荞麦籽粒的物理学特性研究

为了解荞麦籽粒的物理学特性,检测了5个荞麦品种籽、壳和仁的10个物理学特性。结果表明:籽含水率11.6%~13.4%,籽粒度3.8~5.0 mm占90%以上,仁色泽L*、a*和b*值分别约为籽的1.8,1.7,2.6倍,籽千粒重27.1~37.2 g,籽和仁容重分别为578~698,699~795 kg/m~3,籽、壳和仁比重分别约为1.11,0.61,1.13 g/cm3,壳和仁占籽重量比率分别为13.8%~19.2%,80.8%~86.2%,壳厚度约0.18 mm,壳仁间隙0.09~0.12 mm,仁硬度1.07~1.26 kg;不同品种荞麦的籽含水率和千粒重,籽仁容重,壳仁占籽重量比率,壳仁间隙及仁硬度等有较大差异。不同品种荞麦籽粒的这些物理学共性和特异性,对荞麦脱壳技术研究及脱壳生产工艺调整等有重要指导意义。     

荞麦-马尾松花粉格瓦斯饮料发酵条件的优化

以荞麦和马尾松花粉为原料,研制荞麦-马尾松花粉格瓦斯饮料。对5株酵母菌进行发酵试验,以酒精度和总黄酮含量为评价指标,筛选出优良酵母;在单因素试验的基础上,采用正交试验对料液比、发酵温度、发酵时间3个主要因素进行优化。结果表明,选择安琪甜酒干酵母为发酵菌种,最佳发酵工艺参数为料液比1∶6（g∶mL）、发酵温度28 ℃、发酵时间7 d。在此最优发酵条件下制得的荞麦-马尾松花粉格瓦斯饮料的酒精度为6.2%vol,总黄酮含量为92.92 μg/mL。     

苦荞芦丁水解酶的最适作用条件及Cu2+对酶活性的抑制

干燥的苦荞麦种子粉碎后经20mmol/L的醋酸盐缓冲液抽提,Resource Q和Superdex G75 HR 10/300凝胶柱分离纯化,得到一种芦丁水解酶,测定该酶的最适作用条件,研究Cu2+对该酶的抑制作用。结果表明:苦荞芦丁水解酶的分子质量约70kD,最适作用pH值为5.0。反应体系选择20%乙醇时,可保留酶的活性不被抑制,当乙醇体积分数大于50%时,对酶的活性抑制率达90%以上,表明可选用低体积分数乙醇作为芦丁的溶剂,用于芦丁水解酶测活体系及后续槲皮素制备研究。荧光光谱表明,Cu2+与芦丁水解酶以物质的量比1:1的形成稳定的复合物,可以使酶的荧光发生猝灭,水解芦丁的活性降低。表明Cu2+对芦丁水解酶有抑制作用。     

荞麦醋发酵过程中芦丁含量变化规律研究

研究了以陕北荞麦为原料酿造食醋过程中主要功能成分芦丁的含量变化。实验表明,在酒精发酵阶段,随着发酵的进行发酵液中芦丁含量呈上升趋势,发酵残渣中芦丁含量呈下降趋势;而在醋酸发酵阶段,发酵液中芦丁含量呈下降趋势,发酵残渣中芦丁含量呈上升趋势。总芦丁含量没有明显变化。     

荞麦米线加工工艺研究

研究荞麦米线的加工工艺,单因素试验确定影响荞麦米线品质的主要因素为荞麦粉∶早籼米、面粉粒径、含水量和复蒸时间4个因素,正交试验确定产品的最佳工艺条件为荞麦粉∶早籼米为1∶4,面粉粒径为80目,含水量为45%,复蒸时间为4 min。此工艺生产的荞麦米线具有加工工艺简单,营养丰富,口感爽滑等特点。荞麦米线的研制为改良传统食品提供新思路。     

荞麦咖喱擘酥角工艺开发与品质研究

以荞麦粉替代擘酥皮中黄油酥的全部面粉,经叠酥工艺制得荞麦咖喱擘酥角,应用模糊综合评判模型评价咖喱擘酥角。结果表明,荞麦黄油酥数量、蛋水面数量、焙烤温度、焙烤时间是影响成品品质的关键因素,采用L9(34)正交试验确定最佳工艺为荞麦黄油酥300g、蛋水面350g、焙烤温度220℃、焙烤时间20min。模糊综合评判模型评价结果,9个咖喱擘酥角成品的感官品质优劣顺序为3#>2#>6#>8#>4#>5#>9#>7#>1#,结果与L9(34)正交试验结果相同。模糊综合评判结果准确、科学。     

荞麦中芦丁的提取工艺优化

以米荞1号为原料,采用响应面法优化荞麦中芦丁的提取工艺。在单因素试验的基础上,根据Box-Behnken试验设计原理,通过响应面法优化芦丁提取工艺,选取时间、温度、料液比和甲醇体积分数四因素三水平进行中心组合试验,建立芦丁含量的二次回归方程,确定提取芦丁的最佳工艺组合条件。结果表明:提取时间93 min,提取温度77℃,料液比1:32,甲醇体积分数91%。该条件下芦丁提取含量预测值为17.92 mg/g,实测值为18.20mg/g,偏差不大。     

荞麦蛋白的研究进展

荞麦蛋白是天然抗消化蛋白,由球蛋白、清蛋白、谷蛋白和少量醇溶蛋白构成,具有多种优良的功能特性和生理功能。本文探讨了养麦蛋白的结构、制备工艺、加工功能特性以及作为抗消化蛋白的机理,并指出荞麦蛋白作为一种“药食兼用“的天然活性成分具有广泛的应用前景。     

Part III: the influence of serial repitching of Saccharomyces pastorianus on the production dynamics of some important aroma compounds during the fermentation of barley and gluten‐free buckwheat and quinoa wort

The present paper is the last report of a comprehensive study regarding the influence of the serial repitching of Saccharomyces pastorianus TUM 34/70 on the composition of a barley, buckwheat or quinoa fermentation medium. In particular, it focuses on the production dynamics of important volatile compounds typically associated with the aroma of beer. Samples were taken every 24 h after 11 serial repitchings of a single starter culture, analysed for the particular aroma compound content by distillation followed by gas chromatography with flame ionization detection. The term ‘serial repitching factor’ is used for the first time to support the visual evaluation of the influence of serial repitching. Results showed that the levels of methanol in the quinoa wort fermentation were only slightly higher than in barley and in practical terms independent of successive fermentation. The behaviour of acetaldehyde in quinoa was similar to that in barley. However, there was a final 2‐fold lower production of some important aroma compounds compared with barley and buckwheat and for this reason quinoa cannot be recommended as a gluten‐free substitute to produce a bottom‐fermented beer. Regarding the buckwheat wort fermentation, a 2‐ to 3‐times lower final acetaldehyde content than in barley is desirable, whereas a relatively high methanol content is not desirable. Barley and buckwheat showed comparable sum concentrations and similar overall profiles of some important aroma compounds. From this perspective, buckwheat appears to be a promising substitute for barley as a brewing raw material. The overall conclusions of our comprehensive study (Parts I–III) are that buckwheat shows adequate brewing properties to substitute for barley in the commercial preparation of a bottom‐fermented gluten‐free beer‐like beverage, and yeast can be repitched at least 11 times. In contrast, quinoa in practical terms shows no substitutional potential for barley in beer; however, it has many nutritious advantages, thus the commercial preparation of a unique, bottom‐fermented gluten‐free ‘non‐beer‐like’ beverage – where the yeast could be repitched six times at most – appears feasible. Copyright © 2015 The Institute of Brewing & Distilling