桑叶米酒的研制

桑叶是食药两用物品,富含有18种氨基酸、矿物质及黄酮类物质.以桑叶、糯米为原料,经糖化、发酵生产出具有保健功能的桑叶米酒.并对桑叶汁的提取、桑叶汁的添加方式及米酒的稳定性进行了探讨.     

黄芪米酒发酵的条件优化

为开发米酒新产品,以黄米和糯米为主要原料,加入黄芪提取液进行发酵.根据单因素试验结果,设计以黄芪添加量、黄米与糯米质量比和酒曲添加量为因素的L9(33)正交试验,以黄芪米酒的多糖含量、糖度、酸度、出汁率及感官评分为参考指标,得出黄芪米酒发酵的最佳工艺条件:黄芪添加量5％,酒曲添加量0.6％,黄米与糯米质量比1:2,发酵...     

香米米酒加工工艺研究及理化品质分析

以香米、糯米为原料混合发酵酿造香米米酒,通过单因素和正交试验,确定香米米酒发酵的最佳工艺条件;结合感官品质,分析米酒酒精度、糖度、总酸等理化品质指标适合的范围,用气相色谱-质谱联用法(GC-MS)分析香米米酒与纯糯米米酒中的香气成分.实验结果表明:(1)香米米酒发酵的最佳工艺条件为:香米和糯米配比1∶4、酒曲添加量0.8％、发酵温度33℃、发酵时间64 h,米酒质地均一,口感柔和,醇香适度,有特殊的香味;(2)香米米酒酒精度在2.12％～2.60％,糖度在28.75％～34.48％,总酸在0.231％～0.245％,米酒品质较高;(3)乙基苯、乙酸异戊酯、异丙醇等5种香气成分为香米米酒所特有,甲基乙酰甲醇、甲酸异戊酯、苯乙醇3种香气成分在香米米酒中含量显著高于纯糯米米酒.     

糯米百香果果酒加工发酵配方研究

为了加工糯米百香果果酒,以百香果为原料,糯米和白砂糖为辅料,采用闽西客家米酒曲和安琪果酒酵母进行发酵,在单因素试验基础上进行正交试验,优化最佳发酵配方。结果表明,最佳发酵配方为,以100 g百香果果肉计,糯米65 g、果酒酵母0.4 g、客家米酒曲1.75 g、冷开水165 g。按此配方得出的产品具有以下特点:百香果香味浓郁、酒香醇厚、酸甜醇味柔和、且圆润爽口,酒精度15%Vol~18%Vol。     

黑青稞米酒的发酵工艺研究

以黑青稞和糯米为主要原料制作黑青稞米酒。主要以黑青稞米酒综合感官评分为评价指标，在单因素试验的基础上通过正交试验优化黑青稞米酒的发酵工艺。结果表明：最佳工艺为黑青稞与糯米质量比2∶1、酒曲添加量为0.6%(以混合米质量为基准)、发酵温度26℃、发酵时间60 h;在最佳工艺条件下制得的黑青稞米酒酒体呈清澈淡黄色，细腻醇厚，兼具黑青稞独特的香味和米酒典型的醇香，乙醇体积分数为7.12%,还原糖为20.41 g/100 g,总酸为0.39 g/100 g。     

雪菊米酒的研制

以雪菊、糯米为主要原料,研制新型米酒——雪菊米酒。通过单因素试验和正交试验确定最佳工艺条件是:雪菊提取液添加量20%、甜酒曲添加量1.0%、酿酒酵母添加量0.08%、发酵时间5 d。在此条件下制备的雪菊米酒口感细腻、风味独特,兼有雪菊和米酒的营养价值和保健作用。     

糯米化学成分对米酒发酵及其品质影响的研究

以3种不同品种和产地的糯米为原料,研究了其化学构成及发酵过程中米酒的主要理化指标变化规律及品质,分析了糯米的主要化学成分与米酒品质的相关性。结果显示,发酵过程中3种糯米发酵醪的还原糖和可溶性固形物含量均逐渐降低,总酸和酒精度均呈上升趋势。糯米的支链淀粉与直链淀粉的比值及脂肪含量对米酒品质存在显著影响。糯米的支链淀粉与直链淀粉的比值越大,即支链淀粉含量越高,米酒的醇厚感越浓,米酒的感官品质越好;脂肪含量越高,米酒的感官品质越差。酿造优质米酒时应选用支链淀粉含量高、脂肪含量低的糯米为原料。     

混合发酵法制备烟用米酒香料的研究

以糯米、红枣、无花果为主要原料,采用混合发酵法制备烟用米酒香料,以卷烟感官评价为考察指标进行工艺优化。通过正交试验优化得到最佳制备工艺条件为糯米∶红枣∶无花果质量比5∶1∶1,接种量1%,糖化温度30 ℃,糖化时间48 h,后发酵时间72 h。对比米酒香料KB,添加了混合发酵米酒香料的卷烟香气、吃味品质均明显提升,评吸得分为90.3分。在最优工艺条件下,对混合发酵米酒和米酒KB的理化指标及致香物质进行分析。结果发现,混合发酵米酒中的总糖、总酸含量均高于米酒KB,而酒精度差别不大;混合发酵米酒香料中致香物质种类可达26种,多于米酒香料KB（11种）,其中苯甲醇、苯乙醇、4-羟基-3-甲氧基苯乙醇含量均达到了20 mg/L,提高该米酒香料的香气质量。     

基于GC-IMS技术对多菌系复合发酵特色米酸汤的风味特征研究

苗族传统米酸汤是以糯米或籼米为基质经自然发酵而成。为丰富米酸汤产品,明确多菌系复合发酵对米酸汤发酵生产的实际应用价值及米酸汤风味特征。本文以传统自然发酵的米酸汤(A)为对照、采用多菌系复合发酵不同基质米酸汤(红米酸汤-B、紫米酸汤-C、糯米酸汤-D、白米酸汤-E)为研究对象,利用气相色谱-离子迁移谱(Gas chromatography-ion mobility spectroscopy,GC-IMS)技术分析不同基质发酵米酸汤差异特征风味物质。结果表明:与传统自然发酵的米酸汤相比,糯米酸汤含有相对含量较高的乙酸乙酯,红米酸汤、紫米酸汤含有相对含量较高的乙酸丙酯,且经多菌系复合发酵后的红米酸汤、糯米酸汤、白米酸汤中贡献较大的主体风味物质种类皆比传统自然发酵的米酸汤丰富。采用正交偏最小二乘判别分析筛选出18种特征标志物(VIP>1)(Variable Importance for the Projection,VIP),通过热图聚类区分不同米酸汤样品的特征挥发性风味化合物,其中传统自然发酵的米酸汤以丁酸丙酯、丁酸丁酯、2-甲基丙酸乙酯等为特征风味物质,具有独特的菠萝果香味;红米酸汤以罗勒烯、柠檬烯-M、丙酸、乙酸丙酯等为特征风味物质,具有独特的柠檬与丁香香味;紫米酸汤以乙酸异丙酯、乙酸异丁酯、3-甲基丁醛、乙酸丙酯等为特征风味物质,具有独特的苹果样果香味;糯米酸汤以乙醇、乙酸乙酯等为特征风味物质,具有独特的米酒型香味;白米酸汤无特征标志物,但酸类物质较多,具独特的酸感。研究结果表明利用多菌系复合发酵米酸汤,具有改善并丰富米酸汤风味品质的显著优势,通过本实验还确定了不同基质发酵米酸汤的特征风味物质,为丰富米酸汤产品提供科学支撑。     

不同原料对米酒的酚类成分及抗氧化活性的影响

采用4种原料(黄米、红米、糯米、黑米)对米酒进行发酵,通过检测出米酒中的酚类物质,测定不同种类米酒的总多酚、自由基清除能力、还原能力、金属离子螯合能力的变化趋势,进一步分析不同种类的原料对发酵米酒酚类物质和抗氧化活性的影响。结果表明,不同原料发酵米酒的酚类成分及抗氧化活性存在显著差异(P0.05)。以黄米、红米、糯米、黑米为原料发酵制得的米酒总多酚含量分别为174.89、604.07、949.63 mg/L和1037.12 mg/L,黑米中的总多酚含量约是黄米的6倍、红米的2倍。黑米酒中对羟基苯甲酸、芥子酸、对香豆酸含量也远高于其他米酒。黑米酒的ABTS~(+.)和DPPH自由基清除能力分别高达456.41 mg Vc/L和297.57 mg Vc/L,并且还原能力是黄米酒的3倍、红米酒的1.5倍。综上所述,4种米酒中,黑米是酿造米酒的最佳原料。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.