无腥味豆奶浸泡与热烫工艺条件的研究

本文以脂肪氧合酶全缺失型大豆品种“中特一号”为原料,制备无腥味豆奶产品,研究了浸泡和热烫工艺对产品得率、蛋白质溶出率及豆奶产品感观品质的影响,得出最佳工艺:即用0.6%NaHCO3浸泡大豆8h,蛋白质溶出率和可溶性固形物分别为2.8g.100mL-1和6.4 Brix;热烫1m in,蛋白质溶出率为4.8g.100mL-1,可溶性固形物含量达到4.5Brix。     

Effect of Grinding Temperature on Hydroperoxide and Off-flavor Contents during Soymilk Manufacturing Process

ABSTRACT: Hydroperoxides and n -hexanal of soymilk made at different temperatures in the soybean grinding process were investigated. Both hydroperoxides and n -hexanal showed maximum amounts at 30°C, 37.78 μmol/g, and 1.94 mg/g, respectively. However, at 3°C and 80°C, amounts of hydroperoxides were about half of that at 30°C. N -hexanal showed high correlation with hydroperoxides except for at 80°C. It suggests that controlling the grinding temperature is effective to reduce hydroperoxidation and off-flavor content. Protein solubility an important index of soymilk, was decreased as the temperature increased. Grinding soybeans at low temperature is considered an economical method to produce soymilk having less off-flavor and high protein.     

乳酸菌对发酵豆乳风味成分的影响

以实验室保藏的发酵豆乳感官特性具有差异的5株嗜热链球菌为对象,研究了乳酸菌α-乙酰乳酸脱羧酶、α-半乳糖苷酶、β-半乳糖苷酶酶活和乳酸脱氢酶等关键酶的酶活性、发酵豆乳特性和挥发性风味成分间的相互关系。结果表明,发酵豆乳感官评价与乳酸菌的α-乙酰乳酸脱羧酶和α-半乳糖苷酶呈现显著负相关和正相关,与风味成分2,3-丁二酮、2-庚酮和2-壬酮呈显著正相关,与正己醇、2,4-癸二烯醛和2-戊基呋喃呈显著负相关;发酵豆乳酸度值与乳酸菌的β-半乳糖苷酶和乳酸脱氢酶均呈显著正相关。     

Preference Mapping of Soymilk with Different U.S. Consumers

This study determined and compared drivers of liking for unflavored soymilk with different U.S. consumer groups. A highly trained panel documented appearance, mouthfeel and flavor attributes of 26 commercial soymilks. Twelve representative soymilks were then selected for evaluation by consumers from 3 age/cultural categories (n = 75 each category; Caucasian/African American females aged 18 to 30 y; Asian females aged 18 to 30 y; Caucasian/African American females aged 40 to 64 y). Consumers evaluated overall liking and liking and intensity of specific attributes. Results were evaluated by analysis of variance, followed by internal and external preference mapping. Age had no effect on overall liking, while ethnicity did (Caucasian/African American compared with Asian; P < 0.05). Caucasians/African Americans differentiated soymilks more than Asians and assigned a wider range of liking scores than Asians (2.1 to 7.2 compared with 4.0 to 6.1). Three consumer clusters were identified. Sweet taste with vanilla/vanillin and sweet aromatic flavors and higher viscosity were preferred by most consumers and differences between consumer clusters were primarily in drivers of dislike. Drivers of dislike were not identified for Cluster 1 consumers while Clusters 2 and 3 consumers (n = 84, n = 80) disliked beany, green/grassy and meaty/brothy flavors and astringency. Cluster 3 (n = 80) consumers scored all soymilks higher in liking (P < 0.05) than Cluster 2 consumers, and were willing to overlook disliked attributes with the addition of sweet taste, whereas the Cluster 2 consumers were not. These findings can be utilized to produce soymilks with attributes that are well liked by target consumers and to tailor attributes for segments of the population that have not yet been accommodated.     

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.     

纯大豆发酵豆乳的风味物质与微观结构的初探

在研究纯大豆发酵豆乳的基础上,对产品的风味物质与微观结构进行了初步分析和探索。经过色、质谱联用仪分析检索出纯大豆发酵豆乳中风味物质相对百分含量在0.5以上的主要成分与相对百分含量,并经过扫描与透射电子显微镜对产品发酵中产物与成品的微观结构分别进行了观察与分析。     

高静压技术对豆浆中脂肪氧合酶的钝化效果及其动力学分析

研究了高静压技术(HHP)对豆浆中脂肪氧合酶(LOX)活性的钝化作用,并进行失活动力学分析。结果表明:HHP处理能显著钝化豆浆中LOX活性。用300～600MPa压力处理5～20min,对LOX活性有显著的钝化效果(P<0.05),并且随处理压力和处理时间的增加,酶的失活率提高。当压力500MPa,保压时间0min时也有一定的钝化LOX效果;当压力600MPa处理10min以上,豆浆LOX活性被完全抑制。用500MPa处理5min,可以达到与传统巴氏杀菌相同的钝酶效果(P>0.05)。HHP技术钝化豆浆LOX的过程可用一级动力学模型拟合(R2>0.900)。随着压力的升高和处理时间的延长,k值逐渐升高,D值逐渐减小;动力学参数ZP和Va分别为125.94MPa和-45.290cm3/mol。HHP技术在钝化豆浆中脂肪氧合酶活性方面比传统巴氏杀菌彻底,效果更好。其在改善豆浆品质方面具有良好的应用前景。     

Improved Acid, Flavor and Volatile Compound Production in a High Protein and Fiber Soymilk Yogurt-like Product

The effects of added caseinate (CAS), casein hydrolyzate (CASHY) and whey protein hydrolyzate (WPHY) on acid, flavor and volatile compound production in a high protein and fiber soymilk yogurt-like product were studied. High protein and fiber soymilk, produced by blending soaked, boiled and dehulled soybeans with Swiss cheese whey ultrafiltration permeate, was fermented with a mixed S. thermophilus and L. bulgaricus yogurt culture. The concentrations of lactic acid, key volatile compounds, i.e., acetaldehyde, acetone, and diacetyl, and the flavor and texture of the resulting soymilk based yogurt formulated with added CAS or CASHY were comparable to those in a milk yogurt control.