Effects of Riboflavin Photosensitized Oxidation on the Volatile Compounds of Soymilk

ABSTRACT: Soymilks with or without added riboflavin in serum bottles were stored under light or in dark at 20 °C. The headspace oxygen and volatile compounds were determined by gas chromatography. Riboflavin had significant effects on the headspace oxygen depletion and volatile compounds formation in soymilk under light ( P < 0.05). Riboflavin did not have significant effects on the formation of volatile compounds and the depletion of headspace oxygen in dark ( P > 0.05). The volatile compounds increased under light, but not in dark as the added riboflavin increased. Storage temperature at 4 °C or 20 °C did not have significant difference in the effect of riboflavin on the headspace oxygen depletion in soymilk under light. Hexanal, an important beany flavor compound, was identified as the major volatile compound in the riboflavin photosensitized soymilk. Singlet oxygen oxidation was involved in the formation of volatile compounds in soymilk under light. Hexanal could be formed by singlet oxygen oxidation. Ascorbic acid, a quencher for singlet oxygen and the excited triplet sensitizer, significantly inhibited the formation of hexanal and total volatiles in soymilk under light.     

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.     

欧姆加热对豆浆风味物质的影响

为研究欧姆加热对豆浆挥发性物质的影响,采用顶空固相微萃取结合气相色谱-质谱联用技术,对豆浆的风味物质进行分析,利用内标法对各风味物质成分定量分析。通过对比50/30?μm二乙基苯/碳分子筛/聚二甲基硅氧烷（divinylbenzene/carboxen/polydimethylsiloxane,DVB/CAR/PDMS）、100?μm PDMS、65?μm PDMS/DVB 3 种萃取头对豆浆风味物质的萃取效果,筛选出最佳的萃取头,并在最适条件下分析豆浆的风味物质成分,为排除热效应对实验结果的影响,2?种热处理历程尽可能保持一致。结果表明：65?μm PDMS/DVB纤维萃取头较100?μm PDMS和50/30?μm DVB/CAR/PDMS纤维萃取头更适宜豆浆风味物质的测定;从豆浆样品中共检测到35?种挥发性物质,其中醛类物质16?种,醇类物质5?种,酮类物质3?种,酯类物质1?种,杂环烃类物质10?种,主要包括己醛、（E）-2-庚烯醛、1-辛烯-3-醇等,这些物质共同组成豆浆的特征香气;不同加热处理对豆浆风味物质种类的影响不大,但是对特征香气含量有显著影响（P＜0.05）;欧姆加热处理组样品中己醛、1-辛烯-3-醇、（E）-2-辛烯醛的含量分别比传统加热处理组约低45.55%、58.60%、25.56%,且在欧姆加热处理样品组中未检测到（E）-2-己烯醛和正己醇,而这些物质是豆腥味的主要组成成分。因此,利用欧姆加热方式加热豆浆可以显著降低豆浆的豆腥味。本研究可以为欧姆加热技术在豆浆加工业中的应用提供理论依据。     

Production of Volatile Compounds from Irradiated Oil Emulsion Containing Amino Acids or Proteins

Oil emulsions containing amino acids, glutathione, bovine serum albumin, gelatin, or myofibrillar proteins were prepared. The emulsions were irradiated at 0, 2.5, 5.0, or 10.0 kGy absorbed doses and analyzed for volatile compounds. Irradiation increased the production of aldehydes (for example, hexanal, heptanal, octanal, and nonanal) indicating that lipid oxidation of oil emulsion was accelerated by irradiation. Irradiation produced, by radiolytic degradations, new volatile compounds from oil emulsions containing leucine, valine, isoleucine, phenylalanine, methionine, or cysteine. This indicated that radiolysis of protein may play an important role in off-odor generation of irradiated meat.     

Formation of Volatile Sulfur-Containing Compounds by Saccharomyces cerevisiae in Soymilk Supplemented with L-methionine

The formation of volatile sulfur-containing flavor compounds from L-methionine catabolism by Saccharomyces cerevisiae EC-1118 was investigated in soymilk supplemented with this sulfur-containing amino acid with a focus on methionol (3-methylthio-1-propanol). Methionol produced from L-methionine metabolism of yeast in soymilk was extracted by solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). The effects of time (0 – 72 h), L-methionine concentration (0.05–0.20%), yeast extract concentration (0.00–0.30%), initial medium pH (4.5–6.9), and temperature (25–34°C) on the production of methionol were investigated. One-liter scale-up fermentation of soymilk by Saccharomyces cerevisiae EC-1118 was conducted for 48 h under static conditions with 0.15% of L-methionine, 0.10% of yeast extract, initial medium pH of 5.5, and temperature of 25°C, yielding 190 ppm of methionol. GC-olfactometry dilution analysis was conducted on extracts of the fermented soymilk, and no single compound was found to account for the overall odor perception. Methional (3-methylthio-1-propanal) and methionol were determined to be most potent odor-active compounds in the fermented soymilk. The fermented soy milk may serve as a complex sulfur flavor concentrate for applications in foods such as fermented soy products, enzyme-modified, and imitation cheeses.     

水产品中挥发性风味物质提取和分析研究进展

水产品中的挥发性风味物质是影响其风味的重要因素,研究水产品中挥发性风味物质的组成及含量,对于评价水产品质量、指导水产品生产、改进加工工艺等具有重要意义。本文就国内外水产品挥发性风味物质的提取方法和分析技术及其应用情况进行了综述,分析比较了各种提取方法、分析技术的优缺点,并展望了其发展动向,以期为水产品挥发性风味物质的研究提供参考。     

板栗及其膨化制品的挥发性香气成分分析

采用顶空固相微萃取结合气相色谱-质谱联用技术对生板栗粉、煮板栗和3种膨化板栗制品的挥发性香气成分进行分离鉴定。共鉴定出68种挥发性物质,初步认定吡嗪类物质中的甲基吡嗪、2,3-二甲基吡嗪、2-乙基-6-甲基吡嗪、2,6-二甲基吡嗪;呋喃类物质中的2-戊基呋喃、γ-丁内酯、2-糠醇、2,5-二氢-3,5-二甲基-2-呋喃酮和γ-辛内酯及芳香族类物质中的苯甲醛是板栗的特征风味物质。煮制可提升板栗的香气。膨化板栗片的膨化加工方式对其香气成分影响显著,挤压膨化板栗片的香气物质组成和煮板栗比较相似,微波膨化板栗片中易产生具有枯焦气息的2,4-二叔丁基苯酚,油炸膨化板栗片的挥发性成分最复杂,醛类物质较多。     

两歧双歧杆菌发酵橙汁酸豆奶的研究

本文尝试研究豆奶中两歧双歧杆菌的生长情况,以得到风味良好的发酵产品.以大豆与水1∶8的比例制取豆奶,添加一定量的橙汁,并加入两歧双歧杆菌进行发酵.考察了培养温度、橙汁添加量、接种量等因素对产品pH值和活菌教的影响,并在此基础上进行正交试验优化.正交试验结果表明,培养温度为39℃、接种量为5％、橙汁添加量为10％,18 ...     

Volatile Compounds and the Changes in Their Concentration Levels during Storage in Beers Containing Varying Malt Concentrations

ABSTRACT:  Volatile compounds in beers brewed with different amounts of malt were analyzed by using the stir bar sorptive extraction–gas chromatography-mass spectrometry method. We identified 90 compounds—25 esters, 17 terpenes, 14 alcohols, 11 acids, 6 furans, 6 aroma compounds, 5 carbonyls, and other compounds. An analysis of aged beer suggested that the concentration levels of stale flavor compounds—β-damascenone, γ-nonalactone, ethyl cinnamate, and 2-methoxy-4-vinylphenol—in nonmalt beer were different from those in all-malt and standard beer. Additionally, concentrations of these compounds did not increase during storage in most nonmalt beer analyzed in this study. Nerolidol may be a good marker candidate regardless of the malt content.     

萌发大豆制备益生菌发酵豆乳流变特性的研究

以萌发大豆作为主要原料,经瑞士乳杆菌(Lactobacillus helveticus B02)、保加利亚乳杆菌(Lactobacillus bulgaricus AS1.1482)和嗜热链球菌(Streptococcus thermophilus IFFI 6038)组合发酵制成发酵豆乳,研究益生菌发酵豆乳的发酵特性及流变特性。结果表明,大豆经萌发后,游离氨基酸总量增加了近2倍;与未萌发大豆制成的发酵豆乳相比,萌发大豆发酵豆乳中乳酸菌菌落总数显著增加,产生更多的游离H离子及有机酸,且其剪切稀化作用减弱,表观黏度显著下降,更为接近发酵纯牛乳的流变特性。大豆萌发后制成发酵豆乳,可促进乳酸菌的生长及产酸,有助于改善发酵豆乳的流变特性。     

发酵海产品中微生物形成挥发性代谢产物研究进展

挥发性代谢产物一般是由原料和微生物的酶类降解海产品中蛋白质、脂类等大分子形成的小分子物质,对产品品质和风味形成具有十分重要的作用。本文对发酵海产品中形成挥发性代谢产物的微生物类群、挥发性代谢产物的代谢途径和形成过程进行综述,阐明微生物、代谢途径与代谢产物三者之间的内在联系,为发掘和利用发酵海产品中优良的微生物类群,提升产品品质提供借鉴与参考。     

微生物挥发性有机化合物在农产品中的分析及应用研究进展

本文对近年来微生物挥发性有机化合物（microbial volatile organic compounds,MVOCs）在农产品中的分 析和应用的相关文献报道进行了回顾。对农产品中MVOCs的捕集、仪器检测、数据分析方法进行简介,着重论述 了MVOCs在农产品微生物污染检测、发酵食品品质监控、微生物资源开发利用等方面的应用情况。     

Volatile Compounds in Fermented and Acid-hydrolyzed Soy Sauces

ABSTRACT: Volatile compounds in fermented and acid-hydrolyzed soy sauces were isolated and analyzed using solvent extraction and solid-phase microextraction. Quantitatively, alcohols and esters were dominant in the volatiles of fermented soy sauce, whereas heterocyclic compounds, including pyrazines and furans, and acids were relatively abundant in the acid-hydrolyzed soy sauce. The odor-active compounds were also evaluated. The major odor-active compounds of fermented soy sauce were acetic acid, furfuryl alcohol, 2-methoxyphenol, benzeneethanol, benzoic acid, butyric acid, 2-ethyl-4-hydroxy-5-methyl-3(2H) furanone, and 2-methylbutanal, whereas acetic acid, 2-methoxyphenol, formic acid, benzoic acid, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, butyric acid, 2,6-dimethoxyphenol, 3-hydroxy-2-methyl-4H-pyran-4-one, 2-acetyl-5-methylfuran, 2,5-dimethyl-3-ethylpyrazine, and 2-methylbutanal constituted the major odor-active compounds of acid-hydrolyzed soy sauce.     

杏果挥发性风味成分分析

本实验以兰州大接杏等6种甘肃省种植的杏果为实验材料,通过顶空固相微萃取(HS-SPME)和气相色谱-质谱(GC-MS)联用技术,从供试的杏中鉴定108种挥发性物质,主要包括:酯类25种、萜烯及萜烯醇类16种、醛类14种、烃和芳香烃类14种、酮类13种、醇类12种、内酯类9种、酸类5种。其中未见报道的有2-甲基丙酸庚酯、丙酸香茅酯、乙酸香叶酯、γ-己内酯、δ-十一内酯、5-羟基-7-癸烯酸内酯和5-羟基-2,4-癸二烯酸内酯等多种风味成分。     

气相色谱-离子迁移谱分析乳制品挥发性风味化合物

采用气相色谱-离子迁移谱技术分析乳制品中挥发性风味化合物,样品包括2个品牌巴氏杀菌乳、5个品牌超高温瞬时灭菌乳和1个品牌复原乳,共检出29种化合物,主要有醛类、酮类、醇类、酯类及其他类,己酸甲酯、丁酸乙酯、乙酸异戊酯、乙酸乙酯、戊酸乙酯、1-戊醇、柠檬烯构成了巴氏杀菌乳中特征峰区域;糠醛、苯甲醛、4-甲基-2-戊酮、2...     

肉制品烟熏风味物质研究进展

烟熏肉制品具有独特的烟熏风味。烟熏风味主要由挥发性风味物质的种类、含量和气味特性决定,受烟熏材料、烟熏设备和烟熏工艺等因素影响。本文阐述了烟熏特征挥发性风味物质的种类、形成途径与影响因素,丰富了肉制品烟熏风味的形成机制,并就目前烟熏肉制品加工中存在的问题,如风味缺失（特征风味物质的减少）等进行分析,以期为肉制品烟熏风味的调控提供参考。     

美国加州杏仁月饼挥发性风味物质研究

本文主要应用固相微萃取技术以及气相色谱-质谱联用技术（GC—MS），研究烘烤去皮整粒美国加州杏仁、小麦粉月饼、含有50％全脂杏仁粉以及含有50％脱脂杏仁粉月饼中的挥发性风味物质；并考察了在贮藏过程中三种不同的包装方法（普通、脱氧和真空包装）和贮藏时间对含有50％全脂杏仁粉月饼中含有的挥发性风味物质的影响。结果表明：2-甲基丁醛、乙酸、2，5-二甲基吡嗪等是烘烤后去皮整粒杏仁的主要挥发性风味物质：三种月饼中贡献最大的挥发性风味物质都是己醛；在月饼的回软过程中，贮藏时间和包装方法对挥发性风味物质的影响都不显著。     

传统腌腊肉制品挥发性风味物质的研究进展

本文以干腌火腿、腊肉、风鸭、发酵香肠和风干鱼制品为代表,对中国传统腌腊肉制品的挥发性风味物质进行了探讨。从总体上阐述了我国传统腌腊肉制品挥发性风味的形成机理,详尽列表总结分析了不同制品的特征风味化合物,分析它们之间的共性与异性,并从原料特性及加工工艺两个主要方面分析了差异性形成的可能原因。一方面,丰富了传统腌腊肉制品的形成机制,另一方面,为生产调控肉制品的风味提供理论依据。     

肉制品中蛋白质、脂质及其相互作用吸附挥发性风味物质机理研究进展

挥发性风味物质影响肉制品品质优劣,蛋白质与脂质是吸附肉制品挥发性风味物质的重要基质。在肉制品加工过程中,蛋白质与脂质发生结构变化及相互作用,影响风味吸附程度。本文综述蛋白质、脂质及其复合物吸附挥发性风味物质的分子机理,阐述流变学物理保留、蛋白质-脂质化学作用协同吸附挥发性风味物质机制,并从内源风味物质特性与外源环境因素角度阐明风味物质调控规律,以期为肉制品风味调控提供理论参考。