Effects of alkali-treated

Nutritional and Physiological Effects of Alkali-Treated Proteins. The first effect of the alkaline treatment of food proteins is a reduction in the nutritive value of the protein due to the decrease in (a) the availability of the essential amino acids chemically modified (cystine, lysine, isoleucine) and in (b) the digestibility of the protein because of the presence of cross-links (lysinoalanine, lanthionine, and ornithinoalanine) and of unnatural amino acids (ornithine, alloisoleucine, / -aminoalanine, and D-amino acids). The racemization reaction occurring during alkaline treatments has an effect on the nitrogen digestibility and the use of the amino acids involved. 

De Groot, A. P., Slurp, P., Feron, V. J. and Van Beek, L. (1976). Effects of alkali-treated proteins feeding studies with free and protein-bound lysinoalanine in rats and other animals. J. Nutr. 106, 1527-1538. 

Gould, D. H. and MacGregor, J. T. (1977). Biological effects of alkali-treated protein and lysinoalanine an overview. In "Protein Crosslinking Nutritional and Medical Consequences," M. Friedman, Ed., Part B,... 

L. F. (1979). Biological effects of alkali-treated soy protein and lactalbunin in the rat and mouse. 

Karaylannis, N. I., MacGregor, J. T. and Bjeldanes, L. F. (1979b). Biological effects of alkali-treated soy protein and lactalbumln In the rat and mouse. Food and Cosm. Toxicol., 17, 509-604. 

The effect of alkali treatment on molecular weight (compare with the case of the starch components) has been studied treating a 5% solution of rabbit-liver glycogen in 2 N sodium hydroxide, for 90 minutes at 100°, decreased the sedimentation constant (Sits X 1013) from 86 to 57 (that is, by 34%).237... 

Figure 3 Effect of washing of alkali-treated column on the adsorption of arsenite. Completely washed column . arsenite, pH (run 1-1 in Table 4).

Various bituminous coals were demineralized by an experimental two-step leaching process in which the ball-milled coals were first treated with a hot alkaline solution and then with a dilute mineral acid. Different alkalis and acids were studied to determine their relative effectiveness. In addition, the effects of alkali concentration, treatment temperature, and treatment time were evaluated. Under the best conditions, the process reduced the ash content of the coals by 85-90% and the total sulfur content by 70-90%. As the temperature of the alkaline treatment was raised from 150 to 345 C, the removal of sulfur increased greatly whereas the recovery of organic matter declined. When a 1 M sodium carbonate solution was employed for the treatment, the recovery of organic matter was 91-97% for various coals treated at 250 C and 79-89% for the same coals treated at 300 C. 

Since lysinoalanine and at least one D-amino acid are toxic to some animals (35), we wished to distinguish their effects in alkali-treated proteins. Such discrimination is possible, in principle, since we have found that acylating the e-amino group of lysine proteins seems to prevent lysinoalanine formation. Since lysinoalanine formation from lysine requires participation of the e-amino group of lysine side chains, acylation of the amino group with acetic anhydride is expected to prevent lysinoalanine formation under alkaline conditions if the protective effect survives the treatment. This is indeed the case (16). 

The following study illustrates the effect of alkali treatment on the growth-promoting properties of com. The growth-promoting effect was attributed to the release of bound niacin. Rats consumed diets in which the only source of niacin was com meal (O) or alkali-heated com meal ( ), Other rats consumed com meal diets (A) or alkali-treated com meal diets (A.) supplemented with niacin (Figure 9.67). 

Effects of Alkali. Although alkali had been used to treat certain foods for many years, only recently has it been used widely by the texturized protein industry. Alkali-mediated degradation of proteins has long been known (13, 39-44). Some of the main initial reactions are apparently / -eliminations of cystines and substituted serines and threonines. The products (or their intermediates) then alkylate various other amino acid side chains to form substances like lanthionine and lysino-alanine [N -(DL-2-amino-2-carboxyethyl)-L-lysine]. Possible toxicities are currently under investigation (45, 46), but nutritional losses could also be important. 

Hofmann (130) has described three methods for the preparation of a-coniceine, but these yield different products. The action of fuming hydrochloric acid on conhydrine produces the tertiary base a-coniceine, whereas the effect of alkali on iodoconhydrine and that of sulfuric acid on bromoconiine produce -coniceine and 5-coniceine respectively (132). If, on the other hand, bromoconiine is treated with alkali, y-coniceine is obtained. /3-Coniceine is the main product of the dehydration of conhydrine with phosphoric anhydride and pseudoconiceine is obtained as a product of the dehydration of pseudoconhydrine (191). 

It is Important to know the separate effects of racemization and crosslinking for several proteins, especially those important in food systems. Therefore, the purpose of this study was to isolate racemization from crosslinking, examine the effects of racemization on i vitro digestibility of alkali-treated zein and in vivo accumulation of alkali-trated protein by Isolated rat jejunum. 

Ohta, T., I. T. Kim, M. Egashira, N. Yoshimoto, and M. Morita. 2012. Effects of electrolyte composition on the electrochemical activation of alkali-treated soft carbon as an electric double-layer capacitor electrode. Journal of Power Sources 198 408-415. 

Effect of fiber loading From the studies on the dielectric constant of OPF-LLDPE composites, the dielectric constant is found to increase with fiber loading [39]. This trend of increase in effective dipole moment of the composites was due to the polar groups in the filler material [78]. Similar trend for coconut fiber-polypropylene composites were also observed [79]. It is interesting to note that the increase in dielectric constant with OPF loading was more prominent in case of alkali-treated fiber composites. 

Effect of fiber size The dielectric constant of alkali-treated fiber composites changed slightly with fiber size, however untreated fiber composites did not show variation with fiber size [39]. The effective dielectric constant decreases with increasing filler size due to increased interface volume when filler of less particle size was used for a given volume fraction of filler [31]. Also at a given volume fraction of filler, the smaller particle size has more polarization in the interface surface as a result of increased moisture absorption for small size fillers due to increased surface area [78]. Water has unfavorable dielectric properties, which increases the dielectric constant. 

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