Protein content hydrolysates

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). 

Results on the carbon balances for these fermentation experiments with paper sludge hydrolysate are presented in Table 3. Interference of unidentified components in the hydrolysate with the protein content determination disallowed accurate biomass content determination, resulting in an incomplete mass balance. However, similar OD was measured as observed for the mixture of pure sugars (condition C). 

Kang, K. H., Qian, Z. J., Ryu, B. M., and Kim, S. K. (2011). Characterization of growth and protein contents from microalgae Navicula incerta with the investigation of antioxidant activity of enzymatic hydrolysates. Food Sci. Biotechnol. 20,183-191. 

An interesting aspect is gained from checking the content of cystine in hydrolysates of sera obtained from both healthy and diseased persons. In disease the cysteine content in the serum is decreased, as has been shown in patients suffering from carcinoma (43). There exists a parallel with the protein content, and therefore this state may express hypo-proteinemia and may be due to a decrease of albumin alone, even if globulins are simultaneously normal or moderately increased, since the cysteine content in human albumin is more than twice as high as that in human globulin. 

Merino wool top was cleaned by sohxlet extraction using dichloromethane to remove fatty matters and repeated washing with cold water. Hie wool was air dried at about 40°C. The wool proteins were extracted overnight from wool by an extensive treatment with 8M Tris/urea buffer containing (SO mM) dithiothreitol as reduction chemical at pH 9.3 and 25 °C. The reaction was stopped using 20% iodoacetamide. The wool proteins were dialysed against distilled water for 4 days. The protein content of the enzymes and the wool hydrolysate were determined using the Lowry assay [6]. 

Pure urea has a nitrogen content of 466 g/kg, which is equivalent to a crude protein content of 466 X 6.25 = 2913 g/kg. Feed urea contains an inert conditioner to keep it flowing freely, and this reduces its nitrogen content to 464 g/kg, equivalent to 2900 g/kg crude protein. Urea is hydrolysed by the urease activity of the rumen microorganisms with the production of ammonia ... 

Protein is subjected to extensive changes when heated in the presence of carbohydrates. There is a shift of the amino acid composition of coffee protein acid hydrolysates before and after bean roasting (Table 21.4). The total amino acid content of the hydrolysate drops by about 30% because of considerable degradation. 

Fig. 2.8 Interfacial tension of p-lactoglobulin (P-LG), whey protein isolate (WPI) and whey protein hydrolysates (WPH) with varying degree of hydrolysis (DH) at the air-water interface during 15 min (left) and right) interfacial tension after injection of the protein solution into a droplet of water (protein content /e/t 1.2 wt% right, approximately 0.4 wt% final protein content after injection). The interfacial pressure is defined as the difference between the interfacial tension of water and the interfacial tension with protein present...

Fig. 2.12 Development of the interfacial tension of p-lactoglobulin and its hydrolysates at the air-water top) and the oil-water interface (bottom) for 15 min with 0.1 wt% protein content in solution. Left hydrolysates of p-lactoglobulin produced using trypsin. Right hydrolysates of P-lactoglobulin produced using alcalase. Percentage in sample names indicate the degree of hydrolysis...

Fig. 2.14 Amplitude sweeps for the deteimmatirai of the linear viscoelastic regime of p-lactoglobulin and a tryptic hydrolysate with DH 6% produced using trypsin at the oil-water interface, protein content 0.01 wt%, pH 8.0, frequency/= 0.3 Hz...

In 4 neonates the development of an isosmolar coma during parenteral alimentation with protein hydrolysate in excess of 4 g/kg/day has been observed. This hitherto unreported complication of parenteral nutrition is characterized by increasing stupor, diminished muscular activity and finally frank coma. These manifestations developed within 6—12 hours after the protein content of the infusate, casein, protein hydrolysate (Cutter) had been increased to or beyond 4 g/kg/day. During the coma, the serum osmolality was normal, the specific gravity of the urine decreased. Reversal of the clinical symptoms occurred promptly when the protein-containing infusion was discontinued (43 ). 

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. 

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). 

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