益生菌发酵对苹果浆理化性质、抗氧化活性及挥发性风味的影响

目的 探究益生菌发酵对苹果浆理化性质、抗氧化活性及挥发性风味物质的影响。方法 测定苹果浆发酵过程中活菌数、pH、总酸、总糖、还原糖、总酚、黄酮、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)自由基清除能力、铁离子还原能力(ferric reducing antioxidant power, FRAP)和2,2’-联氮-二(3-乙基-苯并噻唑啉-6-磺酸)二铵盐[2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid)ammoniumsalt,ABTS]阳离子自由基清除能力,同时比较了发酵前后挥发性风味物质的变化。结果 发酵体系中活菌数、总酚、黄酮在发酵第3d时达到最大值,分别较发酵前提高了12.63%、17.63%和22.06%;FRAP与ABTS阳离子自由基清除能力在发酵第4d达到最大值,分别较发酵前提高了42.47%和10.45%;可滴定酸含量与DPPH自由基清除能力随着发酵时间的延长逐渐增加,发酵第7 d时,分别升高了126.34%和26.32%; pH、总糖、还原糖含量较...     

马氏珠母贝肉烘烤条件及其产品风味成分的研究

以马氏珠母贝肉为原料,筛选出贝肉烘烤的最佳条件,应用顶空-固相微萃取-气相-质谱（HS—SPME—GC—MS）联用设备测定烘烤贝肉的风味成分。结果表明：烘烤贝肉的最佳条件为烘烤温度155％,时间100min,葡萄糖添加比例为5％;烘烤后主要风味成分有40种,分别为醛类、烃类、杂环类、酯类、酮类、酸类、芳香烃等。醛类物质的相对含量为34．26％,含量最多。十八烷醛占26．71％,是主要香味物质。     

浓缩苹果汁主要技术指标控制的研究

介绍了浓缩苹果汁的主要技术指标，对各项指标的变化进行了分析，制定了相关的工艺控制措施。     

酶法水解虾头生产虾调味汁

本文报告了利用中性蛋白酶水解虾头生产虾调味汁的研究。实验结果表明,水解虾头生产虾调味汁的最佳条件是在酶用量1.4%,水解时间20小时,水解温度40℃,ph6.8。在此条件下,虾头的水解率可达33.6%。水解液具有浓郁的虾风味,可作为调味汁。     

FLAVOUR CHARACTERIZATION BY TRAINED AND UNTRAINED ASSESSORS

The flavours of four beers were characterized by four panels of assessors, using a flavour profiling system. One panel carried out duplicate assessments. The results showed that training and experience improved reproducibility and discrimination, without distorting the general pattern of flavour terms reported. On the basis of the flavour profiles, the assessors could be divided into novices, those with some experience, and experts. Those novices likely to be good assessors could also be identified.     

STUDIES ON YEAST ESTERASE

An esterase (carboxylic acid hydrolase EC 3 1.1.1.) has been prepared from Saccharomyces cerevisiae. This esterase is active at pH 4.4 and, though it is unstable in solution, it can be maintained in an active form either by lyophilization or by coupling to an affinity gel. At pH 4.4, yeast esterase can hydrolyse between 20 and 40% of the esters commonly present in beer, and it is capable of synthesizing ethyl acetate from ethanol and acetic acid in a simple buffered solution without the provision of a co-factor. Different yeast strains yield different amounts of esterase, and there appears to be a positive correlation between the ability of the yeast to form esterase and the level of esters present in fermentations accomplished by that yeast.     

Crossmodal associations and subjective ratings of Asian noodles and the impact of the receptacle

We investigated the crossmodal associations that people hold for Asian noodles, and the influence of the plateware/receptacle. Chinese participants viewed online photographs of natural, red, green, and yellow noodles presented in bowls or plates made from ceramic, glass, paper, or stainless steel. In Experiment 1, the participants reported the first taste/flavour that came to mind, and rated their feelings and taste/flavour expectations concerning the noodles. In Experiment 2, the participants had to choose a taste term from a list to indicate the first taste that came to mind, and rated their feelings about the noodles. The results of both experiments revealed that the red noodles tended to be associated with a spicy taste/flavour; whereas the yellow noodles were often associated with a savoury taste/flavour, and rated as looking more familiar and pleasant than either the red or green noodles. The receptacles used to present the noodles did not influence the observed colour-flavour associations. However, the material of the receptacles appeared to interact with the colour of the noodles in terms of influencing people’s subjective ratings of, and taste/flavour expectations concerning, the noodles. These findings therefore demonstrate the complex interactions that can occur between the colour of the product and the type/material of the receptacle on people’s expectations regarding the taste/flavour of Asian noodles in the Asian marketplace.     

Volatile profile of Stilton cheeses: Differences between zones within a cheese and dairies

Penicillium roqueforti grows and sporulates during the ripening period of blue cheeses and it is responsible for the typical blue cheese flavour formation. However, the sporulation (blue veins) is taking place in a fraction of the total mass and the cheese matrix is highly heterogeneous. The aroma profiles regarding the three different sections of Stilton cheese, blue veins outer crust and white core, were studied using solvent extraction GC–MS, a headspace GC–MS technique (SPME GC–MS) and direct headspace analysis (APCI–MS). Cheeses from different dairies were analysed, allowing the question of how similar are different batches of cheese from different dairies.