共查询到20条相似文献,搜索用时 234 毫秒
1.
本论文对气相色谱法、地衣酚-盐酸法、间苯三酚-冰醋酸法以及Duffau蒸馏法四种不同的戊聚糖含量测定方法进行研究。在研究过程中以气相色谱法为标准,就地衣酚-盐酸法、间苯三酚-冰醋酸法以及Duffau蒸馏法与气相色谱法之间的相关性进行研究,通过研究得到测定谷物中戊聚糖含量的最佳方法,即采用间苯三酚~冰醋酸比色法。研究发现间苯三酚-冰醋酸法与气相色谱法具有较好的相关性,并且该方法测定较快速、准确。并对苯三酚-冰醋酸法测定戊聚糖含量的测定条件进行优化,得到该方法测定的最适条件为:测定样品与抽提试剂的共沸反应时间为30min;采用单波长测定,测定波长为552mm;另外样品中己糖含量对测定结果影响不大。 相似文献
2.
3.
4.
地衣酚-盐酸测定小麦中戊聚糖含量的研究 总被引:11,自引:0,他引:11
对2002-2003年华北地区具有代表性的8个小麦品种的戊聚糖进行了测定.不同品种小麦中戊聚糖的平均含量变化范围为6%~9%.不同生态条件下小麦中戊聚糖含量均有很大差异.采用地衣酚-盐酸法测定小麦中戊聚糖的含量,为小麦更好地用作畜禽饲料提供理论依据. 相似文献
5.
通过对小麦和小麦芽化学组成及戊聚糖含量和结构的分析,阐述了以小麦芽为原料生产啤酒时存在的影响糖化麦汁过滤、麦汁浊度及非生物稳定性的因素,并对实际生产中戊聚糖酶的选择和应用提出了初步的建议。 相似文献
6.
测定30个不同麦芽样品的总氮、可溶性氮、库值、总酚含量以及对应麦汁敏感蛋白及敏感多酚含量,并对结果进行相关性分析发现,麦汁敏感蛋白含量与麦芽可溶性氮呈显著正相关(r=0.686,p0.01),麦汁敏感多酚含量与麦芽总酚呈显著正相关(r=0.646,p0.01),表明麦芽可溶性氮与总酚指标可初步用于评价麦汁中敏感蛋白与敏感多酚含量;其次,选择麦芽可溶性氮与总酚含量差异较大的加麦Metcalfe与澳麦Gairdner、国麦垦七麦芽,按照不同比例进行搭配并制备麦汁,分析发现搭配前后麦汁敏感蛋白及敏感多酚含量呈线性关系,表明可以有选择的使用不同品种麦芽,按特定比例搭配来控制麦汁中敏感蛋白、敏感多酚含量。本研究为从原料角度预测和控制麦汁和啤酒的胶体稳定性提供了支持。 相似文献
7.
木聚糖酶在啤酒中的应用研究 总被引:1,自引:0,他引:1
本文研究了木聚糖酶的特性以及相关酶活的分析方法,引用戊聚糖分析方法应用于本研究中。通过木聚糖酶在啤酒生产中的应用,分析大麦芽、小麦芽和大米中戊聚糖含量的差异;在实验室试验中研究了原辅料配比与木聚糖酶添加量对麦汁戊聚糖含量、黏度、过滤性能等的影响;利用统计方法修约了小麦芽配比与过滤性能、戊聚糖等的线性关系,为生产工艺定量提供依据;确定了相应的大生产工艺方案。大生产试验中,又进一步研究了麦汁过滤性、稳定性、戊聚糖与黏度的关系;研究了发酵过程中的戊聚糖含量变化、冷凝固物特性、发酵液非生物稳定性和风味特性以及过滤性能,同时对成品啤酒进行了综合分析。 相似文献
8.
9.
选用不同总酸含量的麦芽酿造啤酒,采用高效液相色谱(HPLC)法检测麦芽及酿造啤酒中的有机酸含量,以建立麦芽总酸和啤酒有机酸含量的相关性。采用顶空固相微萃取(HS-SPME)和气相色谱质谱联用(GC-MS)法检测啤酒中挥发性化合物成分,并对酿造的啤酒进行感官评价。结果显示,随着麦芽总酸含量的升高,麦汁pH值呈下降趋势,琥珀酸、苹果酸、乳酸和乙酸的含量呈上升趋势。麦芽总酸含量与啤酒中总酸、苹果酸、乳酸含量呈显著正相关,相关系数分别为0.94、0.94和0.92。不同总酸含量麦芽酿造啤酒特征香气物质不尽相同,且感官特征有差异。随着麦芽总酸含量的升高,酿造啤酒的酸味得分呈现升高趋势,花/果香、酚香、酒精刺激感得分呈下降趋势。 相似文献
10.
分析了不同产地(加拿大、澳大利亚)、不同品种(Metcalfe、Copeland、Hind marsh、Bass、Baudin、Scope、Gairdner)麦芽淀粉酶系活力,发现加拿大麦芽淀粉酶活力普遍高于澳大利亚麦芽,且品种间存在显著差异;通过研究麦芽淀粉酶系活力与常规指标的关系,发现常规指标糖化力与β-淀粉酶与极限糊精酶活力存在显著相关性;其次,将酶系活力差异较大的麦芽按照不同比例进行搭配,分析搭配前后酶活力变化,发现搭配后3种酶活实际值均高于按比例计算的理论值,表明麦芽搭配具有协同作用;为进一步研究淀粉酶活力对麦汁糖组分的影响,模拟大生产含辅料的糖化工艺进行麦汁制备,分析配方麦芽淀粉酶活力与麦汁糖组成的关系,发现影响麦汁极限发酵度、可发酵性糖比例的关键酶为极限糊精酶。 相似文献
11.
12.
13.
14.
Brewery mashing extracts virtually all the malto-saccharides from malt, but slightly less carbohydrate is extracted than can be obtained in the laboratory. Fermentation with the ale yeast NCYC 240 results in complete removal of fermentable sugars except maltotriose which is less than half utilized. The concentration of pentosan, β-glucan and total dextrin fractions does not change significantly during fermentation. However, both β-glucan and pentosan fractions decrease very slightly during fining and filtration. The discrepancy between different values obtained for wort fermentability using a yeast method and using procedures involving the analysis of total and individual sugars is mainly due to the presence of non-carbohydrate material, which must be taken into consideration in the yeast procedure when calculating the gravities of the wort and beer. Good agreement is found between fermentability values obtained using chemical and yeast procedures when this correction is applied. 相似文献
15.
为了从源头控制下面发酵啤酒的发酵生产并提高其品质,通过啤酒发酵模拟体系,系统评价英国麦芽(Eng)、加拿大麦芽(Can)和德国麦芽(Ger)对下面发酵啤酒酿造风味的影响。分别测定了3种麦芽的品质指标及所酿啤酒的理化指标;并采用顶空固相微萃取(HS-SPME)和气相色谱质谱联用(GC-MS)法检测了所酿啤酒中风味物质组成和含量上的差异。结果表明,加拿大麦芽的库尔巴哈值(45%)、浸出率(≥77%)、糖化力(414 WK)和α-氨基酸态氮(118 mg/L)等品质指标和酒精度(2.97%vol)、原麦汁浓度(8.63 °P)、实际浓度(2.76%)、外观浓度(1.17%)、实际发酵度(67.97%)和外观发酵度(86.41%)等所酿啤酒的理化指标适中,啤酒中风味物质种类多样(75种)、相对含量丰富(271.82%)、比例协调,是最适合酿造Lager啤酒的麦芽种类。该结果可为高品质啤酒的工业化生产提供理论依据。 相似文献
16.
Elisabeth Steiner Martina Gastl Thomas Becker 《European Food Research and Technology》2011,232(2):191-204
Beer is a complex mixture of over 450 constituents and, in addition, it contains macromolecules such as proteins, nucleic
acids, polysaccharides, and lipids. In beer, several different protein groups, originating from barley, barley malt, and yeast,
are known to influence beer quality. Some of them play a role in foam formation and mouthfeel, and others are known to form
haze and have to be precipitated to guarantee haze stability, since turbidity gives a first visual impression of the quality
of beer to the consumer. These proteins are derived from the malt used and are influenced, modified, and aggregated throughout
the whole malting and brewing process. During malting, barley storage proteins are partially degraded by proteinases into
amino acids and peptides that are critical for obtaining high-quality malt and therefore high-quality wort and beer. During
mashing, proteins are solubilized and transferred into the produced wort. Throughout wort boiling proteins are glycated and
coagulated being possible to separate those coagulated proteins from the wort as hot trub. In fermentation and maturation
process, proteins aggregate as well, because of low pH, and can be separated. The understanding of beer protein also requires
knowledge about the barley cultivar characteristics on barley/malt proteins, hordeins, protein Z, and LTP1. This review summarizes
the protein composition and functions and the changes of malt proteins in beer during the malting and brewing process. Also
methods for protein identification are described. 相似文献
17.
分别采用上面发酵工艺与下面发酵工艺进行100%大麦啤酒及100%麦芽啤酒的酿制,并对其麦汁的氨基酸含量、老化Strecker醛、自由基以及新鲜啤酒中老化Strecker醛的含量等进行了对比分析。研究发现,就麦汁而言,100%大麦麦汁中老化Strecker醛的含量都明显低于100%麦芽麦汁;同样的麦汁,上面发酵方式还原Strecker醛的能力明显优于下面发酵方式。就啤酒而言,经酵母还原后,新鲜啤酒中的老化Strecker醛含量较麦汁含量低,且100%大麦啤酒中老化Strecker醛的含量低于100%麦芽啤酒中的含量。100%麦芽麦汁的自由基含量是100%大麦麦汁的近3倍。这都预示着100%大麦啤酒的风味稳定性(新鲜度)明显好于100%麦芽啤酒。 相似文献
18.
Stefan Coghe Hlne D'Hollander Hubert Verachtert Freddy R. Delvaux 《Journal of the Institute of Brewing》2005,111(1):51-60
Dark specialty malts are important ingredients for the production of several beer styles. These malts not only impart colour, flavour and antioxidative activity to wort and beer, they also affect the course of wort fermentations and the production of flavour‐active yeast metabolites. The application of considerable levels of dark malt was found to lower the attenuation, mainly as a result of lower levels of fermentable sugars and amino acids in dark wort samples. In fact, from the darkest caramel malts and from roasted malts, practically no fermentable material can be hydrolysed by pilsner malt enzymes during mashing. Compared to wort brewed with 50% pilsner malt and 50% dark caramel malt or roasted malt, wort brewed with 100% pilsner malt contained nearly twice as much fermentable sugars and amino acids. Reduced levels of yeast nutrients also lowered the fermentation rate, ranging from 1.7°P/day for the reference pilsner wort of 9 EBC to 1.1°P/day for the darkest wort (890 EBC units), brewed with 50% roasted malt. This additionally indicates that lower attenuation values for dark wort are partially due to the inhibitory effects of Maillard compounds on yeast metabolism. The application of dark caramel or roasted malts further led to elevated levels of the vicinal diketones diacetyl and 2,3‐pentanedione. Only large levels of roasted malt gave rise to two significant diacetyl peaks during fermentation. The level of ethyl acetate in beer was inversely related to colour, whereas the level of isoamyl acetate appeared to be affected by the use of roasted malt. With large levels of this malt type, negligible isoamyl acetate was generated during fermentation. 相似文献
19.
Elke K. Arendt 《Journal of the Institute of Brewing》2011,117(3):411-421
Oats are a cereal with beneficial nutritional properties and also unrealized brewing potential. Furthermore, oats can be tolerated by the majority of people who suffer from celiac disease. Malting of oats produced a malt, which was found suitable for brewing a 100% oat malt beer. The mashing regime, designed by using mathematical modelling, was successfully transferred to a pilot scale plant. The improved lautering performance of oat malt was due to its higher husk content, which also led to a lower extract content in oat wort when compared to barley wort. The protein profile of oat wort, as measured by using Lab‐on‐a‐Chip analysis, revealed that there was no significant difference in the protein profile between oat and barley wort. The fermentation of oat and barley worts followed the same trend; differences could only be seen in the higher pH and lower alcohol content of the oat beer. The flavour analysis of oat beer revealed some special characteristics such as a strong berry flavour and a lower amount of staling compounds when forced aged. This study revealed that it was possible to brew a 100% oat malt beer and that the produced beer was comparable to a barley malt beer. 相似文献
20.
Paulo J. Magalhães Pavel Dostalek José M. Cruz Luís F. Guido Aquiles A. Barros 《Journal of the Institute of Brewing》2008,114(3):246-256
Based on the health‐promoting properties of xanthohumol (XN), the production of an enriched beer in this substance would be of interest to the brewing industry, from the perspective of pointing out the benefits that beer could bring consumer health. For that purpose, in this work efforts were applied to produce a beer enriched in XN. Also investigated was the influence of a XN‐enriched hop product on the content of XN and isoxanthohumol (IXN) in pale and dark beers. It was verified that XN was largely converted into IXN during wort boiling. However, the use of dark malts revealed a positive effect on the thermal isomerisation of XN. These results are indicative of the isomerisation‐inhibiting effect of the stout production process, which resulted in high levels of XN in the beer. Further losses of XN were due to incomplete extraction from the hops into the wort, adsorption to insoluble malt proteins and adsorption to yeast cells during fermentation. It was possible to produce a dark beer enriched in XN (3.5 mg/L) by using coloured malt (caramel malt, roasted malt and roasted malt extract) and a special XN hop extract combined with late hop usage during wort boiling. 相似文献