不同种类啤酒花中黄腐酚含量的研究

以甲醇作溶剂采用超声波提取法对来自不同国家和地区的34个酒花样品中的黄腐酚进行了分离提取,并使用HPLC对其含量进行测定。结果表明不同类型的酒花之间黄腐酚含量存在很大的差异性,苦型啤酒花中黄腐酚含量要高于香型啤酒花;且酒花中黄腐酚的百分含量与α-酸的含量总体上呈现正相关的线性关系;酒花储藏时间的长短会影响黄府酚含量的高低;酒花由原花加工成酒花颗粒的过程中也会导致黄腐酚含量发生变化;此外,啤酒花的产地、年代等因素也都对黄腐酚含量有一定的影响。     

啤酒花中黄腐酚提取和纯化的研究进展

黄腐酚(xanthohumol,简称XN)是啤酒花中主要的异戊二烯基黄酮类物质,目前发现它仅存在于酒花中,其含量约占啤酒花干重的0.1%¹.2%。研究发现黄腐酚具有多种生理功效作用如抗癌、抗氧化、抗艾滋病毒等,因此从啤酒花中提取和纯化黄腐酚的研究备受关注。本文概述了近年来国内外对啤酒花中黄腐酚提取和纯化的研究进展,总结出了黄腐酚的提取纯化流程,重点介绍了多步溶剂法,色谱法,柱层析法,硅藻土吸附法,钠盐沉淀法以及重结晶法分离纯化黄腐酚的工艺,并简要分析其特点,以期为建立高效低廉的黄腐酚提取工业化生产工艺提供理论依据。     

硅胶柱层析分离啤酒花中的黄腐酚

利用硅胶柱层析法对啤酒花浸膏中的黄腐酚进行了分离,采取了2种洗脱方法。方法一是采用石油醚和乙酸乙酯固定比例(2:1)洗脱2次,第1次洗脱后合并含有黄腐酚的洗脱液,浓缩成浸膏,进行第2次洗脱;方法二是以石油醚和乙酸乙酯的混合溶剂梯度洗脱2次,第1次梯度洗脱后合并含有黄腐酚的洗脱液,浓缩成浸膏,进行第2次梯度洗脱。结果表明,方法一的分离效率高、速度快,黄腐酚得率较高(44.88%),但黄腐酚的纯度较低(57.78%);方法二的黄腐酚得率较低(43.16%),但纯度高(81.10%),部分馏分浓缩后有结晶析出,经HPLC检测为黄腐酚结晶单体,纯度达到98.1%,因此可以应用硅胶柱层析法高效分离和纯化啤酒花黄腐酚。     

国产酒花颗粒制品关键有效成分分析及在贮藏中的变化

对3个国产酒花品种青岛大花、扎一香花、马可波罗颗粒制品的的关键有效成分进行了测定并对其潜在的酿造价值进行了探讨,同时对其贮藏特性进行了研究。结果表明:3个品种的酒花颗粒制品的HSI值均高于0.35。马可波罗具有较高的酒花油和α-酸含量(分别为1.04 mL/100 g和(9.67±0.15)%),但从葎草烯/石竹烯比值、香叶烯/(石竹烯+葎草烯)比值、法呢烯的含量和α-酸/β-酸比值这3个指标来看,扎一香花具有较高的酿造价值,而马可波罗的酿造品质不佳。在惰性气体氮气条件下加速贮藏,3个品种酒花的α-酸和酒花油含量逐渐减少,但损失速率逐渐降低,β-酸、总酚、水分含量的变化无明显趋势。     

二氢异构化啤酒花浸膏的工艺优化

二氢异构化啤酒花浸膏是啤酒花中的一个主要的软树脂成分α- 酸经异构化成异α- 酸后氢化还原制备的产物,具有苦味平和、无后苦味等特点,是异α- 酸的还原产物中溶解度最好的一个产品。在正交试验的基础上,通过进一步的单因素试验考察异α- 酸加氢还原为二氢异α- 酸的工艺条件。结果表明,反应温度、催化剂NaBH4的用量、KOH 与异α- 酸的物质的量比及反应时间等都与反应产物二氢异α- 酸的收率有直接关系,其影响程度依次减弱,合成二氢异α- 酸的最佳工艺条件为氢氧化钾与异α- 酸的物质的量比1:1、NaBH4 与异α- 酸的物质的量比0.25:1、反应温度100℃、反应时间2h。在此条件下,进一步的放大实验证明,反应收率可达97% 以上。     

啤酒花苦味酸对血糖调节作用的研究

观察啤酒花超临界CO2 浸膏、β- 酸和六氢β- 酸对糖尿病小鼠血糖的调节作用。对四氧嘧啶复制的糖尿病小鼠的动物模型进行为期1w 的啤酒花超临界CO2 浸膏、β- 酸和六氢β- 酸的高、低剂量(30、15mg/kg)组和阳性药物格列本脲片灌胃治疗,观察小鼠的糖尿病“三多一少”的症状和治疗前后血糖和糖耐量的变化。与模型对照组相比,治疗组糖尿病小鼠的“三多一少”症状得到明显地改善,治疗前后血糖和糖耐量的变化结果表明,超临界CO2 浸膏和β- 酸的高剂量组治疗后的血糖值与正常组(p ＞ 0.05)无明显差异。对治疗后小鼠的血糖值采用单一自由度正交比较的方差分析表明,正常组小鼠的血糖值与模型组有极显著的差异,模型对照组与治疗组之间也具有非常显著的差异(p ＜ 0.01);在各治疗组之间,灌胃优降糖片的小鼠的治疗效果与灌胃不同剂量的β- 酸、六氢β- 酸和超临界CO2 浸膏样品的小鼠的总体治疗效果相当(p ＞ 0.05)。啤酒花超临界CO2 浸膏、β- 酸和六氢β- 酸对小鼠糖尿病症状均有一定的治疗作用,该作用与灌胃样品的剂量呈正相关关系。     

不同储藏条件下啤酒花α-酸变化趋势研究

通过不同的储藏条件研究了香型啤酒花和苦型啤酒花其有效成分α-酸的变化情况。啤酒花样品中分别加入BHT、Vc、BHT和Vc并采用真空袋封装后再用铝箔袋真空复合包装的方法,在0～-4℃、-18℃和室温(20℃)3种条件下避光保存120d,并且定期对其主要成分α-酸指标进行分析,从而确定啤酒花的最佳储藏方法。结果表明:样品中的组分都发生了不同程度的质量劣变。室温下无抗氧化剂且只用真空袋封装储藏的啤酒花的酿造价值下降最为严重。而采用加入Vc并真空复合包装后置于-18℃环境下贮藏能有效的减缓啤酒花中α-酸的损失,α-酸含量最大为初始值的92%。     

啤酒酿造过程酒花苦味物质利用率的研究

本研究采用三种不同酒花添加方案,考察啤酒酿造过程中酒花苦味物质的异构化率、利用率和损失率、在煮沸开始添加相同α-酸量的条件下．不论使用的是C02酒花浸膏还是45型酒花颗粒．它们的异构化率都为53％、研究中,另一试验在回旋沉淀槽添加100g／hL（38BU）酒花颗粒（香型）,其苦味质含量相比前四组的苦味质提高了3．5BU,而晚加酒花的异构化率仅为9．2％、研究中．发酵与过滤后酒花的苦味物质损失21．2％到32．7％．使用酒花颗粒的损失率要略高于使用酒花浸膏,酒花颗粒存在较高的多酚含量．会沉淀较多的蛋白质形成热、冷凝固物,酒花苦味物质α-酸与异α-酸会随着热、冷凝固物而被一同去除。酿造试验的最终酒花利用率范围为20．6％到23．2％。     

浓缩苹果汁加工中酶作用及贮藏稳定性研究

以红富士苹果浓缩汁为材料,采用单因素试验,研究果胶酶和α- 淀粉酶对还原糖、总酸、可溶性固形物等几个指标的影响,同时找出适合浓缩苹果汁澄清的果胶酶和α- 淀粉酶的酶用量、温度和时间。实验结果表明,在酶用量0.1%、温度50℃、时间1.5h 的条件下,浓缩苹果汁的澄清效果较明显。将加入果胶酶和α- 淀粉酶的浓缩苹果汁置于4℃和26℃条件下贮藏,测定其在贮藏过程中还原糖含量、总酸含量、pH 值和透光率等指标的变化。结果表明,在4 ℃贮藏条件下,随着贮藏时间的延长,还原糖含量、总酸含量、pH 值、透光率变化幅度较小,果汁营养成分保持较好,适宜贮藏。     

用啤酒花精提高产品质量和酒花利用率

啤酒花,又名蛇麻花、忽布(Hop),素有“啤酒之魂”的美誉。它是赋于啤酒独特的风味、清爽的苦味和丰富的泡沫之不可缺少的啤酒酿造原料。近年来,随着工业技术的飞速发展,啤酒厂家所用的酒花原料,已不仅仅是简单的整酒花。取而代之的是酒花的制成品,如酒花粉、颗粒酒花,直至当今逐渐推广开来的酒花萃取物——酒花精(或称酒花浸膏)。啤酒花精是用有机溶剂或液体二氧化碳从天然啤酒花萃取制得。它能将啤酒花中的有效成分,如软树脂和酒花油最大限度地提     

THE DETERMINATION OF α- AND β-ACIDS IN HOPS AND HOP PRODUCTS USING HPLC

A rapid reversed phase HPLC method for the analysis for α- and β-acids in hops and hop products is described and has been evaluated. The method uses citric acid in the eluent as a complexing agent to overcome the irreversible adsorption effects shown by some columns, thus allowing optimum eluent pH to be selected. The precision of the method for analysis of hop extract has been determined giving relative standard deviations of 1·0% and 2·1% for α- and β-acids respectively. General agreement with results obtained using a polarimetric α-acids analysis method for hop extracts and hops has been demonstrated.     

STABILITY OF RESINS IN PELLETISED HOPS

The α-acids content and Lead Conductance Value of hop pellets, manufactured from seedless Pride of Ringwood hops grown in Australia and stored at 5°C, 20°C or 30°C, were monitored over a twelve month storage period. No decrease in α-acids content occurred during storage at 5°C, whereas at 20°C the decrease (ca. 7%) was approximately one-third that experienced for baled hops of the same variety. At both 5°C and 20°C the Lead Conductance Value decreased at approximately one-third the rate of that in baled hops. During twelve months storage at 30°C the α-acids content of the hop pellets decreased by approximately 40% and the Lead Conductance Value by 30%. The hop pellets stored at 20°C and 30°C developed rancid odours during the twelve months storage period.     

PREPARATION OF HOP EXTRACTS RICH IN PARTICULAR CONSTITUENTS*

When a column containing powdered hops is extracted with liquid carbon dioxide, chromatographic separation of hop components occurs. They are extracted in the order essential oils, β-acids, α-acids; and the separation is enhanced when finely milled hops are extracted. Early fractions (～0·5 hour) contain a high proportion of the available essential oils when hops are extracted at ?20°C and such extracts are suitable as a replacement for dry hops. Fractions can be obtained from extractions at ～7°C which are rich in α-acids and contain low levels of β-acids. Small amounts of fats and waxes are normally present in fractions collected towards the end of a run when seeded hops are extracted.     

The impact of different hop compounds on the growth of selected beer spoilage bacteria in beer

Beer spoiling lactic acid bacteria are a major reason for quality complaints in breweries around the world. Spoilage by a variety of these bacteria can result in haze, sediment, slime, off-flavours and acidity. As these bacteria occur frequently in the brewing environment, using certain hop products that inhibit the growth of these spoilers could be a solution to prevent problems. To investigate the impact of seven different hop compounds (α-acids, iso-α-acids, tetrahydro-iso-α-acids, rho-iso-α-acids, xanthohumol, iso-xanthohumol and humulinones) on the growth of six major beer spoilage bacteria (Lactobacillus brevis. L. backi, L. coryniformis, L. lindneri, L. buchneri, Pediococcus damnosous), two concentrations (10 and 25 mg/L) of each hop substance were added to unhopped beer. The potential growth of the spoilage bacteria was investigated over 56 consecutive days. A comparison of the results shows a strong inhibition of growth of all spoilage bacteria at 25 mg/L of tetrahydro-iso-α-acids closely followed by α-acids as the second most inhibitory substance. The results showed a high resistance of L. brevis to all hop compounds as well as an inhibition of L. coryniformis and L. buchneri at low concentrations of most hop components. In comparison with the control sample, L. lindneri showed increased growth in the presence of some hop compounds (rho-iso-α-acids, xanthohumol, iso-xanthohumol, humulinones). © 2020 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling     

啤酒花活性成分与抗氧化活性的相关性

以3 个品种的萨斯特啤酒花为原料,比较了其石油醚、氯仿、乙酸乙酯、正丁醇和水相等不同极性溶剂提取物中α-酸、β-酸、总黄酮和总多酚的含量,采用?OH、1,1-二苯基-2-三硝基苯肼自由基、β-胡萝卜素-亚油酸3 种不同的抗氧化活性评价体系对各极性溶剂提取物的抗氧化活性进行了研究,并与其活性成分的含量进行了相关性分析。结果表明,啤酒花各极性部位均具有不同程度的抗氧化活性。α-酸、β-酸在石油醚相中含量较高,在3 个啤酒花样品中的含量范围分别为α-酸444.29～583.81 mg/g、β-酸131.83～293.19 mg/g,在氯仿相中含量相对较低,其余提取物中均未检出;相关性研究表明α-酸、β-酸是石油醚和氯仿相抗氧化活性的主要物质基础。中等极性和极性较大溶剂提取物中啤酒花总黄酮、总多酚含量较高,相关性研究也表明黄酮、多酚类物质是这类提取物抗氧化活性的主要物质基础;其中,3 个啤酒花样品中总黄酮、总多酚在乙酸乙酯相中含量最高,分别为20.43～24.13 mg/g和34.97～40.24 mg/g,正丁醇次之,分别为9.45～11.68 mg/g和12.12～19.14 mg/g。     

QUANTITATIVE ANALYSIS OF HOPS AND HOP EXTRACTS BY HIGH PRESSURE ION EXCHANGE CHROMATOGRAPHY

A new analysis for hop acids in hops and hop extracts is described. It is based on recent developments in high pressure liquid chromatography using pellicular anion exchange column filling material. Quantitative evaluation of α-acids, β-acids and oxidation products in hops and hop extracts is carried out by standard addition of pure humulone. The α-acids are completely separated from other hop substances before quantitation. The results of α-acids determinations must therefore be more accurate than was formerly possible and they are compared with conductometric titration results which are systematically higher. This is to be expected as it becomes more and more obvious that paper strip and conductometric analysis are not selective enough and determine fractions as “α-acids” which are in fact oxidation products of the hop acids.     

ESTIMATION OF α-, β- AND ISO-α-ACIDS IN HOPS,HOP PRODUCTS AND BEER USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Methods are described in which high performance liquid chromatography (HPLC) is used to estimate α-, β- and iso-α-acids in hops, hop products and beer. The chromatography relies on an isocratic elution of components from a polythene ‘cartridge’ column, and the method is calibrated with the pure substances as primary standards. Using such a column over 1000 analyses have been carried out without any significant loss in resolution or precision. The procedures are sufficiently rapid for use in commercial transactions and for quality control purposes. For hops and hop extracts coefficients of variation (%) of 2·5 and 0·8 were obtained respectively for α-acids. Values of 0·9 and 0·3 were obtained for iso-α-acids in isomerised extracts and beers respectively. For some isomerised extracts it has been observed that peaks in addition to those given by the iso-α-acids are present on the chromatogram. The current method recommended by the EBC over estimates the iso-α-acid content since these other constituents are included in the analysis.     

老化的颗粒酒花对啤酒发酵抗氧化能力的影响

分析老化后酒花的主要成分,研究发现在酒花老化过程中α酸和β酸发生氧化降解,前期生成异α酸,随着老化的进行,继而产生葎草灵酮(humulinone)和希鲁酮(hulupones)等衍生氧化物。酒花中的总多酚含量逐渐减少,具有抗氧化性的酚酸也发生氧化聚合,使用液相色谱检测几乎无响应峰。并测定总多酚、DPPH清除率、TRAP值、TBA值等抗氧化指标来分析老化的酒花对麦汁和啤酒的抗氧化能力影响,实验发现老化的酒花对麦汁和啤酒的抗氧化能力影响较大,尤其是风味稳定性系数SI值,波动最为明显。     

玉米萌发过程中淀粉酶性质的研究

本实验研究了玉米萌发过程中各种因素对其中所含淀粉酶活力的影响,并研究了最佳萌发条件下,总淀粉酶、α-淀粉酶和β-淀粉酶活力的变化情况,通过SDS-PAGE凝胶电泳确定了α-淀粉酶和β-淀粉酶的分子量,以SephadexG-100色谱对两种酶进行了分离。结果表明,水分含量、温度、光照以及赤霉素等因素对玉米淀粉酶活力均有影响,在水分35%、温度30℃、赤霉素30mg/L和自然光照条件下萌发,玉米的淀粉酶活力最高;在萌发过程中,α-淀粉酶活力增加得比较缓慢,而且活力也大大低于β-淀粉酶,总淀粉酶和β-淀粉酶活力上升都比较迅速;β-淀粉酶的分子量为189.82×103D,α-淀粉酶的分子量为54.26×103D。