基于主成分与聚类分析法的制备豆浆用大豆的品质指标综合评价

为了获得专门用于制备豆浆的大豆品种,采用主成分因子分析与聚类分析方法对黑龙江地区29个大豆品种进行筛选。首先测定29种大豆理化指标(水分、脂肪、可溶性糖、蛋白质、钙、7S蛋白亚基、11S蛋白亚基质量分数及11S/7S)及其所制备豆浆的品质指标(蛋白质量分数、稳定性、豆浆得率、粒径、蛋白质转移率、感官评分);然后采集这些数据进行主成分因子分析,结果得到6个主成分(综合指标),其累计方差贡献率达84.97%,综合得分前三的品种为'黑农85'、'黑农66'和'黑农71',其综合得分显著高于其他品种(P0.05);再经聚类分析可知:29种豆浆可分为Ⅰ、Ⅱ、Ⅲ、Ⅳ类,每类所含品种分别为14、11、3、1种。主成分因子分析所筛选出的3个品种均在II类中,该类豆浆具有蛋白质量分数、蛋白质转移率、感官评分高,豆浆得率中等的特点,符合豆浆类产品技术指标要求。综上,'黑农85'、'黑农66'和'黑农71'可作为制备豆浆专用大豆品种;主成分与聚类分析方法非常适用于对多样品、多指标的筛选及综合评价。     

主成分分析法综合评价速冻菜用大豆籽粒的品质

为研究同一地域不同品种速冻菜用大豆籽粒的品质,本文选取13种菜用大豆为试验材料,测定硬度、色泽、叶绿素、Vc、可溶性蛋白、可溶性糖等影响速冻菜用大豆籽粒品质的10项主要理化指标,并对各指标进行主成分分析（PCA）。结果表明,提取的4个主成分累计贡献率达89.33%,其中第1、2主成分对速冻菜用大豆籽粒品质的贡献率相近,分别为28.13%、26.55%,可溶性蛋白、色泽、叶绿素、硬度等为影响速冻菜用大豆籽粒品质的主要因子。筛选出的新大粒1号在可溶性蛋白、色泽、叶绿素、硬度等理化指标综合表现出较优品质,其次为通豆6号、徐豆17号和通豆5号,主成分综合评价模型与感官评价结果具有高度一致性。这为速冻菜用大豆品种的筛选与品质评价提供了一定理论依据。     

不同预处理方式对豆浆品质特性的影响

选择大豆4种不同预处理方式,探讨其对豆浆品质特性的影响。对所制得豆浆的蛋白质含量、稳定性、色泽、感官品质、粒径分布进行对比分析,同时采用电镜扫描分析不同预处理方式下大豆微观形态的变化。结果表明:超声波预处理后豆浆蛋白质含量达到最大值为4.026 6%,大豆细胞结构更加紧密,但其稳定性、感官品质均差于冷冻处理制浆;微波预处理对大豆结构破坏程度最大,所制得的豆浆蛋白质损失严重,仅为3.241 4%,其感官品质、稳定性均差于冷冻处理制浆,且色泽偏暗;经过冷冻预处理的豆浆白度增加为75.12,蛋白质含量、稳定性较高,且感官评分最高,综合品质最好。     

大豆自然老化时间对豆浆理化特性及风味品质的影响

为了进一步提高豆浆的品质,探讨不同自然老化时间对豆浆理化特性及风味品质的影响规律,本实验以可 溶性固形物含量、脂肪含量、蛋白质含量、蛋白质提取率、稳定性、沉淀性及粒径分布为豆浆的评价指标,同时 通过顶空固相微萃取-气相色谱-质谱联用技术分析豆浆风味物质的种类及含量变化。结果表明：大豆自然老化12 个 月后所制豆浆与对照组（20 ℃、相对湿度47%下平衡10 h）相比,其可溶性固形物、脂肪、蛋白质含量分别下降了 2.8%、13.79%、9.4%;蛋白质提取率下降了1.73%;稳定系数下降了12.82%;沉淀率上升了48.78%;粒径分布整体 右移,平均粒径从229.6 nm增至312.9 nm;豆浆中主要的豆腥味物质质量分数上升了7.24%,非豆腥味物质质量分 数下降了0.93%。实验结果揭示了大豆自然老化时间对豆浆的理化特性及风味品质的影响规律,即随着自然老化时 间的延长,其理化品质逐渐下降,风味品质也随之变差。     

大豆不同前处理方式对豆浆品质的影响

为探讨大豆不同前处理方式对豆浆品质的影响,选择5 种前处理方式,对所制得豆浆的感官品质、色泽、稳定性、主要营养成分及抗营养因子含量进行对比分析。结果表明：大豆不同前处理方式对豆浆品质有不同的影响。干豆直接制浆虽方便快捷,但所得豆浆品质较差,其感官品质、稳定性均差于浸泡大豆,且主要营养成分如蛋白质、多糖得率低,抗营养因子含量高;高温高压蒸煮大豆制浆,其感官品质、稳定性及抗营养因子的去除效果均差于浸泡大豆,且色泽偏暗,蛋白质损失严重,含量低于干豆制浆;与干豆直接制浆相比,浸泡处理大豆可明显改善豆浆感官品质及其稳定性,且其蛋白质、可溶性固形物、多糖含量显著提高（P＜0.05）,抗营养因子含量显著下降（P＜0.05）;免浸泡豆和NaHCO3溶液泡豆制得豆浆色泽最亮,综合品质最好。     

不同青稞籽粒品质特性与酿酒品质关系分析

青稞酒是以青稞为主要原料酿制的一种独特的蒸馏酒,所选青稞对其酿酒品质具有重要影响。本研究以26 个品种青稞为原料,分别酿造小曲青稞酒,并对青稞的籽粒品质特性、发酵相关品质指标以及青稞酒感官得分和出酒率进行分析,采用主成分分析、通径分析等统计学方法分析青稞品种特性与发酵参数及产酒质量之间的关系。结果表明：不同品种青稞间品质特性存在较大差异,其中‘F1’‘甘青6号’青稞最适合酿造优质小曲青稞酒;青稞籽粒性状中,较高的支链淀粉质量分数有利于青稞酒发酵完全,提高出酒率,而容重、千粒质量及黄酮的质量分数是影响酿酒品质的主要因素。本研究可为青稞酿酒原粮的选择和专用型品种的选育提供参考。     

我国东北大豆品种与豆腐加工特性分析

东北是我国重要的大豆产区,但该地区大豆品种丰富多样,为明确该如何选择该区的大豆食品加工原料和 育种目标,本研究选取32 个东北大豆品种,对各品种的籽粒粗蛋白、脂肪、钙、磷含量和豆乳可溶性蛋白质量浓 度等理化指标及加工制豆腐的得率、保水性、含水量、质构等指标进行了分析。研究发现,当大豆品种具有较高 的豆乳可溶性蛋白质量浓度（大于26 mg/mL）、脂肪含量（18～22 g/100 g）、钙含量（大于200 mg/100 g）和磷 含量（大于700 mg/100 g）时,可加工出得率较高、质地较软的豆腐产品;反之亦然。说明大豆理化成分含量,特 别是可溶性蛋白质量浓度（豆乳）和磷含量对豆腐品质具有重要影响作用。     

早籼稻的品质分析与其压榨型鲜湿米粉加工适应性

为确定压榨型鲜湿米粉用早籼稻的品质范围,保证米粉品质稳定性,本实验以我国早籼稻湖北省和江西省两个主产区生产的40 种早籼稻谷品种为原料,以压榨型鲜湿米粉为最终产品,采用描述性分析及相关性分析对早籼稻理化特性、糊化特性以及米粉的品质特性进行分析。结果表明：测定的15 项早籼稻品质指标中,大部分品质指标的变异系数大于10%,垩白度变异系数最高,达75.9%。相关性分析表明稻谷粒长、垩白粒率、峰值时间与米粉感官评分均呈显著相关性,直链淀粉质量分数、最低黏度、最终黏度、衰减值、回生值与米粉感官评分均呈极显著相关性;回生值与感官评分相关系数最大,达0.579;相对于理化指标,糊化特征参数能更客观反映出米粉的食用品质。基于因子分析法对早籼稻品质指标进行分析处理,结果表明总方差76.264%的贡献率来自前4 个公因子,其中2 个公因子得分与米粉感官评分呈显著相关性,相关系数分别为0.539、－0.332。以逐步回归分析法对这2 个公因子代表的指标进行分析,得出方程：Y米粉感官评分＝51.876＋0.494x直链淀粉质量分数＋0.008x回生值（R2＝0.423）,筛选出直链淀粉质量分数和回生值是影响米粉品质的敏感性指标;基于聚类分析得到适宜加工压榨型鲜湿米粉的早籼稻敏感品质指标阈值区间为直链淀粉质量分数22.24%～26.86%、回生值1 526.5～2 036.7 cP。     

大豆鸡血豆腐的研制

本文以大豆豆浆和鸡血为主要原料,探讨了一种双蛋白内酯豆腐的加工工艺,研制成一种营养丰富的新型双蛋白食品,并对其主要感官理化指标进行分析。研究结果表明：当固形物含量为11%,豆浆鸡血比例为8∶1,GDL添加量在0.25%时,所得产品,胶凝效果好,持水率高,品质细嫩,柔软,豆香浓郁,营养均衡,色泽为咖啡色,较传统豆腐也有所不同,且工艺相对简单,易于推广投入实际生产。     

豆浆豆腐中胰蛋白酶抑制因子活性的研究

豆制品中含有丰富的营养物质,但其中的抗营养因子阻碍人体对营养物质的吸收。分别采用6种不同制浆工艺将5种原料豆进行豆浆、豆腐的制备,测定大豆和豆浆中蛋白含量以及豆浆、豆腐的产量,通过分析不同大豆品种及制浆工艺与豆制品产量及蛋白含量之间的关系,以产量为指标,研究不同大豆品种及其加工工艺对豆制品产量及蛋白含量的影响,选取高产量、高蛋白的豆制品。并采用紫外分光光度计法分别对原料豆、豆浆、豆腐等进行大豆胰蛋白酶抑制因子活性的检测,得出低大豆胰蛋白酶抑制因子活性的品种及加工豆制品的制浆工艺。结果表明,豆制品产量与蛋白含量成正比,不同大豆品种采用不同制浆工艺所制得的豆浆、豆腐中胰蛋白酶抑制因子活性具有显著性差异,为不同大豆品种适用性加工及工业化生产提供理论依据。     

一种家庭豆浆机豆片原料的研制

为了制备专用于家庭豆浆机、不产生豆渣的大豆原料,利用干法粉碎制备脱皮大豆豆粉,然后利用单冲压片机压制成豆片。以豆片为原料利用家用豆浆机按照干豆豆浆程序制备豆浆,以残渣率、粗蛋白含量、蛋白体外消化率及感官评分为指标对豆浆品质进行评价,结果表明将豆粉压制成片可避免以豆粉直接制备豆浆产生的加热管焦糊现象;与脱皮豆相比,豆浆残渣率从8.51%降低到1.30%,感官试验表明,利用豆片制备豆浆,不分渣在口感上亦可完全接受;粗蛋白从2.26%提高到3.08%;体外消化率(氮释放量)从49.82%提高到64.35%;感官评分从82.3分提高到91.8分。因此,利用豆片作为家用豆浆机专用原料可以提高原料利用率、蛋白质消化率及感官品质,且不用分渣,可实现原料(大豆子叶)全利用。     

Protein quality and antioxidant properties of soymilk derived from black soybean after in vitro simulated gastrointestinal digestion

Protein quality and antioxidant properties of soymilk derived from black soybean (eight varieties) in China were analysed following in vitro simulated gastrointestinal digestion (including dialysis). Soymilk from black soybean possessed high okara weight but low yield, protein content and sensory scores. The in vitro digestibility of protein in all black soymilk samples was higher than 60%, and the Shenmu black soybean exhibited the highest digestibility. Non-digested milk from the black soybean exhibited significantly high total phenolic content (TPC) (127.15–173.04 mg/100 mL), ferric-reducing antioxidant power (FRAP) (272.18–366.27 μmol L⁻¹) and DPPH free radical-scavenging activity (61.20–83.81%). These parameters were significantly lower in the non-digested soymilk than those in soymilk after gastric digestion but higher than those of soymilk in the dialysed fraction. Gastric digestion significantly increased bioactive compound levels released from black soymilk, and the bioaccessibility of phenolic compounds was 24.37–36.05%. Hence, black soymilk was sufficiently available for human absorption.     

Comparison of Two Small-Scale Processing Methods for Testing Silken Tofu Quality

In developing a simple, reliable, small-scale method to assess silken tofu quality in our soybean improvement program, we examined two processing methods and two coagulants, glucono-δ-lactone (GDL) or nigari (magnesium chloride) in two experiments. Silken tofu was prepared from a commercial soybean variety (expt 1) or seven soybean varieties (V1–V7) which were grown and harvested together (expt 2). The soybeans were soaked overnight (the soak method, with 55 g soybeans) or ground dry first (the dry method, with 60 g soybeans) before processing. The quality of the silken tofu was evaluated and compared among varieties and coagulant-processing methods and their interactions. Moisture and protein content in soymilk and soybean seeds, soymilk yield and protein and solid recovery in soymilk were determined. Compared with the dry method, the soak method allowed faster soymilk extraction, produced soymilk with lower solid and higher protein content and firmer silken tofu with either GDL or nigari as coagulant. Depending on whether nigari or GDL was used as coagulant, the soak method also produced silken tofu with the highest or the lowest water loss which correlated strongly and negatively with tofu hardness (r?=??0.93***). Differences were detected among varieties for the key quality attributes. Taken together, the soak method with GDL as coagulant would be the preferred combination to use to assess tofu quality.     

紫薯保健豆腐的工艺研究

以黄豆和紫薯为主要原料,通过传统豆腐工艺加工制作新型豆腐.通过单因素与多因素正交试验,确定紫薯豆腐的最佳配方工艺条件.结果表明:温度对产品感官品质的影响最大,其次是豆浆和紫薯汁比例、石膏量、黄豆和紫薯水的添加量;最后确定了最佳的工艺配方:黄豆500 g,紫薯250 g,分别加入水1000mL制备豆浆汁与紫薯汁,豆浆与紫薯汁比例为6:1,石膏量为3.5 g,温度为100℃.产品感官性状良好,不仅含有独特的紫薯营养功能,还为开发新品种豆腐提供了理论参考.     

Effect of Soybean Varieties and Growing Locations on the Flavor of Soymilk

ABSTRACT: The volatile compounds of soymilk prepared from 5 soybean varieties grown in 2 locations were isolated and separated by a dynamic headspace analyzer and capillary gas chromatography. The coefficient of variation for the quantitative analysis of volatile compounds of soymilk by dynamic headspace analysis was less than 3.0%. Soybean varieties and growing locations had significant effects on the volatile compounds of the batches of soymilk at α= 0.05. The higher the soybean protein, the higher was the volatile compounds of soymilk. Correlation coefficient between the protein content and the volatile compounds of the milk was 0.99. Thirty-eight volatile compounds of soymilk were identified by a combination of mass spectrometry and gas chromatographic retention times of standard compounds. Most of the identified compounds were formed by the lipid oxidation of soymilk. However, 2-pentylfuran, dimethyl disulfide, and dimethyl sulfide were formed by singlet oxygen. The beany or green flavor that makes the soymilk unpleasant or unacceptable to Westerners may be due to 2-pentylfuran, which is formed from linoleic acid by singlet oxygen. The beany flavor can be eliminated by processing the soymilk with a minimum exposure to light and air.     

Effect of Soybean Varieties and Growing Locations on the Physical and Chemical Properties of Soymilk and Tofu

ABSTRACT: Soybean varieties and growing location greatly affected the protein content and color of soymilk and the protein content and yield of tofu ( P < 0.05). Protein content of soybeans was the most important affecting factor for the qualities of soymilk and tofu. There were significant correlations between the protein contents of soybeans and soymilks ( P < 0.05). There were also significant correlation between the soybean protein and the total solid content of soymilk (P < 0.05). Tofu moisture content had significant effect on the hardness and yield of tofu (P < 0.05). The correlation between soybean protein and tofu yield was significant at P < 0.05. The protein content and yield of tofu can be predicted by analyzing soybean protein.     

Germination improves the functional properties of soybean and enhances soymilk quality

The effects of soybean variety and germination time on structural changes, antinutritional factor content, antioxidant activity of germinated soybean, and on the functional properties of soymilk were comprehensively investigated. The results showed that the antioxidant activity increased with increasing germination time. The content of antinutritional factors decreased with increasing germination time. Soybean varieties with the lowest tannin and trypsin inhibitor content were DN690 and HJ1. Lipoxygenase activity and phytic acid content showed no significant differences among soybean varieties. The content of α-helices and β-turns in soybean protein decreased with increasing germination time, while the content of β-sheets was increased. Soybean protein was progressively broken down into smaller molecular peptides during the germination process. The digestion and content of soluble protein in soymilk increased with germination. In summary, we show that germination is an effective, cheap, and green method that improves the functional properties of soybean and soymilk.     

Selected odor compounds in cooked soymilk as affected by soybean materials and direct steam injection

ABSTRACT:  Soy odor is a major concern in the consumption of soymilk by Western consumers. The objectives of this study were to determine selected soy odor compounds as affected by soybean materials and direct steam injection and to determine if the steam-injection method affected overall cooked soy aroma of the soymilk and compared to the soymilk cooked by a traditional indirect method. Five varieties of soybeans with or without lipoxygenases were processed by direct-steam injection for up to 20 min at 100 °C. Eight selected odor compounds were analyzed by gas chromatography after extraction using a solid-phase micro-extraction (SPME) method. Hexanal, hexanol, 1-octen-3-ol, 1-octen-3-one, and trans-2-nonenal decreased whereas 2-pentylfuran and trans-2, trans-4-decadienal increased by boiling up to 20 min. The results showed that soybean variety was a significant factor to affect odor compositions. Direct steam injection cooked soymilk resulted in lower odor contents than a traditional indirect cooking method. The advantage of having a low odor composition in the heated soymilk products made from lipoxygenases-null soybean varieties could be attained by using normal soybean materials with direct steam injection.     

PHYSICOCHEMICAL CHARACTERISTICS OF SOFT TOFU FORMULATED FROM SELECTED SOYBEAN VARIETIES1

Currently, hundreds of soybean varieties with a wide range of quality attributes are available. The majority of these soybean varieties have not been evaluated for their quality in soymilk and tofu. In this research, tofu was prepared using the hot ground method by coagulating soymilk from four soybean varieties (Macon, Saturn, OHIOFG1 and OHIOFG2) with calcium sulfate dihydrate. Soybean variety significantly affected yield, held water, color parameters, viscosity, storage modulus, and textural properties of tofu cakes. Soymilk with higher pH, viscosity, and protein produced tofu with higher protein, water held, and yield. Varietal differences should be considered in selecting soybeans for tofu production. Macon soybeans produced the best tofu with regards to quality attributes.     

Stability of soybean seed composition and its effect on soymilk and tofu yield and quality

Soymilk was made from 10 soybean [Glycine max (L.) Merr.] lines grown at three locations for 2 years, using an 18:1 water/soy protein ratio. Tofu was made with either glucono-delta-lactone (GDL) or calcium sulphate dihydrate (CS). Genotype and year effects were substantially greater than location effects on soybean protein content and seed composition; soymilk and tofu yield, solids levels, and pH; and tofu colour, hardness, and firmness. Genotype by location and genotype by year interaction effects were minor relative to the genotype and year effects. Yield of soymilk, GDL tofu, and CS tofu, which averaged 7.39 l, 6.29 kg, and 6.15 kg per kg soybeans, respectively, were all positively correlated with seed protein and stachyose, and negatively correlated with seed oil, free sugar, sucrose and remainder content. Seed protein was positively correlated with tofu hardness and firmness, while seed oil, free sugar, sucrose, and remainder content were generally negatively correlated with tofu quality parameters. Results of stepwise regression analysis showed that seed protein was the major determinant of soymilk yield and solids content, while soymilk yield was, in turn, the major factor determining GDL tofu yield. Procedures used in making soymilk and tofu play a major role in determining which seed component has a major effect on soymilk and tofu yield and quality.