荔枝酒酿造中酿酒酵母同步代谢醋酸的研究

以具有强降酸及耐高浓度酒精能力的酿酒酵母为出发菌株,研究荔枝酿酒过程中同步代谢挥发醋酸的机制。结果表明：酿酒酵母代谢醋酸的量随着起始醋酸浓度的增加先升后降,在初始醋酸浓度为1.5 g/L时,酿酒酵母对醋酸的代谢率最大达48.0％,发酵结束时醋酸含量为0.78 g/L。酿酒酵母代谢醋酸的最快速度是在对数期。醋酸对酿酒酵母主要代谢产物的影响表现为酿造过程中产生了较少的甘油、较高的乙醛和乙醇。丙酮酸脱羧酶（PDC）、乙醇脱氢酶（ADH）、乙醛脱氢酶（ALDH）及乙酰辅酶A合成酶（ACS）酶比活性的变化与乙醇、甘油、乙醛及醋酸含量的变化相一致。酿造过程中存在过量醋酸时,酿酒酵母ACS酶比活性进一步增强,说明过量醋酸的代谢与通过调节酿酒酵母提高其ACS酶活性有关。     

香蕉果酒接种发酵和自然发酵过程中乳酸菌菌落变化及有机酸代谢特征

香蕉营养丰富、活性物质含量高，可作为深加工产品的优质原料。香蕉果酒是香蕉精深加工产品中的重要一类。由于香蕉果浆碳水化合物含量较高、酸度低、糖分高，其酿造过程中适宜各种微生物的生长繁殖，特别是乳酸菌数量的变化与酸类物质的产生密切相关。乳酸菌群落的变化容易增加发酵过程的风险，造成香蕉酒挥发酸含量超标、品质低下等不良结果。因此明确香蕉果酒发酵过程中自然存在的乳酸菌的生长繁殖规律及其对有机酸代谢的影响，可为精准调控发酵过程、提高产品质量提供理论依据。试验设置商业酵母Lalvin K1^TM接种发酵过程（K1）与香蕉果汁自然发酵过程（SF）2组对比，采用实时定量PCR方法和高效液相色谱法对香蕉汁接种发酵（K1）与自然发酵过程（SF）中酵母菌、乳酸菌的生长规律以及有机酸的含量变化进行监测。结果表明：2种发酵处理下，酵母菌和乳酸菌的生长规律有差异；K1酵母菌主导的发酵过程中，乳酸菌的生长受到显著抑制，最大生长量仅为4.0×10⁶ CFU/mL，而酵母菌生物量为1.2×10⁷ CFU/mL；在自然发酵过程中，乳酸菌与酵母菌的生长周期完全错开，但对乳酸菌的生物量无显著影响，乳酸菌与酵母菌的生长量分别达到1.0×10⁷ CFU/mL和1.6×10⁷ CFU/mL。2种发酵过程均表明，酵母菌和乳酸菌的生长存在竞争与抑制关系；有机酸代谢主要与乳酸菌菌落数量相关，不同有机酸的总体变化趋势一致；在发酵过程中，乳酸含量逐渐增加，乙酸含量呈先增后降的趋势，二者在自然发酵样品中的累积量均高于接种发酵；柠檬酸、苹果酸、酒石酸含量整体呈下降趋势。     

甘蔗白酒发酵工艺对产酒和产酯影响的研究

采用甘蔗为原料,榨取甘蔗原汁经加热灭菌后,以选育的甘蔗汁专用酿酒酵母GSIRI-FLA和高产酯异常汉逊酵母GIM2.20为试验菌株,研究分段发酵工艺条件对甘蔗白酒发酵产酒和产酯(香)的影响.研究结果表明:以酿酒酵母菌种先发酵,后加高产酯异常汉逊酵母菌种发酵的发酵工艺,产酒产酯能达到最佳,酿造的白酒保留了甘蔗特有的呈香物质,具有浓郁的蔗香味.     

不同调酸剂对水稻育秧基质调酸效果及对秧苗生长的影响

育秧基质合适酸碱度(pH值)不仅有利于水稻正常生长,同时有利于预防水稻病害.因此,研究不同类型调酸剂对育秧基质的调酸效果,以及育秧过程中对水稻生长的影响很有必要.以我们自己研制的发酵基质作为研究对象,分别添加不同浓度的柠檬酸、稀硫酸、硫磺、磷酸二氢铵,测定基质的pH值和电导率(EC值).播种后12 d取样,结果发现:(...     

用糖蜜生产酒精如何减少蒸馏塔积垢

近年不少以糖蜜为原料生产酒精的蒸馏塔出现积垢很多，有时甚至阻塞，致使停止蒸馏洗塔；有些厂为了避免或减少频繁洗塔而采用“无酸发酵”。本来加酸主要目的是调节酵母生长和发酵的适宜pH值（pH4左右，越偏中性，产甘油越多），另一目的是抑制染菌，（因为细菌适宜繁殖的条件是中性和温度超过35℃）另外还起到凝聚胶体物，降低糖蜜粘度等作用。     

五指山绿茶酒的研制

以五指山绿茶为原料,研究绿茶汁的浸提工艺和绿茶酒的发酵工艺。通过单因素试验,确定最佳浸提条件为：茶水比1∶70(g/mL),浸提温度85℃,浸提10 min,所得的茶汁感官品质良好。通过正交实验优化得到绿茶酒的最佳发酵工艺条件为：酵母接种量0.05%,蔗糖添加量190 g/L,初始pH值4.0,发酵温度28℃。在此条件下生产的绿茶酒色泽黄绿透明;酒香淡雅,茶香怡人;酒体丰满,酸甜适口;具有本品独特的风格。     

辣木引种试种研究初报

以三个辣木品种（系）为试材，分别进行催芽、育苗和定植，观测并研究不同催芽基质、不同育苗天数和不同定植方式对辣木生长的影响。结果表明，以珍珠岩为基质，催芽效果最好；育苗25天，苗高30～40 cm时最适宜定植；大营养袋种植方式生长速度优于大田种植；三个品种（系）在催芽和育苗阶段生长速度有差异，定植后无差异。     

红麻杆配制的基质对白掌生长的影响

以红麻杆作为盆栽基质组成材料,设计6种不同红麻杆含量的基质配方,研究其对白掌生长的影响。结果表明：不同配方的基质对白掌的生长速度、叶片数及根部生长情况均有显著的差异,其中以20%园田土＋19%红麻杆＋60%泥炭＋1%珍珠岩配方对白掌的生长效果最佳。     

云蔗03-194甘蔗组培快繁技术

以甘蔗新品种云蔗03-194的幼嫩叶片作为外植体,采用不同2,4-D浓度对幼嫩叶片的切片进行愈伤诱导,以不同6-BA和KT激素配比对甘蔗愈伤进行分化诱导和增殖培养,以不同NAA浓度及香蕉汁添加量诱导甘蔗组培苗生根。结果表明:适宜甘蔗幼嫩叶片愈伤诱导的培养基为MS+2,4-D 1.5mg/L,诱导分化培养以MS+6-BA1mg/L+KT 0.5 mg/L为宜,增殖培养以6-BA 2.0 mg/L+KT 1.0 mg/L为宜,适宜的生根培养基为MS+NAA 1.5mg/L+30mL香蕉汁。以河沙:红壤土(2∶1)为假植基质,假植成活率达92%～96%,植株生长健壮,长势良好。     

接触刺激在水稻根不对称生长中的作用

为探究接触刺激与 2,4 表油菜素内酯（2,4-Epibrassinolide，2,4-eBL）诱导的水稻（Oryza sativa L.）根不对称生长之间的关系，本研究采用悬吊培养法和根冠蘸蜡法模拟接触刺激的有无。结果表明：仅有 2,4-eBL 或接触刺激存在时，水稻根不对称生长比例较低，不超过 9.7%；而当 2,4-eBL 和接触刺激同时存在时，水稻根不对称生长比例高达 90.7%。采用根冠蘸蜡法模拟接触刺激也得到类似结果。本文研究外源施加 2,4-eBL 诱导水稻根不对称生长的现象及在此过程中接触刺激发挥的关键作用，为探究油菜素类固醇（Brassinosteroids，BRs）与接触刺激之间的关系提供新见解。     

An analysis on flavonoids, phenolics and organic acids contents in brewed red wines of both non-skin contact and skin contact fermentation techniques of Mao Luang ripe fruits (Antidesma bunius) harvested from Phupan Valley in Northeast Thailand

The experiment was carried out at the Department of Biotechnology, Faculty of Technology, Mahasarakham University, Northeast Thailand during the 2006. The study aimed to determine amounts of flavonoids, phenolics and organic acids in ripe fruits and brewed red wines of both non-skin contact and skin contact winemaking techniques where Mao Luang ripe fruits of both Fapratan and Sangkrow2 cultivars were used. The experiment was laid in a Completely Randomised Design (CRD) with four replications. The results showed that mean values of primary data of fresh Mao Luang ripe fruits on weight of 100 berries (g) and mean values of juice:solids, pH, total soluble solid (TSS, 0brix), total organic acids (TOA, mg L(-1)), TSS:TOA (%), total flavonoids contents (TFC, mg L(-l)), total phenolic acids (TPA, mg L(-1)), total procyanidins contents (TPC, mg L(-1)) and reducing sugar (g L(-1)) were 65.62, 3.28, 3.51, 16.50, 49.36, 28.10, 397.90, 76.04, 156.21 and 184.32, respectively. Skin contact Mao Luang red wine gave higher amounts of flavonoids, phenolic acids, anthocyanins of procyanidin B1 and procyanidin B2, organic acids than non-skin contact red wine. The differences were highly significant. Furthermore, ethanol (%) and total acidity (g L(-1) citric acid) were much higher for skin contact wine than non-skin contact wine but a reverse was found with total soluble solids (0brix), pH where non-skin contact wine gave higher mean values than skin contact wine.     

番石榴果汁饮料加工技术

以台湾珍珠番石榴为原料,研究番石榴果汁饮料的加工技术,确定工艺流程,产品的配方和最佳工艺参数。结果表明:打浆前添加质量浓度1.0-1.2 g/L,的维生素C,对番石榴原汁有较好的护色效果;采用1.0 g/L黄原胶+1.0 g/LCMC的复合稳定剂和10 min,4 000 r/min的离心条件,产品有较好的稳定性;以质量浓度250 g/L的番石榴原汁,30:1的糖酸质量比,质量浓度60 g/L,的白砂糖,质量浓度2.30 g/L的柠檬酸,质量浓度20 g/L的蜂蜜为配方可加工出风味独特的番石榴果汁饮料。     

菠萝蜜果醋发酵工艺的优化及香气成分分析

为了提升菠萝蜜的产品附加值,进一步丰富市场中果醋种类,本研究以菠萝蜜为原料,对菠萝蜜果醋发酵工艺进行优化并分析其香气成分。通过单因素试验探讨醋酸菌接种量、发酵温度、乙醇体积分数、初始pH 4个因素对菠萝蜜果醋产酸量的影响,然后采用4因素3水平的响应面设计优化得到最佳发酵工艺。结果表明,菠萝蜜果醋的最佳发酵工艺条件为醋酸菌接种量11%、发酵温度32 ℃、乙醇体积分数5%、初始pH 3.3,在此条件下菠萝蜜果醋的醋酸含量达(44.20±0.41)g/L。采用顶空固相微萃取法（head space-solid phase microextraction, HS-SPME）结合气相色谱-质谱联用技术（gas chromatography-mass spectrometry, GC-MS）,对菠萝蜜果醋的香气成分进行分析,检测出香气成分67种,主要成分是乙酸（26.15%）、乙酸异戊酯（12.78%）、异戊醇（11.01%）、乙酸乙酯（10.99%）、苯乙醇（4.72%）、正癸酸（3.61%）、苯甲醛（3.34%）、乙酸苯乙酯（3.12%）、辛酸（3.08%）、异戊酸（1.31%）、月桂酸乙酯（1.07%）。通过菠萝蜜果醋发酵工艺的优化和香气成分分析,制备出符合相关国家标准和行业标准的新型果醋,初步探明了果醋中香气成分的种类。     

嗜热脂肪土芽孢杆菌CHB1的5 L发酵罐发酵条件初探

优化嗜热脂肪芽孢杆菌CHB1的5 L发酵罐发酵条件。通过单因素法优化发酵罐的通气量、转速、温度、pH等参数，并测定CHB1在5 L发酵罐中的生长曲线。结果表明，最佳发酵条件为：转速180 r/min、通气量6 L/min、发酵温度58 ℃、接种量4％，发酵过程自动流加乙酸控制pH值为8.0，培养21 h。采用自动流加乙酸控制pH值的方法，效果显著，控制pH值为8.0时，发酵效果最好，细胞生物量高达6.07×108 cfu/mL，约是不控制pH值发酵的对照组（3.5×108 cfu/mL）的2倍。     

The suitability of African bush mango juice for wine production

A good quality wine was produced from African bush mango (Irvingia var.gabonensis). Analysis of the African bush mango juice showed that it contained 3.6% total sugar, 1.09% protein, 4.2° Brix soluble solids (SS) 0.5% ash, 50.24% total solids (TS), 66.7 mg/100 ml ascorbic acid and pH 5.12. The juice ameliorated to 23° Brix was inoculated with 3% (w/v) Baker's yeast (Saccharomyces cerevisiae) and held at 30±2°C for 28 days. SS and pH decreased while titratable acidity (TA) increased with increasing period of fermentation. Fermentation was 110% efficient. The wine produced had 8.12% (v/v) alcohol, 0.78% protein, 6.5% Brix SS, 0.64 g/100 ml TA, and a pH 3.10. Sensory evaluation results showed that there was no significant difference (p=0.05) in colour, mouthfeel, sweetness, flavour and general acceptability, between African Bush mango wine and a reference wine. The wine was generally accepted.     

2个荔枝品种胚性愈伤组织诱导体胚发生过程的细胞学观察

以’新球蜜荔’和’大丁香’2个荔枝品种胚性愈伤组织为材料,利用石蜡切片技术研究了’新球蜜荔’和’大丁香’接种在TD(MS+0.1 mg/L NAA+0.5 mg/L TDZ+0.1 g/L肌醇+0.4 g/L水解乳蛋白(LH)+100 m L/L椰汁+60 g/L蔗糖+10 g/L琼脂)培养基(XQTD和DDXTD)与’新球蜜荔’接种在TX(MS+0.1 mg/L NAA+5 mg/L ZT+0.1 g/L肌醇+0.4 g/L水解乳蛋白(LH)+100 ml/L椰汁+60 g/L蔗糖+10 g/L琼脂)培养基(XQTX)上各培养物体胚发生过程中细胞学变化。结果显示:XQTD从6 d开始变褐,9 d时观察到球状凸起,石蜡切片中观察到球形胚结构,12~21 d时观察到球形胚、心形胚和鱼雷形胚等不同形态体胚;而DDXTD从9 d开始逐渐变褐,15~21 d时石蜡切片中能看到少量的球形胚和心形胚。XQTX在第12 d时观察到有完整原形成层的球形胚,21 d时石蜡切片中观察到子叶形胚。2个荔枝品种的体胚发生过程中都观察到内起源和外起源两种起源方式,体胚发生均为单细胞起源,都经历了球形胚、心形胚、鱼雷形胚和子叶形胚等相似的发育过程。     

The effect of some acid-based additives applied to wet grass crops under various ensiling conditions

Some acid‐based silage additives, which are less corrosive and easier to handle than Formic acid 85% (FA), were evaluated in a laboratory‐scale silage experiment. These were Foraform (645 g kg^–1 formic acid, 60 g kg^–1 NH₃), Ensimax [213 g kg^–1 formic acid, 200 g kg^–1 acetic acid, 190 g kg^–1 of dry matter from wood pulp liquor with a high concentration of lignosulphonates (WPL)], and a modified version of Ensimax with a higher proportion of formic acid and a lower proportion of acetic acid. Each single ingredient, and all combinations of ingredients in the original Ensimax, were studied when applied in the quantities they make up in the additive. Untreated silage was used as a negative control and FA as a positive control. The additives were assessed using three different crops and by sealing the silos immediately after filling or after a 24 h delay. Both the full and half of the recommended application rates of the additives and of the single ingredients of Ensimax were studied. No significant differences were found between FA and Foraform when applied at 3 and 4 l t^–1, respectively, which provided the crop with the same dose of pure formic acid. Inclusion of WPL in Ensimax did not influence silage fermentation, i.e. the effect of Ensimax could be ascribed to the effect of formic plus acetic acid alone. Compared with Ensimax, the modified version, in which 148 g kg^–1 of formic acid was substituted for 150 g kg^–1 of acetic acid, clearly improved fermentation in terms of increased concentration of true protein, reduced fermentation of acetic and propionic acid, and reduced ammonia value and pH. When the silos were sealed immediately, sugar concentrations in the silage correlated positively with the application rate of acids, whereas no such relationship was found when the sealing was delayed for 24 h. No consistent relationship was found between the application rate of acids and ethanol concentrations in the silage. Easy‐to‐handle acidic additives like Foraform and Ensimax may replace FA when applied according to their molar concentration of acids. This means that 4·0 l t^–1 of Foraform and 7·3 l t^–1 of Ensimax are equivalent to 3 l t^–1 of FA.     

Use of Red Blood Cell Membranes to Evaluate the Antioxidant Potential of Plant Extracts

Antioxidant phytochemicals in fruits and vegetables of a vegetarian diet may account for the reduced risk of aging and stress oxidative associated diseases. In this study, a simple, rapid and accurate new bioassay for the determination of the antioxidant activity of purified or crude plant extracts and thier interactions is described, based on the fluorimetric determination of thiobarbituric acid reactive substances (TBARS) released by UV-B radiated red blood cell (RBC) ghosts. Pure resveratrol, white and red wine and pomegranate juice (PJ) were used as antioxidant source to test the biological method. TBARS production is a function of radiation time, the number of RBC ghosts in the radiated sample and the loaded antioxidant. The antioxidant activity of resveratrol was detected at a submicromolar concentration range [0.02 μg/mL–0.1 μmol/L]. The activity of red wine was almost 10 times higher than that of white wine, and PJ juice had the highest activity. Submaximal protective effects of PJ and red wine were additive.