烘烤大豆制备发酵豆乳流变学特性的研究

以烘烤大豆为原料,经瑞士乳杆菌(Lactobacillus helveticus,LH-B02)和干酪乳杆菌(Lactobacillus casei,L.casei-01)组合发酵制备发酵豆乳,研究了发酵豆乳的流变特性和物理性质。结果表明,大豆经过烘烤处理后,发酵豆乳表现出较弱的粘弹性和剪切稀化特性,酸乳的凝胶体系更加疏松,感官上表现为口感更加柔软;与未经烘烤的大豆发酵豆乳相比,烘烤处理后大豆发酵豆乳的持水力和亮度都显著下降,颜色趋于绿色和黄色;烘烤赋予发酵豆乳淡淡的烘烤香气,豆腥味降低,风味得到明显的改善。     

萌发大豆制备益生菌发酵豆乳流变特性的研究

以萌发大豆作为主要原料,经瑞士乳杆菌(Lactobacillus helveticus B02)、保加利亚乳杆菌(Lactobacillus bulgaricus AS1.1482)和嗜热链球菌(Streptococcus thermophilus IFFI 6038)组合发酵制成发酵豆乳,研究益生菌发酵豆乳的发酵特性及流变特性。结果表明,大豆经萌发后,游离氨基酸总量增加了近2倍;与未萌发大豆制成的发酵豆乳相比,萌发大豆发酵豆乳中乳酸菌菌落总数显著增加,产生更多的游离H离子及有机酸,且其剪切稀化作用减弱,表观黏度显著下降,更为接近发酵纯牛乳的流变特性。大豆萌发后制成发酵豆乳,可促进乳酸菌的生长及产酸,有助于改善发酵豆乳的流变特性。     

微射流处理对豆乳粉溶解特性的影响

以传统湿法工艺技术制备豆乳粉为基础,为改善豆乳粉溶解性对豆浆进行微射流处理。研究不同微射流压力(0、42.5、89.0、123.5、152.0 MPa)对豆乳粉溶解特性(粒径、可溶性固形物含量、蛋白分散指数、休止角、溶解度、分散性和水合能力)的影响。结果表明:随微射流压力不断增大,豆乳粉平均粒径呈现出先下降后略有增加的趋势;可溶性固形物含量、蛋白分散指数、休止角、溶解度、分散性和水合能力呈现出先升高后降低的趋势;豆乳粉的微观结构表现为颗粒减小、趋向于均匀且分散性增加。当微射流压力为123.5 MPa时,豆乳粉具有较高的蛋白分散指数和水合能力,分别为97.35%和1.94 mL/g,豆乳粉的堆积密度较高,与对照组相比增加了25.81%。研究表明,当微射流压力为123.5 MPa时,豆乳粉具有良好的溶解特性。     

高压微射流对姜汁黑豆酸奶流变学特性的影响

以生姜和黑豆为原料,利用瑞士乳杆菌（Lactobacillus helveticus）LH-B02、干酪乳杆菌（Lactobacillus casei）L casei-01、干酪乳杆菌NO1分别与嗜热链球菌ST3组合发酵制备姜汁黑豆酸奶样品,研究了高压微射处理对姜汁黑豆酸奶理化性质、流变学特性和微观结构的影响。结果表明,高压微射流均质能够明显提高酸奶的酸度和持水力,改善酸奶的流变学特性、黏弹性,并使剪切稀化特性明显增强,其中弹性模量、粘性模量及屈服应力t0明显提高,微观结构更加致密。其中以干酪乳杆菌NO1和嗜热链球菌ST3制备的姜汁黑豆酸奶总体可接受性最好（评分为8.54）,酸度为83.88°T、持水力为86.66%、屈服应力t0为8.94 Pa、表观黏度η50值为0.26 Pa·s。     

植物乳杆菌ST-Ⅲ在豆乳中的发酵特性及发酵豆乳的贮藏稳定性

通过测定植物乳杆菌ST-Ⅲ在发酵豆乳过程中的生长曲线、酸化曲线、蛋白水解能力和豆乳表观黏度、终产品感官分值,以及发酵豆乳在不同贮藏温度下植物乳杆菌ST-Ⅲ菌数、pH值、持水力和感官变化,研究植物乳杆菌ST-Ⅲ在豆乳中的发酵特性和发酵豆乳产品的贮藏稳定性。结果显示,植物乳杆菌ST-Ⅲ在豆乳中生长良好,到达发酵终点时的菌数为6.1×108 CFU/mL(对数值为8.78),表观黏度可达0.24Pa·s,感官品质较佳;发酵豆乳在低温(4℃)条件下各指标变化差异较小,贮藏稳定性明显优于常温(25℃)时。表明植物乳杆菌ST-Ⅲ具有发酵豆乳制品的优势与潜力。     

适合豆乳发酵的乳酸菌筛选及其应用

以大豆和脱脂奶粉为原料,利用筛选得到的干酪乳杆菌(Lactobacillus casei)L4-4和发酵乳杆菌(L.fermentum)L6-2混合发酵制备酸豆乳。通过单因素实验确定了混合发酵的工艺条件:菌种配比为1∶1,接种量为5%,发酵时间12 h,发酵温度为37℃。分析了混合发酵和单菌株发酵酸豆乳感官指标和营养成分的异同,与单菌株发酵相比,混合发酵的酸豆乳感官指标优于L4-4,而对营养物质的细化作用好于L6-2。     

豆腐乳中乳酸菌的分离鉴定与发酵特性研究

目的分离鉴定农家自制传统发酵豆腐乳中的乳酸菌,探讨其作为豆类乳酸菌发酵饮品菌株的可行性。方法利用MRS(man rogosa sharp)培养基分离豆腐乳中的乳酸菌,通过形态学观察、生理生化特性和16S rDNA基因序列分析进行鉴定,并将所分离到的乳酸菌与适合于豆类植物发酵的植物乳杆菌FJAT-7926(Lactobacillus plantarum FJAT-7926)和干酪乳杆菌FJAT-7928 (Lactobacillus casei FJAT-7928)进行发酵特性的对比研究。结果从豆腐乳中分离出1株乳酸菌,命名为FJAT-46777,该菌株菌体细胞为圆端直杆状或圆端弯曲杆状,无芽孢,革兰氏阳性,过氧化氢酶阴性,生理生化特征与发酵乳杆菌(Lactobacillus fermentum)一致,对菌株的16S rDNA基因进行扩增测序、分子系统发育树分析,也表明其为发酵乳杆菌。发酵乳杆菌FJAT-46777发酵的豆乳中乳酸菌增殖速度最快,最终活菌数最高,为9.42 lg(CFU/mL); pH值下降最快,最终pH值最低,为3.91;滴定酸度上升速度最快,最终滴定酸度最高,为62~ΟT。结论分离自豆类自然发酵食品中的发酵乳杆菌FJAT-46777,对豆类植物为主的基质具有更优良的发酵特性,发酵时间快,乳酸菌含量高,产酸能力强,适用于发酵豆乳的开发。     

鼠李糖乳杆菌发酵大豆酸乳工艺优化研究

以大豆为主要原料,将鼠李糖乳杆菌(Lactobacillus rhamnosus)进行活化、驯化与保加利亚乳杆菌(Lactobacillus bulgaricus)和嗜热链球菌(Streptococcus thermophilus)按一定比例混合制备发酵剂,通过单因素实验和正交实验优化确定酸豆乳发酵的生产工艺。结果通过单因素实验确定上述三个菌种按1∶0.5∶1混合作为工作发酵剂;正交实验研究结果表明影响豆乳发酵的显著因素依次为料水比、接种量、发酵时间和蔗糖添加量,最佳条件是:接种量为5%,磨制豆浆料水比为1∶8,蔗糖添加量为8%,在43℃条件下发酵5h,该条件下生产的酸豆乳,具有浓郁的风味和细腻酸甜的口感。     

乳酸菌发酵对青稞β-葡聚糖加工特性及其耐缺氧和抗疲劳作用影响

该文研究植物乳杆菌(Lactobacillus plantarum,LP)、保加利亚乳杆菌(Lactobacillus bulgaricus,LB)、鼠李糖乳杆菌(Lactobacillus rhamnosus,LR)发酵对青稞β-葡聚糖加工特性及其耐缺氧、抗疲劳作用的影响。结果表明,LB发酵制备青稞β-葡聚糖的含量高于LP和LR,达到(5.14±0.22)%。保加利亚乳杆菌发酵后得到的β-葡聚糖(Lactobacillus bulgaricus β-glucan,LBG)中多糖均一性较高,起泡能力和溶解性均显著高于植物乳杆菌发酵后得到的β-葡聚糖(Lactobacillus plantarum β-glucan,LPG)、鼠李糖发酵后得到的β-葡聚糖(Lactobacillus rhamnosus β-glucan,LRG)和未发酵得到的β-葡聚糖(no fermentation β-glucan,NFG)起泡稳定性显著高于LPG、LBG和NFG。LPG、LBG、LRG与NFG相比,密闭缺氧存活时间延长了26.6%、42.3%和36.4%,游泳存活时间延长了22.6%、40.3%和4...     

一株乳酸菌的鉴定及其在酸豆乳加工中的应用

对从酸菜汁中分离到的一株乳酸菌菌株L4进行鉴定,通过传统的形态学及生理生化特性分析,初步确定菌株L4为乳酸杆菌属(Lactobacillus)。通过序列比对及构建系统发育树,表明L4与植物乳杆菌(Lactobacillus plantarum)相似性在90%以上,鉴定菌株L4为植物乳杆菌。对菌株L4在豆乳中发酵的酸化能力、后酸化能力及耐受酸能力进行了研究。结果表明,该菌株在豆乳中37℃发酵,15h酸度值为58°T左右;用此菌株发酵的豆乳在4℃贮藏期间也很稳定,20d内酸度变化范围极小,约为4°T;耐受酸能力较强,在pH值为3.0条件下处理120min,菌数存活率为91.2%。     

应用不同大豆蛋白制备大豆酸奶

本研究应用不同的大豆蛋白为原料制备大豆酸奶,并对其影响因素进行了分析。使用常用的保加利亚乳杆菌和嗜热链球菌,逐渐增加其中的豆乳含量进行驯化培养。结果表明,豆乳与牛乳比为8:2发酵效果较好。经发酵实验,分别确定了不同原料的最佳固形物含量、发酵时间、杀菌温度等影响因素。     

乳酸菌培养物的生长特性及其对豆奶质构和风味的影响

研究了Lactobacillus casei (LC), Lactobacillus helveticus (LH) and Lactobacillus rahmnosus (Lactobacillus casei subsp. rahmnosus 6013) (LR)生长特性及其对大豆奶酪风味的影响.研究表明,经过6 h的发酵,LC、LH和LR的菌落数分别增长至8.74、7.69和8.69 log (CFU/mL);37 ℃时,分别接种LC、LH、LR和添加有Glucono-δ-内酯(GDL)的大豆牛奶都明显出现可滴定酸度增加、pH减少的现象.这三种乳酸菌都能够利用大豆糖源.经质构分析发现,菌种可引起大豆牛奶质构发生变化,其凝乳的能力可与GDL媲美.菌种通过产酶、产酸而水解大豆蛋白,从而导致质构变化形成凝乳.这些菌种可释放18种游离氨基酸(FAA),其中包括可作为奶酪风味物质前体化合物的天门冬氨酸、异亮氨酸、亮氨酸、蛋氨酸、苯丙氨酸和缬氨酸.这些菌种均能利用大豆脂肪酸(FA),而在大豆凝乳中出现某些FA消失的现象表明所选的菌种还能分别完全消耗特定的FA.可见,这三种乳酸菌在大豆牛奶中可引起质感及风味前体物的变化,正是生产大豆奶酪所必需的效果,故选择它们作为制备大豆奶酪的适用菌种.     

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.     

酸豆乳生产菌种的驯化研究

将嗜热链球菌、保加利亚乳杆菌分别活化,然后在不同比例的牛奶和豆乳培养基中进行连续传代驯化,使其逐步适应豆乳的发酵环境。再用驯化后的菌种发酵豆乳,可使其菌数接近酸牛奶的水平,菌数比驯化前提高了5.9倍,酸度比驯化前提高63%,风味也得到明显的改善。     

乳蛋白对豆乳凝胶物性学特征的影响机理

为改善豆乳酸奶制品,分别从体系层面、颗粒层面和分子层面研究不同类型的乳蛋白——乳清分离蛋白（whey protein isolate,WPI）、乳浓缩蛋白（milk protein concentrate,MPC）和酪蛋白酸钠（sodium caseinate,NaCas）对豆乳凝胶特性的影响及机理。结果表明：WPI（≥20%）、40% NaCas的加入可以有效增强豆乳凝胶强度,其中WPI（≥20%）的作用最为显著。低替代比例的乳蛋白可以显著减小凝胶颗粒的粒径,而高比例的WPI会大幅度增大体系的凝胶颗粒。在微观结构方面,MPC的添加使得凝胶结构更为致密规则,NaCas的添加形成了细丝网状结构,而WPI的添加使得凝胶结构趋于不规则、致密。聚丙烯酰胺凝胶电泳及其光密度扫描结果显示,添加WPI（≤20%）可能会促进大豆7S蛋白的β亚基参与凝胶,而NaCas则会阻碍大豆11S蛋白碱性亚基的凝胶化。     

EFFECT OF SOLID CONTENT AND SUGAR COMBINATIONS ON THE QUALITY OF SOYMILK-BASED YOGURT

A research to evaluate the effect of two levels of solids and two sugar combinations in the quality of a soymilk yogurt-type food was carried out. Yogurts were elaborated by inoculating lactic cultures ( Lactobacillus dellbruckii spp. bulgaricus and Streptococcus salivarius spp. thermophilus ) into soymilk with 8% and 11% solid levels and glucose/sucrose and glucose/fructose mixtures. Also, a control treatment with cow milk was prepared. Yogurts were analyzed after two days of preparation for their chemical (protein, lipids, titrable acidity and pH), physical (syneresis and viscosity) and sensory characteristics (quality and acceptability). Protein content of soymilk based yogurts ranged between 3.56 and 4.45 g/100 g. The higher titrable acidities (0.66% and 0.63% lactic acid) were shown by treatments with higher solids level, which also shown the lowest syneresis. All soymilk yogurts were yellowier than the control. The highest sensory acceptability was for the 8% solids treatment enriched with glucose and sucrose.

PRACTICAL APPLICATIONS

There are an increasing number of people suffering of lactose intolerance, which need an alternative product to milk. Besides, some people have adopted a strictly vegetarian way of life. Soymilk has been used for a long time by this part of the population; however, it usually has a beany flavor, which can cause some rejection among occidental consumers. A fermented product from soymilk, such as soymilk yogurt, may offer a good alternative for those people. In soymilk production it is necessary to carefully adjust the amount of solids and the sugar used in fermentation in order to obtain a well accepted commercial product. Soy yogurt could be used to formulate a number of different new products like desserts, high fiber yogurt, fruit-added yogurt and so on.     

Microbiological,physicochemical and rheological properties of fermented soymilk produced with exopolysaccharide (EPS) producing lactic acid bacteria strains

Growth of Lactobacillus plantarum 70810, Lactobacillus rhamnosus 6005 and a commercial yogurt starter culture in soymilk was investigated in the present study. It was found that the fermented soymilk using L. plantarum 70810 had significantly higher viable cell counts, water holding capacity (WHC, 88.27%), apparent viscosity (1840.35 mPa s) and exopolysaccharide (EPS) amount (832.15 mg/L) than the other two starter cultures in soymilk. Direct observation of microstructure in fermented soymilk indicated that the network structures of EPS-protein could improve the texture of fermented soymilk. Considering that the beneficial effects of L. plantarum 70810 in fermented soymilk, volatile compounds in fermented soymilk were further identified. Then the growth and fermentation characteristics of L. plantarum 70810 including changes in viable cell counts, pH, titratable acidity, apparent viscosity and EPS production during storage were investigated. In comparison to original soymilk base, the concentrations of the characteristic flavor compounds for fermented soymilk using L. plantarum 70810 increased, whereas hexanal, 2-pentylfuran and 2-pentanone in relation to beany flavor of soymilk decreased. In addition, fermented soymilk using L. plantarum 70810 maintained high viable cell count (>10⁸ cfu/mL), apparent viscosity (966.43 mPa s) and amounts of EPS (635.49 mg/mL) during storage at 4 °C for 21 days.     

Sogurt, a Yogurt-like Soybean Product: Development and Properties

Two sogurt products were prepared by fermenting a formulation containing soymilk, 0.15% calcium acetate, 0.5% gelatin, and lactose (0 or 2%) with Lactobacillus casei and Streptococcus thermophilus. Commercial plain yogurt was used as a control. Sogurts were evaluated for aroma, taste, texture, titratable acidity, pH, and color. Sogurts had beany and raisin aromas, more bitter and astringent tastes than yogurt, and slightly sandy mouth- feel. Sogurts and yogurt did not differ (P < 0.05) in intensity of butter aroma. Sogurt with lactose did not differ (P < 0.05) from yogurt in acidity. Sogurts were yellower and firmer than yogurt.     

Growth of probiotic bacteria and bifidobacteria in a soy yogurt formulation

Soy beverage and cows' milk yogurts were produced with Steptococcus thermophilus (ATCC 4356) and Lactobacillus delbrueckii subsp. bulgaricus (IM 025). The drop in pH during fermentation was faster in the soy beverage than in cows' milk, but the final pH values were similar. Yogurts were prepared with a yogurt starter in conjunction with either the probiotic bacteria Lactobacillus johnsonii NCC533 (La-1), Lactobacillus rhamnosus ATCC 53103 (GG) or human derived bifidobacteria. The presence of the probiotic bacteria did not affect the growth of the yogurt strains. Approximately 2 log increases in both L. rhamnosus GG and L. johnsonii La-1 were observed when each was added with the yogurt strains in both cows' milk and the soy beverage. Two of the five bifidobacteria strains grew well in the cows' milk and soy beverage during fermentation with the yogurt bacteria. High pressure liquid chromatography (HPLC) analyses showed that the probiotic bacteria and the bifidobacteria were using different sugars to support their growth, depending on whether the bacteria were growing in cows' milk or soy beverage.