黑曲霉β-D甘露聚糖酶的纯化及基本性质

设计了利用硫酸铵分级沉淀，凝胶过滤层析和羟基磷灰石吸附层析相结合及二次羟基磷灰石吸附层析二种分离方案，使一种黑曲霉β－Ｄ甘露聚糖酶得到纯化，纯化酶经聚丙烯酰胺凝胶电泳显示基本为单一蛋白带。凝胶过滤法测的全酶相对分子质量为４９０００，ＳＤＳ－ＰＡＧＥ法测得相对分子质量为５１０００．聚丙烯酰胺等电聚焦测得此纯化酶等电点为３．８．     

一种新颖促钙吸收的功能食品因子——卵黄高磷蛋白磷酸肽(PPP)

以卵黄高磷蛋白为原料,经部分脱磷后,再用胰蛋白酶水解,从而制备出一种新型的促钙吸收的功能食品因子——ＰＰＰ。原料蛋白经０．１、０．２、０．３ 及０．４Ｎ ＮａＯＨ处理３ｈ,脱磷率分别为３４．６％ ,８１．６％ ,９２．５％ 及９６．３％ 。脱磷蛋白再经胰蛋白酶水解４ｈ,水解液的ＳＤＳ－ＰＡＧＥ图谱显示得到小分子磷酸肽。经ＢａＣｌ２ 沉淀及超滤分离得到ＰＰＰ,其平均聚合度分别为１０ 和２０。钙溶解试验表明,在ｐＨ７．８,２００ｍ ｇ／ＬＰＰＰ可从磷酸钙沉淀中溶解出３６．３ｍ ｇ／Ｌ钙,从而证明ＰＰＰ在促进钙吸收方面具有潜在的应用价值。     

一种新颖促钙吸收的功能食品因子——卵黄高磷蛋白磷酸肽(PPP)

以卵黄高磷蛋白为原料,经部分脱磷后,再用胰蛋白酶水解,从而制备出一种新型的促钙吸收的功能食品因子——ＰＰＰ。原料蛋白经０．１、０．２、０．３ 及０．４Ｎ ＮａＯＨ处理３ｈ,脱磷率分别为３４．６％ ,８１．６％ ,９２．５％ 及９６．３％ 。脱磷蛋白再经胰蛋白酶水解４ｈ,水解液的ＳＤＳ－ＰＡＧＥ图谱显示得到小分子磷酸肽。经ＢａＣｌ２ 沉淀及超滤分离得到ＰＰＰ,其平均聚合度分别为１０ 和２０。钙溶解试验表明,在ｐＨ７．８,２００ｍ ｇ／ＬＰＰＰ可从磷酸钙沉淀中溶解出３６．３ｍ ｇ／Ｌ钙,从而证明ＰＰＰ在促进钙吸收方面具有潜在的应用价值。      

固体发酵与液体发酵生产纤维素酶产率与催化性能比较

对绿色木霉产纤维素酶固体发酵和液体发酵进行比较研究,结果显示：固体发酵产率（７４２￣８２７Ｕ／ｇ）比液体发酵产率（６４０￣６６３Ｕ／ｇ）高２５％,其中ＣＩ酶提高２８％,Ｃｘ酶提高４２％,β－葡萄糖苷酶提高４９％,且酶组份比例高于液体发酵。ＳＤＳ－聚丙烯酰胺凝胶电泳图谱明显多出４、５条轻带。酶解未经预处理的稻草糖化率也明显高于液体发酵,联系大规模生产进一步阐述了固体发酵比液体发酵具有投入,成本低,省     

Asp,NigerNo.3单宁酶纯化及性质的研究

Ａｓｐ．ＮｉｇｅｒＮｏ．３单宁酶通过超滤、ＤＥＡＥ－ｃｅｌｌｕｌｏｓｅ离子交换层析,ＳｅｐｈａｄｅｘＧ－１５０柱层析以及Ｓｅｐｈａｒｏｓ－６Ｂ柱层析四步纯化后,经过ＳＤＳ－聚丙烯酰胺凝胶电泳鉴定显现－条蛋白质带,酶的总活力回收率达到１１％,纯化倍数为１１３．５;     

十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS－PAGE）检测牛奶中掺杂的豆奶

十二烷基硫酸钠聚丙烯酰胺凝胶电泳（ＳＤＳ－ＰＡＧＥ）是检测和半定量牛奶、豆奶混合物中的豆奶和牛奶蛋白的非常有效的方法。蛋白分离不需要制备缓冲液,考马斯兰染色可快速给出重现性好,灵敏度高和背景染色弱的结果,样品只需稀释到合适的浓度（总蛋白浓度大约３．６ｎｇ）。从电泳谱图上可清晰地看到７条牛奶蛋白带和１３条豆奶蛋白带,本文给出了它们的分子量。当牛奶和豆奶混合时,许多蛋白带都可用于检测混合物中的豆奶和牛奶。牛奶中掺杂的豆奶含量达５％即可被检测到。这是一种简单,快速和准确的方法。     

纤维素酶提取甜菜果胶的工艺条件

对酶法提取甜菜废粕果胶得率的影响因素进行了研究．结果表明,８０ 目甜菜粕粉在５０℃、加酶量１５ Ｕ／ｇ、ｐＨ ４．８ 的Ｎａ２ＨＰＯ４－ Ｃ６Ｈ８Ｏ７ 缓冲溶液,料液比１∶１０～１∶１４、提取时间９０ ｈ 的条件下,果胶提取率达９０％ ～９２％ ,果胶粘均相对分子质量为５．６×１０４,高于酸法果胶的提取率（４２．０％ ）和粘均相对分子质量（４．３×１０４）．为甜菜果胶生产和品质的进一步改良奠定了基础．     

四川名茶矿质元素含量研究

分析了四川名茶矿质元素含量及特点。在所分析的１８种元素中，四川名茶Ｋ，Ｐ，Ｓ，Ｃａ，Ｍｇ元素含量较高（＞１５００ １０＾－６），Ｂａ，Ｃｒ，Ｖ，Ｃｏ，Ｓｅ含量较低（＜１０ １０＾－６）；与普通绿茶相比，四川名茶含有较高的Ｋ，Ｚｎ，Ｐ，Ｎａ，Ｎｉ，Ｃｕ，Ｓ，Ｓｅ，Ｃｏ元素，其高幅为０．３８％－１１５．６５％，而Ｍｇ，Ｍｎ，Ａｌ，Ｃａ，Ｂａ，Ｖ，Ｒｂ，Ｆｅ，Ｃｒ元素则为７．３２％－４６．６７％；红岩迎     

叠氮化钠对花生下胚轴酯酶同工酶的影响

用不同浓度的叠氮化钠处理花生４个品种，通过聚丙烯酰胺凝胶电泳对花生下胚轴的酯酶同工酶谱进行测定。实验结果表明，ＮａＮ３对花生酯酶同工酶谱主要影响的酶带有Ｍ１，Ｍ放Ｓ１带。汕油２７品种经０．１，１．５和１０ＭＭＯＬ．ｌ＾－１ＮａＮ３处理，其酶变出现新的酶带。     

应用HPLC反相色谱快速测定增鲜味精中的鸟苷酸和肌苷酸

本文描述了一种快速测定增鲜味精中的５’－鸟苷酸（５’－ＧＭＰ）和５’－肌苷酸（５’－ＩＷＰ）的方法。样品经过简单的前处理溶解、衍生并由ＯＤＳＣ－１８反相柱分离。流动相为０．５％ＫＨ_２ＰＯ_４缓冲液（ｐＨ４．５～５．０）。ＵＶ（紫外）－检测器波长为２５４ｎｍ。增鲜味精中的５００μｇ／１００ｇ５’－ＧＭＰ和５００μｇ／１００ｇ５’－ＩＭＰ能全部分离并定量测定。相关系数分别为０．９９８９（５’－ＧＭＰ）和０．９９９６（５’－ＩＭＰ）。回收率达分别达１０２．２％（５’－ＧＭＰ）和１０１．９％／（５’－ＩＭＰ）。变异系数分别为４．７％（５’－ＧＭＰ）和２．６％（５’－ＩＭＰ）。     

绿色高效连续分离技术制备蛋黄中活性蛋白质和磷脂

为了实现蛋黄功能性成分的充分利用，采用绿色溶剂从新鲜蛋黄中高效连续分离具有生物活性的卵黄免疫球蛋白（immunoglobulin Y, IgY）、卵黄高磷蛋白（phosvitin, PV）和磷脂（phospholipids, PL）。首先采用水稀释法（稀释倍数为1:10）分离水溶性组分与脂蛋白，通过35%饱和(NH₄)₂SO₄和0.5% NaCl（w/v）对上清液进行盐析并用8% PEG 6000纯化IgY。脂质组分中的PV在pH5.0，90 ℃条件下的NaCl溶液（w/v）中进一步纯化。采用乙醇/乙酸乙酯比例为1:2（v/v）提取蛋黄中全部脂类，进一步采用乙酸乙酯在0 ℃下提纯蛋黄总脂中的PL。经脱盐、冷冻干燥后，IgY、PV和PL的纯度分别为97.38%、78.63%和85.94%。IgY和PV的得率分别为6.15、10.15 mg/mL。蛋黄总脂中PL的含量为35.18%。因其良好的多不饱和脂肪酸/饱和脂肪酸比率（0.70）和相对较低的n-6/n-3比率（5.37），该PL产品可应用于食品加工中。本方法简便、环保并且高效，可从蛋黄中依次分离出高纯度IgY、PV和PL，并为蛋黄的综合利用提供技术支持。     

Egg yolk protein and egg yolk phosvitin inhibit calcium, magnesium, and iron absorptions in rats

ABSTRACT:  Egg yolk decreases the absorption of iron. The effects of egg yolk protein and egg yolk phosvitin on the absorption of calcium, magnesium, and iron were investigated by in vivo studies. Male Wistar rats were fed purified diets containing casein, soy protein, or egg yolk protein for 14 d. The apparent absorptions of calcium, magnesium, and iron in the rats fed the yolk protein-based diet were lower than those in rats fed the casein- and soy protein-based diets. The apparent phosphorus absorption and the apparent protein digestibility in the yolk protein group were lower than those in the casein and soy protein groups. In the feces of the yolk protein group, serine comprised more than 30% of the amino acids. The addition of egg yolk phosvitin to the casein diets at levels of 1% and 2% (w/w) produced effects on calcium and magnesium absorptions similar to those produced by the diet containing yolk protein. The tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern suggested that phosphopeptide fragments having molecular masses of 28, 22, and 15 kDa were evident in the contents of the small intestine of the rats fed phosvitin diets. These results indicate that yolk protein, when compared with casein and soy protein, decreases calcium and magnesium absorption via the resistance of phosvitin to proteolytic action.     

Bioactivities of hen's egg yolk phosvitin and its functional phosphopeptides in food industry and health

Phosvitin, one of the most noteworthy bioactive components of hen egg yolk, is an amphiphilic protein that stands out with its unique composition and functionality in the food industry and health. Phosvitin consists of 4% of egg yolk dry matter and 11% of egg yolk proteins. It is considered as the most phosphorylated protein with 10% phosphorus. Besides, some potential novel phosphopeptides containing clusters of phosphoserines can be derived from hen's egg yolk phosvitin. Phosvitin, which has many functional features thanks to its unique structure, is known primarily for its metal bonds binding (iron, calcium, etc.) feature. On the other hand, its phosphopeptides may increase the bioavailability of metals compared to phosvitin. Although this feature of phosvitin may partially decrease the bioavailability of especially iron in the egg, it allows the phosvitin to have many bioactivities in the food industry and health. Lipid oxidation, which is a serious problem in the food industry, can be inhibited by adding phosvitin and its derived phosphopeptides to the food production chain via inhibiting bivalent iron. Because phosvitin is an amphiphilic protein capable of chelating, it also shows potential antibacterial effects against the Gram-negative bacteria. Moreover, the literature has recently been attempting to define the promising relationship between phosvitin and its phosphopeptides and plenty of health-promoting activities such as immune-enhancing, melanogenesis inhibitor, anti-ageing, and anticancer. In this review, current information on the hen's egg yolk phosvitin and its phosphopeptides and their bioactivities in the food industry and health are discussed and some future directions are given.     

Release of Iron from Phosvitin by Heat and Food Additives

Most of the iron in egg yolk is bound by phosvitin. Heating whole egg or yolk in a double boiler does not release this iron. Also, heating a 0.125 mg/ml solution of phosvitin in distilled water for 20 and 40 min at 110°C did not free iron. A second phosvitin solution mixed equally with 0.04M citric acid, 2 M NaCl and 0.03M Na₂ EDTA. Only EDTA released (ca) iron from phosvitin without heating.     

卵黄高磷蛋白工业化提取工艺的研究

以鸡蛋为原料,旨在寻找一种从鸡蛋中批量提取卵黄高磷蛋白的工业化提取工艺。通过反复试验,确定了提取卵黄高磷蛋白的最佳工艺条件为:以9倍于蛋黄质量的水除去蛋溶液中的水溶性蛋白,比值为1:3的乙醇与己烷混合溶液脱脂后,利用1.80mol/L NaCl溶液提取卵黄高磷蛋白,同时通过膜透析的方法脱盐使其纯度得到提高,最终产品纯度可以达到(以N:P比值计)3.28。     

Selective removal effect of subcritical fluid extraction on egg yolk lipids and characterization and enzymatic improvement of defatted egg yolk powder

This study investigated the effects of subcritical fluid extraction on lipid removal and the physicochemical properties of egg yolk powder. In addition, two-step enzymatic hydrolysis was used to improve the physicochemical properties. The content of total lipids and cholesterol decreased to 30.2% and 10.5 mg/g after subcritical propane-butane extraction, respectively, while phospholipids were retained. Protein solubility, surface hydrophobicity and total sulfhydryl results showed that this partial defatting avoided further quality deterioration of egg yolk powder. Scanning electron microscopy and confocal microscopy showed that the surface morphology and distribution of proteins and lipids changed with defatting degree. After two-step enzymatic hydrolysis, protein solubility of subcritical propane-butane extraction egg yolk powder significantly increased to 31.4% and soluble peptides with an average molecular weight lower than 1000 Da accounted for 70.0%. The improved defatted egg yolk powder is rich in protein, peptides and phospholipids and has great potential as a nutritional supplement.     

Strength of Protein Gels Prepared with Microbial Transglutaminase as Related to Reaction Conditions

Influence of gelling reaction conditions on the strength of several protein gels prepared with microbial transglutaminase (TGase) was investigated. A method was developed to gel proteins and measure gel breaking strength in a micro well plate. Enzyme concentration range for maximum gel breaking strength varied from 10 to 40 units/g protein. Maxima gel breaking strengths were achieved at 50°C for SPI, caseinate and gelatin and 65°C for egg yolk and egg white proteins. Optimum pH resulting in strong gels was pH 9 for SPI, caseinate, and egg yolk, and pH 6 for gelatin and egg white. Adjusting pH was promoted in egg white the formation of ?-(γ-glutamyl)lysine crosslinks and increased its gel breaking strength.     

鸡蛋贮藏过程中蛋黄内源抗氧化组分与氧化进程的关系

为证实蛋黄内源抗氧化组分对鸡蛋氧化进程的调控作用,本研究将新鲜鸡蛋于22 ℃、相对湿度65%条件下贮藏50 d,通过对贮藏过程中蛋黄氧化的表征及亲脂抗氧化组分（lipophilic antioxidant component,LAC）、亲水抗氧化组分（hydrophilic antioxidant component,HAC）抗氧化能力的比较,探究抗氧化组分与蛋黄氧化进程的关系。结果表明,贮藏过程中蛋黄蛋白质发生氧化降解,总巯基含量平均值下降29.69%,羰基含量平均值上升1.2 倍,十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析表明,贮藏过程中蛋黄卵黄高磷蛋白、高密度脂蛋白等蛋白发生降解,双烯值、丙二醛含量显著增加（P＜0.05）。鸡蛋贮藏过程中LAC对自由基的清除能力大于HAC,与磷脂相比,类胡萝卜素具有相对较高的自由基清除率。相关性分析结果显示蛋黄氧化程度与磷脂、类胡萝卜素抗氧化能力呈显著负相关（P＜0.05）,磷脂抗氧化能力与类胡萝卜素抗氧化能力呈显著正相关（P＜0.05）,与蛋黄蛋白质相比,LAC对蛋黄脂质氧化的调控作用更显著。结论：在贮藏过程中LAC对蛋黄氧化具有潜在调控作用,抗氧化组分之间可能存在协同增效作用。     

A STUDY OF TURKEY EGG YOLK 1. COMPOSITION AND ELECTROPHORETIC SEPARATION OF COMPONENTS1

Yolks from fresh eggs produced by Broad Breasted White turkeys were blended and analyzed. Proximate composition was determined and components were separated in 7% polyacrylamide gel. Turkey egg yolk was compared with chicken egg yolk. Turkey egg yolk contained a higher percentage of solids, fat, and protein than chicken egg yolk. When separated electrophoretically, components of chicken egg yolk migrated faster than those in turkey egg yolk. Turkey yolks could be resolved into 10 or 11 distinct components; chicken yolk, into 11 or 12 components, depending on electrophoretic technique.