首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A sensitive and specific method is described for quantifying various cholesterol oxidation products in foodstuffs, including 7β-hydroxycholesterol, cholesterol-α-epoxide, cholestane-triol, 7-ketocholesterol and 25-hydroxycholesterol. A chloroform-methanol extract of the food was fractionated over two successive silica columns. Two fractions containing different classes of oxysterols were then analyzed as trimethylsilyl derivatives by capillary gas liquid chromatography, using on-column injection and a temperature gradient from 70 to 200°C. The detection limit was about 0.5 μg/g dry weight for egg yolk powder. Fresh egg yolk contained only 1.2 μg/g of total oxides per g dry weight, showing that artifactual oxidation during the procedure was minimal. Recovery of 5 pure oxysterols added to egg yolk at levels of 6.5 and 10 μg/g was between 93 and 102%. In commercial egg yolk and whole egg powder stored for one year, total amounts of oxysterols ranging from 21 to 137 μg/g dry weight were found. In duplicates of mixed Dutch diets, total amounts ranged from 3.6 to 6.2 μg/g dry weight. Duplicates containing mostly fried and baked foods did not have higher levels than duplicates in which foods had been prepared by boiling or left raw. We conclude that a normal mixed diet provides only minor amounts of cholesterol oxidation products.  相似文献   

2.
Three mixtures of precooked white corn flour with 10, 20 and 30% amaranth flour were prepared. The sedimentation and consistency of the mixtures differed from those of the white corn flour, but without altering the capacity of dough formation to prepare arepas. The protein, fiber, and ash contents were higher than those of the precooked white corn flour. The functional properties of water and oil absorption increased in 20 and 10%, respectively. During the three-month storage, the protein and fat contents were not altered. Acceptability tests of the arepas were carried out and results indicated that those mixtures prepared with 10% and 20% substitution levels were acceptable from the sensory point of view. The protein quality was analyzed in terms of protein efficiency ratio (PER), which proved to be higher than that of the commercial white corn flour (PER 1.93), and the apparent digestibility was 92%. As far as lysine is concerned, results showed that arepas prepared with the mixture containing 10% amaranth (1.6 g lysine/100 g protein) and 20% (2.0 g lysine/100 g protein) also proved to be higher than the commercial white corn flour arepas (0.7 g lysine/100 g protein). Based on the above findings, enrichment of commercial white corn flour with grain amaranth flour, prior to the preparation of arepas, a product of high consumption in Venezuela as part of the habitual diet, is recommended.  相似文献   

3.
D. L. Wood  Joel Bitman 《Lipids》1980,15(3):151-156
Di-(2-ethylhexyl)phthalate (DEHP), a commonly used plasticizer, is now seen as an environmental pollutant. DEHP has been found to inhibit lipid and sterol synthesis in rats and mice. The effects of DEHP on various aspects of lipid metabolism were examined in chickens. White Leghorn laying hens were fed either a standard laying mash control diet (C) or the control diet containing 1% DEHP (DEHP) or 1% DEHP and 5% tallow (DEHP-T) for 28 days. DEHP and DEHP-T lowered feed consumption 10% but did not significantly affect body weight. After 3 weeks on the diets, egg production was 15–20% less in DEHP-T than in C and DEHP hens. No differences were observed in egg weight, percent shell, white or yolk among the groups. DEHP and DEHP-T did not alter egg lipid or egg cholesterol concentrations. DEHP and DEHP-T lowered plasma lipid concentration about 20% and free and total cholesterol 20–30%. Liver weights increased, being 30, 34 and 39 g for C, DEHP and DEHP-T hens, respectively, after 28 days. Total liver lipid and cholesterol increased 19% and 26% in DEHP hens and 54% and 79% in DEHP-T hens when compared to controls. In contrast, the fat content of pectoralis major muscle decreased significantly in DEHP and DEHP-T hens. These results, in showing that DEHP alters plasma and tissue cholesterol but not yolk cholesterol, demonstrate again that egg cholesterol is remarkably resistant to alteration by dietary means.  相似文献   

4.
The effects of cholesterol on droplet size distribution and rheological properties of cholesterol-reduced egg yolk-stabilized emulsions were determined. Oil-in-water emulsions were prepared by using spray-dried eggs submitted to different levels of cholesterol reduction (14–81 wt% of cholesterol removed). Cholesterol was extracted in a modified Jennings apparatus with subcritical CO2 (9°C and 4.66·106 Pa). Oscillatory and steady flow tests, as well as droplet size distribution measurements, were carried out on the cholesterol-reduced egg yolk-stabilized emulsions. The rheological parameters increased with the level of cholesterol reduction up to 40–80 wt% for emulsions having the same total amount of egg yolk. Opposite results, however, were obtined with some emulsions stabilized by a highly cholesterol-reduced (≈80 wt%) egg yolk. These results were explained by taking into account two opposite phenomena: an increase in the concentration of surface-active agents as cholesterol content decreased, and a lipoprotein structural rearrangement induced by cholesterol removal.  相似文献   

5.
Physical characterization and oxidative stability of egg powder microencapsulated by spray drying were studied in this work. The wall material (gelatin, lactose, pullulan, and their mixtures) and liquid egg mixtures were prepared by homogenization at 22,000 rpm for 60 s. The spray drying was carried out at pilot-scale spray dryer (Niro Mobile Minor, Søborg, Denmark). The spray-dried egg powders were analyzed for moisture content, water activity, peroxide value, total cholesterol oxidation products (TCOPs), particle properties, and bulk properties. Using gelatin as wall material resulted in a significant increase in the moisture content and water activity of egg powder during storage and it improved flowability. Egg powders containing pullulan as wall material showed a fibrous structure and had the lowest bulk density. Adding lactose as wall material increased the oxidative stability, which was indicated with lowest peroxide value and TCOPs level of egg powder.  相似文献   

6.
Nakane S  Tokumura A  Waku K  Sugiura T 《Lipids》2001,36(4):413-419
Hen egg yolk and white were found to contain high amounts of lysophosphatidic acid (acyl LPA) in addition to small amounts of lysoplasmanic acid (alkyl LPA). The levels of acyl LPA in hen egg yolk (44.23 nmol/g tissue) and while (8.81 nmol/g tissue) were on the same order as or higher than the levels of acyl LPA known to be required to elicit biological responses in various animal tissues. Noticeably, there is a marked difference between the fatty acid composition of egg yolk acyl LPA and of egg white acyl LPA; egg yolk acyl LPA predominantly contains saturated fatty acids as the acyl moiety, whereas egg white acyl LPA primarily contains polyunsaturated fatty acids. We found that the level of acyl LPA, especially polyun-saturated fatty acid-containing acyl LPA, in egg white was augmented markedly during the incubation at 37°C, while there was no change in egg yolk. We confirmed that egg white contains both the substrate, i.e., polyunsaturated fatty acid-containing lysophosphatidylcholine (LPC), and the enzyme activity catalyzing the hydrolysis of polyunsaturated fatty acid-containing LPC to the corresponding acyl LPA. Egg yolk LPA and egg white LPA may play separate physiological roles in the development, differentiation, and growth of embryos.  相似文献   

7.
Soybeans were used as extenders of common beans in the form of whole beans and precooked, powdered form. Mixtures containing 20, 25, 30, 35, 40, 45 and 50% soybeans were studied. Sensory evaluations (preference tests) showed no preference for mixtures containing up to 50% soybeans over 100% common beans. On the other hand, nutritional differences were detected between common beans and mixtures with more than 20% soybean. The mixture with 50% common beans and 50% soybeans contained 27.9% crude protein, 13.2% lipids and 47.2% carbohydrate. The amino acid composition was improved particularly by increasing cystine from 0.6 to 1.2% of the protein and methionine from 0.7 to 1.2%. The protein efficiency ration (PER) values fo the 50:50 mixture for rats was 1.6 compared to 1.0 for the common bean. Acceptability of the 50:50 mixture in different institutional trials did not differ in consumption from that of common beans and no sign of physiological disturbance was observed. When the mixture was precooked, dried and ground to a powder, it served as an excellent base for an instant soup. The formulation containing 80% of the 50:50 mixture, 10% corn starch and seasonings had (%) 21.3 protein, 10.8 lipid, 5.3 crude fiber and 51.9 carbohydrate with total metabolizable energy of 390 Kcal/100 g and an NDP Cal%=12. The hydration capacity of the 50:50 mixture was 162 g water/100 g mixture whereas that of the soup with all ingredients added was 205 g water/100 g soup. The acceptability as well as the storage stability of the soup was good.  相似文献   

8.
Results from extraction of cholesterol and other lipid components from dried egg yolk using supercritical carbon dioxide at the range of temperature from 40°C to 60°C and pressure between 150 bar und 350 bar for 2.5 hours and 2.7 kg CO2 consumption is described in this paper. The solubility of lipids and cholesterol increased with the increase of pressure at a constant temperature of 50°C, while at a constant pressure, more cholesterol was removed at 45°C than that at other temperatures. Nearly 60 percent cholesterol was removed at 45°C and 250 bar. Lipids were more efficiently extracted at 60°C than at 40°C at 250 and 350 bar, however, a decrease in the total extracted lipids was observed with the increase in temperature at 150 bar. The removed total lipids from dried egg yolk at 250 bar/55°C was over 80 %.  相似文献   

9.
Phospholipids have been shown to modulate intestinal cholesterol absorption in cells and animals, a process that is regulated by several transporter proteins. Of these proteins, Niemann–Pick C1‐Like 1 (NPC1L1) is a major contributor to this process. The mechanism by which phospholipids modulate cholesterol absorption remains unknown. Here, we evaluate the effects of egg‐yolk phospholipids on cholesterol absorption and transport in human colon carcinoma cell line (Caco‐2 cells) and on the expression of NPC1L1 and others proteins associated with cholesterol absorption (ABCG5, ABCG8, ABCA1, ACAT2, MTP, CAV‐1, ANX‐2). The roles of SREBP‐1 and SREBP‐2 in this process were also investigated. The results show that egg‐yolk sphingomyelin (CerPCho) and phosphatidylcholine (PtdCho) inhibit cholesterol transport in the Caco‐2 monolayer in a dose‐dependent manner. These might be due to the decrease of the cholesterol solubility in micelles as well as to the increases in the micellar sizes and the bile acid‐binding capacity. Furthermore, the treatments with egg‐yolk CerPCho or PtdCho at 1.2 mmol/L reduced the expression levels of NPC1L1 protein to 21 or 22%, respectively, and its mRNA to 9 or 31% of that in the control group (p < 0.05). Moreover, there was a general inhibitory effect of egg‐yolk PtdCho and CerPCho on the mRNA levels of SREBP‐1, and SREBP‐2. These results suggest that the inhibitory effect of egg‐yolk CerPCho and PtdCho on cholesterol transport might be due to their interference with the physicochemical properties of micelles and their regulations on the expression of the NPC1L1 gene.  相似文献   

10.
Mayonnaise samples were prepared using DAG oil as the oil phase; the properties and stability were compared with mayonnaise samples prepared from TAG oil. Normal (nontreated) egg yolk and phospholipase A2 (PLA2)-treated egg yolk were used as emulsifiers. The DAG oil mayonnaise prepared with nontreated egg yolk (DAG-M) was unstable, with cracks forming within 4 wk at 40°C. This type of fracture was not observed for TAG oil mayonnaise prepared with nontreated egg yolk (TAG-M). 31P NMR and quantitative analyses of phospholipids suggested that the phospholipids of egg yolk lipoprotein were dissolved in DAG-M oil droplets, which might result in the coalescence and fracture of the DAG-M. Phospholipids were not dissolved in TAG-M oil droplets. No crack formation was observed for DAG oil mayonnaise prepared with PLA2-treated egg yolk (DAG-PLM) after storage for more than 4 wk at 40°C. 31P NMR spectroscopy and quantitative analyses of phospholipids indicated that the dissolution of phospholipid molecules into the oil droplets was almost prevented in DAG-PLM. The stability of DAG-PLM is improved probably because the PLA2 treatment changes the molecular polarity of egg yolk phospholipids and prevents them from dissolution into the DAG oil droplets from oil/water interface.  相似文献   

11.
Vibrio spp. are major causes of mortality in white shrimp (Litopenaeus vannamei) which is lacking adaptive immunity. Passive immunization with a specific egg yolk antibody (IgY) is a potential method for the protection of shrimp against vibriosis. In this study, immune effects of the specific egg yolk powders (IgY) against both V. harveyi and V. parahaemolyticus on white shrimp were evaluated. The egg yolk powders against V. harveyi and V. parahaemolyticus for passive immunization of white shrimp were prepared, while a tube agglutination assay and an indirect enzyme-linked immunosorbent assay (ELISA) were used for detection of IgY titer. Anti-Vibrio egg yolk was encapsulated by β-cyclodextrin, which could keep the activity of the antibody in the gastrointestinal tract of shrimp. The results showed that the anti-Vibrio egg powders had an inhibiting effect on V. harveyi and V. parahaemolyticus in vitro. Lower mortality of infected zoeae, mysis, and postlarva was observed in groups fed with anti-Vibrio egg powders, compared with those fed with normal egg powders. The bacterial load in postlarva fed with specific egg powders in seeding ponds was significantly lower than those fed with normal egg powders in seeding ponds. These results show that passive immunization by oral administration with specific egg yolk powders (IgY) may provide a valuable protection of vibrio infections in white shrimp.  相似文献   

12.
Cholesterol rich-foods consumption has been related as a causing factor for heart ischemic disease. Because the high cholesterol content of the yolk, the egg consumption has been decreased in spite of it, egg is a complete food, rich in many nutrients, and economically accessible. The cholesterol content in egg yolk has also important properties for the human organism. The present work had the objective to review the scientific literature about egg's cholesterol, describing the possible consequences on the human health and wellbeing, its effect when they are enriched, and the chemical composition in relation to its lipidic profile. Information for this review was collected through national and international inquiries. According to this information, most of the studies on egg consumption are not related to the risk of cardiopathies in healthy people. Also, in people with diabetes mellitus, there is scarce evidence to drawn any conclusion about egg consumption and cardiopathies. Omega-3 egg enrichment presumably possesses a protective effect against cancer, despite its cholesterol content remains unaltered. Many of the Food Chemical Composition Tables contain different values on egg's fat composition, so it should be continuously update to reduce these discrepancies. Also, more studies on omega-3 enriched eggs are necessary for deeper conclusions on their cardio-protective effect.  相似文献   

13.
The objective [corrected] of this work was to elaborate "cotija" type cheese prepared with whole milk and chickpea (Cicer arietinum L.), inoculated with S. Thermophilus and to compare its physicochemical, microbiological and sensorial characteristics with a commercial cheese. Two mixture were selected 70:30 and 80:20 (whole milk:chickpea paste). Both mixture were ground, pasteurized and inoculated with. S. Thermophilus, to develop taste and aroma. Two rennet concentrations (1:10,000 and 2:10,000), lactic acid and 50% CaCl2 solution were used in both products. Results showed that cheese made with 70:30 mixture and 1:10,000 rennet concentration gave a weak curde and 12% of total solids were lost; in the same way as 70:30 mixture and 2:10,000 rennet concentration. Nevertheless, cheese made with 80:20 mixture and 10,000 or 2:10,000 rennet concentration showed hard consistency of its curd. Addition of 10% sodium chloride solution to he 80:20 mixture cheese, made better whey drain, and a "cotija" type cheese with similar sensory characteristics as a whole milk cheese, was obtained. Chemical and physical analysis of the extended "cotija" type cheese showed 14.3 +/- 0.42 and 15.5 +/- 0.21 g/100 g of protein and lipid content respectively. Microbiologically, the extended "cotija" type cheese is pathogenic microorganisms free for human consumption. Sensory evaluation of the chickpea "extended" cheese showed a 80% acceptance while the acceptance of the whole milk commercial cheese was 90%.  相似文献   

14.
Lysophosphatidic acid (lysoPtdOH), a lysophospholipid mediator, exerts diverse physiological effects, including angiogenesis, through its specific G‐protein‐coupled receptors. Previously, we showed that unfertilized hen egg white contains polyunsaturated fatty acid‐rich lysoPtdOH and lysophospholipase D (lysoPLD). Here, we examined whether lysoPtdOH was produced by lysoPLD in the presence and absence of a hen fertilized ovum and what the physiological role of lysoPtdOH in hen egg white is. Mass spectrometry showed that fertilized hen egg white contained about 8 μM lysoPtdOH before incubation with an ovum, mainly comprised of 18:1‐ (12.6 %), 18:2‐ (37.8 %) and 20:4‐molecular species (41.5 %). In an early gestation period, the lysoPtdOH was increased up to 9.6 μM, concomitant with a decrease in the level of polyunsaturated lysophosphatidylcholine (lysoPtdCho). Moreover, lysoPtdOH‐degrading activities were found in egg white and the vitelline membrane, showing that these enzymes control lysoPtdOH levels in egg white. In an egg yolk angiogenesis assay, two lysoPtdOH receptor antagonists, Ki16425 and N‐palmitoyl serine phosphoric acid (NASP), inhibited blood vessel formation induced by exogenously added 18:1‐lysoPtdOH and its precursor lysoPtdCho on the hen yolk sac. Ki16425 and NASP also inhibited blood vessel formation in the chorioallantoic membrane (CAM). Furthermore, the relatively higher levels of LPA1, LPA2, LPA4 and LPA6 mRNA were present in the yolk sac and CAM. These results suggest that lysoPtdOH produced from lysoPtdCho by the action of lysoPLD in hen egg white is involved in the formation of blood vessel networks through several lysoPtdOH receptors on various extraembryonic membranes, including the yolk sac membrane and CAM.  相似文献   

15.
苯醚菌酯·戊唑醇防治白粉病生物活性   总被引:1,自引:0,他引:1  
苯醚菌酯(ZJ0712)·戊唑醇复配而成的新型杀菌剂,经室内生物活性测定结果表明苯醚菌酯·戊唑醇以1:10混配时,该组合物对小麦白粉病、黄瓜白粉病和草莓白粉病均具有很高的杀菌活性.模拟田间药效试验结果表明组合物在10~40 mg/L的处理剂量下,对黄瓜白粉病的防效也在98.40%~71.5%之间.苯醚菌酯·戊唑醇的作用机制虽然不同,但2种有效成分组合在一起,对白粉病具有明显的增效作用,并还能有效延缓抗性的产生.  相似文献   

16.
Non‐alcoholic fatty liver disease (NAFLD) is a major cause of cardiovascular disease. The relationship between egg consumption and NAFLD is still controversial for its high cholesterol content. In this study, the effects of different egg components (egg white (EW), egg yolk (EY), and whole egg (WE)) on NAFLD are examined using oleic acid (OA)‐induced HepG2 cells with UPLC‐ESI‐MS/MS approach. The results show EY could affect the lipid profile effectively by increasing phosphocholine (PC), phosphatidylglycerol (PG), and carnitine (CAR). Orthogonal projections to latent structures?discriminate analysis (OPLS‐DA) combine with S‐plot analysis select 10, 82, and 20 potential biomarkers in EW, EY, and WE group, respectively. Up‐regulated TG, DG, and down‐regulated lysophosphatidylcholines (lysoPC), lysophosphatidylethanolamine (lysoPE) biomarkers are found in EY group, while down‐regulated TG and FFA are found in EW and WE group. Glycerolipid and choline metabolism are the most involved pathways affected by EY and WE. In addition, the mechanism is associated with the expression of Pla2g15, Pnpla6‐1, Gad1, and involved lipogenic genes ABC1 and PPARα. This study suggests that WE treatment can ameliorate OA‐induced hepatic steatosis by inhibiting TG accumulation, while EY seems slightly accelerate hepatic steatosis. Furthermore, the effects are closely associated with its effects on glycerolipid metabolism. Practical applications: Nonalcoholic fatty liver disease (NAFLD) is a worldwide disease, while the associations between egg consumption and NAFLD are still poorly understood. This study investigates the effects of egg components on NAFLD in oleic acid (OA)‐induced HepG2 cells based on a targeted lipidomics approach. The results indicate that WE (whole egg) treatment could ameliorate OA‐induced hepatic steatosis by inhibiting TG and FFA accumulation, which is closely associated with glycerolipid metabolism. The results provide knowledge and understanding of the effects of egg on NAFLD and involved mechanism, and further provided nutritional guidelines for egg consumption.  相似文献   

17.
The objective of this work was to establish the experimental conditions for the production of yogurt extended with chickpea (Cicer arietinum), inoculated with St. thermophilus and L. bulgaricus and compare its chemical, microbiological and sensorial characteristics versus a yogurt made of skimmed milk. Results indicated that 70:30 and 80:20 (skimmed milk and chickpea extract) mixtures obtained by chemical score fulfilled with the proposed objectives. Yogurt made with 70:30 mixture added with modified starch (ULTRA SPERCE M and COL-FLO), did not remove syneresis present in these products and did not improve its sensory characteristics neither. Nevertheless, yogurt made with 80:20 mixture and modified starch (ULTRA SPERCE M) removed syneresis and present flavor and texture characteristics alike yogurt made of milk, this "extended" yogurt was accepted by the 80% of the judge and fulfill with yogurt specification established in the mexican regulations for this products.  相似文献   

18.
Fish silage was prepared from some fish species of the shrimp by-catch caught in Golfo Triste, Carabobo, Venezuela. Fish were ground until a particle size that would guarantee the liquefaction process was achieved. The process was accelerated by the incorporation of a 3.5% w/w acid mixture, formed by diluted sulfuric acid (1:3) and concentrated formic acid, in a proportion of 1:4. The silage process occurred spontaneously at room temperature during 17 days. Chemical, physical and microbiological tests were conducted in order to characterize both the raw material and the final product. The raw material used had adequate levels of freshness, so that it was suitable for use, thus producing a first-grade silage. A first biological evaluation was carried out in rats in order to estimate the protein quality of the silage by means of certain biological parameters such as PER, NPR and apparent digestibility percentage of the protein. The results of the first experimental period demonstrated that the fish silage protein was of optimal quality, since the biological response in rats was similar to that of the control group fed the casein diet.  相似文献   

19.
The purpose of this study was to examine the effect of biopolymer encapsulation on the digestion of total lipids and cholesterol in egg yolk using an in vitro human digestion model. Egg yolks were encapsulated with 1% cellulose, pectin, or chitosan. The samples were then passed through an in vitro human digestion model that simulated the composition of mouth saliva, stomach acid, and the intestinal juice of the small intestine by using a dialysis tubing system. The change in digestion of total lipids was monitored by confocal fluorescence microscopy. The digestion rate of total lipids and cholesterol in all egg yolk samples dramatically increased after in vitro human digestion. The digestion rate of total lipids and cholesterol in egg yolks encapsulated with chitosan or pectin was reduced compared to the digestion rate of total lipids and cholesterol in other egg yolk samples. Egg yolks encapsulated with pectin or chitosan had lower free fatty acid content, and lipid oxidation values than samples without biopolymer encapsulation. Moreover, the lipase activity decreased, after in vitro digestion, in egg yolks encapsulated with biopolymers. These results improve our understanding of the effects of digestion on total lipids and cholesterol in egg yolk within the gastrointestinal tract.  相似文献   

20.
Free plant sterols cannot be dissolved in oil or water. Using free plant sterols and egg yolks, we developed a plant sterol-egg yolk lipoprotein complex (PSY) that can be dispersed in water and considered suitable for use in processed foods. The cholesterol-lowering activity of PSY was equal to that of free plant sterols and plant sterol esters. Consumption of a freeze-dried PSY-containing omelet reduced serum and hepatic cholesterol concentrations. The results suggest that PSY has cholesterol-lowering activity equivalent to that of free plant sterols and plant sterol esters. Moreover, the cholesterol-lowering activity of PSY was maintained in processed foods.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号