大米水解物替代氢化植物油的研究

以不同DE值为指标,酶解大米制备氢化植物油的替代品,并将所得样品应用于重油蛋糕中.通过对产品的比容、质量损失、瓤芯质地结构、硬度、弹性等质构指标进行分析,以及对产品外观、质构、可接受度等指标进行感官分析评价.结果表明:以DE值为3的大米水解物替代40%油脂所生产的产品,与原高脂产品对照相差不大,证明所获得的脂肪替代物成功模仿了氢化植物油在重油蛋糕生产中所起的作用.     

大米淀粉为基质制备低DE值麦芽糊精的研究

研究了以大米淀粉为原料制备脂肪模拟物的工艺条件,通过单因素试验研究了酶添加量、反应时间、反应温度和底物浓度对产品DE值的影响,并在此基础上通过正交试验确定了制备工艺的最佳条件:酶添加量2ml,水解时间15min,水解温度92℃,该条件下制备的水解物DE值2.72。利用这种糊精替代奶糖中的油脂,其结构特性可达到或接近对照产品的品质。     

马铃薯淀粉基脂肪模拟物的工艺研究

马铃薯淀粉有着高黏度、抗剪切、风味温和、不易凝沉和老化的优点,因此本文以马铃薯淀粉为原料,研究了利用酶法水解制备低DE值脂肪模拟物的工艺条件.首先通过单因素试验研究了酶添加量、反应时间、反应温度和底物浓度对产品DE(Dextrose Equivalent)值的影响,并在此基础上通过正交试验确定了制备工艺的最佳条件:酶添加量6.5 U/g(以淀粉干基计),底物浓度25%,反应时间10 min,反应温度95℃,在该条件下制备的水解产物DE值为2.5.     

不同DE值麦芽糊精的酯化工艺研究

自制糯玉米麦芽糊精为原料,采用辛烯基琥珀酸酐(OSA)对麦芽糊精进行酯化.探讨了葡萄糖当量(DE)值、反应温度、反应时间、糊精乳浓度、pH值以及辛烯基琥珀酸酐用量等因素对产品取代度的影响.结果表明:酯化麦芽糊精的产品取代度随麦芽糊精DE值的增大而减小.通过单因素实验得到DE值为5%、11%、18%的麦芽糊精最佳酯化工艺条件具有一致性,即在反应温度35℃,反应时间5 h,糊精乳质量分数45%,pH值8.5,酯化剂用量3%(占糊精干基比)条件下,三种DE值麦芽糊精酯化产品的取代度均达到最大值,分别为0.020 3、0.017 9、0.016 1.     

马铃薯淀粉基质脂肪模拟物制备工艺的研究

研究了以马铃薯淀粉为原料制备脂肪模拟物的工艺条件,通过单因素试验研究了酶添加量、反应时间、反应温度和底物浓度对产品DE(dextroseequivalent)值的影响,并在此基础上通过正交试验确定了制备工艺的最佳条件:酶添加量6u/g(淀粉),水解时间10min,水解温度95℃,底物质量分数15%,该条件下制备的水解物DE值2.5。最后通过X衍射仪和扫描电镜对产品进行了微观结构的分析,DE在2～3之间的模拟物,颗粒的晶型结构仍然存在,水解反应发生在无定型区,颗粒直径明显下降,粒径在3～8μm,平均粒径5μm。     

木薯淀粉酸化机械活化复合变性制备糊精的研究

采用稀盐酸对木薯淀粉进行酸化,酸化淀粉预干燥后进行机械活化处理的工艺制备糊精。以产品的溶解度和葡萄糖值（DE值）作为评价指标,分别考察稀酸浓度、机械活化时间、机械活化温度等因素对产品性能的影响。研究结果表明：采用酸化机械活化复合变性的方法可制备出高溶解度低DE值的糊精。     

籼米基脂肪替代品对速溶咖啡口感的影响

研究了籼米为基质的脂肪替代品的制备工艺。通过单因素试验研究了耐高温α-淀粉酶添加量、籼米粉目数和水解时间对产品DE值的影响,并通过正交试验确定了制备籼米为基质的脂肪替代品的最佳工艺条件:酶添加量4.0 U/g米粉,水解时间30 min,籼米粉目数100目。制备的产品DE值3.0左右,干燥后产品为白色粉状物。利用提取脂肪替代品后的沉淀继续制备DE值13~17的麦芽糊精,工艺条件为:酶添加量40.0 U/g米粉,水解时间40 min。最后,添加质量分数6%的脂肪替代品和9%的麦芽糊精复配出的速溶咖啡口感最佳。     

液化工艺对甘薯渣制备低聚异麦芽糖含量的影响

以甘薯渣为原料,低聚异麦芽糖含量为指标,结合耐高温α-淀粉酶的酶解特性通过单因素试验和多重比较分析确定了最佳液化DE值和DE值在整个工艺的影响,再通过正交设计并应用SPSS软件对其数据分析对液化工艺进行优化。结果表明:以甘薯渣淀粉为原料制备低聚异麦芽糖时,最佳液化DE值为17,液化时底物浓度为15%、加酶量为0.15%、时间为2 h。     

水热器支持液化水解精确控制

音速蒸汽与高速液料准确作用产生的可调控加热区强力剪切为淀粉浆的透彻蒸煮提供了良好的条件。针对目前诸多淀粉深加工工厂关心的精准控制液化液DE值以应用于低DE值糊精或其他有关产品生产的市场情况,东潮公司就水热器技术与酶制剂配合进行多项研发,通过将喷射蒸煮透彻和酶制荆对精准控制液化水解程度（包括DE值）的各类数据,帮助业内更清楚解析物理剪切作用和水解化学的相互关系。     

以机械活化玉米淀粉为原料酶法制备低DE值麦芽糊精

以机械活化玉米淀粉为原料制备低DE（Dextrose Equivalent）值麦芽糊精,通过单因素实验研究了机械活化时间、反应时间、反应温度、酶添加量、底物浓度、pH对产品DE值的影响,并在此基础上进行了正交实验。结果表明,经机械活化预处理后的淀粉酶解反应活性明显提高,酶解速度加快,酶解时间大大缩短,而原淀粉在相同条件下几乎不与酶作用。正交实验确定了制备工艺的最佳条件为：酶添加量3u·g-1淀粉干基,pH6.5,水解温度45℃,底物浓度10%,水解时间4min,按此条件所得的麦芽糊精DE值为2.35%。并用红外光谱和X-射线衍射对麦芽糊精进行了分析。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.