不同处理方式下毛竹笋发酵过程中主要营养物质对比分析

通过对不同处理方式下毛竹笋发酵过程中主要营养成分进行对比分析,为鲜笋发酵保鲜提供理论依据;结果表明:在4种处理方式中(竹笋经漂烫或不漂烫后采用自然发酵或乳酸菌接种发酵处理),漂烫乳酸菌发酵竹笋保鲜效果最好,经处理保藏63 d后,竹笋中可溶性糖、粗纤维和蛋白质含量分别为0.13%,8.87%和0.36/100(g/g),K和Ca含量分别增加了458.48 mg/kg和50.53 mg/kg,Fe、Mg等各元素损失最小;与其他3种方法相比,此法能够有效保持竹笋中可溶性糖和蛋白质含量,降低毛竹笋的粗纤维含量,减缓毛竹笋木质化的速度,加快竹笋与发酵液之间矿物质元素的交换,有利于提高竹笋中的矿物质元素含量,改善发酵毛竹笋食用品质并有效延长其贮藏期。     

不同处理方式下毛竹笋发酵过程中质地变化分析

为了评价发酵对毛竹笋食用品质的影响,研究了不同处理方式下毛竹笋在发酵过程中其质构、微观结构和色泽的变化。结果表明:不同处理方式下,毛竹笋的硬度、脆性、凝聚性等质构特性显著下降,不同发酵方式对硬度、脆性、凝聚性等影响较大,而对弹性和回复性的影响不明显;4种处理方式中,以漂烫乳酸菌发酵竹笋保鲜效果最好,以该法保藏63 d之后,毛竹笋硬度、脆性、凝聚性、咀嚼性、弹性和回复性分别为:67.87 N,77.68 N,0.302,6.61 N,0.345,0.511,损失相对较小;通过扫描电镜观察竹笋的微观结构发现,毛竹笋在发酵之后,其薄壁细胞组织出现明显的皱缩,细胞间隙增加;其中漂烫乳酸菌发酵竹笋样品细胞结构保持较为完整;经过不同处理以后,毛竹笋色泽变化较明显,总色差ΔE2,其中漂烫乳酸菌发酵竹笋样品色差最小为8.71,具有较好的护色效果;综合评价发现,漂烫乳酸菌发酵较其他3种方式更能有效保持毛竹笋的质构特性,护色效果最佳。     

马铃薯雪花全粉制酒工艺优化

以马铃薯雪花全粉为原料,安琪酿酒活性干酵母(angel active dry yeast,ADY)为发酵剂,制得马铃薯酒;通过单因素和正交试验优化马铃薯酒发酵的工艺条件。结果表明:最佳发酵工艺条件为料水比1∶7.0(g/mL),发酵温度18℃,糖化酶添加量120 U/g,蛋白酶添加量4 U/g,ADY添加量为0.005%,按此工艺发酵,所得酒度为5.3%vol,总高级醇含量为103.23 mg/L。     

毛竹冬笋不同部位营养成分及活性成分分析

为了了解毛竹冬笋的营养价值,促进毛竹冬笋的开发利用,对毛竹冬笋笋头、笋肉和笋壳3个不同部位中蛋白质、总糖、矿物质元素、氨基酸组成以及活性物质多酚和黄酮含量进行了研究,并与其他品种竹笋肉进行比较。结果表明:毛竹冬笋肉中蛋白质、总糖及灰分含量高于笋头和笋壳,与其他品种竹笋相比,冬笋肉中营养成分含量上相对比较丰富,食用价值高;笋肉中Na、Mg、K、Ca、Cu、Zn元素含量均高于笋头和笋壳,笋头中微量元素Mn、Fe的含量较高,笋壳中矿质元素含量最低;氨基酸分析显示,笋壳中氨基酸总量、必需氨基酸和非必需氨基酸含量较高,笋头次之,笋肉最低;笋肉中多酚和黄酮含量分别为10.31、3.49 mg/g,显著高于笋头和笋壳中的含量。     

三种不同生产工艺的荔枝酒品质对比

为了探索冷冻浓缩工艺对荔枝酒品质的影响,以荔枝汁为原料,通过直接发酵、发酵-冷冻浓缩、冷冻浓缩-发酵3种工艺分别生产发酵荔枝酒、发酵-浓缩荔枝酒、浓缩-发酵荔枝酒,并对比分析3种荔枝酒的基本组分、游离氨基酸含量、挥发性物质和感官评价。结果显示:发酵荔枝酒的酒精度为8.48%、总酸为4.80 g/L、单宁含量为0.53 g/L、游离氨基酸总量为40.38 mg/L、醇酯比为0.86,果香清淡,口感一般。发酵-浓缩荔枝酒和浓缩-发酵荔枝酒的酒精度为16.10%和16.47%、总酸为9.57 g/L和7.70 g/L、单宁含量为1.02 g/L和1.13 g/L、游离氨基酸总量为102.97 mg/L和493.17 mg/L,均显著高于发酵荔枝酒(p0.05),其中发酵-浓缩荔枝酒的醇酯比为0.50,酒香增加,但由于酸度及不良风味物质偏高,口感欠佳,而浓缩-发酵荔枝酒的醇酯比为0.26,果香浓郁,口感甜润饱满,酒体醇厚。荔枝汁先冷冻浓缩再发酵的工艺可以生产更高品质的荔枝酒。     

响应面法优化乳酸菌发酵方竹笋蔸膳食纤维条件的研究

目的:优化以凝结芽孢杆菌和嗜热链球菌发酵方竹笋蔸获得改性膳食纤维的条件,提高膳食纤维的溶胀率。方法:以浓度为50%(m/v)的笋蔸匀浆为发酵基质,运用响应面法研究了发酵时间、发酵温度、接种量以及菌种比例对笋蔸膳食纤维溶胀率的影响。结果:发酵时间、发酵温度、接种量和菌种比例等因素对方竹笋蔸膳食纤维的溶胀率均有显著性影响,最佳工艺条件为发酵时间30 h、发酵温度41.8℃、接种量2.46%、凝结芽孢杆菌:嗜热链球菌=3:1。结论:经响应面优化得到最佳工艺条件发酵,方竹笋蔸膳食纤维的溶胀率提高为8.56 m L/g。     

毛竹笋持久性有机污染物分布特征

以浙江省毛竹笋为对象,研究不同部位、不同季节和不同区域的毛竹笋中21 种有机氯、18 种多氯联苯和16 种多环芳烃三类持久性有机污染物的分布特征。结果表明：有机氯在笋肉中分布高于笋壳,笋肉上部高于下部,春笋污染为冬笋的4 倍,污染较重地区为上虞,含量最高的为毒杀芬（约105 μg/kg）。多氯联苯在笋肉中分布高于笋壳,笋肉下部高于上部,春笋污染高于冬笋,污染较重地区为武义,含量最高的为PCB52（1.14 μg/kg）;多环芳烃在笋肉和笋壳中分布接近,笋肉上部略高于下部,春笋污染为冬笋的1.5 倍,污染较重地区为永嘉,含量较高的为菲（5.85 μg/kg）。参照现有的限量标准,毛竹笋中55 种持久性有机污染物未超标,处于相对安全水平。研究结果不仅完善了竹笋的质量安全理论基础,也为环境污染的修复治理提供相应的参考。     

3种竹笋膳食纤维制备工艺的比较

竹笋纤维具有良好的天然生理活性,利用笋蔸制备活性食用纤维添加剂,变废为宝,成本低,具有良好的应用前景。文中以笋蔸为原料,研究了简便处理、酸碱处理、发酵处理3种竹笋膳食纤维制备工艺,并对产品生理活性、感官品质、得率与纯度进行了比较。结果表明:发酵处理法为最好,该法处理后过120目筛的竹笋膳食纤维,得率为51.23%;纯度为92.62%;持水力为8.40 g/g;溶胀性为7.60 mL/g;同时感官品质也明显提高。     

双酶糖化协同蜂蜜接合酵母发酵黄酒的工艺

为改善传统客家黄酒易染杂菌、成品酒批次间不稳定等缺点,以黑糯米为原料,采用双酶糖化后接种蜂蜜接合酵母的工艺酿造黑糯米黄酒。通过单因素和正交试验设计,得出黑糯米酒的最佳酿造工艺条件为:α-淀粉酶添加量32 U/g、液化温度80℃、液化时间200 min;糖化酶添加量170 U/g、糖化温度60℃、糖化时间25 h;蜂蜜接合酵母接种量体积分数20%,发酵温度28℃,经过10 d前发酵,其总糖为43.5 g/L,总酸为4.8 g/L,酒精度可达12.3%vol。以该工艺酿出的黑糯米酒酒味纯正,芳香清甜,口感醇厚,带有糯米特有的香味。     

单曲/混曲对液态发酵法生产米酒的影响

对比单曲和混曲液态发酵对米酒出酒率和感官质量等指标的影响。结果表明,混曲和单曲的原料出酒率、淀粉出酒率分别为60.10%和61.14%、80.02%和82.21%。单曲产品总酸平均为0.16 g/L、总酯平均为0.13 g/L;混曲产品的分别为0.14 g/L、0.175 g/L。混曲和单曲的乙酸乙酯平均含量分别为0.16 g/L和0.11 g/L,混曲发酵米酒弥补了单曲发酵感官及风味上的不足,为改善液态发酵法米酒的酒质具有实用意义。     

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.     

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.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

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

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

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.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status