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Changes in chemical composition of Alxa bactrian camels reared in Inner Mongolia (China) during lactation were investigated. Colostrum and milk samples from 10 nomadic female camels in their first season of lactation were collected periodically from parturition until 90 d postpartum (PP). The average contents of gross composition were 14.23% protein, 4.44% lactose, 0.27% fat, 0.77% ash, and 20.16% total solids in colostrum at 2 h PP, and the respective mean values were 3.55, 4.24, 5.65, 0.87, and 14.31% for regular milk on d 90. A 15-fold increase was shown in fat content during the first 24 h, whereas a sharp decrease was shown during the first 12 h of lactation in protein, ash, and total solids contents. Variation in lactose content was small (4.24 to 4.71%) throughout the study period. Total N, nonprotein N, casein N, and whey protein N were found to be 2.23, 0.06, 0.86, and 1.31 g/100 mL for the colostrum at 2 h PP; and 0.56, 0.04, 0.45, and 0.07 g/100 mL for the milk at 90 d PP. Percentages of caseins increased steadily, whereas whey proteins declined gradually until 3 mo of lactation. Gas liquid chromatography analysis of milk fat showed that the content of even-numbered saturated fatty acids (C12:0-C18:0) in camel colostrum (2 h to 7 d PP) was lower than that of regular milk (15 to 90 d PP). The predominant saturated fatty acids were C14:0, C16:0, and C18:0, regardless of the stage of lactation. There was a considerable level of polyunsaturated fatty acids (mainly C18:1) in Alxa camel's milk fat. The levels of Ca, P, Na, K, and Cl were 222.58, 153.74, 65.0, 136.5, and 141.1 mg/100 g, respectively, at 2 h PP; the values of the minerals were 154.57, 116.82, 72.0, 191.0, and 152.0 mg/100 g, respectively, for the regular milk on d 90. The levels of vitamins A, C, E, B1, B2, B6, and D were 0.97, 29.60, 1.45, 0.12, 1.24, 0.54 mg/L, and 640 IU/L, respectively, in Alxa camel milk at 90 d PP. Vitamin A and C contents were higher and vitamins E and B1 were lower than those in colostrum. Sodium dodecyl sulfate-PAGE and densitometry results demonstrated that Alxa camel colostrum is rich in immunoglobulins, serum albumin, and 2 unknown fractions, which are reduced in amount (%) within 2 d of lactation. It seems that there is lack of beta-lactoglobulin in Alxa camel milk, whereas casein and -lactalbumin start at a low level and increase gradually until they reach their regular levels in the milk.

Garden cress (Lepidium sativum) belonging to the family Cruciferae grown in India, Europe and US is an underutilized crop. The edible whole seed is known to have health promoting properties. Hence, it was assumed that these seeds can be a functional food. A preliminary work on chemical composition of seeds was carried out and the possibility of using it as nutraceutical food ingredient in dietary fiber formulation was explored. Three fractions namely whole meal (WM), endosperm and bran were analyzed for chemical composition. The yield of the endosperm and the bran fraction were 72 and 28%, respectively. The WM, endosperm and bran had 22.5, 27.7 and 12.6% protein, 27.5, 33.1 and 6% fat, 30, 13.6 and 75% dietary fibre (DF), and 1193.00, 945.15 and 1934.57 mg% potassium respectively. The major protein on SDS-PAGE was of 29.5 kDa. The most abundant amino acid was glutamic acid (19.3%) and the essential amino acid, leucine was the highest (8.21 +/- 0.01%) and methionine the lowest (0.97 +/- 0.02%). The major fatty acid was linolenic acid (30.2%) and low amount of erucic acid (3.9%) was also present. Bran having high water holding capacity and high DF, its use as source of DF was explored. The product contained 12% protein, 4% fat and 74.3% DF and exhibited desirable functional properties such as dispersibility, gelling ability, stability, formed homogenous mild alkaline suspension and was comparable to proprietary DF.

The susceptibility of beta-LG and sodium caseinate to proteolysis by pepsin and trypsin was investigated using SDS or urea-PAGE. The effects were studied of heat, urea, and 2-mercaptoethanol on proteolysis. Native beta-LG was resistant to hydrolysis by pepsin or trypsin because of its compact globular structure. Heat treatment of beta-LG solutions at 90 to 100 degrees C for 5 or 10 min caused changes in the structure or conformation of the protein that rendered it accessible to pepsin and enhanced the extent of proteolysis by trypsin. The susceptibility of beta-LG to proteolysis by pepsin was markedly increased in the presence of urea (3 to 6 M), and the effect was reversible after removal of urea by dialysis. Proteolysis by trypsin was also increased by the presence of 2% 2-mercaptoethanol. Sodium caseinate was very accessible to pepsin without pretreatment and was extensively hydrolyzed at pH 1 to 5 in the presence of 5 M urea (which prevented the protein from precipitation in the isoelectric region); optimal pH was about 2. The activity of pepsin on sodium caseinate at pH 2 was not significantly affected by urea concentration up to about 8 M. The results indicated that the changes in conformation and structure of beta-LG that were induced by heating, reduction, or urea rendered the protein susceptible to peptic hydrolysis.

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