小黄鱼加工副产物发酵条件的优化及其营养评价

摘 要：目的 为更充分的利用小黄鱼加工副产物, 对酶解处理后的水解产物进行发酵处理。方法 采用响应面分析法优化小黄鱼加工副产物发酵最佳条件。结果 枯草芽孢杆菌发酵最佳条件为发酵时间5 d, 发酵温度29 ℃, 菌种添加量5.3%, 豆粕添加量10.1%, 在此条件下, 小黄鱼加工副产物酶解液发酵后所得氨基酸含量可达39.68 mg/mL。发酵处理后, 发酵液鱼腥味较酶解液明显减轻, 且其碳氮比、乳酸、硝态氮含量显著高于酶解液(P<0.05); 氨基酸总量较酶解液提高27%, 其中苏氨酸、丝氨酸、脯氨酸及甘氨酸等9种氨基酸含量显著提高(P<0.01), 苦味氨基酸天冬氨酸、胱氨酸及精氨酸含量显著降低(P<0.01)。结论 对鱼类副产物酶解液进行进一步发酵处理, 不仅提高了产物的营养水平, 而且更充分的利用水产资源, 提高水产品附加值。     

响应面法优化双酶复合水解鳕鱼加工副产物的加工工艺

目的采用响应面法对复合酶酶解鳕鱼加工副产物的工艺进行优化,实现副产品的综合利用。方法采用胰蛋白酶和风味蛋白酶,运用单因素实验、Box-Behnken中心组合设计和响应面分析法,研究鳕鱼加工副产物的最佳酶解条件。结果最佳条件为:复合酶比例(胰蛋白酶和风味蛋白酶)(m:m)2:1,酶解温度45.52℃,液固比(m:m)3.19:1,加酶量2.93%,pH 7.5,酶解时间6 h。在此条件下,酶解鳕鱼加工副产物所得氨基酸含量理论预测值为16.3523 mg/mL,验证实验的氨基酸含量为16.33 mg/mL,与响应面预测值基本吻合。结论用胰蛋白酶和风味蛋白酶复合水解鳕鱼加工副产物得到的酶解液氨基酸含量较高,可作为鱼蛋白有机肥用于农牧业生产。     

枯草芽胞杆菌与酵母菌混合发酵奶牛精饲料的研究

对混菌发酵奶牛精饲料的发酵条件进行了研究。采用枯草芽孢杆菌与酵母菌混合发酵的方法,研究菌种比例、麸皮含量、水分、腐植酸钠添加量对发酵产物中淀粉酶和中性蛋白酶含量的影响。结果表明:奶牛精饲料的最佳发酵条件为:枯草芽孢杆菌与酵母菌的接种比例为3∶7,麸皮添加量为5%,水分为65%,腐植酸钠在种子液中的添加量为2%,在发酵底物中的添加量为2%。在此条件下发酵奶牛精饲料,测得产品中中性蛋白酶含量为1 476.00U/g,淀粉酶含量为6 339.24U/g,与未发酵精饲料相比,中性蛋白酶含量是未发酵精料的3倍,淀粉酶含量是未发酵精料的1.52倍。     

β-淀粉酶酶解甘薯淀粉条件分析

麦芽糖可以诱导枯草芽孢杆菌产生中温α-淀粉酶,甘薯淀粉的β-淀粉酶酶解产物主要为麦芽糖。应用高效液相色谱示差折光检测法对不同酶解条件下甘薯淀粉β-淀粉酶酶解产物进行分析。结果表明,液化酶加入量为5~10U/g干淀粉时,酶解产物中葡萄糖的含量最高可达0.94%±0.048%,其含量较低,不会对枯草芽孢杆菌产α-淀粉酶具有阻遏作用。酶解最佳条件为液化酶加入量5U/g干淀粉,β-淀粉酶最佳加入量为200U/g干淀粉,酶解最佳温度为60℃,最佳酶解时间为28h时,此条件下甘薯淀粉酶解产物中麦芽糖含量达75.8%±1.7%。甘薯淀粉β-淀粉酶酶解产物可以诱导β-淀粉酶酶解产物枯草芽孢杆菌发酵生产中温α-淀粉酶。研究对枯草芽孢杆菌发酵生产中温α-淀粉酶碳源优化具有重要意义。     

响应面法优化加酶提高罗非鱼下脚料和豆粕混合发酵水解度的工艺研究

以罗非鱼下脚料和豆粕为原料,在加入枯草芽孢杆菌、酵母菌、乳酸菌发酵的前提下,添加中性蛋白酶。在单因素的基础之上,以水解度为响应值,对混合发酵的工艺条件进行中心复合设计,确立了最佳工艺条件为:中性蛋白酶添加量0.1%,发酵温度40℃,发酵时间53h。在此条件下,水解度为31.94%,比纯菌种发酵提高4.7%。     

酶菌协同发酵产青钱柳多糖工艺优化

以青钱柳干燥后叶子为原料,青钱柳多糖的含量为评价指标,采用复合酶（纤维素酶与半纤维素酶质量比1∶1）对原料进行酶解处理,再经过混合菌种（粗糙脉孢菌（Neurospora crassa）和枯草芽孢杆菌（Bacillus subtilis）质量比1∶1）对酶解液进行发酵,并采用单因素试验及响应面试验对酶菌协同发酵产青钱柳多糖的工艺进行优化。结果表明,最优工艺条件为：料液比8∶100（mg∶mL）、纤维素酶与半纤维素酶质量比1.8∶1.0、复合酶添加量0.8%、酶解时间2.5 h、蔗糖添加量8.0%、粗糙脉孢菌和枯草芽孢杆菌质量比2∶1、混合菌添加量5.0%、发酵时间60 h。在此优化条件下,青钱柳多糖含量达到3.34 mg/mL。     

发酵型裙带菜调味酱脱腥和制作工艺研究

目的优化収酵型裙带菜调味酱脱腥和制作工艺。方法本文以盐渍裙带菜为原料,通过清洗脱盐、破碎匀浆、脱腥、调配収酵、包装杀菌等工艺制作得収酵型裙带菜调味酱,重点研究了β-环状糊精包埋法和八角、桂皮、甘草掩蔽液脱腥法2种方法的脱腥效果,幵对产品的调配和収酵条件迚行了优化。结果添加2%的1:0.3:0.3遮蔽液(甘草、八角和桂皮)迚行脱腥效果最优,加入80%白菜、10%辣椒面、1%鲜姜、2%蒜、4%葱、6%食盐、8%白糖迚行调配,再添加10%鱼露常温収酵72 h,在此制作工艺和配方条件下得到的収酵型裙带菜调味酱风味最佳。结果本研究结果丰富了市场上裙带菜产品,为裙带菜资源利用探索了新途径。     

杜衡挥发油的水酶法提取及其抗菌活性研究

本文首先采用水酶法提取杜衡挥发油的工艺,然后研究其抗菌作用。结果表明：最佳工艺条件为酶加量3%、料液比10ml10mL/g、pH值4.5、酶解温度45℃和酶解时间2h,此条件下最佳提取率为7.9%;杜衡挥发油对大肠杆菌、酵母菌、金黄色葡萄球菌和枯草芽孢杆菌的MIC为0.0625%,对黑曲霉和蜡样芽孢杆菌的MIC为0.125%;对蜡样芽孢杆菌是高敏感,其余5种都属极敏感。杜衡挥发油对食物中的常见腐败菌有一定的抑制作用。     

一步法混菌固态发酵豆粕的工艺研究

利用酵母菌、米曲霉、乳酸菌和枯草芽孢杆菌一步法混菌固态发酵豆粕。通过正交试验确定酵母菌、米曲霉、乳酸菌和枯草芽孢杆菌最佳接种比例为1∶3∶1∶3。采用响应面试验优化豆粕的最佳发酵条件为:初始温度32.4℃,含水量45.8%,接种量12%。在最佳发酵条件下,发酵豆粕中小分子肽含量由1.22%提高到5.41%,粗蛋白含量由46.0%提高到55.1%。通过SDS-PAGE和发酵豆粕的物理特性分析得出,发酵豆粕中大分子蛋白基本降解为14.4 kDa以下的小分子肽,且具有浓郁的酸香和醇香风味。     

豆粕混菌液体发酵制种技术试验研究

利用热带假丝酵母和枯草芽孢杆菌混菌发酵进行液体制种。结果表明:受接种量、豆粕含量和培养温度的影响,两株菌种菌数的增长速度具有相对一致的变化趋势;受培养时间的影响,热带假丝酵母菌先增后降,枯草芽孢杆菌先降后增;热带假丝酵母在pH3.5时菌数最大,枯草芽孢杆菌在pH4.5～7.5范围内适宜生长。在豆粕质量分数15%、葡萄糖质量分数1%、初始pH4.5的液体培养基上,两菌分别接种10%,在发酵温度28℃、摇床转速160r/min条件下培养5d,热带假丝酵母菌和枯草芽孢杆菌菌数达到最大,分别为752.5×106和264.2×107 cfu/ml。     

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.     

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.     

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.     

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.     

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.     

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.