番木瓜芒果复合发酵果醋工艺研究

番木瓜、芒果通过果胶酶取汁、酒精发酵、醋酸发酵等工艺生产果醋。果醋加工工艺条件为番木瓜与芒果混合果汁配比2∶1,果胶酶的添加量200mg/L,酒精发酵中初始糖度16°Bx,酵母接种量11%,发酵温度28℃。醋酸发酵的初始酒精度控制在8%vol,醋酸菌菌种接种量11%,发酵温度30℃。     

响应面法优化芒果果醋发酵工艺研究

以芒果为原料,在单因素试验的基础上,运用Box-Behnken试验设计原理对液态发酵芒果原浆果醋的生产工艺条件进行优化研究。结果表明:芒果酒精发酵阶段,在发酵时间为3d的条件下,酒精发酵优化工艺参数为:料液比1∶2、酵母接种量0.2%、发酵温度34℃、初始糖度18%,在此条件下,芒果酒精发酵酒精度6.62%。醋酸发酵最佳工艺条件为:醋酸菌接种量7.7%、发酵温度32.5℃、装料量30%、发酵时间7d,在此条件下,果醋的酸度为3.99g/dL,且其理化及卫生指标均符合国家相关标准。     

胡萝卜苹果复合果醋的研究

以苹果、胡萝卜为原料经过酒精发酵和醋酸发酵,制得了胡萝卜、苹果复合果醋。通过对影响酒精发酵的接种量、温度、时间进行研究,结果表明酒精发酵最佳工艺条件为接种量为5%,温度为30℃,发酵时间6 d;对醋酸发酵的初始酒精度、接种量、温度、pH研究表明,醋酸发酵最佳工艺条件为初始酒精度为8(%,体积分数),接种量为10%,温度在30℃,pH为3.5,发酵时间14 d。     

橘子葡萄复合果醋及其饮料的研制

以橘子和葡萄为原料,通过酒精发酵、醋酸发酵等工艺制得橘子葡萄复合果醋,以发酵制得的复合果醋为主要成分,添加适量果汁和蔗糖等辅料,调配成复合果醋饮料。通过正交试验确定醋酸发酵的最优工艺条件为发酵时间70 h,发酵温度34℃,醋酸菌种子液接种量体积分数6%;橘子葡萄复合果醋饮料的最佳配制方案为发酵果醋体积分数85%,果汁体积分数15%,蔗糖质量浓度2 g/100 m L。工艺可制得酸甜适度,口感爽润,色泽上佳的橘子葡萄复合果醋饮料。     

柿子原浆果醋加工工艺研究

对柿子原浆果醋的加工技术进行了研究,并分析了柿果醋加工过程中酒精、糖及醋酸含量的变化规律.结果表明:在柿果浆加水量为30%的条件下,酒精发酵的工艺参数为酵母菌接种量0.1%,发酵温度30℃,发酵周期4 d;醋酸发酵的工艺参数为发酵温度34℃、醋酸菌接种量为0.5‰,每天搅拌3次.使用该技术生产的柿果醋风味良好,具有一定保健功能.     

沙果果醋发酵生产工艺研究

以优质沙果为原料,研究了沙果果醋发酵的生产工艺条件。在确定了生产工艺中酒精发酵适合参数的基础上,采用正交实验对醋酸发酵条件进行了优化。优化结果表明:沙果果醋醋酸发酵的最佳条件为初始酒精浓度7%、接种量10%、发酵温度30℃、发酵时间5天。     

芦荟果醋饮料的生产工艺

以芦荟为主要原料,采用液体深层发酵工艺,经酶解、酒精发酵和醋酸发酵制作芦荟醋,再辅以蜂蜜、蔗糖等调配成芦荟果醋饮料.酒精发酵的条件为温度28～30℃,pH 4.5～5.0,时间6～7 d,活化酵母菌的接种量为2%,醋酸发酵的条件为温度30～32℃,时间约5～6d,醋酸菌接种量为12%.     

葡萄果醋发酵饮料工艺条件的研究

以玉米、麸皮为主要原料,经酒精发酵后加入葡萄皮渣进行醋酸发酵制得葡萄果醋,再经调配,制成风味独特的葡萄果醋饮料.通过单因素实验、正交试验,优化了工艺条件和配方.结果表明,以玉米、麸皮汁为发酵基料(基料糖含量为12°Bx,pH4.5)的酒精发酵条件为:酵母接种量10%、发酵温度30℃,经酒精发酵3d,酒精体积分数达到6%时进入醋酸发酵;醋酸发酵条件为:葡萄皮渣与玉米和麸皮的质量比为1∶2、糖含量3°Bx、醋酸菌接种量10%、发酵温度30℃、发酵5d.葡萄果醋发酵饮料配方为:葡萄果醋12%、柠檬酸0.2%、蔗糖10%.     

菠萝皮渣果醋高效发酵工艺

以菠萝皮渣为主要原料、果酒酵母和沪酿1.01 醋酸菌粉为菌种,采用半固态发酵和二次补糖工艺,对菠萝皮渣酒精发酵和醋酸发酵工艺进行研究,以确定最优酿造工艺参数和实现菠萝皮渣果醋的高效生产。结果表明：菠萝皮渣酒精发酵条件为酵母添加量0.3%、发酵温度22℃、糖度16°Brix、pH3.5、发酵时间6d;醋酸发 酵最佳工艺条件为添加的葡萄糖质量分数2%、初始乙醇体积分数8%、发酵温度29℃、醋酸菌粉添加量0.09%、发酵时间3～4d,得到总酸量(以醋酸计)达6.78g/100g 的菠萝果醋半固态混合物,醋酸转化率为82.5%。经浸泡、过滤和陈酿1～2 个月后,所得菠萝果醋成品总酸含量(以醋酸计)为3.672g/100mL,色泽金黄,清亮透明,既有酸香,又有菠萝果香,口味柔和爽口。半固态果醋发酵法与液态果醋发酵法相比,能明显提高总酸产量和缩短发酵时间。     

海带猕猴桃复合果醋的工艺研究

以海带、猕猴桃为主要原料,经脱腥试验、酒精发酵,醋酸发酵后,制得复合果醋。通过正交试验,确定了在pH4.5下进行醋酸发酵的最佳工艺条件为：发酵液酒精含量为6%,醋酸菌的接种量为10%,发酵温度为30℃,发酵时间为12d.     

酵素中具有抑菌能力乳酸菌的筛选及鉴定

该研究探讨了从酵素中分离纯化具有抗菌性能的12株乳酸菌，对其进行生理生化实验和API鉴定。利用牛津杯法对阪崎大肠杆菌、鼠伤寒沙门氏菌和宋内志贺氏菌、大肠杆菌、金黄色葡萄球菌进行抑菌特性研究，并探讨了乳酸菌是否产生物胺能力和偶氮还原酶。结果表明，酵素源的12株乳酸菌对肠道致病菌均具有不同程度的抑菌活性，其抑菌圈直径为14~22 mm，对大肠杆菌的抑菌效果较好，其抑菌圈直径为15~23 mm，对金黄色葡萄球菌的抑菌圈直径为14~24 mm，12株乳酸菌都不具有产生物胺和偶氮还原酶的能力。通过生理和API生化鉴定确定XZJ003、XZJ006、XZJ015均为副干酪乳杆菌，通过16S rDNA和同源性确证XZJ015为副干酪乳杆菌，该研究结果对今后益生菌的深入研究和功能性食品的开发具有一定的作用。     

关于酵母延迟期的研究

通过试验研究,在玉米发酵生产酒精的过程中,酵母的生长曲线中生长延迟期的长短与酒母的接种量、酵母的培养时间密切相关。     

On the importance of adequately choosing the ingredients of yoghurt and enriched milk for their antioxidant activity

The antioxidant activity of several dairy products, yoghurt enriched with green tea and lemon, fermented milk, yoghurt with strawberry pulp, 'low-calorie' yoghurt with inulin and milk enriched with vitamin E and their ingredients were analysed. Yoghurt enriched with green tea and lemon showed the best lipidic antioxidant capacity. All the dairy products analysed were very good OH· radical scavengers. The dairy products analysed were unable to scavenge H₂O₂ except green tea. The antioxidant activity of these samples resisted high temperatures in the Rancimat test; of the ingredients analysed, the best antioxidant activity was found for vitamin E followed by green tea, pectin, Lactobacillus acidophilus , lemon pulp and cornstarch. Antioxidant activity did not suffer variations during storage at an unfavourable temperature (40 °C), as demonstrated by the linoleic acid assay. Yoghurt enriched with green tea and lemon, yoghurt with strawberry pulp and low-calorie yoghurt with inulin produced the best results in the Trolox equivalent antioxidant capacity (TEAC) assay.     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.