浅谈提高啤酒的风味稳定性

阐述了啤酒风味老化及其预防的机理,并从原料、麦汁制造、发酵、贮酒、过滤、灌装、抗氧剂的使用及成品贮存等方面探讨了提高啤酒风味稳定性的措施。     

提高啤酒风味稳定性的方法

啤酒的风味稳定性是指啤酒灌装后，酒的风味长期不变的可能性。引起啤酒风味不稳定的主要原因是发生氧化反应。提高啤酒风味稳定性的方法有：（1）选用性能优良的啤酒酵母；(2)向成品啤酒中加入10^2-10^6个酵母／ml；（3）选用抗氧化剂，如亚硫酸盐、抗坏血酸、异抗坏血酸、异抗坏血酸钠、葡萄糖氧化酶、超氧化物岐化酶。（孙悟）     

啤酒风味稳定性评估的研究进展

啤酒生产过程中,啤酒风味稳定性的分析、评价和预测已成为越来越重要的课题。近20年来,国际上对啤酒风味稳定性的研究已有了很大进展,从传统的感官品评法发展到根据风味老化指示物质的量与感官品评法结合的对比法,并建立了一系列啤酒风味稳定性的评估方法,为啤酒的实际生产和提高啤酒质量提供了指导。(孙悟)     

影响啤酒风味稳定性的物质及其控制

该文试论几种主要的羰基化合物的形成、变化和对啤酒风味的影响。经实验证明反－２－壬烯醛、呋喃醛、２－甲基醛等与老化味存在着直接关系。论述了氧在老化反应中所起的作用,以及提高啤酒的风味稳定性,应采取的工艺措施。     

保持啤酒风味稳定性的机理与方法

啤酒罐装后口味的退化与两个化学反应有关 :氧化反应和光化学反应。从这两个反应角度指出造成风味退化的原因 ,以及保持风味稳定性可采取的方法     

Flavor and Oxidative Stability of Roasted High Oleic Acid Peanuts

A new peanut line has been developed at the University of Florida with about 80% oleic and 3% linoleic acid. Volatiles and sensory characteristics of roasted normal and high oleic acid peanuts stored at 25°C were compared. Volatiles were analyzed using adsorbent trapping and GCMS, a 20-member trained panel was used for sensory evaluation, and a GC sniffer port was used to evaluate odor characteristics of volatile isolates. Peroxide values were lower for high oleic (HO) peanuts than normal peanuts during storage at 25°C and 40°C. The hexanal content of the peanuts was higher for normal than HO. Peanutty flavor was more stable for HO than normal after 6 wk storage. Painty and cardboard flavors were higher in normal peanuts than HO during storage. Differences for both painty and cardboard flavors were significant after 6 wk storage. Pyrazines were more stable in HO peanuts. Shelf life was estimated from sensory data to be two times longer in HO peanuts.     

Stability of Metabolically Conjugated Precursors of Meat and Milk Flavor Compounds in Various Solvents

The stability of selected metabolic conjugates (phenylglucuronide, phenylphosphate, and naphthylsulfate) was determined in model systems composed of water and various ratios (3:1, 1:1, 1:3) of selected solvents (hexane, chloroform, ethyl acetate, diethyl ether, or methanol) held at either 22°C or 40°C for 30 min under various pH conditions (pH 1.5, 3.2, or 6.5). Notable hydrolysis occurred only for the more polar solvents held in contact with acidic aqueous phases. Conditions were identified for minimizing hydrolysis of conjugates during extraction of fat and free alkylphenols from milk and meat products with diethyl ether. They were pH near neutral, short exposure time, near ambient temperature, presence of excess water, and saturation of aqueous phase with sodium chloride.     

低度名优白酒风味特征稳定性的研究

通过对中国低度名优蒸馏白酒的发展及其风味特征、关键技术的研究,总结了影响名优低度白酒质量的重要因素。结合中国蒸馏白酒的发展方向,提出既具有中国蒸馏白酒个性特征又与国际接轨的意见和建议。     

Oxidative Stability in Raw and Roasted Pecans: Chemical, Physical and Sensory Measurements

To develop predictive relationships for sensory responses of crunchiness and rancid aroma and flavor, raw and roasted pecans were stored under two different relative humidities (55 and 65%) up to 8 mo. In response to relative humidity, rancid scores did not differ with either raw or roasted pecans. Rancid scores in raw and roasted pecans during storage most closely paralleled peroxide value and thiobarbituric acid reactive substances, respectively. Multiple regression models employing two or three oxidative and chemical measurements led to better prediction of sensory scores. In general, primary oxidative products of triacylglycerols factored into the models for raw pecans while secondary oxidative products of total lipids factored into the models for roasted pecans.     

Lipid Classes, Fatty Acids, Flavor and Storage Stability of Washed Sheep Meat

Lamb was used for all experiments, except flavor evaluations for which mutton was used. Washing ground lamb 4 times with high-pH (8.2) tap water, at a meat-to-water ratio of 1:4 and with a 15 min extraction/washing cycle, sharply lowered total fat content (primarily by removing neutral lipids), lipid oxidation potential, and the volatile branched-chain fatty acids which reportedly contribute to undesirable species-related flavor of sheep meat. A trained sensory panel determined that washed-cooked mutton had "very weak" species-related flavor (<2 on a 9-point scale).     

Possible implications of milk pasteurization on the manufacture and sensory quality of ripened cheese

Cheese made from raw milk represents an important proportion of the traditional cheeses, particularly in South European countries. Besides destruction of pathogenic bacteria, the most significant changes in milk relevant to cheesemaking, which are induced by pasteurization are:

• a partial elimination of the milk microorganisms which may grow in cheese during ripening,

• a partial or total activation or inhibition of the plasmin/plasminogen complex, cathepsin D, lipoprotein lipase and alkaline phosphatase. Enzymes from psychrotrophic bacteria, acid phosphatase and xanthine oxidase, which may be active during ripening, withstand pasteurization.,

• a slight (7%) denaturation of serum proteins and little or no modification of the cheesemaking properties (coagulation, acidification by lactic acid bacteria).

From experimental work carried out on several cheese varieties, comparing pasteurized or microfiltered milk and raw milk cheeses, it was found that facultatively heterofermentative lactobacilli, Micrococcaceae, enterococci, and propionibacteria in Swiss-type cheese, are found at higher levels in raw milk cheese. The main biochemical modification of cheese during ripening concerns the nature and extent of proteolysis. Although there is no clear trend in the breakdown of _s1- and β-caseins, milk pasteurization leads to a significant decrease of the amount of small peptides and free amino acids and to different HPLC profiles. Experiments carried out with sensory analysis show that, in all cases, pasteurized or microfiltered milk cheeses have received lower flavour intensity scores than raw milk cheeses. From this review, it is concluded that the indigenous milk microflora, with its diversity of species and strains, appears to be mainly responsible of the specific sensory properties of raw milk cheeses.     

Thermal Stability of Some Metabolically Conjugated Potential Precursors of Flavor Components in Meat and Milk

The stability of selected metabolic conjugates (phenylphosphate, phenylglucuronide, naphthylglucuronide, and naphthylsulfate) was evaluated in model systems. Phenylphosphate was less stable than the glucuronides and the sulfate, especially under neutral (pH 6.8) and acidic conditions (pH 1.5). Phenylphosphate was completely degraded after 1.7 hr at 100°C, and after 0.3 hr at 150°C at pH 6.8. The glucuronide and sulfate conjugates were especially stable under neutral conditions (pH 6.8) requiring > 5 hr for complete hydrolysis at 100°C. All conjugates were quite stable to hydrolysis under alkaline conditions (pH 11). The presence of certain organic solvents (ethyl acetate or ethyl ether) caused rapid hydrolysis of conjugates under very mild conditions (40°C for 30 min). This information may improve under-standing of flavor production from animal products.     

鸡肉香精感官评价研究

采用模糊数学法对鸡肉香精的感官质量进行综合评定,结果表明,一种鸡肉香精的综合评定级别为优,该方法能客观的做出评价结论。     

饮料乳化香精的稳定性研究

本文简要介绍了乳化香精的制备技术,综述了乳化香精的稳定性问题,详细阐述了控制乳化香精稳定性的主要措施.     

荸荠山楂复合果汁饮料加工工艺的研究

以荸荠、山楂为主要原料,对其复合制作果汁饮料的工艺技术要点进行了研究。其配方为：荸荠汁（用荸荠果肉与水按1：1比例研磨过滤制成）30％,山渣汁（将山楂果肉与水按照1：3比例浸提制成）20％,柠檬酸0.1%,苹果酸0.1%,蔗糖10%,CMC-Na 0.2%。采用90℃、20min的杀菌条件,研制出的复合果汁饮料口感和风味最佳。     

Volatile Concentration and Flavor of Beef as Influenced by Diet

Yearling steers (48) were finished on one of three intense pasture rotation systems: (1) Tifleaf pearl millet; (2) millet with restricted grain; or (3) millet followed by grain ad libitum in the feedlot. In both 20% fat ground beef and subcutaneous fat, gamey/stale off-flavor decreased and roasted beef flavor increased when steers were fed grain. Compounds (59) including acids, alcohols, aldehydes, diterpenoids, hydrocarbons, and lactones, were identified in the purge-and-trap volatiles. Lactones positively correlated with roasted beef flavor and negatively correlated with gamey/stale off-flavor, whereas diterpenoids positively correlated with gamey/stale off-flavor and negatively correlated with roasted beef flavor.     

剑南春芳香滋味特色的来源奥秘

中国名酒剑南春由于其独特典型的风格深受消费者的肯定和喜爱.而自然生态环境、水质、酿造设备、特定的发酵剂、科学的粮食配比、独特的生产工艺以及独特的陶坛储存是剑南春芳香滋味特色的来源.