翠碧1号烟叶烘烤过程中色素降解及化学成分变化

为优化翠碧1号配套烘烤工艺,提高烟叶质量,考虑到翠碧1号采收成熟度难把握、烤后烟叶外观质量较差等问题,开展了不同成熟度烟叶烘烤过程中色素及化学成分代谢研究。结果表明,烘烤过程中随着温度的提高,叶绿素和类胡萝卜素不断降解,相同部位叶绿素和类胡萝卜素随着采收成熟度提高而降低。就降解速度而言,叶绿素降解主要在38℃之前,类胡萝卜素降解主要在42℃之前,但到46℃后色素含量基本趋于稳定;适熟的鲜烟叶在烘烤过程中其淀粉降解较快,烤后烟叶水溶性糖和还原糖含量较高,总体化学成分较协调。因此,下部叶适当早采以降低烟叶采收成熟度、中部烟叶适当提高烟叶采收成熟度、上部烟叶采取适宜的成熟度,有利于烟叶外观及内在品质的提高。     

烤烟成熟过程中鲜烟颜色值与色素含量变化及相关分析

为研究烤烟成熟过程中鲜烟叶颜色值与色素含量的变化以及相关性,测定了各部位4 个成熟度鲜烟叶的颜色值和色素含量,并进行了相关性分析.结果表明,在烟叶成熟过程中,各部位烟叶的亮度值L＊、红度值a＊、黄度值b＊均不断增大,且各部位烟叶不同成熟度间各颜色值差异显著性不同,颜色值变化趋势存在差异,其中,中、上部叶红度a＊值变化较大,增幅显著.各部位烟叶叶绿素a、叶绿素b、总叶绿素、类胡萝卜素含量均逐渐减小,类叶比值不断增大.下、上部叶类叶比值增幅基本保持不变,而中部烟叶黄绿面积在70%～80%到80%～90%时类叶比值增幅较大.各颜色值均与各色素含量、类叶比值呈显著或极显著性相关关系.表明成熟过程中烤烟叶片颜色值与色素含量关系密切,叶片颜色值变化可以指示烟叶各色素含量的变化,可以将色差计作为判断烟叶成熟度的辅助工具.     

贵州烤烟色素含量和颜色值随生育期的变化及其相关性

为了进一步探讨贵州烤烟生长特性,以K326、毕纳1号、贵烟1号、贵烟2号和K326有机烟为材料,研究了大田生育期（35、70、105 d）烟叶质体色素含量和颜色参数值的变化幵进行了相兲分析。结果表明,生育期烤烟烟叶质体色素含量和颜色参数（H＊除外）值均呈逐渐下降的趋势。毕纳1号35 d和105 d质体色素含量显著高于其他材料;K326有机烟70 d和105 d质体色素含量显著低于其他材料,但其L＊、b＊和C＊值显著高于其他材料。不同烤烟材料生育期烟叶L＊和H＊值差异均显著,且b＊和C＊值105 d显著高于35 d和75 d。不同烤烟材料烟叶质体色素含量与颜色参数值相兲均显著,其中质体色素含量与L＊、a＊值相兲系数较大,在0.805~0.866之间。线性回归分析表明,变量叶绿素b R2值（R^2=0.915）最大,变量类胡萝卜素R2值（R2=0.847）最小;自变量中线性回归系数正值Xa＊最大,其次是XH＊。相对类胡萝卜素,烤烟生育期烟叶叶绿素含量与颜色参数值的线性回归性更好。     

不同外观烤烟类胡萝卜素及其降解产物含量的差异分析

分别采用HPLC及GC/MS测定了不同外观的烤烟烟叶中类胡萝卜素及其降解产物的含量.结果表明:①烤烟叶黄素、β-胡萝卜素及类胡萝卜素含量随颜色加深逐渐升高,随成熟度的提高逐渐降低,随油分增多而降低,随色度增强而基本表现出降低趋势(宁化中部烟叶略有不同).②郏县、宁化和宜良烤烟类胡萝卜素降解产物总量分别以金黄、浅桔红和正黄时最高;以成熟烤烟最高,欠熟或过熟时均降低;随油分增多而降低.③郏县烟叶为金黄、宁化烟叶为浅桔红、宜良烟叶为正黄,成熟度均为成熟,油分充足,色度较强时,烟叶类胡萝卜素降解最为充分.烟叶外观指标对类胡萝卜素含量的影响大小依次为颜色、色度、油分、成熟度,对于降解产物的影响依次是颜色、成熟度和油分,色度对其影响依产地的不同而异.     

几个烤烟品种成熟期及采后的色素和水分含量变化

为了探索采收至烘烤环节烟叶品质发生变化和红大品种较难烘烤的原因,通过对不同烤烟品种鲜烟叶跟踪检测的方法,测定了鲜烟叶色素和水分含量的变化。结果表明,红大叶绿素a、叶绿素b含量均较高,导致烟叶烘烤前期变黄较快,但较难彻底变黄,需延长凋萎期时间;自由水和总水分含量较高,烘烤过程中易失水烤青或失水过少发生烤糊,束缚水含量较少,导致定色期缓冲能力较弱,难以定色。烟叶采后未及时进烤,导致烤后品质降低的主要原因是离体烟叶内部所发生的剧烈生物学反应,烟叶内有利于品质形成的色素前体物质提前降解。     

豫中烟区烤烟移栽期和成熟度与质体色素及降解产物的关系

通过调整移栽期和采收期,探索豫中地区烟叶成熟度与质体色素及其降解产物变化的关系。结果表明,叶龄30 d后,随着成熟度的增加,烟叶叶绿素及类胡萝卜素含量呈下降趋势;中部叶质体色素含量及其降解率以5月6日移栽较高,上部叶以4月27日移栽较高。调制后烟叶的质体色素含量中部叶高于上部叶,且随着烟叶推迟采收表现出逐渐降低的趋势,但移栽期对质体色素含量影响不大。中部、上部叶类胡萝卜素降解产物及新植二烯的含量以5月6日移栽各推迟5 d采收处理最高。综上所述,合理的移栽期及适当的推迟烟叶采收有利于质体色素的形成和其降解产物的提高。     

雪茄烟叶晾制过程色素降解和膜脂过氧化对颜色变化的影响

  目的  探究雪茄烟叶在调制过程中色素降解和膜脂氧化对烟叶颜色形成的作用。  方法  以“德雪7号”中部叶为试验材料,测定了雪茄烟叶晾制期间色素及膜脂含量的变化,并探究了色素、膜脂与烟叶颜色变化之间的关系。  结果  ① 烟叶在晾制过程中,叶绿素和类胡萝卜素逐渐降解,类胡萝卜素/叶绿素含量呈现先增大后减小的趋势;②烟叶的膜脂含量（MGDG、DGDG、PL）降低, 且随着晾制时间的延长,DGDG/MGDG比值逐渐增大;③雪茄烟叶的变色程度与色素和膜脂含量之间均呈极显著负相关关系。  结论  雪茄烟叶在晾制过程中,色素降解和膜脂代谢是烟叶颜色形成的重要因素。      

上6片烟叶烘烤过程中水分与颜色及化学成分的协同变化

为优化上部烟叶烘烤技术,设置优化烘烤工艺和常规烘烤工艺2个处理,通过对烘烤过程中烟叶样品的采集分析,研究了烘烤过程中烟叶水分与颜色、内在化学成分的协同变化及烤后烟叶的品质差异。结果表明:(1)上部烟叶烘烤前期失水较难,叶片失水集中在变黄后期至定色期。(2)烘烤过程中烟叶失水与颜色及化学成分变化密切相关,随烟叶含水率由75%左右(鲜烟叶)降至60%左右,烟叶颜色由黄绿色变为浅黄色,淀粉大量降解;烟叶含水率由60%左右降至10%左右(叶片基本干燥),烟叶颜色由浅黄色变为深橘黄色,游离氨基酸含量(质量分数)明显下降。(3)烘烤过程中,烟叶含水率与颜色参数明度值(L值)和黄度值(b值)呈极显著正相关,与红度值(a值)呈极显著负相关,还原糖含量与颜色参数L值、b值和a值均呈显著正相关。(4)针对豫中产区上6片烟叶,烘烤过程中应避免变黄期不排湿、定色前期湿球温度大幅度降低而快速排湿,重视烘烤中后期的工艺参数的调控,促进烟叶内在化学成分的合理转化。     

烘烤过程中烟叶色素的降解及与化学成分的相关分析

研究了河南不同生态区烟叶在烘烤过程中叶绿素的降解及与化学成分的相关性，结果表明，叶绿素在变黄期降解量最大，平均为鲜叶含量的74．75％，且直至于筋期仍能缓慢降解，降解速度最快时期为开烤后24－36h。类胡萝卜素的降解总体上随着烘烤的进行，类胡萝卜素的含量逐渐下降，降解速度仍以灰黄期较快。在烘烤过程中，叶绿素和烘胡萝卜素的含量变化与水分含量呈极显著正相关，与总糖和还原糖含量呈极显著负相关。     

不同成熟度烟叶烘烤过程中生理生化变化研究

对不同成熟度的鲜烟叶在烘烤过程中主要生理生化变化规律及其烤后质量进行了系统的研究.结果表明,不同成熟度烟叶在烘烤过程中淀粉酶活性的变化规律均呈双峰曲线,变黄前、中期各处理烟叶淀粉酶活性的升高和淀粉相对降解量呈动态正相关,但后期相关性不高,说明淀粉的降解与多种因素有关,不仅仅受淀粉酶的影响.烟叶淀粉和色素的降解规律一致,均在变黄期(45℃以前,含水量30%以上)快速降解,特别是烘烤的前48 h降解量最大,之后变缓.淀粉和叶绿素含量随成熟度的提高而明显降低.在烘烤过程中,成熟度适宜的烟叶SOD和POD等保护酶活性较高,而PPO活性较低,棕色化发应不容易发生.适熟鲜烟叶淀粉含量较高,烘烤中降解较快,烤后烟叶外观质量较好,淀粉含量低而糖含量高,主要化学成分比较协调,感官评吸质量较理想.     

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.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.