牦牛及犏牛奶蛋白质和氨基酸含量分析

测得红原阿坝牦牛及红原犏牛奶蛋白质平均含量分别为５．２１％、６．１６％、５．０９％；奶中１７种氨基酸总量分别为２１９３．８８、２３４１．２０、１９９９．６４（ｍｇ／１００ｇ）；必需氨基酸／非必需氨基酸分别为１．０３８，０．８８１，０．

喝牛奶产生不良反应的原因及对策

谈到饮奶,我们就无法回避很多人喝牛奶后所产生的各种不良反应:腹胀、腹泻、肠鸣、呕吐、皮肤湿疹等症状。科学研究发现,牛奶中的蛋白质和乳糖是导致这些症状发生的主要根源。 一、牛奶蛋白质引起的 过敏反应 牛奶蛋白质所引起的过敏,主要发生在两岁以下的儿童中。

蛋白价高

马克恩主义的创始人之一思格斯在1874年写下一句名言:“生命是蛋白体的存在形式”。蛋白质是构成人体各种组织器官、维持正常生命活动不可缺少的营养物质。牛奶中含有2.7％～3.5％的蛋白质,在总蛋白质中大约78％～83％为酪蛋白,10％～15％为乳白蛋白,4％～6％为乳球蛋白。你可不要小看这些蛋白质。

Nutritional evaluation of caseins and whey proteins and their hydrolysates from Protamex

Whey protein concentrate (WPC 80) and sodium caseinate were hydrolyzed by Protamex to 5%, 10%, 15%, and 20% degree of hydrolysis (DH). WPC 80, sodium caseinate and their hydrolysates were then analyzed, compared and evaluated for their nutritional qualities. Their chemical composition, protein solubility, amino acid composition, essential amino acid index (EAA index), biological value (BV), nutritional index (NI), chemical score, enzymic protein efficiency ratio (E-PER) and in vitro protein digestibility (IVPD) were determined. The results indicated that the enzymatic hydrolysis of WPC 80 and sodium caseinate by Protamex improved the solubility and IVPD of their hydrolysates. WPC 80, sodium caseinate and their hydrolysates were high-quality proteins and had a surplus of essential amino acids compared with the FAO/WHO/UNU (1985) reference standard. The nutritive value of WPC 80 and its hydrolysates was superior to that of sodium caseinate and its hydrolysates as indicated by some nutritional parameters such as the amino acid composition, chemical score, EAA index and predicted BV. However, the E-PER was lower for the WPC hydrolysates as compared to unhydrolyzed WPC 80 but sodium caseinate and its hydrolysates did not differ significantly. The nutritional qualities of WPC 80, sodium caseinate and their hydrolysates were good and make them appropriate for food formulations or as nutritional supplements.

Comparison Between MIR and NIR Spectroscopic Techniques for the Determination of Fat and Protein Contents in Milk

To compare mid-infrared(MIR)and near-infrared(NIR)spectroscopies for the determination of the fat and protein contents in milk,the same sample sets with varying concentrations of fat and protein were measured in the MIR range of 3 200-700 cm-1 and NIR range of 9 000-4 000 cm-1.The spectral features in the two regions were analyzed.The MIR spectra of milk were characteristic due to the MIR inherent molecular specificity,whereas the NIR spectra were relatively characterless due to the NIR low selectivity.Partial least squares(PLS)regression models for fat and protein were developed by using both MIR and NIR spectra.MIR data with no pretreatment gave better results than NIR data.The square correlation coefficient(R2)and the root mean square error of prediction(RMSEP)were 0.98 and 0.10 g/dL for fat and 0.97 and 0.11 g/dL for protein.With NIR techniques,satisfactory results were not obtained with raw data.However,NIR data after pretreatment gave similarly good results to the ones using MIR method.This paper indicates that either of the MIR and NIR spectral methods is reliable for the determination of the fat and protein contents.

Can mean platelet volume play a role in evaluating the severity of acute pancreatitis?

AIM To investigate serum mean platelet volume(MPV) levels in acute pancreatitis(AP) patients and assess whether MPV effectively predicts the disease severity of AP.METHODS We included 117 consecutive patients with AP as the AP group and 34 consecutive patients with colorectal polyps(before endoscopic treatment) as the control group. Complete blood counts, liver function, platelet indices(MPV), coagulation parameters, lactate dehydrogenase(LDH) and C-reactive protein(CRP) were measured on days 1, 2, 3 and 7 after admission. Receiver operating characteristic curves were used to compare the sensitivity and specificity of MPV, white blood cell(WBC), LDH and CRP in predicting AP severity. The Modified Glasgow Prognostic Score(m GPS) and the 2012 revised Atlanta criteria were used to evaluate disease severity in AP.RESULTS MPV levels were significantly lower in the AP group than in the control group on day 1(P = 0.000), day 2(P = 0.029) and day 3(P = 0.001) after admission.In addition, MPV values were lower on day 1 after admission than on day 2(P = 0.012), day 3(P = 0.000) and day 7(P = 0.002) in all AP patients. Based on the m GPS, 78 patients(66.7%) were diagnosed with mild and 39 patients(33.3%) with severe AP. There was no significant difference in mean MPV levels between patients diagnosed with mild and severe AP based on the m GPS(P = 0.424). According to the 2012 revised Atlanta criteria, there were 98 patients(83.8%) without persistent organ failure(OF) [non-severe acute pancreatitis(non-SAP) group] and 19 patients(16.2%) with persistent OF(SAP group). MPV levels were significantly lower in the SAP group than in the non-SAP group on day 1 after admission(P = 0.002). On day 1 after admission using a cut-off value of 6.65 f L, the overall accuracy of MPV for predicting SAP according to the 2012 revised Atlanta criteria(AUC = 0.716) had a sensitivity of 91.8% and a specificity of 47.4% and was superior to the accuracy of the traditional markers WBC(AUC = 0.700) and LDH(AUC = 0.697).CONCLUSION MPV can be used at no additional cost as a useful, noninvasive biomarker that distinguishes AP with persistent OF from AP without persistent OF on day 1 of hospital admission.

Fermented Goat Milk and Cow Milk Produced by Different Starters of Lactic Acid Bacteria： Quality Studies

Lactic acid bacteria （LAB） is widely used as culture starters in dairy fermentation. The aim of this study was to investigate the quality of fermented goat milk and cow milk, as well as the viability of LAB in the same products. Fermentations were performed with pasteurized goat milk or cow milk added with skim milk （18% of solids） using three separately different starters; yoghurt starter （a combination of Streptococcus thermophilus FNCC-0040 and Lactobacillus bulgaricus FNCC-0041）, single starter of Lactobacillus acidophilus FNCC-0029 and Lactobacillus casei FNCC-0051. The parameters observed were pH, acidity, nutritional quality including protein, fat and lactose content and product＇s viscosity. Acidity, pH and viability of LAB were also monitored during storage at refrigerated temperature （4 ℃） for 28 days. Results show that the different LAB starters did not affect the pH, acidity, lactose and protein content. Differences on LAB starters affected fat content and viscosity. The highest score of viscosity （30.00 Pa.s ± 7.02 Pa.s） was observed on products fermented by yoghurt starters, followed by products obtained using starter of L. acidophilus （17.7 ±11.4） and L. casei （8.62 ±0.35）. Protein content, acidity, pH and viscosity were not significantly different between products obtained from goat milk and cow milk. Fat content in fermented goat milk was higher （5.03% ±0.62%） than in fermented cow milk （3.52% ±0.37%）, however, lactose content was higher in fermented cow milk （5.16% ±0.40%） than in fermented goat milk （4.53% ±0.35%）. Total LAB concentration in fermented cow milk during storage was 8.03± 0.52 logt0 cfu/mL, while in fermented goat milk was 7.81 loglo cfu/mL ± 0.67 loglo cfu/mL. There was a 10.83% decrease in LAB viability in fermented cow milk and 11.40% in fermented goat milk after 28 days of storage. In conclusion, quality of fermented milk is affected by the starters applied, raw milk source and storage period.

Analysis of influence of water temperature on milk powder proteins using MALDI-TOF MS

The influence of water temperature on protein composition in the reconstitution of milk powder was evaluated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS）. 11 ion peaks in the matrix-assisted laser desorption/ionization （MALDI） spectra were examined to study the alteration of relative quantities of milk proteins when water at different temperature was employed in the reconstitution of milk powder. A discrepancy factor Dij was implemented to represent the degree of milk proteins＇ denaturation. Data obtained indicated that Dij value increased with rising water temperature, and thermal damage to milk proteins became evidently when the water temperature exceeded 60℃. The results confirmed that nutrient loss occurred when milk proteins denatured in water at high temperatures.

ahospholipase Applications in Cheese Production

Phospholipase is an enzyme that hydrolyzes phospholipids releasing a variety of products, like for example lyso-phospholipids, free fatty acids, di-acylglycerols, choline phosphate and phosphatidates, depending on the site of hydrolysis. In cheese production, lysophospholipids act as surface-active agents in the cheese curd, helping emulsification of water and fat during processing and reducing syneresis. Phospholipases are more specific and have little or no activity toward di- or triglycerides. As a result of phospholipid hydrolysis, flavor defects do not occur due to the main formation of palmitic, oleic, and stearic acids, which are non-volatile short chains fatty acids. According to the scientific studies the use of phospholipase is able to increase the yield of cheese and reduce the environmental impacts of cheese production. Protein and fat largely determine cheese yield. Depending on the milk composition, 75% to 78% of milk protein and 85% to 95% of milk fat are entrapped in the cheese curd. The remaining protein and fat are lost in the whey and, to a lesser extent, in the brine. Crucially in the production of pasta filata cheese fat losses occur in the hot stretching step, where the fresh curd is molded and stretched in hot water. The lysophospholipid-casein complexes should be studied to understand the mechanism leading to cheese yield improvements.

The Relationships Between Milk Constituents and Various Milk Properties in Anatolian Buffaloes

The objectives of this study were to investigate the relationships among milk composition, renneting time, urea concentration, acidity, density and pH of Anatolian Buffaloes＇ milk. As a total of 115 individual milk samples from 53 Anatolian buffalo cows that calved in 2004 and 2005 on days of their lactations 30 ± 15, 60 ± 15, 90 ±15, 120 ± 15, 150 ± 15, 180± 15, 210 ±15, 240 ± 15 and 270 ± 15 in 8 units of lhkpmar village were collected in morning milkings in June, September, December and March. Samples were analysed for total dry matter （TDM）, fat, protein, ash, density, pH, acidity, renneting time and urea content. Data were classified according to the following environmental factors： lactation stages： （30 ± 15, 60 i 15, 90 ±15 days）： 2 （120±15, 150 ± 15, 180 ± 15 days）： 3 （210 ± 15, 240 ± 15, 270± 15 days）; calving year： 1 （2004）, 2 （2005）; calving season： 1 （January-May）, 2 （September and October）; month of samples collection： 1 （June）, 2 （September）, 3 （December）, 4 （March）; lactation order： 1 and 2：1, 3 and 4：2, 5 and 6：3. Means and correlation coefficients for the characteristics investigated were calculated. There were negative significant correlations between daily milk yield with TDM, fat and protein percentages, and between pH and all of the milk constituents. Density reduces as TDM, fat and protein contents increase. Relationships between density and coagulation time with milk yield and pH were not significant. Relationships between milk urea concentration with none of milk constituents, milk yield, density, pH and titratable acidity were not significant statistically. It was concluded that genetic selection has to be directed towards increasing fat, protein and total not fat dry matter yields. Under selection programs in which milk yield is taken into consideration, fat and protein yields also increase, but fat and protein concentrations decrease.

New Software for the Identification and Characterization of Peptides Generated during Fontina Cheese Ripening Using Mass Spectrometry Data

The aim of this work was to design and implement a new bioinformatics software which is able to identify the protein peptides from the peaks which arise from in-source or MS/MS fragmentation. The oligopeptide fraction was extracted from Fontina cheese at different ages of ripening and subsequently analyzed by LC/MS/MS. On the resulting total ion chromatograms, the peptides were identified by a method based both on the in-source fragmentation detectable with a single-quadrupole mass analyzer and by a new software which was developed. This software performs an in-silieo digestion of the major milk proteins, it calculates all the possible peptide fragments which are generated by the loss of the first N- or C-terminal amino acids, and finally, it matches the experimental ion chromatogram with the in-silico which generated theoretical spectrum to identify the exact amino-acid protein sequence of the unknown oligopeptide. With this tool, the useful insights into the proteolytic processes which occur during Fontina cheese aging are obtained, which leads to a better knowledge about the functional features of the proteolysis end product.

Nutritional Properties of Commercial Flavored Milk

Consumers are becoming increasingly health conscious, and food product choices have expanded. Flavored milk increases milk consumption in children and providing adequate calcium intake as well as associated nutrients. About 40% of the sugar in flavored milk is naturally occurring lactose beverages. The goal of this study was to test the truthfulness of the labeling concerning protein, fat and sugar content of the flavored milk. Moreover, the compliance with the Gulf standard was tested. Ten different brands of flavored milk were used in this study. As per labeled on the package, this study found that： one company did not mention clearly that their products are nonfat milk. We also found that there were variations in the percentage of fat between the ten types of flavored milk. For calcium content, all companies indicated clearly the calcium content except company eight. Concerning laboratory analysis, one company considered as mislabeled since they stated on the package that the percentage of fat 1.1-1.2 and the lab analysis showed it contained 3.1%. All companies were truthful about protein content. Moreover, for calcium, all companies have low calcium content than what has stated on the package except one company.

Development of Value Added Dahi by Incorporating Cereal and Fruits

A study was conducted for the development of value added dahi by incorporating fruit pulps, cereal flour and whey proteins concentrate （WHC） to increase the nutritional and sensory quality. Value added dahi （VAD） was prepared by using skim milk, oat flour and WPC. VAD with 1% oat flour, 1% whey protein concentrate was found to be highly acceptable by sensory evaluation and curd tension study. Statistically there was a highly significant difference （P 〈 0.05） between skim milk dahi （control） and VAD VAD scored highest sensory score for all the sensory parameters studied. Curd tension found to be markedly increased in value added dahi with increased firmness of the product. Value added stirred dahi was prepared with oat flour, whey protein concentrate, papaya, fig pulps and sugar with different combination in order to assess the suitable level of addition with maximum acceptability. Value added stirred dahi （VADl） with 1% oat flour, 1% WPC, 5% papaya pulp, 4% sugar combination was found to be acceptable among the other combinations. Storage studies evaluated by sensory score revealed that the value added dahi can be stored up to 7 days at 5 ^（2. A significant increase in acidity and decrease in pH were noticed in the VAD1 during the storage period but within the permissible limit. Statistical analysis revealed no significance difference （P 〉 0.05） in total count and yeast and mould count between VAD0 （control） and VADl during storage 5 ~C. Total yield of value added dahi increased along with cost of production due to increased cost of ingredients （fruits and whey protein concentrate） used for value addition.

怎么?什么?为什么?

为什么没事儿 少跷二郎腿? 喜欢跷二郎腿的人要注意了！医师提醒,跷腿容易造成下背痛,且这种后遗症已成为目前职业病的榜首。 对于长期久坐的上班族来说,下背痛可能是困扰最多的一项疾病。专家表示,下背痛已成为现代职业病中的首位,而大多数的原因是腰部过于前凸或后弯,而上班族大多因跷二郎腿而引起腰部受力面不平均,长期压迫就易造成下背痛。