Rheological and Functional Properties of Catfish Skin Protein Hydrolysates

ABSTRACT:  Catfish skin is an abundant and underutilized resource that can be used as a unique protein source to make fish skin protein hydrolysates. The objectives of this study were to isolate soluble and insoluble proteins from hydrolyzed catfish skin, study the rheological and functional properties of the protein hydrolysates, and evaluate the properties of emulsions made from the protein powders. Freeze-dried catfish skin soluble (CSSH) and insoluble hydrolysate (CSISH) powders were analyzed for proximate analysis, emulsion stability, fat absorption, amino acids, color, and rheological properties. CSSH had significantly ( P  < 0.05) higher protein, ash, and moisture content but lower fat content than that of CSISH. The yield of CSSH (21.5%± 2.2%) was higher than that of CSISH (3%± 0.3%). CSISH had higher emulsion stability than CSSH. CSSH was light yellow in color and CSISH was darker. The mean flow index values for emulsion containing CSSH (ECSSH) and CSISH (ECSISH) were both less than 1, indicating that they were both pseudoplastic fluid. The   G '  and   G "  values for the ECSISH were higher than that of ECSSH, indicating that the viscoelastic characteristic of the emulsion containing CSISH was greater than that of the emulsion containing CSSH. The study demonstrated the CSSH and CSISH had good functional and rheological properties. They have potential uses as functional food ingredients.     

鲽鱼骨胶原蛋白的结构及流变学特性

采用酸法和酶法从鲽鱼骨中提取制备得到酸溶性胶原蛋白(ASC)和酶溶性胶原蛋白(PSC),对ASC与PSC进行紫外吸收(UV)、红外吸收(FTIR)、亚基组成(SDS-PAGE)、热稳定性(DSC)、微观结构(SEM)以及流变学特性(DHR)分析。UV显示:ASC与PSC分别在227 nm与226 nm处有最大紫外吸收峰。FTIR图谱表明:ASC与PSC保持了三螺旋结构。SDS-PAGE电泳图表明:ASC与PSC是Ⅰ型胶原蛋白。DSC测定ASC与PSC的热变性温度分别为52.24℃与49.65℃。SEM显示:ASC与PSC呈现交织状纤维网状结构。DHR表明:1%的ASC溶液或PSC溶液在振荡频率0.1~10 Hz范围主要表现为弹性且具有较高的凝胶稳定性。     

褐藻胶对蛋黄酱流变特性的影响

探讨了改善蛋黄酱品质的最佳褐藻胶添加量,利用流变仪研究了不同添加量的褐藻胶对蛋黄酱流变特性的影响.静态流变特性的研究表明:蛋黄酱样品呈现出触变性、假塑性,流变学方程为Herschel - Bulkley;温度对蛋黄酱样品的表观粘度的影响符合Arrhenius模型.动态流变性质的研究表明:蛋黄酱样品显示弱凝胶的特性.实验表明:添加褐藻胶的能显著提高蛋黄酱的流变学稳定性,其中褐藻胶添加质量分数为2.0％的蛋黄酱样品比添加量为2.5％的蛋黄酱样品在流变学特性、感官特性上更接近全脂类蛋黄酱.     

4种蛋黄酱的流变特性比较研究

针对4种蛋黄酱样品(丘比蛋黄酱、丘比蛋黄酱(2005)、丘比香甜味蛋黄酱、丘比千岛酱),对其进行成分、流变特性(静态流变特性和动态流变特性)及感官评定实验。静态流变测定表明：蛋黄酱样品呈现出触变性、假塑性;动态流变测定表明：蛋黄酱样品显示弱凝胶特性。结果表明：丘比蛋黄酱的流变学特性、感官特性最优,丘比蛋黄酱(2005)其次,丘比香甜味蛋黄酱再次,丘比千岛酱最差。     

Influence of Alginate Concentration and Molecular Weight on Functional Properties of Mayonnaise

The rheological properties of mayonnaise containing alginates from Macrocystis pyrifera as stabilizers were studied using a controlled stress rheometer and a texture analyser penetrometer. Dynamic oscillatory tests of the emulsions were carried out in strain sweep and frequency sweep modes. The rheological parameters used for this study were the storage (G′), loss (G″) and complex (G*) moduli and the strain, which determined the limit of the linear viscoelastic region (γ_c). The effect of alginate concentration (0.2, 0.5 and 0.8 g/100 g) and molecular weight (MW: 76, 120 and 154 kDa) on physical properties was examined and the best combination useful to minimize differences between the alginate emulsion and mayonnaise with modified corn starch as commercial reference was identified (0.35 g/100 g and 108 kDa). The storage modulus increased with alginate content and it became independent of the molecular size above a critical value between 76 and 120 kDa. A positive effect of MW on γ_c was observed at 0.2 g/100 g alginate and the critical strain decreased with increasing polymer concentration up to 0.5 g/100 g. Results under small-amplitude oscillatory shear tests (linear viscoelastic properties) were interpreted in the context of the weak gel model. Two material parameters were determined to describe the rheological structure of the emulsion: the coordination number (z) and the parameter A (G* at 1 Hz). Mayonnaises with alginate concentrations of 0.5 and 0.8 g/100 g and at all the MW had coordination numbers which were not significantly different from those of the reference sample. The emulsion strength of alginate samples with polymer concentration of 0.5 and 0.8 g/100 g was significantly higher than the control.     

不同品种花生蛋白流变特性的研究

对8种花生蛋白的流变特性进行了探讨。静态流变特性测定结果表明,8种花生蛋白的流变模型为幂率模型,均为非牛顿流体。在同样的流动方式下,忠毅9616的黏度最大,花育16次之,其他几种变化无明显差别。动态流变特性测定结果表明,随着温度的升高,不同品种花生蛋白的贮藏模量、损失模量以及损失系数均呈现出不同的变化趋势。其中,忠毅9616品种蛋白的贮藏模量最大,红珍珠次之,花育16最小;红珍珠、奇山208、的损失模量高于其他几种,花育16最低;忠毅9616的损失系数最小,奇山208最大。     

Protease Inhibitors Affect Physical Properties of Arrowtooth Flounder and Walleye Pollock Surimi

The effects of protease inhibitors from potato, bovine plasma and egg white on the punch, torsion and color tests of arrowtooth flounder and pollock surimi were determined. At 2% addition, the inhibitors increased the strength of arrowtooth gels while variable results were found with pollock gels. Bovine plasma produced a gel with a yellow hue while the gel with potato inhibitor was darkest.     

鲱鱼蛋白的营养和功能特性

介绍了鲱鱼蛋白质的制备,营养和功能特性,表明了鲱鱼蛋白能作为一种比较好的功能添加剂,营养补充剂和乳化剂。     

添加鱼皮胶原蛋白蛋黄酱加工工艺的研究

通过正交试验确定鱼皮胶原蛋白作为乳化剂在蛋黄酱生产中加入的最佳配方,配方为鱼皮胶原蛋白2%,蛋黄15%,醋酸0.3%.水10%.结果表明,鱼皮胶原蛋白代替部分蛋黄,起到一定的乳化效果,同时还能增加蛋白质的含量.鱼皮胶原蛋白舍有多种氨基酸,易于消化吸收,一直受到食品领域的关注,而且胶原蛋白作为一种蛋白质,还具有各种生理功...     

海鲜菇蛋白质功能特性及消化性的研究

以海鲜菇粉为原料,采用纤维素酶辅助碱提酸沉法提取出蛋白质,对其功能特性及消化性进行研究。结果表明,随着离子强度的增加,海鲜菇蛋白质的溶解性(Solubility)、持水性(Water holding)、乳化性(Emulsifying)及乳化稳定性(Emulsion stability)、起泡性(Foaming)及泡沫稳定性(Foaming stability)均呈现先升高后降低的趋势;随着蔗糖浓度的提高,溶解性逐渐降低,持水性、乳化性、起泡性及泡沫稳定性呈现先升高后降低的趋势,乳化稳定性呈现先降低后升高的趋势;随着温度的提高,溶解性、持水性、持油性(Oil holding)、乳化性及乳化稳定性、起泡性及泡沫稳定性均呈现先升高后降低的趋势;随着pH的升高,溶解性、起泡性、乳化性及乳化稳定性均呈现先降低后升高的趋势,在等电点附近达到最小值,泡沫稳定性呈现先升高后降低的趋势,在等电点附近达到最大值。海鲜菇蛋白质溶液经过模拟胃消化后,其消化率为35.5%,水解度17.13%,游离氨基酸含量0.42 mg/mL,多肽含量1.16 mg/mL,胃消化液还原力0.55,DPPH·、O2-·和·OH的清除率分别为66.14%、67.36%和69.44%;模拟肠消化后,其消化率为87.65%,水解度20.88%,游离氨基酸含量0.93 mg/mL,多肽含量0.83 mg/mL,肠消化液的还原力0.23,DPPH·、O2-·和·OH的清除率分别为35.02%、27.17%和37.75%。通过试验证明了离子强度、温度、时间和蔗糖浓度对海鲜菇蛋白质的功能特性有一定影响;该蛋白质在胃肠中消化率较高,是一种易消化优质蛋白质。     

Functional and Nutritional Properties of Red Salmon (Oncorhynchus nerka) Enzymatic Hydrolysates

The effects of different proteolytic enzymes and different reaction durations (25, 50, 75 min) on functional and nutritional properties of red (sockeye) salmon head hydrolysates were evaluated. Degree of hydrolysis values for the 75‐min digestion ranged from 6.4% to 16.7%. Oil yield (4.9% to 10.6 %) from red salmon heads was affected by the enzyme used. Protein hydrolysate powders were yellowish and contained 62.3% to 64.8% protein with high levels of essential amino acids. Increased degree of hydrolysis values were weakly correlated with increased hydrolysate solubility. Maximum emulsion stability and fat adsorption were observed for the dried hydrolysate generated in the 25‐min reaction time. Water adsorption of hydrolysate powders ranged from 1.0 mL to 3.3 mL water/g dried hydrolysate.     

聚合乳清蛋白包埋油脂功能特性的研究

研究了聚合乳清蛋白包埋鱼油和月见草油后凝胶功能特性的变化. 结果表明,鱼油凝胶的乳化性、乳化稳定性明显优于月见草油凝胶-P＜001- ,随着凝胶天数的增加,鱼油和月见草油凝胶的乳化性和乳化稳定性均有所降低;鱼油凝胶乳化性第4天出现明显下降-P＜005- ,月见草油凝胶乳化性下降不明显-P＞005- ;鱼油凝胶黏度明显低于月见草油凝胶黏度,平均比月见草油凝胶低1657%,随着凝胶形成天数的增加,黏度均近似成线性模型增长;两种凝胶在实验所设定的剪切速率范围内均表现为剪切变稀,呈假塑性;鱼油凝胶硬度略高于月见草油凝胶,但差异不显著-P＞005- ,随着凝胶形成天数的增加,凝胶硬度都略有增加,但增加不显著-P＞005- .     

右旋糖酐/蚕豆蛋白复合凝胶的流变特性

为研究乳酸菌右旋糖酐对蚕豆蛋白食品相关性质的影响，采用哈克流变仪和质构仪等测定了添加不同浓度右旋糖酐时GDL诱导的酸致蚕豆蛋白复合凝胶质构和流变特性等指标。结果表明：添加右旋糖酐能显著增加蚕豆蛋白凝胶保水性，空白组蚕豆蛋白凝胶保水性为60.38%，1%右旋糖酐与蚕豆蛋白形成的复合凝胶保水性为70.08%（p<0.05）；右旋糖酐浓度在0.25%~1%之间，对复合蛋白凝胶色泽有一定影响；0.5%右旋糖酐与蚕豆蛋白形成的复合凝胶强度为0.27 N，与空白组蚕豆蛋白凝胶（0.37 N）差异显著，可软化含高蚕豆蛋白食品质构特性；右旋糖酐/蚕豆蛋白复合凝胶流动曲线符合carreau模型（R2>0.99），具有假塑性流体的特性；应变扫描的弹性模量G''均高于黏性模量G''，说明右旋糖酐/蚕豆蛋白复合凝胶的弹性占主导；频率扫描结果显示添加右旋糖酐可软化蚕豆蛋白凝胶，使凝胶G''、G''降低，更易于加工。在蚕豆食品中添加右旋糖酐可改善蚕豆蛋白的质构和流变特性，为拓展其应用范围提供参考。     

Properties of soluble protein powders from Alaska pollock (Theragra chalcogramma)

Soluble protein powders were produced from pollock by‐products and evaluated for their functional, nutritional and rheological properties. Soluble protein powders were made from pollock viscera (PVSP), viscera without liver (PVWLSP), heads (PHSP), frames (PFSP), trimmings (PTSP), and liver (PLSP) and had protein contents ranging from 65.0% to 78.9%. Yield of PVWLSP was higher than that of other pollock proteins powder and PTSP had the highest nitrogen solubility value (85.7%). Emulsion capacity and emulsion stability of the pollock protein powders ranged from 29% to 34.5% (mL of oil per 200 mg of protein) and 65.3% to 77.6%, respectively. Highest and lowest fat adsorption values were observed for PFSP (10.6 mL of oil per gram of protein) and PVSP (4.1 mL of oil per gram of protein), respectively. Fish protein powder samples were good sources in K, P, and Mg and amino acids. Emulsions made with pollock soluble protein powders exhibited viscoelastic characteristics.     

米胚分离蛋白营养和功能性评价

利用氨基酸自动分析仪检测米胚4种Osborne分离蛋白中的氨基酸组成,以氨基酸评分(AAS)、蛋白质功效比值(PER)、生物价(BV)及体外消化率为评价标准,对米胚蛋白各组分的营养价值进行评价。结果表明:谷蛋白的氨基酸评分最高,为80.90,清蛋白、球蛋白、谷蛋白符合FAO/WHO推荐的参考蛋白模式,其PER值与优质蛋白的衡量标准值2.00接近,BV值较高,在体外的营养消化效率较好,醇溶蛋白的品质相对较差。对米胚四种蛋白的起泡性、起泡稳定性、吸水性、吸油性等功能性质进行测定,结果表明:pH 5时4种蛋白的起泡性最低,起泡稳定性最好;清蛋白、球蛋白的吸水性比醇溶蛋白、谷蛋白好,醇溶蛋白的吸油性最好;米胚蛋白各组分的表面疏水性较高,需进一步进行改性处理。     

白灵菇蛋白质的理化及功能特性

为充分开发利用白灵菇蛋白质(Pleurotus nebrodensis proteins,FPs),以残次级白灵菇为原料,采用碱浸提分段盐析法依次制备60%、80%、90%盐饱和度析出蛋白质(F60、F80、F90),统称为分段盐析蛋白质组分(FPs),测定FPs的析出率、理化性及FPs中F60的功能特性。结果表明:F60的析出率最高,达65.62%。FPs间的二硫键含量无显著性差异(p>0.05);FPs的蛋白质条带中共同含有分子量约为31 kDa的蛋白质条带,蛋白质条带间存在差异。F60较F80、F90富含分子量为14.4 kDa的蛋白质条带,具有较高的表面疏水性与荧光发射光谱峰值,β-折叠结构出现频率更高。F60具有优良的溶解性、起泡性、易消化水解,具有潜在的应用价值。白灵菇蛋白质是一种优质的新型蛋白质资源。     

南瓜籽蛋白质的制备及其功能性质研究

采用碱溶酸沉法制备南瓜籽分离蛋白,通过正交试验确定最佳的提取工艺条件,并对所制得的分离蛋白的部分功能性质进行研究。结果表明,南瓜籽分离蛋白提取的最佳条件为pH11.0、温度50℃、料液比1:30(m/V)、提取时间1.5h。此时提取率为85.52%,纯度为91.07%。南瓜籽分离蛋白的等电点在5.5 左右;吸水性和吸油性都在1.2～1.6g/g 左右;乳化能力在适宜pH 值达到80% 以上;起泡性则相对较弱。     

谷氨酰胺转氨酶对米渣蛋白糖基化反应产物结构和流变性的影响

为了探讨谷氨酰胺转氨酶(TG)对植物蛋白美拉德反应改性的作用,本文利用米渣蛋白(RDP)分别与葡萄糖、核糖、麦芽糊精1:1进行干法糖基化反应,研究TG的添加(10μ/g的RDP)对反应产物结构和流变学特性的影响。结果表明:随着反应的进行,核糖与RDP糖基化反应的接枝度最大,TG酶能够提高糖基化反应接枝度;内源荧光λmax红移且强度降低,红外光谱显示不同产物的结构变化显著,但TG对产物的结构影响不大;糖基化反应可降低表面疏水性,而TG促其增大;糖基化反应主要是Lys和Arg含量减少,组氨酸含量增加,且核糖更利于与自由氨基的反应,TG对产物氨基酸组成无影响;糖基化产物溶液都是假塑性流体,核糖接枝产物表观粘度最大,TG促使表观粘度增高;三种糖基化产物动态模量随剪切频率增大而变化较大,其中核糖反应产物表现出类似凝胶特性,G′G″且较RDP均增加,TG提高核糖、葡萄糖反应产物的G′与G″。     

蛋白质酶水解物功能特性及其在食品工业应用

介绍蛋白质酶水解物功能特性,总结蛋白质酶水解物在老年食品,运动员食品、减肥食品、疗效食品和普通食品中应用。     

大豆分离蛋白对肌原纤维蛋白加热过程中结构及流变特性的影响

大豆分离蛋白（soybean protein isolate,SPI）作为优质的植物蛋白常被用于肉制品加工中,以提高产品产量和质地。研究添加SPI对肌原纤维蛋白（myofibrillar protein,MP）凝胶特性及MP加热过程中结构和流变特性的影响。结果表明：添加10%、20% SPI能提升混合凝胶的凝胶强度及保水性（P＜0.05）;加热过程中混合蛋白凝胶二级结构发生改变,但其变化规律尚不明确;添加SPI使混合凝胶储能模量及损耗模量下降;混合凝胶上清液十二烷基硫酸钠-聚丙烯酰胺凝胶电泳图谱显示,肌球蛋白重链、肌动蛋白、SPI部分亚基均是参与凝胶形成的蛋白质。