Low cholesterol egg powder. Nutritive and quality characteristics of the product

The purpose of this study is to obtain a low cholesterol egg powder for the preparation of different foods for persons whose egg consumption is restricted. Egg white and yolk mixtures prepared in different proportions were dehydrated; the following dried mixtures were obtained: A (1:1), B (2:1) and C (3:1) of egg white:yolk respectively. These mixtures were evaluated using the following parameters: proximal analysis, microbiological assay and protein quality evaluation. Physical characteristics of the powder and the sensorial tests of foods prepared with these mixtures were carried out. The fat and the cholesterol content in the mixture C were decreased by 40% and 20% respectively. The microbiological tests showed that the three mixtures were safe for human consumption. The PER of sample A (whole egg) was 3.65 and for the mixture C 3:1 egg white:yolk was 3.05. The PER of the 50:50 protein mixtures eggs white and yolk: with corn lime treated flour (HMN) were higher than that of the casein standard. The sensorial tests of the foods prepared with all the mixtures were acceptable.     

Kairomones for the egg parasiteTrichogramma evanescens Westwood

In observation-cage experiments some new contact kairomones for the egg parasiteTrichogramma evanescens Westwood are demonstrated.T. evanescens females search significantly longer on cabbage leaves treated with the wing scales of two hosts,Pieris brassicae L. andP. rapae L. Further, egg washes ofP. brassicae containing an oviposition deterrent pheromone for the butterflies, were found to have a contact-kairomonal effect on the parasite.T. evanescens females search significantly longer on cabbage leaves sprayed with a methanol or water wash ofP. brassicae eggs than on leaves treated with the solvent only.Hymenoptera: Trichogrammatidae.Lepidoptera: Pieridae.     

N.m.r. study of egg yolk lecithin in aromatic solvents. Magnetic nonequivalence in the methylene protons of the fatty acyl chains

¹H and ¹³C n.m.r. chemical shifts and also spin-lattice relaxation times of phospholipids, mainly egg yolk lecithin, were measured in organic solvents, especially aromatic solvents. The use of aromatic solvents promotes the difference in the magnetic shielding environment of the internal methylene protons of the fatty acyl chains and as a result, a doublet peak for the methylene groups was observed in the solvents, especially mesitylene. The ¹H and ¹³C n.m.r. T₁ measurements indicate the remarkable gradient in the motional freedom along the fatty acyl chains as well as the marked decrease in the motional freedom of the polar head group and also, the high-field component of the doublet peak for internal methylene protons has a shorter T₁ value than the low-field component. Thus, it was concluded that the low-field component in the doublet comes from the methylene protons located relatively in the neighbourhood of the carbonyl groups and the high-field component the methylene protons located relatively in the neighbourhood of the terminal methyl groups of the fatty acyl chains.     

蛋黄磷脂的提纯

利用蛋白质不溶或微溶于某些溶剂的特点,用混合溶剂萃取粗蛋黄磷脂制备精蛋黄磷脂的工艺,该工艺易于实现工业化生产,磷脂纯度可达98%以上。     

预分解窑结蛋机理研究

对预分解窑所产生的大蛋进行了化学分析、Ｘ－射线衍射分析及电子探针分析,运用微机统计了中控室的操作参数,指出预分解窑结蛋的关键原因在于煤粉的不完全燃烧。     

Phosphatidylinositol metabolism during fertilization in the sea urchin egg

Fertilization of the sea urchin egg results in a transient decline in the amount of phosphatidylinositol (PI) to a level equal to about 50% of that present in the unfertilized egg. This response begins as early as 15 seconds after insemination. The level of PI reaches a minimum at 30 seconds post-insemination, and returns to the original value between 2 and 5 min later. Pulse labelling studies with³²PO₄ and [³H]-inositol showed that the incorporation of these two isotopes into 1-(3-sn-phosphatidyl)-L-myoinositol 4,5-biphosphate [PtdIns(4,5)P₂] increased as much as 50% within one minute after insemination. This suggests that at least part of the reduction in PI levels represents the phosphorylation of PI to form PtdIns(4,5)P₂. We also found that the production of [³H]-labelled 1D-myoinositol 1,4,5 triphosphate [Ins(1,4,5)P₃] present in the trichloroacetic acid (TCA) soluble fraction of eggs increased over five-fold during the first 10 min post insemination. The temporal correlation between the early burst of PtdIns(4,5)P₂ and Ins(1,4,5)P₃ formation and the transient increase in intracellular free calcium known to occur in the fertilized egg suggest that the production of PtdIns(4,5)P₂ and ultimately Ins(1,4,5)P₃ may be associated with calcium mobilization within the egg.     

The emulsifying properties of egg yolk phosphatidylcholine

The effects of lipid concentration and w/w ratios on the formation of emulsions by some combinations of phosphatidylcholine, cholesterol oleate, cholesterol and triglyceride were studied, with the following results. Phosphatidylcholine emulsified cholesterol oleate and triglyceride, the degree of dispersion and emulsion stability increasing with phosphatidylcholine concentration. Cholesterol reduced the degree of dispersion of phosphatidylcholine-triglyceride emulsions but enhanced the emulsion stability. Triglyceride disrupted the colloidal phase of phosphatidylcholine and cholesterol in high concentrations and did so more effectively when the proportion of cholesterol to phosphatidylcholine was high.     

真空冷冻干燥鸡蛋粉的实验研究

用电阻法测定了蛋清、蛋黄以及全蛋混合液的共晶点温度，通过对蛋清、蛋黄以及全蛋的多次冻干实验．分析了三种蛋粉的冻干曲线，探索了真空冷冻干燥鸡蛋粉的工艺。     

蛋壳制备乳酸钙的研究

对蛋壳的壳膜分离及综合利用制取乳酸钙进行了研究。采用酸浸法分离壳膜，高温煅烧分解蛋壳，中和法制备乳酸钙，产率可达９０．８％。     

Selective extraction of phospholipids from egg yolk

Solubility differences of phospholipids and tri-glycerides in methanol have been used with advantage for the selective quantitative extraction of phospho-lipids, almost free of triglycerides, from egg yolk. Cholesterol, a comparatively minor component of egg yolk lipids, is easily removed from the methanolic solution of phospholipids by low temperature crystal-lization (5 C), if required.     

Constituent fatty acids of salmon egg fat

Summary and Conclusions 1. The constituent fatty acids determined by the Hilditch method in the fat from the sample of pink salmon eggs are reported. Forty-five per cent of the fatty acids were 20 and 22 carbon atoms long, with an average unsaturation of 7.3 hydrogen atoms for the C₂₀ acids and 11.8 hydrogen atoms for the C₂₂ acids. 2. The Hammond and Lundberg correlation of refractive index, carbon chain length, and unsaturation was used to measure the alteration that occurred in the fatty acid esters of salmon egg fat during the vacuum distillation step of the Hilditch method of analysis. The alteration by heat of the unsaturate fraction in the vacuum distillation was significant even in the first overhead subfractions. Analysis by the Hilditch method resulted in low values for unsaturation and chain length of the constituent fatty acids in the unsaturated fat. The Fishery Products Laboratory is operated jointly by the U. S. Fish and Wildlife Service and the Alaska Fisheries Experimental Commission.     

Lipase from egg of southern corn rootworm

The lipolytic activity in homogenates and aqueous extracts of acetone powders of eggs of the southern corn rootworm (Diabrotica undecimpunctata howardi Barber) was studied. The general properties were determined using as substrate olive oil in an emulsion stabilized by gum arabic. Bovine serum albumin or Triton X-100 were required in the assay system; they protected the enzyme from spontaneous denaturation. The lipase had activity optima at pH 7 and at 45 C. The preparation was inactive towards triacetin, and activity increased in the series tripropionin<tributyrin<trihexanoin< trioctanoin<tridecanoin. Activity towards tridecanoin. Triolein was hydrolyzed to oleic acid and glycerol with no marked accumulation, even transient, of partial glycerides.     

Sterculic derivatives and pink egg formation

Sterculyl alcohol has been methylated and reduced to form the methoxyl and hydrocarbon derivatives. These two derivatives, sterculyl alcohol and the polymers of sterculic acid and methyl sterculate were fed to laying hens. The sterculic derivatives caused pink egg formation but the polymers did not. Supported in part by National Cotonseed Products Association, Inc., Dallas, Texas. Arizona Agricultural Experiment Station Technical Paper No. 693.     

Chromatographically homogeneous lecithin from egg phospholipids

Chromatographically homogeneous egg lecithin, as determined by TLC on Silica Gel G, has been isolated from crude egg phosphatides by column chromatography on alumina through modification of existing, lengthy methods. The modified method involved application of crude egg phosphatides to a column of alumina in the proportion of 1 g phosphatide/25 g alumina, and elution of the lecithin fraction with the 2-component solvent system chloroform:methanol, 9:1 by vol. This method of purification separated lecithin from other choline and non-choline components of crude phosphatides, avoided overloading of the alumina column, and made unnecessary the need for a second chromatographic fractionation of partially purified lecithin on silicic acid, which is needed in existing methods of purification of lecithin. The use of fresh yolks permitted easier removal of pigment from the final product than was possible with commercially dried yolks. Phosphatides extracted from dried yolks were much more highly colored than were the phosphatides extracted from fresh yolks and the color presisted through chromatography on alumina. The fatty acid/phosphorus molar ratio of the purified lecithin was 2.00, which is the theoretical FA/P molar ratio of phosphatidylcholine; other materials with this ratio were not present. Presented at the AOCS Meeting, New Orleans, 1964. A laboratory of the So. Utiliz. Res. & Dev. Div., ARS, USDA.