高温储藏条件下不同水分含量小麦品质变化研究

以开麦21为原料,对其进行鼓风干燥和调质处理,使其水分含量分别为12.5%,9.5%,7.7%和5.9%,在35℃下密封储藏,研究其储藏过程中生活力、电导率、过氧化氢酶活动度、湿面筋含量、干面筋含量和面筋吸水率的变化,探讨高温密闭储藏下小麦的水分含量与其储藏品质变化的规律。结果表明:35℃条件下,水分含量高的小麦其生活力、过氧化氢酶活动度、湿面筋含量和面筋吸水率降幅大;水分含量为7.7%的小麦电导率增幅最小。     

热管低温储粮技术对小麦品质的影响

为研究热管低温储粮技术在储粮方面的实际应用效果,设计建造了基于热管原理的低温储粮仓,研究了储藏过程中粮食温度、水分减量、电导率值、过氧化氢酶活动度、脂肪酸值的变化情况;结果发现:在一年(2012年9月到2013年9月)的试验周期内,试验仓粮食降温速度和低温时间明显高于对照仓,在小麦品质方面:试验仓水分、过氧化氢酶活动度分别下降了0.12%、14 mg H2O2/g,比对照仓低0.11%、39.13%;脂肪酸值和电导率值分别增加7.65 mg KOH/100 g、5.1μS/cm,比对照仓低42.48%、45.16%,证明该低温储粮技术蓄冷效果明显,同时具有降低粮食水分减量、抑制脂肪酸值升高、保持籽粒活性,防止粮食劣变陈化的效果,为该储粮技术的大规模应用和推广提供理论参考。     

不同温度对偏高水分玉米储藏品质变化规律的影响

偏高水分玉米储藏难度大,品质劣变速度快,严格控制适当的储藏温度有利于延缓其品质劣变,提高其储藏品质。该试验选择水分含量为14.5% 的玉米作为偏高水分玉米样品,将其在不同温度下储藏6 个月,探究低温（15 ℃）、准低温（20 ℃）、常温（25 ℃）和高温（30 ℃）等不同温度对偏高水分玉米储藏品质的影响。结果表明,偏高水分玉米在15、20 ℃下储藏6 个月之后,品质保持良好;25 ℃下储藏6 个月时,其色泽、生活力、发芽势、发芽率均发生了不同程度地下降,玉米粉轻微老化,脂肪酸值为51.88 mg/100 g,呈宜存状态;30 ℃下储藏6 个月时,其色泽、生活力、发芽势、发芽率均剧烈下降,电导率迅速增加,玉米粉老化程度严重,脂肪酸值增至84.05 mg/100 g,呈重度不宜存状态。根据上述品质指标综合评价,建议粮库选择20 ℃储藏偏高水分（14.5%）玉米,可在保证玉米储藏品质的同时有效提高经济效益。     

不同品种糙米储藏期间品质变化规律的研究

为探讨糙米储藏品质的变化规律及其影响因素,选择辽宁地区常见的稻谷品种辽星、盐粳218、田丰202、锦稻201和盐丰407作为实验原料,分别在准低温储藏(20℃)和农户常规储藏条件下储藏一年(2014.12~2015.12),对糙米样品的水分、脂肪酸值、电导率、过氧化氢酶活性、发芽率、品尝评分值和直链淀粉等品质指标进行了跟踪测定,并对测定数据进行相关分析。试验结果表明:随着糙米储藏时间的延长,糙米脂肪酸值和电导率将逐渐增大,而水分、过氧化氢酶活性、发芽率和品尝评分值将逐渐降低;储藏方式以及品种的差异也对糙米储藏品质指标显著影响(p0.05)。通过综合分析糙米品质指标变化规律,确定田丰202和锦稻201耐储性。并对田丰202的储藏品质指标进行了相关性分析,分析表明可以采用过氧化氢酶、电导率、脂肪酸值和发芽率指标来反映糙米的耐储性。     

糙米储藏期间品质变化研究

在农户储藏方式下,通过研究1年储藏期内糙米的水分含量、脂肪酸值、电导率、发芽率及品尝评分值的变化,探索储藏时间对辽宁省本地5种糙米品质的影响。结果表明:各种糙米样品在储藏期间各指标的变化趋势基本相同,脂肪酸值和电导率在储藏期间逐渐增高,发芽率呈现下降趋势,而品尝评分值先升高后降低,糙米水分含量变化受环境温湿度影响,呈上下波动趋势。     

温度与水分对薏仁米贮藏过程中脂肪氧化的影响

以兴仁薏仁米为试验材料,探讨不同温度(15, 25和35℃)和水分(10.5%, 12.0%和13.5%)对薏仁米储藏过程中脂肪氧化的影响。结果表明,薏仁米的储藏温度和水分越高,其油脂氧化速率越快。180 d时,不同温度下薏仁米的脂肪酸值、过氧化值、电导率增加范围分别为182.84%～233.46%, 167.09%～314.01%和33.13%～74.02%,肪酶活动度下降范围为22.49%～47.69%,不同水分下其增加范围分别为87.60%～259.31%, 109.76%～254.66%和0.97%～15.15%。脂肪酸值和过氧化值受温度与水分的影响最显著;温度对电导率的影响大;温度与水分对丙二醛含量影响差异显著,与样品调节水分的前处理密切相关;与温度的影响相比,含水量高低对脂肪酶活性影响更大。低温与低水分能有效延缓薏仁米贮藏过程中的脂肪氧化。     

不同储藏条件下糙米脂肪酸值变化研究

对不同水分、温度、氧气浓度条件下储藏的糙米定期进行脂肪酸值测定,糙米的水分分别为13.5%、14.5%、15.5%、16.5%,放入温度分别设定为30、25、20、15℃的恒温箱中储藏,氧气的体积分数为2%、5%、8%、21%,储藏时间为180天,每30天检测1次.结果表明,随着储藏时间的延长,糙米样品中脂肪酸值呈先增加继而又下降的趋势;经方差分析得出,储藏时间、温度、水分、氧气浓度对糙米脂肪酸值影响极显著(P<0.01),温度、水分越高,糙米的脂肪酸值上升越快;低浓度氧气可延缓脂肪酸值变化.经过多重差异比较得出,用4种不同温度储藏糙米,其脂肪酸值差异极显著(P<0.01);在温度为20～30℃及不同水分条件下储藏糙米,其脂肪酸值差异均极显著(P<0.01);在15～C条件下,15.5%与14.5%差异显著(P<0.05),其他水分梯度差异极显著(P<0.01);水分16.5%的糙米储藏在25℃,氧气体积分数分别为8%、21%条件下,其脂肪酸值差异不显著,其他浓度氧气差异极显著(P<0.01);水分14.5%的糙米储藏在15℃,不同体积分数的氧气条件下,其脂肪酸值差异均极显著(P<0.01).实验证明,低温、低水分储藏糙米可以抑制脂肪酸值的上升,低浓度氧气可以延缓脂肪酸值的下降.     

高筋小麦储藏品质变化的研究

研究选用郑麦366和西农979两种高筋小麦为研究对象,对小麦进行微波灭活,调节其生活力分别为0%、40%和90%,将其在35℃条件下恒温储藏,通过研究其在储藏过程中的发芽率、电导率、过氧化氢酶、湿面筋和糊化特性的变化,探讨小麦品质变化与其生活力之间的关系。为研究高筋小麦的储藏特性打下了一定的基础。结果表明:储藏过程中生活力越高的小麦其发芽率、湿面筋含量和过氧化氢酶活动度降低幅度越大;生活力越小的小麦电导率升高幅度越小;生活力为40%的小麦的峰值粘度、最终粘度和回生值变化的最多,衰减值变化最少。     

环境温度对油菜籽储藏品质的影响

采用不同温度(15、25、35℃)对不同水分含量(6.2％、7.9％、10.6％、12.3％)的国内普通双低油菜籽进行模拟储藏,系统研究了不同温度和水分含量对油菜籽储藏期间色泽及主要品质指标的影响.结果表明:油菜籽红度值a*和游离脂肪酸(FFA)含量均随着储藏时间延长而增加,储藏温度和水分含量愈高,增加速率越大;油菜籽过氧化氢酶活动度、氮可溶性指数均随着储藏时间延长而下降,其中在35℃条件下,高水分含量的油菜籽过氧化氢酶活动度、氮可溶性指数下降迅速.油菜籽红度值a*与FFA含量、过氧化氢酶活动度、氮可溶性指数等品质指标具有显著相关性,测定其色泽可有效表征油菜籽储藏过程中的品质变化.     

不同储藏条件下粳稻谷脂肪酸值及气味变化研究

将不同水分(12.5％、13.5％、14.5％、15.5％)的粳稻谷分别置于不同温度(15、20、25、30℃)的恒温箱中储藏4个月,每30 d检测1次脂肪酸值和气味.结果表明:随着储藏时间的延长脂肪酸值先增加继而有下降趋势,温度和水分越高,粳稻谷的脂肪酸值越大.水分为15.5％的粳稻谷在30、25、20、15℃条件下储藏60 d后,脂肪酸值(mgKOH/100 g)上升至47.36、42.60、36.47、32.77;25℃条件下,水分为15.5％、14.5％、13.5％、12.5％的粳稻谷储藏90 d后脂肪酸值分别上升至44.79、42.11、42.47、39.47.水分为14.5％的粳稻谷在30、25、20、15℃条件下储藏120 d后,气味值分别升高了1.69、1.56、1.03、1.21;30℃条件下,水分为15.5％、14.5％、13.5％、12.5％的粳稻谷储藏120 d后气味值分别升高至1.79、1.60、1.28和1.02.脂肪酸值与气味值回归方程为y=-1.522 +0.144x-0.002x2,R =0.917,R2 =0.841.     

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.     

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.     

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.     

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