Hydrolysates, soy

Chandra RK Five-year follow-up of high-risk infants with family history of allergy who were exclusively breast-fed or fed partial whey hydrolysate, soy, and conventional cow s milk fomulas. J Pediatr Gastroenterol Nutr 1997 24 3S0-388. (Ib)... 

Synonyms Lauryidimonium hydroxypropyl hydrolyzed soy protein (INCI) Protein, hydrolysates, soy, [3-... 

Protein hydrolysates, soya, reaction prods, with isostearoyl chloride, compds. with 2-amino-2-methyl-1-propanol. See AMP-isostearoyl hydrolyzed soy protein Protein, hydrolysates, soy, [3-(dodecyldimethylammonio)-2-hydroxypropyl], chlorides. See Laurdimonium hydroxypropyl hydrolyzed soy protein Protein hydrolysates, spinal cord. See Hydrolyzed spinal protein... 

DCP and 0.01 0.5 mg/kg of 2,3-DCP. Their actual amounts depend primarily on the content of lipids in the raw proteinaceous material, the concentration and amount of hydrochloric acid and the temperature during hydrolysis. Chloropropanols are also found in soy sauces made from mixtures of acid and enzymatic protein hydrolysates. Soy sauces produced exclusively by traditional fermentation do not contain chloropropanols. 

Plasteins ate formed from soy protein hydrolysates with a variety of microbial proteases (149). Preferred conditions for hydrolysis and synthesis ate obtained with an enzyme-to-substrate ratio of 1 100, and a temperature of 37°C for 24—72 h. A substrate concentration of 30 wt %, 80% hydrolyzed, gives an 80% net yield of plastein from the synthesis reaction. However, these results ate based on a 1% protein solution used in the hydrolysis step this would be too low for an economical process (see Microbial transformations). 

The sulfur amino acid content of soy protein can be enhanced by preparing plasteins from soy protein hydrolysate and sources of methionine or cystine, such as ovalbumin hydrolysate (plastein AB), wool keratin hydrolysate (plastein AC), or L-methionine ethyl ester [3082-77-7] (alkaU saponified plastein) (153). Typical PER values for a 1 2 mixture of plastein AC and soybean, and a 1 3 mixture of alkah-saponified plastein and soybean protein, were 2.86 and 3.38, respectively, as compared with 1.28 for the soy protein hydrolysate and 2.40 for casein. 

The enzymatic hydrolysates of milk casein and soy protein sometimes have a strong bitter taste. The bitter taste is frequently developed by pepsin [9001 -75-6] chymotrypsin [9004-07-3] and some neutral proteases and accounted for by the existence of peptides that have a hydrophobic amino acid in the carboxyhc terminal (226). The relation between bitter taste and amino acid constitution has been discussed (227). 

NSP content of soy bean meal and HWS was determined by the method of Englyst and Cummings [5]. The starch was enzymatically hydrolysed, the residue was dried and the sugar composition was determined. 

Table IV). Huff et al (11) extended these observations to include enzymatic hydrolysates of the native proteins and amino acid mixtures equivalent to soy or casein. In this experiment amino acid contents were identical among the diets fed as the three forms of each protein but the structure was different (Table V). 

Table V. Serum Cholesterol Levels in Rabbits fed Casein, Soy Protein, Their Hydrolysates and Their Amino Acid Mixtures...

Intact soy protein Enzymatic hydrolysate Amino acid mixture... 

In contrast, the whey proteins are relatively small globular proteins. a-Lactalbumin represents about 20 % of the protein content of bovine whey (3.5 % of total bovine milk protein), and it is the principal protein in human milk (Brew and Grobler, 1992). Nanotube assembly has been discovered in some solutions containing a hydrolysed derivative of this protein. And it appears that the a-lactalbumin nanotube is unique in the sense that it is the only artificial nanotube that has so far been made from a food protein (Graveland-Bikker et al., 2004 Graveland-Bikker and de Kruif, 2006). As for p-lactoglobulin, it has the capacity under certain specific conditions to form nano-fibres in aqueous media (as can various other globular food proteins, such as ovalbumin, soy proteins, and bovine serum albumin) (van der Linden, 2006 Nicolai, 2007). 

Kirchgessner and Steinhart (52) studied the in vitro digestion of soy protein isolate with pepsin. They showed that a relatively higher percentage of the essential amino acids threonine, valine, isoleucine, leucine and phenylalanine were found in the undigested residue and therefore would be present in lower proportions in the hydrolysate. Myers et al. ( ) hydrolyzed a soy protein isolate with a fungal acid protease. They also found that the essential amino acid content of the hydrolyzate was lower than the isolate, but, as prepared by their continuous process, the hydrolyzate PER was not significantly reduced as compared to the isolate PER. 

Figure 7. Emulsifying activity (expressed as volume percentage of the emulsified layer) of pepsin hydrolysates of soy protein as a function of pH and hydrolysis time. No hydrolysis (A) 2 h ( ) 8 h (X) 17 h ( ) 24h(O) (39).

Degradation of proteins by proteases has important implications for the quality of many foods. These include beneficial effects in the development of desirable attributes, such as texture and flavor, e.g. in cheese manufacturing, meat tenderization, beer brewing, soy and fish sauce manufacturing, and production of protein hydrolysates of various origins for different functional or nutritional purposes. The proteases involved may be endogenous to the foods or they may be added for specific pur-... 

Various applications of PITC in analyses of acid hydrolysates of purified proteins and peptides (91) and of hydrolysates of feeds (92) have been described. Bidlingmeyer et al. (93) showed reversed-phase chromatographic analysis of free amino acids and hydrolysates of foods (soybean flour, mozzarella cheese, beer, and soy sauce) with formation of PITC derivatives to be a fast, reproducible method that presented a very good correlation with the results obtained by ion-exchange chromatography. 

Enzymatic hydrolysis is a nondestructive alternative to saponification for removing triglycerides in vitamin K determinations. For the simultaneous determination of vitamins A, D, E, and K in milk- and soy-based infant formulas and dairy products fortified with these vitamins (81), an amount of sample containing approximately 3.5-4.0 g of fat was digested for 1 h with lipase at 37°C and at pH 7.7. This treatment effectively hydrolyzed the glycerides, but only partially converted retinyl palmitate and a-tocopheryl acetate to their alcohol forms vitamin D and phyllo-quinone were unaffected. The hydrolysate was made alkaline in order to precipitate the fatty acids as soaps and then diluted with ethanol and extracted with pentane. A final water wash yielded an organic phase containing primarily the fat-soluble vitamins and cholesterol. 

Pati et al. [93] Choline Milk, milk powder and soy lecithin hydrolysates Choline oxidase/ immobilised onto an electropolymerised polypyrrole film Pt electrode ... 

S. Pati, M. Quinto, F. Palmisano and P.G. Zambonin, Determination of choline in milk, milk powder, and soy lecithin hydrolysates by flow injection analysis and amperometric detection with a choline oxidase based biosensor, J. Agric. Food Chem., 52(15) (2004) 4638-4642. 

Nagaoka, S., Miwa, K., Eto, M., Kuzuya, Y., Hori, G., and Yamamoto, K. 1999. Soy protein peptic hydrolysate with bound phospholipids decreases micellar solubility and cholesterol absorption in... 

Cheese whey demineralization Desalting of protein hydrolysates (i.e., soy sauce), sugar solutions, molasses, and polysaccharide dispersions Deacidification of fruit juices Tartaric wine stabilization Flavor recover from pickle brines... 

Recently, plant hydrolysates have also been tested as additives for serum-free culture media (Donaldson and Shuler, 1998 Franek et al., 2000 Heidemann et al., 2000). Donaldson and Shuler (1998) demonstrated that a peptide obtained from soy hydrolysate (Hy-Soy ) played an important role in a serum-free medium developed for insect cells. Ikonomou et al. (2003) also showed the effectiveness of culture medium supplemented with the soy hydrolysate SE50MAF in the growth of High Five cells. 

Jackson, H.A., Jackson, M.W., Coblenz, L., and Hammerberg, B. 2003. Evaluation of the clinical and allergen-specific serum immunoglobulin-E responses to oral challenge with cornstarch, corn, soy and a soy hydrolysate diets in dogs with spontaneous food allergy. Vet Derm 14 181-187. 

Preparation of cheeses and soy derivatives Solubilization of protein concentrates Production of protein hydrolysates Gluten modification in bread doughs Chillproofing of beer Plastein formation Tenderization of meats Quality determination of proteins... 

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