properties of the protein concentratesINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2009Thutiyaporn Chittapalo Summary Alkaline extraction for the preparation of protein concentrate from rice bran was compared with a range of ultrasonic treatments. Results revealed that the extraction time decreased, and the reaction rate constant increased, with increasing ultrasonic power. The reaction rate constants were 0.0065, 0.0130, 0.0237 and 0.0924 at 40, 60, 80 and 100 W respectively. The defatted rice bran protein concentrate (DRBPC) using ultrasonication (100 W for 5 min) and conventional methods showed no significant difference in bulk densities (P > 0.05) but it had higher yield (%) and was lighter brown using ultrasonication (P , 0.05). The SEM showed that the residual rice bran after extracting protein using ultrasonication exhibited more damage than the conventional method. The functional properties of both samples were not significantly different (P > 0.05) in terms of foam and emulsifying stability. However, the water and oil absorption, foam capacity and emulsion activity were significantly different (P , 0.05). The nitrogen solubility index of both DRBPC samples gave similar profiles with the lowest solubility at pH 4,6. [source] Effects of NaCl Concentration on Salting-in and Dilution During Salting-out on Soy Protein FractionationJOURNAL OF FOOD SCIENCE, Issue 4 2006N. A. Deak ABSTRACT:, Glycinin and ,-conglycinin are the main storage proteins in soybeans that can be fractionated by using alkali extraction, SO2, salting-in with NaCl, salting-out by dilution and pH adjustment to produce a glycinin-rich fraction, a ,-conglycinin,rich fraction, and an intermediate fraction, which is a mixture of the two proteins. Two different strategies were employed to optimize the procedure to achieve high efficiency in recovering the ,-conglycinin,rich fraction. The first strategy was to optimize salting-in effects of NaCl, and the effects of NaCl concentration on the yields and purities of the protein fractions were investigated. The maximum protein yield of the ,-conglycinin,rich fraction was obtained at 500 mM NaCl, but at the expense of purity. The optimum NaCl concentration was 250 mM, at which good protein yield (18.5%) and purity (84.5%) were achieved. At higher NaCl concentrations, the protein yields of the intermediate fractions were significantly lower, and the protein loss in the whey fraction increased. The second strategy was to improve the salting-out step for the ,-conglycinin,rich fraction. At 0- and 0.5-fold dilution, the purities and yields of the ,-conglycinin,rich fractions were significantly lower than at 1.0- and 2.0-fold dilution. There were no differences in protein yields or purities when using 1.0- or 2.0-fold dilution. According to these results, the recommended NaCl concentration for the salting-in step is 250 mM and the dilution factor for salting-out is 1.0. [source] Extraction and Application of Dietary Fiber and Cellulose from Pineapple CoresJOURNAL OF FOOD SCIENCE, Issue 4 2002T. Prakongpan Pineapple core dietary fiber (PDF) was obtained by alcoholic extraction; pineapple core cellulose (PC) was a product of alkali extraction with a bleaching process. Total dietary fiber content of PDF and PC was 99.8% and 95.2% (dry basis), respectively, and their water activity was 0.25. PC contained 91.2% cellulose with a pH value of 4.0, while that of PDF was 6.2. The fiber product with large particle size gave higher values than the product with smaller particles for pH, water and oil retention capacity, settling volume and emulsifying activity. Both had rough, pitted surfaces and presented showed good functions in cake-type doughnuts, golden layer cake and beef burgers. [source] Down-Regulation of Lignin Biosynthesis in Transgenic Leucaena leucocephala Harboring O -Methyltransferase GeneBIOTECHNOLOGY PROGRESS, Issue 3 2006Smita Rastogi In the present study, a 0.47 kb OMT gene construct from aspen, encoding for an enzyme O -methyltransferase (OMT, EC 2.1.1.6), in antisense orientation was used to down-regulate lignin biosynthesis in Leucaena leucocephala. The plants were transformed with Agrobacterium tumefaciens strain harboring the antisense gene, and the transformation was confirmed by PCR amplification of the npt II gene. The integration of a heterologous antisense OMT gene construct in transformed plants led to a maximum of 60% reduction in OMT activity relative to control. The evaluation of total lignin content by the Klason method revealed a maximum of 28% reduction. Histochemical analyses of stem sections depicted a reduction in lignin content and normal xylem development. The results also suggested a probable increase in aldehyde levels and a decrease in syringyl units. Lignin down-regulation was accompanied by an increase in methanol soluble phenolics to an extent that had no impact on wood discoloration, and the plants displayed a normal phenotype. Concomitantly, an increase of up to 9% in cellulose content was also observed. Upon alkali extraction, modified lignin was more extractable as evident from reduced Klason lignin in saponified residue and increased alkali soluble phenolics. The results together suggested that the extent of down-regulation of OMT activity achieved may lead to quality amelioration of Leucaena with respect to its applicability in pulp and paper manufacture as well as nutritive and easily digestible forage production. [source] | ||||||||||