Investigation of Potential Taste Reduction of Catechin and Grape Seed Dimeric Phenols in Water by Wine Proteins

Soluble glycoproteins were isolated from Semillon wines made over a 5-y period, from 1990 to 1994, by precipitation with ammonium sulfate and fractionated by chromatography on Sephadex G-100. The total phenols were extracted with 50% aqueous ethanol from Semillon seeds, and the four seed phenol fractions (catechins, dimeric phenols, and oligomeric and polymeric tannins) were fractionated by diatomaceous earth partition chromatography of the total phenols. The proteins, catechin, and dimeric fraction alone appeared unchanged during storage in a wine-like model solution (aqueous 10% ethanol solution of pH 3.0) at 20 °C from 3 to 48 ch. However, the oligomeric and polymeric tannins, as well as the total phenols, gave rise to appreciable turbidity. The possible sensory effects of added proteins were investigated using paired comparisons between pure compounds (catechins and dimers) and the same compounds mixed with proteins. The hypothesis was that the proteins would decrease the taste of the catechins and dimers by decreasing their availability to interact with the taste receptors. Results corroborated the hypothesis when lower concentration of phenols and proteins were used. However, at higher concentrations, the reverse trend was observed. It is hypothesized that higher protein concentrations increased the total taste intensity by adding a taste of their own.     

红葡萄酒中单宁分析方法与感官收敛性的关系

研究目的是使用多种分析方法评价红葡萄酒收敛性与单宁浓度之间的相互关系。选择40个红葡萄酒样品,使用不同的分析方法测定单宁含量,包括在280nm处的吸光度、4-二甲基氨基肉桂醛、蛋白质沉淀、间苯三酚反应以及凝胶渗透色谱法,结果显示：红葡萄酒中单宁测定方法与感官收敛性之间存在明显差异。感官收敛性与蛋白质沉淀方法的相关性最大（r^2=0.82）,其次为间苯三酚法（r^2=0.73）和凝胶渗透色谱法（r^2=0.74）,表明蛋白质沉淀法是感官收敛性最有用的分析方法。     

葡萄酒MLF高耐受性优良乳酸菌的筛选与鉴定

以活菌数为指标,以L450为对照菌株,考察了从自然发酵葡萄酒中分离的14株乳酸菌对酒精度、SO2浓度、p H值的耐受能力,筛选出高耐受性优良菌株。通过菌落形态、菌体形态、生理生化特征和16S r DNA分子测序进行优良菌株鉴定。结果表明:菌株G23与L42综合耐受能力最强且优于对照菌株L450,二者被鉴定为植物乳杆菌,可作为葡萄酒MLF高耐受性优良乳酸菌。     

Storage Stability of Chicken as Affected by Map and Lactic Acid Treatment

The effects of MAP and/or pretreatment with lactic acid buffer were studied on the shelf-life of broiler carcasses, under conditions simulating market storage (4 and 7°C) in the State of Kuwait. Pretreatment with lactic acid buffer increased treated carcass shelf-life by 6–7 days when stored at 4°C and 5–6 days at 7°C. Likewise, pretreatment of MAP carcasses with the same buffer extended the shelf-life to >36 and 35 days, compared with 22 and 13 days for the untreated MAP carcasses. Pretreatment of poultry with lactic acid buffer, with or without MAP, provides a potential alternative for improving the storage quality of poultry.     

Astringency,bitterness and color changes in dry red wines before and during oak barrel aging: An updated phenolic perspective review

To understand effects of using oak barrels on the astringency, bitterness and color of dry red wines, phenolic reactions in wines before and after barrel aging are reviewed in this paper, which has been divided into three sections. The first section includes an introduction to chemical reactivities of grape-derived phenolic compounds, a summary of the phenolic reactions that occur in dry red wines before barrel aging, and a discussion of the effects of these reactions on wine astringency, bitterness and color. The second section introduces barrel types that determine the oak barrel constituents in wines (primarily oak aldehydes and ellagitannins) and presents reactions between the oak constituents and grape-derived phenolic compounds that may modulate wine astringency, bitterness and color. The final section illustrates the chemical differences between basic oxidation and over-oxidation in wines, discusses oxygen consumption kinetics in wines during barrel aging by comparing different oxygen consumption kinetics observed previously by others, and speculates on the possible preliminary phenolic reactions that occur in dry red wines during oak barrel aging that soften tannins and stabilize pigments via basic oxidation. Additionally, sulfur dioxide (SO₂) addition during barrel aging and suitability of adopting oak barrels for aging wines are briefly discussed.     

两种乳酸菌在干红葡萄酒中MLF的比较

将两种乳酸菌MBR和VINIFLORA分别接种于赤霞珠干红葡萄酒中进行苹果酸-乳酸发酵(MLF).结果表明,在试验条件下,乳酸菌MBR的降酸幅度和降酸速率均高于乳酸菌VINIFLORA;MBR产生的挥发酸低于乳酸菌VINIFLORA;pH值变化在正常范围内;影响MLF的主要因素是SO2的含量和pH值的高低.说明在进行MLF时,乳酸菌MBR的发酵特性优于乳酸菌VINIFLORA.     

国内外红葡萄酒氨基酸含量比较分析与研究

应用日立L-8800型氨基酸自动分析仪,色谱条件：标准分析柱4．6mm×60．0mm,反应柱温度57．0℃,反应器温度135．0℃。测定了国内外16个品牌的红葡萄酒。结果表明,红葡萄酒中含脯氨酸、苏氨酸、赖氨酸等17种氨基酸,其中以脯氨酸含量最高,约占17种氨基酸总量的54．8％～90．6％。测定的7种国外品牌红葡萄酒和9种国产品牌红葡萄酒对比研究结果显示,氨基酸组成和含量十分接近。     

Aroma Composition of a White Wine of Vitis vinifera L. cv. Emir as Affected by Skin Contact

Free and glycosidically bound flavor compounds of a white wine from cv. Emir were analyzed by GC-MS, and 75 compounds were identified. The wine was high in volatile phenols. Skin-contact with the juice before fermentation increased amounts of free and glycosidically bound flavor compounds. Quantities of certain compounds were significantly different between control and skin-contact wines.     

原生质体电融合法构建葡萄酒降酸酵母的研究

以发酵性能优良的葡萄酒酵母F83和具有降解苹果酸能力的酒类酒球菌作为亲本菌株,进行电融合,构建发酵性能良好且具有降解苹果酸能力的葡萄酒酵母菌株.结果表明,两亲本菌株原生质体电融合的最佳条件为:交变电压55 V,交变电场频率1000 kHz,脉冲宽度30μs,脉冲个数5个.共获得13株融合株,其中10号融合子发酵、降酸性能较佳.     

Sorbate Tolerance by Lactic Acid Bacteria Associated with Grapes and Wine

Ten strains of lactic acid bacteria capable of growth under pH and ethanol conditions similar to those of table wine were studied for tolerance to potassium sorbate in laboratory media. For all strains there was little inhibition at sorbate levels up to 300 ppm. Between 300 ppm and 1000 ppm, inhibition of Leuconosroc oenos was variable among strains, and the Lactobacillus strains studied showed virtually no inhibition by sorbate levels up to 1000 ppm. Thus, there were significant inhibitory effects on growth of some strains in laboratory media at higher sorbate concentrations, but not at the commercially applied concentrations of200–300 ppm and less.     

选用自然和遗传增强型微生物降低葡萄酒的苹果酸

对自然筛选酵母ICV-GRE和71B、苹果乳酸茵Lavia31、遗传增强型酵母ML01在Vignoles葡萄酒产品中苹果酸生物脱酸作用进行比较.ICV-GRE酵母消耗18%的苹果酸,不产生乳酸.Lavin31与ICV-GRE一样增进葡萄酒发酵,转化残留的苹果酸,同时消耗一些柠檬酸.由于ICV-GRE酵母有苹果酸的消耗量,ICV-GRE Lavin31处理与ML01相比,产生少量乳酸和较低可滴定酸度.ML01在初发酵60h期间,有效地把5.7g/L(100%)苹果酸转换成乳酸,71B酵母消耗1.9 g/L(33%)的苹果酸,无乳酸生成,用ML01生产的葡萄酒比其他处理产生较高的总SO2.二级实验发现,ML01酵母可产生34.6 mg/L的SO2,是ICV-GRE的3倍多,是71B的6倍多.     

美洲种葡萄Conquister干红葡萄酒香气的GC／MS分析

采用液-液萃取法提取美洲种葡萄Conquister葡萄果汁和干红葡萄酒中的香气成分,应用色谱面积归一法测定各成分的相对含量。结果表明,从美洲种葡萄Conquister葡萄汁中共鉴定出68种香气成分,相对含量较高的分别为乙酸乙酯、5-羟甲基-2-呋喃甲醛、2,3-二氢-3,5-二羟基-6-甲基-4(H)吡喃-4-酮、乙酸、(E)-2-己烯-1-醇、1-己醇、乙酸异丙酯、糠醛、2-丁烯酸乙酯、乙醇等;从干红葡萄酒中共鉴定出68种香气成分,相对含量较高的分别为乙醇、异戊醇、乙酸异戊酯、苯乙醇、辛酸乙酯、乙酸乙酯、葵酸乙酯、辛酸、7-[2-(乙酰基)-3à,5á-二甲氧基环戊基-1]-己酸乙酯、1-己醇。     

Wine industry residue as antioxidant in cooked chicken meat

The effectiveness of grape extracts as food ingredient has been tested in various systems. The objective of this study was to evaluate the efficiency of four concentrations of residues of the wine industry in delaying lipid oxidation in processed chicken meat stored under refrigeration. The development of oxidation during the 14‐day storage was evaluated through the thiobarbituric acid reactive substances method (TBAS). The analyses of phenolic compounds and antioxidant activity were performed in grape residue extracts through DPPH (1,1‐difenil‐2‐picrilidrazil) method, lipid peroxidation inhibition and Rancimat. The profile of polyphenols was determined using reversed‐phase high‐performance liquid chromatography. Isabel grape extract (IGE) and Niagara grape extract (NGE) showed significant content of phenolic compounds. NGE and IGE had high antioxidant activity. The addition of grape extracts significantly increased the oxidative stability of processed and cooked chicken meat during the storage time. The extracts from both grape varieties when applied in concentrations of 40 and 60 mg of GAE, presented results similar to that of Butyl hydroxy toluene (BHT).     

Starch Digestibility as Affected by Polyphenols and Phytic Acid

The rate of wheat starch digestibility in the presence or absence of polyphenols (catechin or tannic acid) and/or phytic acid at concentrations found in legumes was determined in an in vitro dialysis system. Addition of tannic acid and phytic acid reduced the starch digestibility 13 and 60% respectively, at 5 hr. Combined tannic and phytic acid reduced the digestibility at a level (63%) which did not differ significantly from that with only phytic acid. Catechin had no significant effect on rate of starch digestibility.     

Metal-Catalyzed Oxidation of Ascorbate, Deoxyribose and Linoleic Acid as Affected by Phytic Acid in a Model System

Antioxidant activity of phytate was investigated in metal-catalyzed model systems. In a dose-dependent manner, phytate facilitated oxidation of Fe (II) to Fe (III) and inhibited formation of thiobarbituric acid-reactive substances (TBARS) from Fe (II)- or hemeprotein-catalyzed deoxyribose degradation. In the presence of 100 μM Fe (III), phytate inhibited reduction of Fe (III) to Fe (II) by 100 μM ascorbic acid and it consequently inhibited ascorbate oxidation. Phytate inhibited hemeprotein- and H₂O₂-catalyzed TBARS formation from linoleic acid micelles. Inhibition by phytate of iron + ascorbate-dependent lipid peroxidation depended on the concentration of ascorbate. These results indicate that phytate may be a useful antioxidant in the protection against oxidative deterioration of foods.     

橡木桶与红葡萄酒的桶贮管理

橡木桶是贮存红葡萄酒的容器，在贮酒过程中葡萄酒发生复杂的物理、化学变化，可提高红葡萄酒的品质。世界上橡木的种类大约为250种，应用最多的是欧洲橡木和美洲橡木。酿制橡木香气浓郁的葡萄酒，宜选用美国的白栎；酿造橡木香、果香、酒香协调幽雅的葡萄酒，则选用欧洲橡木或中国橡木。桶贮管理包括酒的管理、环境管理和橡木桶的管理。（孙悟）     

有机酸指纹图谱快速鉴定山葡萄酒及葡萄露酒原汁含量的方法研究

建立有机酸液相指纹图谱鉴定山葡萄酒及其露酒原汁含量的分析方法.采用Shimpack VP-ODS色谱柱,以磷酸二氢钾(0.02mol/L,pH2.9)-甲醇(98∶2,v/v)为流动相,210rnm检测波长,测定不同品种山葡萄原酒及不同原汁含量山葡萄酒及其露酒中的有机酸,利用中药色谱指纹图谱相似度评价系统,建立山葡萄原酒有机酸标准指纹图谱,分析不同原汁含量山葡萄酒及其露酒有机酸图谱与标准指纹图谱的相似度关系.结果表明,10种不同品种(双红、双优、左优红、北冰红、公酿一号)山葡萄原酒指纹图谱与标准指纹图谱之间的相似度均在0.877以上,表明所建立的标准指纹图谱是有效的,可较好的反映山葡萄酒的品质;原汁含量为0％～100％的山葡萄酒及其露酒相似度变化为0.144～0.885,变化显著,依此建立起的不同原汁含量与一定相似度值域范围的对应关系,可限量鉴定山葡萄酒及其露酒的原汁含量.该方法快速、准确、易行,为鉴别山葡萄酒及其露酒的品质和真伪提供了检测依据.     

Volatile Composition of Vernaccia di Oristano Sherry-Like Wine as Affected by Biological Ageing

Forty compounds were identified by gas chromatography and gas chromatography/mass spectrometry in the volatile fraction of Vernaccia di Oristano, an Italian sherry-like wine produced in Sardinia since the 11th century. The individual aromatic compounds were identified and quantified in the original wine, both after biological ageing by inoculation of the original wine with Saccharomyces cerevisiae var bayanus and S cerevisiae var prostoserdovii , and after ageing under sterile conditions. The effects of flor yeasts in terms of production or subtraction of flavour components are discussed.     

Gelation Properties of Ovalbumin as Affected by Fatty Acid Salts

The physicochemical properties of heat-induced ovalbumin (OVA) gels containing fatty acid salts (FAS) were investigated. Water-holding ability and transparency markedly increased in the presence of sodium caprate or sodium laurate. At 9% of the protein concentration transparent and hard gels formed; at 7%, transparent and soft gels formed. Scanning electron microscopy showed that the transparent gels had a more homogeneous structure than turbid gels without FAS. Differential scanning calorimetry indicated that denaturation temperature of OVA was decreased and the peaks became broader after addition of FAS.     

Acid Milk Gel Formation as Affected by Total Solids Content

Reconstituted skim milk with varying concentrations of total solids was coagulated using glucono-δ-lactone (GDL). Microscopic, turbidimetric and rheological procedures were used to examine mineral solubilization, buffering capacity, casein dissociation and micellar solvation during gelation. Total solids of the milk affected pH of the onset of gelation attributable to differences in colloïdal calcium phosphate in the casein particles during acidification. Firmness and elasticity of the resulting gel increased with total solids from a more direct contribution of dry matter during the last stage of acid milk gel formation.