Apparatus for quantitative headspace analysis of the characteristic odorants of baguettes

 An apparatus, based on the principle of dynamic headspace analysis, has been developed for the analysis of potent odorants released from two types of baguette (“intensifiée”, INT and “artisanal”, ART) which differ in their odour profiles. The odour profiles of model mixtures containing the odorants at concentrations found in bread were evaluated by headspace analysis using the apparatus as an olfactometer and were compared to the odour profiles of the baguettes. The results indicated that losses of methylpropanal, 2- and 3-methylbutanal and an increase of hexanal and (E)-2-nonenal led to a stale flavour. Because the concentrations of methylpropanal and (E)-2-nonenal were higher in the ART crust than in the INT crust, the change from a pleasant baguette odour to a stale odour was slower in ART baguettes. We suggest that the apparatus designed for quantitative headspace analysis could also be suitable for determination of the release of flavour compounds from other foods. Received: 17 March 1997     

高效液相色谱分析啤酒中的肌苷、肌苷酸

采用Nova-pak C18色谱柱(150×3.9mm id,4μm),水(含0.5%H3PO4)、甲醇为流动相,梯度洗脱,流速0.60mL/min,柱温30℃,测定波长(λ)248nm,直接进样同时分离了肌苷和肌苷酸。结果显示,在肌苷、肌苷酸含量分别为0.5mg/L～10mg/L时,呈线性关系,加样平均回收率为91.6%、96.8%,相对标准偏差为0.8%～2.6%。     

提升啤酒酵母抽提物整体风味优化工艺条件的研究

研究了利用美拉德反应提升啤酒酵母抽提物整体风味的相关参数,包括还原糖、含硫氨基酸、杂环化合物、反应的pH、反应温度和反应时间等,通过单因子和正交试验对美拉德反应的条件进行了优化。结果表明,通过美拉德反应可明显提升啤酒酵母抽提物的整体风味,制备风味化啤酒酵母抽提物的最优化工艺条件为:啤酒酵母抽提物配制成50%浓度,添加1．5%木糖、1．5%核糖、1%半胱氨酸、1%蛋氨酸、0．5%硫胺素和0．5%VC,调节pH7．5,在反应釜内升温至105℃,保温回流反应2h。采用优化反应条件制备的风味化啤酒酵母抽提物具有肉香浓郁、滋味饱满、圆润、鲜美、肉质感强,使啤酒酵母抽提物的整体风味得到明显改善。     

GC/MS应用于奶味香精色谱指纹图初步构建的研究

采用液-液萃取(LLE)及气相色谱/质谱法(GC/MS)对某种奶味香精的致香成分进行提取、分离和鉴定,确认出其中的17种成分,并用峰面积归一化法测定了各成分的相对含量。其主要成分为:胡椒醛(16.210%)、香兰素(16.838%)、乙基香兰素(9.817%)、δ-十一内酯(32.657%)、τ-辛内酯(6.050%)、辛酸乙酯(5.163%)等,相对标准偏差在1.91%～9.67%之间。结果表明该方法简单、快速、准确,便于推广,可用于此类香精色谱指纹图的建立。     

Characterization and detection of toxoflavin‐producing Burkholderia in rice straws and Daqu for Chinese Maotai‐flavour liquor brewing

Rice straws are widely used in Daqu (starter) preparation for Maotai‐flavour liquor brewing to provide adequate thermal insulation, water retention and aeration. As the straws have direct contact with the Daqu during its preparation, the microorganisms carried by the straws can be transferred to the Daqu. In this study, yellow pigment‐producing strains were isolated from the rice straws using a dilution plate method. Most of these strains were characterized as toxoflavin‐producing Burkholderia spp. by 16S rRNA sequencing, toxA gene‐specific PCR and toxoflavin detection. The PCR assays revealed the existence of Burkholderia in the Daqu samples. The toxoflavin content in a number of Daqu samples was determined using HPLC. The highest observed content of toxoflavin in the Daqu was >8 mg/kg, close to its LD₅₀. Although no toxoflavin was detected in the distilled liquor, the safety problem regarding the use of rice straws in Daqu preparation is still noteworthy, since Burkholderia and toxoflavin can be transferred and can accumulate during the brewing process. The results can contribute to a further assessment of the contamination risk in liquor brewing caused by Burkholderia and to safer production in this traditional process. Copyright © 2015 The Institute of Brewing & Distilling     

中温发酵酸乳的挥发性风味成分与感官特性的研究

通过正交实验研究了球杆菌比例、全脂乳浓度、发酵终点以及蔗糖添加量对中温发酵酸乳的感官和挥发性风味成分的影响。以九个不同工艺配方为研究对象,采用描述分析感官评价法和固相微萃取结合动态顶空方法对酸乳的感官评价值和风味成分进行测定,并运用主成分分析法和偏最小二乘分析法得到感官结果和仪器测定结果的相关性。结果表明:球杆菌比例和全脂乳浓度是影响酸乳风味和挥发性风味成分的重要因素。偏最小二乘回归分析得到3种气味、3种滋味和2种余味与挥发性成分、乳酸和柠檬酸量的相关性。      

Initial dynamic flavour release from sodium chloride solutions

Initial dynamic flavour release from solutions of sodium chloride was theoretically modelled. Predictions were validated by experimental data obtained applying a computerised apparatus for real time measurements. Modelling was based on the convective mass transfer theory, combining physicochemical properties of flavours and sodium chloride solutions, and on parameters of the apparatus. Hydration of dissociated ions and concurrent decrease of free water volume, together with solution polarity, were found to be rate limiting for the release process. Predicted and experimental data showed a significant positive correlation between solute concentration and release for each flavour compound used. Nevertheless, reduced volume of free water influenced flavour compounds to a different extent, resulting in changing overall release profiles.Abbreviations ANOVA analysis of variance - DMR test Duncans multiple range test - c _hs headspace volatile concentration - t time (s) - c ₀ initial volatile concentration in the liquid - k mass transfer coefficient (m s^–1) - A interfacial area (m²) - V _hs headspace volume (m³) - Re Reynolds number - Sc Schmidts number - P volatile permeability (m² s^–1) - H _ln logarithmic vertical distance (m) - n stirrer rotations (s^–1) - d stirrer diameter (m) - kinematic viscosity (s m^–2) - D volatile diffusion coefficient (m² s^–1) - effective film thickness of flowing air at the interface (m) - V _f volumetric air flow rate (m³ s^–1) - p partial pressure (Pa) - S aqueous solubility (kg m^–3) - molar fraction - h _n hydration number - h _n0 hydration number at infinitely low solute concentrations - c constant - V _water,h volume of hydration water (mL) - V _mol,water molar volume of water (cm³ mol^–1) - n _NaCl mole number of NaCl - V _sol volume of the liquid (mL) - V _mol,NaCl molar volume of sodium chloride (cm³ mol^–1) - f ₁ and f ₂ factors - V _r reactor volume (mL) - V _Cl,h volume of hydrated Cl^– (mL) - n _Cl mole number of Cl^– - N _A Avogadros number - r _Cl,h radius of hydrated Cl^– (m) - V _Na,h volume of hydrated Na⁺ (mL) - n _Na mole number of Na⁺ - r _Na,h radius of hydrated Na⁺ (m) - S _sol solubility of flavours in NaCl solutions - z exponent     

紫甘薯发酵饮料的研制

以紫甘薯为主要原料,通过对紫甘薯发酵配料、菌种配比的筛选及对发酵液风味的改良,研制了具有乳香和果香复合香味的紫甘薯发酵饮料,为紫甘薯的深加工提供了科学依据。     

肉味香精的过去、现在和将来

介绍了肉味香精的研究进展，包括肉香风味物质的分离、鉴定和合成，美拉德反应技术在肉味香精生产中的应用，脂类物质的作用，肉味香精技术的研究进展，国内肉味香精工业的发展等。并对肉味香精今后的发展趋势作了预测。