Fermentation and Properties of Calcium-fortified Soy Milk Yogurt

Calcium-fortified soy milk yogurt containing 190 mg calcium/100g was produced and evaluated for textural and microstructural properties. The soy milk base contained 10% full fat soy flour, 2.25% soy protein isolate, 2.75% high fructose corn syrup, 1.55% calcium lactogluconate, and 1.25% potassium citrate. The mixture was heated 5 min at 80°C, cooled to 42°C, and inoculated with yogurt cultures. Calcium-fortified soy milk required a higher rate of inoculation (5%) than non-fortified soy milk (2.5%) and had higher titratable acidity and more syneresis. Calciumfortified soy milk yogurts showed comparable gel strength with that of commercial regular yogurt. Gels from nonfortified soy milk yogurts were hard and brittle. Addition of calcium did not significantly affect microstructure of the yogurts.     

Determination of Sensory Thresholds of Selected Calcium Salts and Formulation of Calcium-fortified Pocket-type Flat Bread

Pita bread loaves were prepared from flours fortified with calcium carbonate, calcium sulfate, and tricalcium dicitrate at 8 ascending levels to provide ranges of 800 to 2500, 700 to 1500, and 400 to 2000 mg of added Ca/100 g flour, respectively. The detection thresholds of calcium salts in pita bread were determined by the 3‐alter‐native forced choice (3‐AFC) test and construction of dose‐response curves. Detection thresholds determined by calculating geometric mean of individual best estimate thresholds, using criterion of 50%‐above‐chance and probit analysis of 3‐AFC data, were in the middle region of calcium concentrations. Analysis of dose‐response curves yielded values for thresholds outside the range of surveyed calcium concentrations. The detection threshold of CaSO₄ (2724 mg/100 g) in pita bread was significantly higher (P < 0.01) than those of calcium carbonate (1984 mg/100 g) and tricalcium dicitrate (2132 mg/100 g). Calcium‐fortified pita bread was similar (P < 0.01) to its regular counterpart when formulated to contain 1254.6, 1772.5, or 1155 mg/100 g of CaCO₃, CaSO₄, or tricalcium dicitrate, respectively. At the indicated levels of fortification, calcium‐fortified pita bread is expected to provide between 61% and 126.5% of the recommended daily intake for calcium for Middle Eastern populations.     

热处理及植酸与脂肪对豆浆中大豆蛋白凝胶体系的影响研究进展

豆浆由于其优异的特性已经成为大豆食用的重要形式.热加工处理在豆浆加工工艺中起到至关重要的作用,不同程度的热处理会使豆浆中大豆蛋白发生不同程度的变性,从而会影响豆浆加工后产品的品质与特性.本文综述了近年来豆浆加工工艺中不同热处理条件对大豆蛋白结构、组分及其凝胶特性的影响规律,钙、镁、植酸盐、脂肪与大豆蛋白的互作对豆浆混合...     

热处理对豆浆总酚含量及其抗氧化能力的影响

以绥农56大豆为原料,研究热处理对豆浆中总酚含量和体外抗氧化能力的影响.结果 表明:一定程度的热处理可适当提高豆浆中总酚含量.豆浆在100℃处理20 min时,总酚含量1.54mg/g,且脲酶呈阴性;豆浆热处理过程中,DPPH自由基清除能力先减弱后增强,从42.80％增加至50.46％;ABTS·+清除能力先增强后减弱...     

崂山奶山羊乳的热稳定性影响因素研究

本文以崂山奶山羊乳为研究对象,对山羊乳的一般理化性质进行分析,并重点探讨了山羊乳的热稳定性。采用热凝固时间法(HCT)测定不同泌乳期、温度、pH值及相关助剂对山羊乳热稳定性的影响。结果表明,山羊乳的pH接近中性、酸度为11~23°T,且与泌乳期呈正相关关系。羊乳的稳定性随泌乳期的延长而增强,随加热温度的升高而急剧减弱。pH对羊乳的热稳定性影响较大,pH越大,HCT值越大,当待测乳样的pH值超过6.5时,乳样不再发生沉淀。在pH=6.0、140℃加热条件下,加入适量浓度为0.01~0.20mol/L的柠檬酸盐、磷酸盐、EDTA均可改善羊乳的稳定性,且添加物浓度越大,改善效果越好。添加钙离子亦可改变羊乳的热稳定性,其稳定性随钙离子浓度的升高而降低。羊乳热稳定性随蔗糖浓度的增大呈现出先升高后降低的趋势,添加浓度为35%的蔗糖时,待测羊乳的HCT值最高,羊乳的热稳定性最好。     

Impact of source and level of calcium fortification on the heat stability of reconstituted skim milk powder

Calcium enrichment of food and dairy products has gained interest with the increased awareness about the importance of higher calcium intake. Calcium plays many important roles in the human body. Dairy products are an excellent source of dietary calcium, which can be further fortified with calcium salts to achieve higher calcium intake per serving. However, the addition of calcium salts can destabilize food systems unless conditions are carefully controlled. The effect of calcium fortification on the heat stability of reconstituted skim milk was evaluated, using reconstituted skim milks with 2 protein levels: 1.75 and 3.5% (wt/wt) prepared using low and high heat powders. Calcium carbonate, phosphate, lactate, and citrate were used for fortification at 0.15, 0.18, and 0.24% (wt/wt). Each sample was analyzed for solubility, heat stability, and pH. The addition of phosphate and lactate salts lowered the pH of milk, citrate did not have any major effect, and carbonate for the 1.75% protein samples increased the pH. In general, changes in solubility and heat stability were associated with changes in pH. Calcium addition decreased the solubility and heat stability. However, interestingly, the presence of carbonate salt greatly increased the heat stability for 1.75% protein samples. This is due to the neutralizing effect of calcium carbonate when it goes into solution. The results suggested that the heat stability of milk can be affected by the type of calcium salt used. This may be applied to the development of milk-based calcium enriched beverages.     

铁强化酱油的工艺研究

本文就酱油酿造过程中发酵与温度、时间的关系进行了研究。在实验中，重点对铁强化剂的选择、铁强化剂添加量的确定及控制、铁强化剂添加工艺、含铁量测定等进行了研究，并研制出铁强化酱油。结果表明，在酱油中添加180～210mg/100ml的NaFeEDTA，相当于20～30mg/100ml的铁，即在强化食品的允许剂量范围内，不影响制品的色、香、味、体及各项理化指标，包括pH、密度、氨基氮、固形物含量、糖分、总酸，且制品含铁量高，性能稳定，口感好。     

高蛋白低脂肪豆奶的研制

以豆粕为主要原料生产豆奶,着重研究了豆粕与水的配比、乳化稳定剂的用量、均质的工艺条件以及杀菌温度等对豆奶稳定性的影响.实验结果表明,豆奶生产中,控制豆粕和水的配比为1:6.7,其它配科添加量的质量比分别为:白砂糖5.00%,六偏磷酸钠0.05%,糊精3.00%,KHN-9993复配乳化剂0.25%,大豆油0.50%;压强30 MPa下均质两次,均质温度83℃;杀菌温度为121℃,时间15min.此条件生产的豆奶成本低廉,工艺可行,稳定性高,质量优良.     

豆浆热处理过程中3种大豆异黄酮苷原的热降解比较

将大豆加工成豆浆并分别用95、121和140℃处理不同时间，以高效液相色谱（HPLC）法检测其中的3种大豆异黄酮皆原，染料木黄酮（genistein）、黄豆苷原（daidzein）和大豆黄素（glycitein）的含量变化，与原粒大豆、生豆浆进行比较。结果发现，染料木黄酮、黄豆苷原和大豆黄素的热稳定性存在较大差异，在95℃下，染料木黄酮在60min的处理时间内稳定，而黄豆苷原和大豆黄素的T（loss0.5）值（损失50％含量的时间）分别为1442s和453s，表明95℃下3种大豆异黄酮的热稳定性表现为：染料木黄酮〉黄豆苷原〉大豆黄素。而在121℃和140℃的处理条件下，3种大豆异黄酮苷原均随着处理时间的延长而出现不同的热降解，黄豆苷原、大豆黄素和染料木黄酮在121℃的T（loss0.5）值分别为26．36、37．88和1015s，而在140℃下，黄豆苷原、大豆黄素和染料木黄酮的T（loss0.5）值则分别缩短为6．94、8．47和369s，结果表明在121℃和140℃下，3种大豆异黄酮的热稳定性表现为：染料木黄酮〉大豆黄素〉黄豆苷原。     

Reduction of Moniliformin in Corn by Heat Processing

The effects of autoclaving, baking, extrusion, frying, and roasting on the stability of moniliformin (MON) in spiked (5 μg/g of MON) corn‐based food products were investigated. Roasting corn meal at 218 °C for 15 min had the most significant effect (p ≤ 0.05) on the reduction of MON (44.6%). Autoclaving creamed corn at 121 °C for 65 min resulted in only 10% reduction of MON. Reductions of MON ranging from 5.4 to 28.9% were observed when corn chips were prepared from spiked masa. MON was reduced by 42.2% when corn muffins were baked and by 26.7% when corn grits were extruded. Overall, MON showed heat stability similar to or greater than other Fusarium mycotoxins such as deoxynivalenol and fumonisin B₁     

内蒙古阿拉善双峰驼驼乳IgG的分离纯化及其热稳定性研究

本文采用硫酸铵沉淀法两次沉淀乳清蛋白,并结合离子交换层析法,从双峰驼初乳中分离纯化驼乳IgG。再用SDS-PAGE鉴定其纯度,测定其分子量。然后用分离纯化的驼乳IgG免疫家兔,制备效价至少为1:32的兔抗驼IgG抗血清。内蒙古阿拉善双峰驼驼乳分别于65、75、85和100℃加热30min,用SDS-PAGE检测驼乳中IgG的变性程度。同时采用单向免疫扩散法测定驼乳中IgG的活性。结果表明,于75℃,加热30min,驼乳IgG的活性丧失68.9%,而参考值的牛乳IgG活性则完全丧失。因此,驼乳IgG的热稳定性比牛乳IgG的热稳定性高。     

Feasibility of using dialysis for determining calcium ion concentration and pH in calcium-fortified soymilk at high temperature

Abstract: Dialysis was performed to examine some of the properties of the soluble phase of calcium (Ca) fortified soymilk at high temperatures. Dialysates were obtained while heating soymilk at temperatures of 80 and 100 °C for 1 h and 121 °C for 15 min. It was found that the pH, total Ca, and ionic Ca of dialysates obtained at high temperature were all lower than in their corresponding nonheated Ca‐fortified soymilk. Increasing temperature from 80 to 100 °C hardly affected Ca ion concentration ([Ca²⁺]) of dialysate obtained from Ca chloride‐fortified soymilk, but it increased [Ca²⁺] in dialysates of Ca gluconate‐fortified soymilk and Ca lactate‐fortified soymilk fortified with 5 to 6 mM Ca. Dialysates obtained at 100 °C had lower pH than dialysate prepared at 80 °C. Higher Ca additions to soymilk caused a significant (P≤ 0.05) reduction in pH and an increase in [Ca²⁺] of these dialysates. When soymilk was dialyzed at 121 °C, pH, total Ca, and ionic Ca were further reduced. Freezing point depression (FPD) of dialysates increased as temperature increased but were lower than corresponding soymilk samples. This approach provides a means of estimating pH and ionic Ca in soymilks at high temperatures, in order to better understand their combined role on soymilk coagulation.     

Heat Stability of Oil-in-Water Emulsions Containing Milk Proteins: Effect of Ionic Strength and pH

Emulsions (20 wt% soybean oil; 2 wt% protein) made with caseinate at pH 7 and with whey protein isolate (WPI) at pH 7 and 3 were stable to heating at 90 and 121°C. WPI emulsions destabilized at pH values between 3.5 and 4.0. In the presence of KCI (12.5–200 mM), large particles were formed in WPI emulsions at pH 3 and the emulsions were viscous. At pH 7, moderate concentrations of KCI decreased the heat stability and gels were formed. KCI had less effect on WPI emulsions made at pH 3. Combining the emulsions with caseinate allowed some control of the heat-induced gelation.     

热处理对豆浆中大豆异黄酮含量及降解动力学的影响

大豆中苷元型异黄酮可直接被人体消化吸收,而其他异黄酮必须要经过水解去除糖基后才能被吸收利用。本研究通过模拟工业生产中常用的巴氏杀菌(95℃)、高温短时杀菌(121℃)和超高温瞬时杀菌(143℃),阐述了豆浆加热过程中异黄酮单体之间的转化,并对主要异黄酮的热降解进行了动力学分析,以期为生产高比例苷元型异黄酮的豆浆提供理论依据。生豆浆中丙二酰型异黄酮含量最高,其次分别为糖苷型和苷元型。3种热处理均导致丙二酰型异黄酮含量降低,符合一级降解动力学,且温度越高,降解速率常数越大。95℃处理主要导致丙二酰型向糖苷型转化,而143℃时异黄酮主要发生降解而非转化。121℃处理后,豆浆中苷元型异黄酮含量显著增加,比生豆浆提高50%,显著提高了豆浆品质。相对其他两个热处理温度,高温短时杀菌能减少异黄酮分解提高苷元型含量,更适合于豆浆工业化生产。     

热处理对牛乳成分的变化影响及热损标识物的选择

牛乳是一种成分组成十分复杂的高级营养食品,热处理是乳品工业中不可或少的一个环节,通过杀灭微生物可以延长货架期或改变性状。但乳的加热处理会改变乳成分的物理化学状态,促使乳中一些热敏物质发生变化,尤其是乳蛋白（免疫球蛋白、酶、乳清蛋白）发生变性,造成牛乳营养成分损失,甚至产生可能有害的新物质。本文对牛乳热处理过程中发生的成分变化以及热损标识物的选择作了详细综述。     

热处理对汉麻乳稳定性的影响及蛋白结构表征

为研究热处理对汉麻乳稳定性及其蛋白结构的影响,本实验通过汉麻乳氮溶解指数、离心沉淀率、乳化特性、乳液表面电位和粒径等指标监测汉麻乳热处理过程中稳定性的变化,利用傅里叶变换红外光谱表征热处理对汉麻乳蛋白二级结构的影响.结果表明:随着热处理温度的升高(55～95℃),汉麻乳氮溶解指数由58.55％逐渐减小到39.81％,离...     

Heat Inactivation Kinetics of Trypsin Inhibitors During High Temperature-Short Time Processing of Soymilk

Heat treatment of soymilk was studied in the conventional batch boiling process and under High Temperature-Short Time (HTST) conditions. Reduction in total trypsin inhibitor was assayed enzymatically, and individual inhibitors, the Kunitz and the Bowman-Birk inhibitor, were assayed by ELISA technique. Standard first-order reaction kinetics and thermodynamics were applicable for inactivation, and results indicated that the mechanism was not protein unfolding, because entropy changes were zero or negative. The two inhibitors were inactivated at the same rate around 137°C. Therefore, a simple first-order kinetic model which gave a good, slightly conservative estimate of residual anti-trypsin activity under HTST conditions could be established.     

大豆蛋白的热处理改性及热聚集行为研究进展

大豆蛋白的热处理改性有助于提高其功能特性及生物有效利用率,从而拓宽其在食品工业中作为配料应用的范围。热处理主要通过对大豆蛋白热聚集行为的影响,从而达到影响大豆蛋白功能性质及生物有效利用率的目的。因此,本文拟对大豆蛋白的热处理改性及大豆蛋白(包括大豆分离蛋白、大豆球蛋白及大豆伴球蛋白)的热聚集行为的研究进展进行综述。希望通过对上述方面的综述,能为广大科研人员及企业生产单位提供一定的借鉴。     

Heat Curing of Soy Protein Films at Selected Temperatures and Pressures

Vacuum and temperature effects on moisture content, water vapor permeability (WVP), color (L, a, b, and ΔE), tensile strength (TS), elongation (E), and total soluble matter (TSM) of soy protein isolate (SPI) films were examined. SPI films were cured at 60, 72.5, or 85 °C and at 101.3, 81.32, or 61.32 kPa for 24 h. As a result of heat-curing moisture content, WVP, E, and TSM decreased, and total color difference and TS increased. Pressure, individually and interactively with temperature, significantly affected film moisture content, TS, and TSM.     

海南椰奶清补凉饮料的生产工艺研究

海南椰奶清补凉是一款营养丰富的特色小吃,但其工业化生产工艺研究甚少.本文对椰奶清补凉辅料配方、乳化剂复配、均质和杀菌等方面进行研究,优化其工业化的生产配方、工艺和稳定性.结果表明:加糖量,椰果肉与水质量比,绿豆、西米和椰果的质量比分别为10%、1:3、1:2:3时综合感官评定分最高;单甘酯、Span-20、Tween-...