【作者】 王妮娅；

【导师】 杜金华；

【作者基本信息】 山东农业大学 ， 食品科学， 2008， 硕士

【摘要】 啤酒是世界上最重要的低酒精度饮料酒。本文研究了发酵度、麦汁α-AN含量、小麦芽使用量对8oP啤酒酿造的影响。主要研究结果如下:1用8oP定型麦汁,采用下面发酵法酿造4种成品啤酒(发酵度分别为57.6%、63.4%、67.9%、72.5%)。在相同条件下,进行发酵试验并跟踪主发酵过程总酸、pH值、α-AN、酒精度、还原糖与真正浓度的变化。发酵延滞期均为1天,总酸先降后升,pH值、α-AN、还原糖与真正浓度逐渐降低,酒精度逐渐升高。成品酒中α-AN残留量随发酵度升高而增加,为麦汁的12.3%～19.4%;pH值下降1.79～1.89;总酸、还原糖含量随发酵度升高而增加,分别为0.62～0.77mL/100mL 0.1mol/L NaOH与3.2～4.80g/L。浊度随发酵度的增加而降低,色度变化不大。感官品尝显示发酵度为57.6%时,8oP啤酒风味最佳。2使用RP-HPLC检测到啤酒中9种主要有机酸,并测定了成品啤酒的缓冲容量。使用SAS9.0统计软件对成品啤酒中有机酸与缓冲性之间的相关性进行了分析,结果显示乳酸与缓冲性极显著相关,相关系数为-0.99008(P﹤0.01);α-酮戊二酸与缓冲性显著相关,相关系数为-0.96944(P﹤0.05);富马酸、琥珀酸与缓冲性一般相关,相关系数分别为0.91313、0.93816(P﹤0.10)。3使用酵母营养盐将8oP定型麦汁的α-AN含量调整为109.0、120.5、130.1、139.3、148.5、159.5mg/L,接种啤酒酵母进行发酵,酿造了6种成品啤酒。原浓为7.86～8.10oP之间、酒精度为3.71～3.83%(v/v)、真发为58.13～59.20%。SAS9.0统计结果表明,麦汁α-AN与原浓、真浓、色度显著正相关(P<0.05);与还原糖一般相关(P<0.1);与啤酒总酸(1.40～1.70mL/100mL 0.1mol/L NaOH)一般相关(P<0.1);啤酒总氮及啤酒α-AN呈极显著正相关性(P<0.01)。使用气相色谱检测啤酒中的风味物质(醇类、醛类、酮类、酯类、酸类、烷烃类等),并对所有风味物质与麦汁α-AN之间的关系进行分析,发现异丁醇、异戊酸与麦汁α-AN极显著相关(P﹤0.01);活性戊醇+异戊醇、庚酸乙酯、辛酸、四甲基吡嗪与麦汁α-AN显著相关(P﹤0.05);3-羟基-2-丁酮、乙醛、庚酸与麦汁α-AN一般相关(P﹤0.1)。感官品尝显示8oP啤酒麦汁α-AN含量为120.5mg/L时,风味最优。α-AN含量超过130mg/L时,口味尚纯正,但有特殊酯香味,并且双乙酰含量较高。4按0、5、10、15、20%的比例添加小麦芽进行糖化,将所得麦汁调为8oP后,进行分析。研究发现随着小麦芽用量的增加,阿拉伯木聚糖、β-葡聚糖含量呈上升趋势,粘度逐渐增大,过滤速率逐渐减小,还原糖与α-AN呈下降趋势。使用SAS9.0分析发现各指标之间以及各指标与小麦芽用量之间具有较好的相关性。对糖化曲线中各个点取样分析,研究得到52℃时阿拉伯木聚糖含量最高(1556.25～1601.56mg/L);β-葡聚糖在78℃含量最高(57.45～82.02mg/L);还原糖含量在63℃、72℃、78℃时含量相近,在35.08～37.29g/L之间。5在糖化过程中按0%、5%、8.5%、10%的小麦芽添加量制备了4种8oP麦汁,接种啤酒酵母进行发酵。研究发现小麦芽用量对啤酒中主要的风味物质醇、醛酸、酯、有机酸的生成量无显著影响;也不影响啤酒的感观指标。更多还原

【Abstract】 Beer is one of the most important low alcohol beverages in the world. In this research, real attenuation, the content ofα-AN and dosage of wheat malt were studied to investigate the effects of 8oP beer’s brewing. The main results were as follows:1 Four beers (the real attenuations was 57.6%, 63.4%, 67.9%, 72.5%, respectively) were brewed by bottom fermentation using 7oP wort. The brewing were carried on under same conditions while some indexes including total acid, pH value,α-AN, alcoholic, reducing sugar and real extract content were determined at one day interval during the main fermentation. After one day’s lag phase, the total acid decreased firstly and then increased after two days fermentation. The pH value,α-AN, reducing sugar and real extracts content decreased gradually while alcoholic continuously increased. The residueα-AN of finished beer enhanced with the increasing of real attenuation, which was equal to 12.3%～19.4% that of wort; The pH value was decreased by 1.79~1.89; Total acid and residue reducing sugar enhanced with the increasing of real attenuation and their contents were 0.62~0.77 mL/100mL 0.1mol/L NaOH and 3.2~4.80g/L, respectively. Turbidity of beer decreased with the increasing of real attenuation and the chroma didn’t change significantly. Sensory evaluations show that 8oP beer with 57.6% real attenuation had best sensory quality.2 Four 8oP beers (real attenuation was 57.6%, 63.4%, 67.9% and 72.5%, respectively) were brewed by bottom fermentation method. Nine organic acids in beers were detected by reversed phase high performance liquid chromatography (The recovery of addition standards were 92.07~108.85 and coefficients of variation were 0.803~1.706). The buffer capacity of beers was detected too. Correlativity between organic acids and buffer capacity was analyzed by SAS 9.0. The conclusions were that lactic acid had great significant correlation with buffer capacity and the correlation coefficient was -0.99008 (P﹤0.01);α-ketoglutaric acid had significant correlation with buffer capacity and the correlation coefficient was -0.96944 (P﹤0.05); fumaric acid, succinic acid had commonly correlation with buffer capacity and the correlation coefficients were 0.91313、0.93816 (P﹤0.10) respectively.3 Six 8oP beers (α-AN of wort were 109.0, 120.5, 130.1, 139.3, 148.5, 159.5mg/L, respectively, which were adjusted by yeast nutriment ) were brewed by bottom fermentation method. Relationships between wortα-AN and their physical and chemical index, such as original gravity (7.86~8.10oP), alcohol content (3.71~3.83%, v/v), real attenuation (58.13~59.20%), were analysed by SAS9.0. The results indicated that there were significant correlations between wortα-AN and original gravity, real gravity, and chroma (P<0.05). And wortα-AN positively related with reducing sugar of beers (P<0.1). The total acid (1.40~1.70mL/100mL 0.1mol/L NaOH) had commonly correlation with wortα-AN (P<0.1). The total nitrogen,α-AN had extremely significant positively related with the wortα-AN (P﹤0.01).Flavor matters including alcohols, aldehydes, ketones, esters, acids, alkanes were detected by gas chromatography. Correlativity between all flavor matters andα-AN contents were analyzed by SAS 9.0. The conclusions were that isobutanol and isovaleric acid had very significant correlation withα-AN (P﹤0.01); alcohol + isopentanol, ethyl heptanoate, caprylic acid, tetramethylpyrazine significant correlation withα-AN (P﹤0.05); acetaldehyde, acetoin, heptoic acid had commonly correlation withα-AN (P﹤0.1). Sensory evaluation showed that the beer with 120.5 mg/Lα-AN had the best flavor.4 Five 8oP worts were prepared by using different dosage of wheat malt (0%, 5%, 10%, 15%, 20%) in saccharification and the indexes were analyzed. With the increasing dosage of wheat malt, Arabinoxylan andβ-glucan had an ascending tendency, viscosity increased gradually while filtration rate decreased, reducing sugar andα-AN showed a decreasing tendency. Correlativity between each index of wort and the dosage of wheat malt and indexes of wort were analyzed by SAS 9.0. The conclusions were that there better correlation between each index and dosage of wheat malt and each index. Sampling and analysis of each temperature point in saccharification curve, the maximum content of Arabinoxylan was found at 52℃(1556.25~1601.56mg/L);β-glucan had the maximum content at 78℃(57.45~82.02mg/L) and reducing sugar had similar content at 63℃, 72℃、78℃(31.54~42.62g/L).5 Four 8oP worts were prepared by using 5%, 7%, 8.5% and 10% wheat malt dosage, inoculated with bottom beer yeast. The research results showed that adding up to 10% of wheat malt did not affect the flavor compounds such as alcohols, aldehyde acid, and organic acids, and esters. And it did not affect the sensory characteristic of beers.更多还原