Research Progress of Volatile Substances Analysis and Sensory Evaluation of Soymilk

Soybean is one of the important crops in China. Soymilk, a traditional neutral plant-based protein drink, is rich in high quality proteins. Although soybean milk is rich in nutrients, its marketing among consumers, especially those in Western countries who are used to peaceful flavor, has been limited due to the adverse flavor impact brought by its special composition. In recent years, with the increasing attention to the nutritional value of soymilk, the flavor of soymilk has become a popular research object for scholars at home and abroad. The flavor components of soymilk are mainly volatile small molecular compounds produced by enzymatic reactions catalyzed by lipoxygenase(LOX). After formation, they interact with protein macromolecules to form the overall flavor of soymilk. At present, there are many methods to control the off-odor of soymilk at home and abroad, including physical heating methods, chemical methods, biological enzymatic digestion methods, mask methods, and a variety of breeding methods. These methods effectively reduce the off-odor of soymilk, but all of them have shortcomings. Currently, the sensory characteristics of the beany odor in soymilk are evaluated mainly by traditional human sensory scoring along with the assistance of modern instrument analysis of volatile flavor substances using headspace solid phase microextraction(SPME) gas chromatography coupled with-mass spectrometry(GC-MS). This paper summarized the research results of volatile flavor substances in soymilk in recent years and the sensory evaluation methods of soymilk at home and abroad, and looked forward to the future development direction, hoping to provide some theoretical bases and reference detection methods for solving the problem of soymilk flavor in the future.

唾液联合乳杆菌M18-6对发酵豆乳风味品质及其抗氧化活性的影响

本实验利用前期实验室筛选出能够稳定快速发酵大豆蛋白的体系和具有较强抗氧化能力的唾液联合乳杆菌M18-6发酵豆乳,并分析其对发酵豆乳风味品质和抗氧化活性的影响。结果表明,随着发酵时间的延长,大豆蛋白以及脂肪等物质逐渐分解,发酵豆乳的粒径呈下降趋势,使其质地趋于细腻、光滑。同时,采用顶空固相微萃取-气相色谱-质谱技术和气相色谱-离子迁移谱技术相结合,对发酵前后豆乳的挥发性成分进行分析,发现主要产生豆腥味的己醛随着发酵时间的延长浓度逐渐降低,1-辛烯-3-醇的浓度也呈下降的趋势;双乙酰、乙偶姻、2-庚酮以及其他产生果香味等风味物质随着发酵时间的延长,其浓度逐渐增加,使豆乳呈现良好的风味。进一步利用丙烯酰胺诱导Caco-2细胞构建氧化损伤模型,探究唾液联合乳杆菌M18-6发酵豆乳的抗氧化性,结果显示发酵豆乳的羟自由基清除能力较强。与氧化损伤模型组相比,经过发酵豆乳处理后Caco-2细胞的过氧化氢酶、超氧化物歧化酶活力分别提高了1.67倍和29.80倍,谷胱甘肽浓度也提高了12.83倍,综上,经过唾液联合乳杆菌M18-6发酵的豆乳具有显著的修复氧化损伤细胞作用。

豆浆中风味物质形成、与蛋白的互作机制及生物法改善豆浆风味的研究进展

豆浆作为一种营养丰富的植物基蛋白饮品,在全球范围内受到消费者的喜爱。然而,其特有的不良风味往往影响消费者的接受度,限制了豆浆产品的市场推广。本文探讨豆浆中风味物质的形成机理、这些风味物质与豆浆中的蛋白质之间的相互作用机制以及通过生物方法改善豆浆风味的研究进展。通过无脂氧合酶大豆品种的开发、酶处理和微生物发酵等生物方法,可以有效地改善豆浆的风味,同时保持其营养价值。最后对未来改善豆浆风味的研究方向做出展望,以期为豆浆及其制品的品质提升和市场推广提供理论依据,为推动我国大豆制品市场的发展做出贡献。

Radical Scavenging Ability of Soymilk Fermented with Compound Lactic Acid Bacteria towards DPPH Free Radical

The DPPH scavenging ability of soymilk fermented with lactic acid bacteria under different fermentation conditions were investigated in this paper. According to the result, the optimal combination of starter species was S. thermophilus, L. plantarum and L. helveticus at a ratio of 2∶1.5∶1.5. The optimal fermentation parameters were temperature of 37 ℃, solids content of 12% and fermentation time of 6 h.Under above conditions, the fermented soymilk showed the highest ability to scavenge DPPH free radicals（84.3%）. Besides, the radical scavenging ability of fermented soymilk was compared with that of Baiyu lactone soymilk and bean curd which were coagulated by chemical method. The result indicated that the scavenging rate of lactone bean curd of Baiyu lactone soymilk and bean curd was only32.1% and 23.2%. According to the comparison, the free radical scavenging ability of soymilk was significantly improved by lactic acid fermentation. This product which had no beany flavor would be beneficial to human health.

Metabolite Profile of Lactic Acid-Fermented Soymilk

Isoflavone aglycone-rich soymilk fermented by Lactobacillus delbrueckii subsp. delbrueckii, strain TUA-4408L (F4408) has stronger lipid metabolism-modulating effects than isoflavone aglycone-poor soymilk fermented by Lactobacillus delbrueckii subsp. delbrueckii, strain TUA-4404L (F4404). As such, fermentation products other than isoflavone aglycones may also exert lipid metabolism-modulating effects. Therefore, the present study aimed to compare the metabolites in soymilk (SM), F4404, and F4408 via a metabolomics approach. Various aglycones including isoflavones, flavones, flavonols, and flavanones increased in both F4404 and F4408 compared with SM. The increases in isoflavone and flavanone aglycones were greater in F4408 than in F4404. Some types of dipeptides and free amino acids, especially ornithine, increased in both fermented soymilks. The increase in free amino acids, especially ornithine, was higher in F4408 than in F4404. Thus, F4408 exhibited stronger glycosidase and protease activities than F4404. Functional components produced by lactic acid fermentation are known to improve lipid metabolism. Therefore, it is suggested that not only isoflavone aglycones but also other functional components exert lipid metabolism-modulating effects in fermented soymilks, especially soymilk fermented using TUA-4408L.

Effects of Soymilk on Serum Insulinemic Status and High Sensitivity C-Reactive Protein Levels in Healthy Postmenopausal Women of Bangladesh

Background: Postmenopausal women are at increased risk for cardiac diseases because many risk factors are aggravated by menopause. Isoflavones are phytoestrogens present in natural sources, and they may modulate risk factors favorably, involving mechanisms similar to estrogen. The study aimed to assess the effects of soymilk on serum insulinemic status and hs-C reactive protein (CRP) levels of postmenopausal women of Bangladesh. Methods: Thirty-six women (aged 50 ± 5 years, M ± SD) participated in a randomized, un-blind, open-ended, crossover study design for 52 days. During the study period, the patients made four visits (before and after the intervention including the washout period). The soymilk group consumed 350 mL of milk twice a day for 21 days;the milk contained ~30 mg of isoflavones. Fasting blood glucose (FBG), postprandial glucose (PPG), HbA1c, serum insulin, and hs-CRP were measured on day 0, day 21, day 31, and day 51 with a 10-day washout period. Paired t-test was performed to determine the effects of soymilk on the CVD risks among postmenopausal women and a student t-test was performed for group comparison. Statistical tests were considered significant at p value of ≤0.05. Results: The mean (±SD) BMI of the postmenopausal women was 25.14 ± 3.55 kg/m2. In the consumption of soymilk no significant changes were found in glycemic, insulinemic, and hs-CRP levels between and within the groups. After crossover, a significant change was observed in FBG (5.18 ± 0.49 vs 5.56 ± 0.43, p = 0.005) in the soymilk group. No significant changes were observed in other parameters within or between the groups. However, FBG and hs-CRP levels were found to improve but not significantly at the end of 51 days. Conclusions: Soy isoflavones did not improve serum insulinemic status and hs-C reactive protein (CRP) levels among Bangladeshi postmenopausal women. Further studies need to be elucidated by considering a follow-up study with a large sample size.

Development of Bergamot Yam Soymilk Yogurt

[Objectives]This study was conducted to develop a bergamot yam soymilk yogurt.[Methods]With bergamot yam and soybeans as the main raw materials,the nutritious bergamot yam soymilk yogurt was finally obtained through soymilk deodorization,strain acclimation and process optimization.[Results]Soybeans were soaked in a 1∶1 mixture of 0.2%sodium chloride and 0.2%sodium bicarbonate for 10 h,and then added with water for grinding,and the obtained slurry was filtered.The filtrate was heated at 100℃for 20 min on a low fire and mixed with skim milk in a ratio of 6∶4,and the obtained soymilk achieved the best deodorizing effect.Strains adapted to the soybean milk fermentation system were obtained by gradually increasing the ratio of soybean milk in the acclimation medium and performing passage.The curding time before the product acclimation was 6.5 h,and that after acclimation was 5.8 h,which meant that the time was shortened by 0.7 h,and the acidity increased significantly.Finally,an orthogonal experiment was carried out,determining that the optimal fermentation process was soybean-to-water ratio 1∶5,sucrose 8%,bergamot yam 8%,and fermentation time 6 h.[Conclusions]This study provides a reference for the deep processing of bergamot yam.

不同干燥方式对发酵豆乳粉品质的影响

以活菌数、水分含量、感官品质、消化特性、贮藏稳定性、干燥能耗和得率为指标,探究发酵豆乳粉的最佳干燥方式。结果表明:真空冷冻干燥处理的发酵豆乳粉具有较高的乳酸菌活菌数、抗性淀粉含量和贮藏稳定性,并具有较好的色泽、外观和冲调性,但其能耗高,生产效率较低;喷雾干燥处理的发酵豆乳粉具有较好的色泽、外观和冲调性,且水分含量低,其乳酸菌活菌数和贮藏稳定性略低于真空冷冻干燥,贮藏6个月后的活菌数仍能保持在7.31 lg CFU/g,且其干燥速度快,能耗小,适于发酵豆乳粉的规模化生产;与其他两种方式相比,45℃热风干燥处理的发酵豆乳粉冲调性和贮藏稳定性最差。综上,考虑到生产效率、能耗优势和产品质量,建议在发酵豆乳粉生产中运用喷雾干燥技术。

桦褐孔菌发酵豆乳的工艺探究及品质分析

为开发出一种新型桦褐孔菌发酵豆乳饮料,采用液体发酵技术,以东北黄豆为原料,以桦褐孔菌为发酵剂研制发酵型功能性豆乳饮料。以桦褐孔菌发酵豆乳多糖含量作为指标,采用单因素试验及响应面法对桦褐孔菌豆乳发酵工艺进行优化。结果表明:桦褐孔菌豆乳的最佳发酵工艺条件为接种量6.3%、豆浆添加量119 mL、发酵温度28℃、发酵时间4 d,测得多糖含量4.55μg/mL。发酵后饮料添加5%蔗糖、0.10%乳酸和2.00%的蜂蜜可明显提高产品适口性和品质。

浸泡时间对豆浆品质的影响及相关性分析

研究大豆浸泡时间(6、8、10、12、14、16 h)对豆浆理化特性和感官品质的影响,为大豆浸泡时间的选择提供理论支撑。实验以大豆水分含量及分布、可溶性蛋白质含量、固形物含量、粒径、黏度、稳定性及感官评分作为考察指标,分析浸泡时间对豆浆品质的影响并确定大豆适宜的浸泡时长;采用Pearson相关系数对浸泡时间、大豆水分组成与豆浆品质的关系进行分析。低场核磁共振结果表明,T21、T22、T23信号值随着浸泡时间延长而升高,大豆吸附水的占比增加,大豆浸泡12 h后水分达到饱和状态。豆浆的品质研究结果表明,随着浸泡时间的延长,豆浆的蛋白质转移率、体积平均粒径、黏度均呈现先升高后降低的趋势,总固形物含量显著降低(P<0.05),豆浆稳定性先降低后升高;豆浆的感官评分值随着大豆浸泡时间的增加先增加后降低,8 h豆浆的感官综合评价值最高为1.0466,其次是10 h的豆浆。基于以上结果,优选大豆浸泡时间为8 h,虽然该时间的豆浆黏度低,口感浓度评分低,亮度值低;但是其可溶性蛋白质含量最高,为0.905 g/100 g,蛋白转移率可达到16.61%;总固形物含量仅次于6 h的豆浆,含量为3.185 g/100 g;而且色差b值最低,感官综合评价值最高。相关性分析结果表明:浸泡时间与大豆结合水占比、自由水占比呈显著负相关,与吸附水占比呈显著正相关(r=-0.9638、-0.8241、0.9391);豆浆的品质指标受到浸泡时间影响,其中浸泡时间与豆浆可溶性蛋白质、总固形物含量、L值呈显著负相关,与a值呈显著正相关关系(r=-0.9122、-0.9726、-0.8238、0.9385)。

豆浆固形物含量及浆液深度对腐竹生产及品质的影响

目的:确定腐竹高效优质生产适宜的豆浆固形物含量和浆液深度。方法:探究豆浆固形物含量和浆液深度对腐竹得率、成膜速率、营养成分、机械性能、蒸煮损失率和复水比等的影响。结果:当豆浆固形物含量为6%,豆浆浆液深度为6 cm时,腐竹得率(34.68%)和营养物质含量最高,其蛋白质含量为51.05%,脂肪含量为23.42%,且抗拉强度和复水性较好,分别为3.74 MPa和3.80 g/g。结论:综合考虑腐竹得率、成膜速率和食用品质等指标,建议采用豆浆固形物含量6%,豆浆浆液深度6 cm进行腐竹的高效优质生产。

枯草芽孢杆菌BSNK-5发酵豆乳营养组分的动态变化规律研究

为开发具有健康功效的新型优质蛋白产品,该文利用枯草芽孢杆菌(Bacillus subtilis)BSNK-5发酵豆乳,动态分析了发酵过程中豆乳各营养组分的变化规律。结果显示,B.subtilis BSNK-5在豆乳基质中生长旺盛,呈指数级增长;发酵至84 h时,粗蛋白下降了23.50%,生成了多肽和氨基酸等小分子产物,发酵后期由于氨基酸的过度降解导致水解氨基酸含量下降了42.90%;在氨基酸组成上,必需氨基酸含量占比提高了13.34%,蛋氨酸和赖氨酸含量分别提高了106.90%和18.50%,表明B.subtilis BSNK-5的发酵平衡了豆乳氨基酸的组成和比例。发酵过程中,脂肪含量增加,脂肪酸含量峰值出现在24 h,其中亚油酸占比达到49.28%;大豆异黄酮明显由糖苷型转变为苷元型,苷元型异黄酮含量峰值出现在48 h,以大豆苷转化率最高,大豆素占比约为52.15%。综上,B.subtilis BSNK-5的发酵有效促使了豆乳营养价值和生物利用度的提高,而发酵时间直接影响了各营养组分的富集。该研究结果为豆乳品质控制、功能性发酵豆制品开发、植物蛋白资源补充提供理论依据。

产β-葡萄糖苷酶植物乳植杆菌c4-3发酵豆浆的营养评价和代谢分析

大豆中富含多种营养物质,其中配基型异黄酮(soybean isoflavone aglycones,SIA)在人体中的吸收利用率最佳,β-葡萄糖苷酶可以将难以利用的糖苷型异黄酮(soybean isoflavone glycoside,SIG)转化为SIA。选取一株前期筛选到的产β-葡萄糖苷酶的植物乳植杆菌c4-3用于豆浆的发酵,经12 h发酵后pH值从6.47降至4.4;SIA含量明显升高,其中金雀异黄酮和大豆苷元分别从9.68 mg/L和13.93 mg/L增加至26.61 mg/L和68.43 mg/L。进一步通过非靶向代谢组学研究发现,植物乳植杆菌c4-3发酵豆浆中除异黄酮外,γ-氨基丁酸的含量也上升了44.03%,儿茶素、磷酸吡哆醇的含量分别上升了18.12倍和1.03倍。

豆奶粉主要致敏蛋白及降低致敏性方法研究进展

我国豆奶粉市场发展前景广阔,其行业发展迅速,豆奶粉已经成为多数人群的日常食品,但豆奶粉的致敏性一直是行业面临的瓶颈问题,其原料中的大豆、牛乳均为主要的食物过敏原,这限制了豆奶粉的广泛应用。因此,本文综述了豆奶粉中致敏蛋白结构特性、致敏机理以及致敏性检测技术,阐述了降低豆奶粉致敏性的方法,并对我国低致敏豆奶粉行业进行了总结和展望,以期为我国低致敏豆奶粉的新产品开发、质量安全性、标准的建立及规范等提供参考。

豌豆肽-大豆复配豆乳粉冲调品质及风味特性

为强化豆乳粉的品质功效,丰富其风味,探讨添加不同比例豌豆肽对豆乳粉品质、功效及风味的影响。以溶解度、结块率、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率、胆固醇清除率等为评价指标,考察豆乳粉的冲调品质以及产品的体外生物功能;采用傅里叶变换红外光谱仪、纳米粒度仪、激光共聚焦扫描显微镜、顶空固相微萃取-气相色谱-质谱联用等技术手段分析复配豆乳粉结构特性、风味品质的变化。结果表明,当豌豆肽添加量为30%时,复配豆乳粉的蛋白含量较纯大豆豆乳粉提升了13.05%,溶解度提升了11.23%,结块率降低了4.20%,DPPH自由基清除率提升了19.84%,胆固醇清除率提升了21.25%;且在70℃的冲调温度下,各项指标显著优于原豆乳。结构分析结果发现豌豆肽的添加改变了复配豆乳粉中蛋白质的二级结构,平均粒径变小,乳液粒径分布均一,从而提高了复配豆乳粉的溶解性。风味分析结果发现添加豌豆肽豆乳粉的香叶基丙酮、肉豆蔻酸、3-甲硫基丙醛、2-甲基吡嗪、2,5-二甲基吡嗪等关键性呈味物质发生改变,己醛、反式-2-壬烯醛、壬醛、正己醇、1-辛烯-3-醇、萘等豆腥味物质含量降低。

近红外光谱检测油莎豆乳中蛋白质和总固形物含量研究

利用近红外光谱技术快速检测油莎豆乳中蛋白质含量、总固形物含量,实验分别采用凯氏定氮法和考马斯亮蓝法测定蛋白质含量,采用常压干燥法测定总固形物含量;分析比较S-G平滑法、标准正态变量变换(SNV)、多元散射校正(MSC)、一阶微分(FD)、二阶微分(SD)5种光谱预处理方法,利用分段建模法筛选出最佳光谱建模区域,采用留一法交叉验证主成分分析方法确定的主成分数量,结果表明平滑S-G+二阶导数的光谱预处理效果最佳,以1200~1800 nm范围为PLS建模光谱波段,采用考马斯亮蓝法、凯氏定氮法构建的蛋白质含量近红外模型的预测相关系数R分别为0.9755,0.9692,预测均方根误差分别为0.276,0.287;总固形物含量模型的预测相关系数R为0.9699,预测均方根误差为0.326,独立测试集样品的预测值和实测值之间的残差值均较小,接近0,残差和分别为-0.02,0.01,-0.02,研究结果表明建立的近红外光谱快速检测油莎豆乳蛋白质含量、总固形物含量的方法能够满足检测要求,可为油莎豆乳行业健康发展提供技术支撑。

基于代谢组学的豆乳中乳酸乳球菌乳酸亚种发酵特性分析

目前,国内外关于乳酸乳球菌乳酸亚种的应用研究主要集中于其在牛乳发酵中的特性,而其在豆乳发酵中的应用研究较少。本研究基于发酵指标,采用代谢组学和感官评价对乳酸乳球菌乳酸亚种菌株在豆乳中的发酵特性进行分析。结果表明:具有优良蔗糖代谢特性的DYNDL21-2、DYNDL1-2和FJNDD18M83株乳酸乳球菌乳酸亚种菌株展现出良好的生长和产酸能力;在乳酸乳球菌乳酸亚种发酵豆乳中,菌株DYNDL21-2、FJNDD18M8发酵能明显下调己醛和多种呋喃类杂环化合物的丰度,有效降低豆腥味强度;菌株FJNDD18M8发酵能明显上调乙醛、乙偶姻及2,3-丁二酮等物质丰度,增强发酵豆乳产品的乳香和奶油风味,有效改善豆乳风味。综上,乳酸乳球菌乳酸亚种菌株在豆乳发酵过程中具有优良的发酵特性和较强的代谢能力,但菌株间存在一定的差异。

百合酸豆奶配方优化及抗氧化性研究

以大豆、百合、蔗糖为主要对象,探究蔗糖添加量、百合汁添加量、菌种添加量和发酵时间4个单因素不同的水平对百合酸豆奶的总酸含量和感官评分的影响程度。基于Design Expert软件设计试验方案,运用Box-behnken建立数据模型和二阶多项非线性回归方程,用感官得分为指标优化百合酸豆奶原料组分比例,获得百合酸豆奶的蔗糖添加量、百合汁添加量和菌种添加量的最佳配比。结果表明,百合酸豆奶的最佳配方为蔗糖添加量8.3%,百合汁添加量11.8%,菌种添加量0.3%,优化后验证试验的样品感官评分为89.85分(n=3),与预测值90.15分接近,偏差为0.33%。测得百合酸豆奶持水性为81.01%,黏度为1287.90 mPa·s,百合多糖的含量为187.01 mg/100 g。百合酸豆奶对DPPH、O2-·和ABTS自由基清除率分别为57.81%,65.82%,78.91%,百合酸豆奶的自由基清除率大小顺序为ABTS·>O2-·>DPPH·,自由基的清除率为未添加百合酸豆奶的1.58倍,1.52倍和1.26倍,表明百合酸奶的抗氧化性能力明显高于普通豆酸奶。

不同豆浆浓度和浆液深度对腐竹生产的影响

通过水浴加热方法研究了豆浆浓度和浆液深度对腐竹产率和成膜速度的影响。结果表明:在豆浆浓度小于5.5%时,腐竹的产率和成膜速度随着豆浆浓度的增加而增加,当豆浆浓度大于5.5%时,腐竹的产率和成膜速度反而随着豆浆浓度增加而降低,同时腐竹的品质也有所下降。控制豆浆浓度为5.5%,腐竹的产率随浆液深度的增加而增大,成膜速度随浆液深度增加而减小,浆液深度在5 cm左右时,腐竹的品质较好。

利用3种凝固剂制作新鲜软质大豆干酪的工艺研究

以豆乳为原料,分别以葡萄糖酸内酯、氯化镁和木瓜蛋白酶为凝固剂制作新鲜软质大豆干酪。用正交试验法对发酵剂、凝固剂及食盐的添加量等参数进行优化,并将3种大豆干酪的主要理化指标及感官与牛奶新鲜软质干酪进行比较。结果表明,以葡萄糖酸内酯为凝固剂制备新鲜软质大豆干酪的最适工艺参数为发酵剂添加量0.020%、葡萄糖酸内酯添加量0.20%、食盐添加量1.0%;氯化镁为凝固剂的最适工艺参数为发酵剂添加量0.020%、氯化镁添加量0.20%、食盐添加量1.0%;木瓜蛋白酶为凝固剂的最适工艺参数为发酵剂添加量0.010%、CaCl2添加量0.02%、木瓜蛋白酶添加量0.05%、食盐添加量1.0%。3种大豆干酪的水分含量相近,木瓜蛋白酶大豆干酪感官得分最高,氯化镁大豆干酪的蛋白含量最高,而葡萄糖酸内酯大豆干酪的产率最高。与相同工艺下制作出的牛乳新鲜软质干酪相比,新鲜软质大豆干酪蛋白质含量与之相近,脂肪含量只有牛乳干酪的1/3,水分含量和出品率高于牛乳干酪,而感官评分上大豆干酪略低。新鲜软质大豆干酪可作为一种牛乳新鲜软质干酪的低脂保健型替代品。