响应面法在植脂稀奶油搅打特性优化中的应用

运用SAS的TwoLevel设计从影响植脂稀奶油搅打性的几个因素中选出3个主要因素：酪蛋白酸钠、植物油和Span60。运用Box—Behnken设计的响应面分析法(Response surface analysis)对三者进行了优化，以确定主要因素的最佳水平。优化分析表明：在酪蛋白酸钠2．04％(质量分数)，植物油25．1％(质量分数)，Span600．43％(质量分数)时植脂稀奶油的打发率达到最大值332％。     

不同蛋白酶水解酪蛋白及其对产物功能性质的影响

采用Alcalase 2．4L和Protamex两种蛋白酶分别水解酪蛋白酸钠（蛋白质含量88．03％）至5％、10％、15％和20％等不同的水解度（DH），并对酪蛋白酸钠及填水解产物的各种功能性质进行了分析测定。结果表明：酪蛋白酸钠经水解后，蛋白质、水分和灰分含量发生变化，游离氨基量增加且增加与DH相关；水解产物中的多肽分子量较小，平均分子量小于8103D，并且分子量随DH的增大而减小，在DH为15％和20％的水解产物中多肽分子量均低于5043D：水解产物的溶解性随DH的增大而增强，在pH4．0～5．0、DH10％～20％的范围内产物溶解度84．8％～98％，说明在等电点条件下，酪蛋白酸钠水解后溶解性得到改善：与酪蛋白酸钠相比，水解产物的乳化性和起泡性减弱；不同水解产物的氨基酸组成差异不是很大，与酪蛋白酸钠也很接近。     

酪蛋白酸钠溶液粘度变化的数学模型

研究了浓度为１２－２０％酪蛋白酸钠溶液在６６－９０℃的粘度变化。在ＰＨ值为６．８－７．５的范围内，ＰＨ值对酪蛋白酸钠的粘度没有显著的影响。酪蛋白酸钠溶液粘度的和与溶液的浓度和温度都叶线性关系（Ｒ＾２〉９５％）。酪蛋白酸钠溶液的粘度浓度方程的斜率和截距都与温度呈二次方程的关系（Ｒ＾２＝９４．９１％，Ｒ＾２＝９３．５９％），并由此推导出关于浓度和温度对酪蛋白酸钠溶液粘度相互 半对数方程（Ｒ＾２＝９４．     

酪朊酸钠磷酸化方法的研究

研究了用三聚磷酸钠对酪肟酸钠改性。提高其乳一或起泡性,采用回归正交设计和快速登高法,攻出以ＥＡ为指标的酪蛋白钠磷酸化的最佳条件为：酪蛋白钠浓度３％,三聚磷酸钠浓度为０．７％,反应温度４２℃,ＰＨ８．０８,反应时间４．４ｈ。其磷酸化为加入１４个原子的磷／分子酪蛋白;,以ＦＯ为指标的酪蛋白钠磷酸化最佳条件为：酪蛋白钠２３％,三聚磷钠的浓度０．７％,反应温度３３℃,ＰＨ．,反应时间２．２ｈ。其磷酸化水平     

响应面优化牦牛乳蛋白营养粉配方

研究了以牦牛乳蛋白、脱脂奶粉为主要原料,在单因素试验的基础上采用响应面试验设计优化牦牛乳蛋白营养粉配方。结果表明,酪蛋白多肽、酪蛋白酸钠、脱脂奶粉及乳清蛋白的配比对产品蛋白含量影响较大,酪蛋白多肽、酪蛋白酸钠、脱脂奶粉及苹果粉的配比对产品感官影响较大。通过响应面优化,得到的产品最佳配料比为:酪蛋白多肽16%,酪蛋白酸钠14%,乳清蛋白25%,脱脂奶粉32%,聚葡萄糖10%,苹果粉3%。牦牛乳蛋白营养粉需在温度低于30℃、相对湿度小于65%的条件下贮藏。     

响应面法优化干酪可食用复合保鲜膜制备的研究

为了有效提高壳聚糖和酪蛋白酸钠应用于干酪保鲜膜,在单因素试验的基础上,通过中心组合试验设计原理,运用响应面法优化干酪保鲜膜性能,以酪蛋白酸钠、壳聚糖、甘油添加量为考察因素,进行三因素三水平试验,并获得多元二次回归方程。结果表明,采用5%酪蛋白酸钠水溶液、2%壳聚糖冰乙酸溶液和2%甘油混合形成混合液进行成膜,所得可食膜的综合性能较优,其水溶性为35.8%、断裂伸长率为75.4%、拉伸强度为9.58 MPa、杨氏弹性模量为13.47 MPa。     

酪蛋白酸钠在肉食品中的开发与应用

食品添加剂现正向天然、营养、多功能方向发展。目前我国食品添加剂品种数得到较大发展以后，对于食品添加剂的应用已日益引起人们重视。此外，我国肉类产量居世界第一，但肉制品却相对不多，即使包括整个熟肉食品在内，也仅占约肉类总产量的20％，远远低于发达国家70％～80％的肉食加工水平。而肉食加工和其它现代食品加工一样，都离不开食品添加剂，其中酪蛋白酸钠在肉食品中的应用，是我国近年来发展较快的一项食品添加剂应用技术。l酪蛋白酸钠发展简介酪蛋白酸钠又称酪肪酸钠或酪蛋白钠，亦曾称之为食用干酪素。本世纪60年代前即已有生…     

曲拉制酪蛋白酸钠的工艺研究及功能性评价

优化酪蛋白酸钠制备工艺,提高酪蛋白酸钠功能品质。以曲拉为原料,探究加水量、碱溶解时的pH、加热时间等因素对酪蛋白酸钠产率和功能性质的影响。通过响应面优化实验,得到酪蛋白酸钠的最佳工艺条件为加水量35%,碱溶pH为7.0,加热时间20 min。此条件下酪蛋白酸钠的产率达到最大45.85%,粗蛋白91.13%、乳糖0.36%、脂肪1.33%、水分4.41%、灰分4.83%、pH7.50。功能性评价结果显示,当酪蛋白酸钠浓度为2%时,乳化性为13.39%,起泡性为17.65%,持水性为0.75(g/g),粘度为5.59 mPa·s。且产品具有酪蛋白酸钠特有的滋味和气味,呈乳白色粉末;无杂质;颗粒大小均匀。以上研究结果表明经优化工艺制得的酪蛋白酸钠各理化指标符合GB 1886.212-2016标准。     

反应条件对酪蛋白水解度的影响

通过单因素实验和正交实验研究了用胰蛋白酶水解牛乳酪蛋白的工艺条件。研究结果表明：胰蛋白酶水解酪蛋白的最佳工艺条件是：pH7．5，温度60℃。底物浓度5％，酶添加量62．44U／g，水解时间140mino在此条件下酪蛋白的水解度达到16．8％。     

酶促交联罗非鱼肉重组工艺研究

在低温下,以罗非鱼碎肉为原料,酪蛋白酸钠与谷氨酰胺转氨酶为复配交联剂,以凝胶强度为重组鱼肉质构的分析指标,在单因素实验基础上运用响应面设计方法对酶促交联鱼肉重组工艺进行优化并初探其交联机理。结果发现:NaCl添加量2.3%、谷氨酰胺转氨酶添加量1.1%、酪蛋白酸钠添加量1.5%、最佳反应时间为0.5 h;经过验证,此条件下重组鱼肉制品的凝胶实际值是3409.5 g×mm与理论预测值3493.5 g×mm基本一致,且比重组前鱼碎肉的凝胶强度提高了1.6倍。同时,由SDS-PAGE凝胶电泳图可知谷氨酰胺转氨酶和酪蛋白酸钠复配交联剂主要作用在相对分子质量为200和40 KDa的蛋白质。     

Effect of sorbitan monostearate on the physical characteristics and whipping properties of whipped cream

In this work, the effects of sorbitan monostearate (Span 60) level on the particle size distribution, microstructure and apparent viscosity of the emulsion were investigated. Average particle size (d_4,3), surface protein concentration, partial coalescence of fat and overrun of whipped cream during whipping were also determined. As Span 60 level increased (0–0.8%) in emulsion, the apparent viscosity was increased gradually, and the particle size range was narrowed, which was also detected by microstructure. A positive effect of whipping time was observed on the average particle size, partial coalescence of fat, surface protein concentration and overrun during whipping, respectively. An increase of Span 60 level resulted in a reduction of d_4,3 values and partial coalescence of fat during 0–1 min whipping, then increasing after whipping for 2–5 min (0.6% Span 60 as the critical level). A negative behaviour was observed between surface protein concentration and Span 60. Moreover, Span 60 could improve the overrun and organoleptic properties of whipped cream efficiently.     

改善牛肉脂肪品质替代品的研究

以植物油为溶剂,水为溶质,添加卵磷酯、单硬脂酸甘油酯、山梨醇酐单油酸酯(Span80)、乳清蛋白等其他添加成分,研制肥牛脂肪替代品,采用了4因子二次通用旋转组合设计,得出最佳配比为单硬脂酸甘油酯0.434%,山梨糖醇酐脂肪酸酯0.110%,卵磷酯0.504%,乳清蛋白0.410%。用冲淡法检测乳状液类型为W/O型。乳状液稳定性的检测结果,测其体积比率为0.59%,达到了稳定体系的要求。     

Perception of melting and flavor release of ice cream containing different types and contents of fat

Temporal effects of dairy and vegetable fats (0 to 18%) on perception of strawberry flavor release and melting of ice cream were studied using the time intensity sensory method. Also, aroma and flavor attributes of the ice cream samples were evaluated. Only slight effects of fat on the rate of flavor release and flavor intensity were perceived. A slightly faster flavor release from the vegetable fat compared with dairy fat was noticed. Polydextrose and maltodextrin as bodying agents in the fat-free ice cream significantly increased flavor release and melting rate of the ice cream. Increasing fat content slightly retarded melting of ice cream in the mouth. No significant effect of the fat quality on perceived melting was noticed. Significant differences in aroma and flavor attributes of the fat-free and other samples were perceived. Intensity and sharpness of the strawberry aroma and flavor were greater in fat-free samples and they were perceived as nontypical. Fattiness and creaminess were highly correlated. Maltodextrin and polydextrose increased perceived fattiness and creaminess of fat-free ice cream.     

Stability and physical properties of recombined dairy cream: Effects of soybean lecithin

Recombined dairy cream, which primarily comprises anhydrous milk fat and milk protein, has significant advantages compared to natural cream; however, its most notable disadvantage is poor stability. The objective of this study was to investigate the effects of lecithin on the stability and physical properties of recombined dairy cream (20% fat, and 1.5% protein) in terms of the creaming rate, mean oil droplet size and distribution, surface protein concentration, ζ-potential, and apparent viscosity. The results clearly showed that lecithin can significantly improve the stability of recombined dairy cream by decreasing the creaming rate, especially at a concentration of 0.6% (w/w). Increasing the lecithin concentration decreased the mean oil droplet size and the surface protein concentration but slightly increased the ζ-potential. The apparent viscosity decreased and surprisingly increased at 0.6% (w/w). We can infer that lecithin initially displaces proteins from the oil surface and may interact with both proteins and polysaccharides, forming a much more stable structure.     

Microstructure,texture, colour and sensory evaluation of a spreadable processed cheese analogue made with vegetable fat

‘Requeijão cremoso’ is a spreadable processed cheese that shows ample acceptance on the Brazilian market. In this work, analogues of this cheese, made by substituting 25% and 50% of the dairy fat with vegetable fat, were studied with respect to physical–chemical composition, texture profile, microstructure and sensory acceptance. The substitution of part of the dairy cream by vegetable fat resulted in increased adhesiveness and hardness. The traditional cheese presented a uniform protein network in which numerous small fat particles were dispersed, whilst in the analogues, the fat globules were present in smaller numbers and with greater diameters, a behaviour intensified by increasing proportions of vegetable fat. In the sensory analysis, the traditional cheese and the analogue with 50% vegetable fat were better evaluated than the analogue with 25% vegetable fat.     

The effect of vegetable fat on the physicochemical characteristics of dates ice cream

The effects of vegetable fats in low-calorie dates ice cream were studied. Fourteen different formulations were optimized by 'simplex lattice design'. Three types of fat (palm mid-fraction, palm olein and rice bran oil) were chosen to investigate their particle size distribution, melting resistance, amount of protein in the aqueous phase, colour, viscosity, total solids, percentage of overrun, fat and calorie value in ice cream. Statistical significance was determined by using analysis of variance and compared with the Duncan multiple range test using the SAS program. The significance level was 95% ( P  = 0.05). The types of fat used in an ice cream formulation have an impact on the colour, particle size diameter, viscosity and caloric value. A high percentage of palm mid-fraction (> 12%) gave a high intensity of brightness, but less redness and yellowness, while a high percentage of palm olein and rice bran oil gave high intensity of redness and yellowness. Moreover, viscosity was associated with formulations characterized by a high solid fat content. The more unsaturated and the longer the fatty acid chains of the vegetable fat used in the formulation, the more pronounced was the fat globule destabilization. However, the effect of the different fats on melting resistance was less pronounced.     

Effect of temperature of CO2 injection on the pH and freezing point of milks and creams

The objectives of this study were to measure the impact of CO2 injection temperature (0 degree C and 40 degrees C) on the pH and freezing point (FP) of (a) milks with different fat contents (i.e., 0, 15, 30%) and (b) creams with 15% fat but different fat characteristics. Skim milk and unhomogenized creams containing 15 and 30% fat were prepared from the same batch of whole milk and were carbonated at 0 and 40 degrees C in a continuous flow CO2 injection unit (230 ml/min). At 0 degree C, milk fat was mostly solid; at 40 degrees C, milk fat was liquid. At the same total CO2 concentration with CO2 injection at 0 degree C, milk with a higher fat content had a lower pH and FP, while with CO2 injection at 40 degrees C, milks with 0%, 15%, and 30% fat had the same pH. This indicated that less CO2 was dissolved in the fat portion of the milk when the CO2 was injected at 0 degree C than when it was injected at 40 degrees C. Three creams, 15% unhomogenized cream, 15% butter oil emulsion in skim milk, and 15% vegetable oil emulsion in skim milk were also carbonated and analyzed as described above. Vegetable oil was liquid at both 0 and 40 degrees C. At a CO2 injection temperature of 0 degree C, the 15% vegetable oil emulsion had a slightly higher pH than the 15% butter oil emulsion and the 15% unhomogenized cream, indicating that the liquid vegetable oil dissolved more CO2 than the mostly solid milk fat and butter oil. No difference in the pH or FP of the 15% unhomogenized cream and 15% butter oil emulsion was observed when CO2 was injected at 0 degree C, suggesting that homogenization or physical dispersion of milk fat globules did not influence the amount of CO2 dissolved in milk fat at a CO2 injection temperature of 0 degree C. At a CO2 injection temperature of 40 degrees C and at the same total CO2 concentration, the 15% unhomogenized cream, 15% vegetable oil emulsion, and 15% butter oil emulsion had similar pH. At the same total concentration of CO2 in cream, injection of CO2 at low temperature (i.e., < 4 degrees C) may produce a better antimicrobial effect during refrigerated shelf life due to the higher concentration of CO2 in the skim portion of the cream.     

脂肪球在搅打乳状液中的部分聚结及其作用

综述了脂肪球在搅打乳状液中的部分聚结现象和搅打条件、脂肪种类、脂肪球吸附膜对部分聚结的影响。以冰淇淋和搅打奶油为例 ,说明脂肪球的部分聚结对于搅打乳状液最终形成充气的泡沫结构起关键作用 ,控制脂肪球的部分聚结程度对于改善搅打乳制品的质量、性能具有重要意义。联系控制脂肪球的部分聚结在冰淇淋生产中的实际应用 ,介绍了近来国际上有关脂肪球部分聚结的研究进展。