煎炸米糠油营养成分及煎炸油条品质分析

利用米糠油连续煎炸油条32 h,通过对煎炸米糠油中谷维素、维生素E、植物甾醇含量,以及煎炸油条含油率、酸值、过氧化值、羰基值检测和感官指标评价,分析研究米糠油在煎炸过程中营养成分的变化及煎炸油条的品质。结果表明:经过32 h的连续煎炸,煎炸油条中米糠油的酸值(KOH)从0.73 mg/g逐渐增加至1.32 mg/g,过氧化值呈现波动增长的变化趋势(由0.05 g/100 g增大至0.08 g/100 g),羰基值从12.50 meq/kg逐渐增加至61.72 meq/kg;煎炸米糠油中谷维素含量相对稳定,植物甾醇含量有所降低(从1.67%降低至1.23%),维生素E含量从57.04 mg/100 g显著降低至1.18 mg/100 g;煎炸油条的平均含油率为12.38%;煎炸油条的含油率低、感官效果好。     

葵花籽油在油条煎炸过程中的品质变化研究

以富含油酸、亚油酸的葵花籽油为原料,探讨葵花籽油在煎炸过程中的品质变化。结果表明:葵花籽油在190±5℃煎炸24 h,酸值(KOH)由0.26 mg/g增加至0.89 mg/g,过氧化值由4.40mmol/kg上升为8.20 mmol/kg,羰基值由8.39 meq/kg上升至74.47 meq/kg,丙二醛的含量由0.25mg/100 g上升至2.07 mg/100 g,总反式酸含量由0.45%增加至1.40%,维生素E含量由39.52mg/100 g下降为14.23 mg/100 g,极性组分由3.80%升至35.30%,煎炸12 h羰基值为44.44meq/kg,18 h极性组分含量为26.70%,指标含量已接近GB 7102.1—2003《食用植物油煎炸过程中的卫生指标》相关规定标准。因此,葵花籽油不宜在高温条件下长时间煎炸食品,且煎炸时间不宜超过12 h。     

煎炸不同食物对煎炸油品质的影响

为了探究不同食物对煎炸油劣变程度的影响,将大豆油在180℃条件下煎炸鸡胸肉和土豆,连续煎炸7 d,每天煎炸6 h;分别检测煎炸油的酸值、羰基值、总极性成分含量和脂肪酸组成及含量,分析不同食物对煎炸油品质影响的差异性和相关性,并讨论不同食物成分对煎炸油理化指标影响的原因。结果显示:煎炸鸡胸肉的煎炸油的酸值(KOH)、羰基值、总极性成分含量分别上升到3.14 mg/g、66.69 meq/kg、40.02%,各指标之间呈极显著相关性(P0.01),相关系数大于0.95;煎炸土豆的煎炸油的酸值(KOH)、羰基值、总极性成分含量分别上升到1.48 mg/g、192 meq/kg、47.16%,各指标之间呈极显著相关性(P0.01),相关系数大于0.86;煎炸鸡胸肉的煎炸油饱和脂肪酸、不饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸呈极显著相关性(P0.01),煎炸土豆的煎炸油上述脂肪酸呈显著相关性(P0.05)。煎炸不同食物对煎炸油品质产生不同的影响。     

煎炸专用调和油的品质性能研究

选取花生油、玉米胚芽油、大豆油、棕榈油4种油脂调和配制煎炸专用调和油,进行32 h连续煎炸油条试验及煎炸油品质检测分析,研究调和油在煎炸过程的品质变化及煎炸性能。结果表明:从煎炸初始至煎炸结束,煎炸专用调和油的酸值(KOH)由0.25 mg/g增加至1.09 mg/g,过氧化值由5.48 mmol/kg增加至7.06 mmol/kg,极性组分含量由4.13%增加至33.65%,反式脂肪酸含量由0.66%增加至0.86%,维生素E总量由83.06 mg/100 g降低至4.21 mg/100 g,总甾醇含量由99.66 mg/100 g降至22.45 mg/100 g;对照GB 7102.1—2003《食用植物油煎炸过程中的卫生标准》中极性组分小于等于27%的规定,其连续煎炸寿命为20 h,并且煎炸过程油烟少、泡沫少、油质清澈,油条香气浓郁、不油腻;与单一油脂相比,煎炸专用调和油优化的脂肪酸组成及丰富的天然抗氧化成分使其具有煎炸寿命长、煎炸性能稳定、营养健康的独特优势,是一种优良的煎炸专用调和油。     

餐饮煎炸专用调和油配方的研究

选取花生油、玉米油、大豆油、棕榈油进行调和配制餐饮专用煎炸调和油。用制得的煎炸调和油进行32 h不间断地煎炸油条试验,考察煎炸过程中油脂感官指标、理化指标及卫生指标变化情况。结果表明:该调和油的酸价由0.25 mg/g增加至1.09 mg/g,过氧化值由5.48 mmol/kg增加至8.44 mmol/kg,极性组分由4.13%增加至33.65%,反式脂肪酸由0.66%增加至0.86%;该调和油具有独特的脂肪酸组成,含有多种天然生物活性组分,煎炸得到的油条品质好,试验所得调和油是一种即营养又健康的适合煎炸的调和油。     

煎炸方式和煎炸食材对花生煎炸油中3-氯丙醇酯和缩水甘油酯含量的影响

以花生油为煎炸油,采用不同煎炸方式（连续煎炸32 h、间歇煎炸15 h）对不同食材（油条、薯条、鸡翅、豆腐）进行煎炸实验,并对煎炸过程所取油样中3-氯丙醇酯（3-monochloropropane-1,2-diol esters,3-MCPDE）、缩水甘油酯（glycidyl esters,GEs）含量和极性组分（polar components,PC）质量分数进行检测,分析煎炸方式和煎炸食材对花生煎炸油中3-MCPDE和GEs含量的影响。结果表明：在32 h连续煎炸过程中,油条、薯条、豆腐、鸡翅及空白煎炸油中3-MCPDE含量由初始的0.84 mg/kg分别于煎炸12、4、12、16、8 h时达到最大值（分别为2.08、2.96、17.45、7.12、8.02 mg/kg）,之后呈现下降趋势;GEs含量从初始的2.43 mg/kg至连续煎炸32 h时分别升高至20.80、7.20、5.00、2.10、66.34 mg/kg;PC质量分数达到27%的限量时,不同食材煎炸油中3-MCPDE和GEs总量排序为：空白煎炸油（66.51 mg/kg）＞油条煎炸油（21.48 mg/kg）＞豆腐煎炸油（12.93 mg/kg）＞薯条煎炸油（8.51 mg/kg）＞鸡翅煎炸油（6.60 mg/kg）。在15 h间歇煎炸过程中,煎炸开始3 h后,油条、薯条、豆腐、鸡翅及空白煎炸油中3-MCPDE含量由最初的0.84 mg/kg分别升高至9.96、2.17、4.60、11.02、5.41 mg/kg,至15 h煎炸结束时,其含量又分别变化为3.51、1.58、12.88、11.81、3.72 mg/kg;GEs含量由最初的2.43 mg/kg分别增加至46.47、9.06、9.00、40.36、47.05 mg/kg;经15 h间歇煎炸,5 种煎炸油PC质量分数均未超标,此时3-MCPDE和GEs总量排序为：鸡翅煎炸油（52.17 mg/kg）＞空白煎炸油（50.87 mg/kg）＞油条煎炸油（49.98 mg/kg）＞豆腐煎炸油（21.88 mg/kg）＞薯条煎炸油（10.64 mg/kg）。同样的煎炸方式、不同食材煎炸油中3-MCPDE、GEs及PC 3 种组分的总相对含量增幅排序为：32 h连续煎炸时,空白煎炸油＞油条煎炸油＞薯条煎炸油＞鸡翅煎炸油＞豆腐煎炸油;15 h间歇煎炸时,鸡翅煎炸油＞油条煎炸油＞空白煎炸油＞豆腐煎炸油＞薯条煎炸油。同样的煎炸食材,煎炸时长相近（间歇煎炸15 h、连续煎炸16 h）时,连续煎炸油中3-MCPDE、GEs及PC 3 种组分总相对含量的增幅普遍低于间歇煎炸。综上,油脂煎炸过程中形成3-MCPDE和GEs的含量及其安全风险应引起高度关注。     

不同抗氧化剂对调和油煎炸性能影响研究

将大豆油、棕榈油、菜籽油、葵花籽油按照一定比例配制成调和油,并向其中分别添加复配天然抗氧化剂(维生素E、茶多酚、迷迭香)和TBHQ,利用上述调和油分别进行32 h连续煎炸油条试验,对不同煎炸时间所取油样进行极性组分、酸值、过氧化值等指标检测,分析研究抗氧化剂对调和油煎炸性能的影响。结果表明:经32 h煎炸,未添加抗氧化剂、添加TBHQ及添加复配天然抗氧化剂调和油的极性组分从3.76%分别增加至27.5%、28.30%、30.72%;酸值(KOH)从0.2 mg/g分别增加至1.3、1.1、1.1 mg/g;过氧化值从1.5 mmol/kg分别增加至4.9、4.3、6.7 mmol/kg。以GB 7102.1—2003所规定煎炸油极性组分含量小于等于27%作为煎炸油寿命的评价指标,3种调和油的煎炸寿命分别为28、28、26 h。3种调和油所煎炸油条的含油率分别为9.01%、13.21%、10.01%。3种调和油煎炸过程不饱和脂肪酸含量分别减少4.6%、3.8%、3.6%,反式脂肪酸含量分别增加126%、未增加、144%。VE损失率分别为81.43%、80.61%和86.65%。综合分析,添加抗氧化剂对调和油高温煎炸油条过程的氧化稳定性似乎没有明显作用,天然抗氧化剂与TBHQ相比,虽然在提高调和油煎炸稳定性方面并不具有明显优势,但效果相近,并且天然抗氧化剂在提高食品安全方面的意义显得更为重要和具有开发前景。     

以棉籽油为基料油的煎炸专用调和油煎炸品质的研究

以棉籽油为基料油,添加大豆油、菜籽油、棕榈油进行调配,制成煎炸专用的植物调和油。用制得的煎炸调和油进行不间断地煎炸薯条试验,考察煎炸油在煎炸过程中油脂色泽、理化指标及品质的变化情况。结果表明:煎炸调和油的脂肪酸组成合理,满足单不饱和脂肪酸/多不饱和脂肪酸=4.0:0.6的最佳摄入比例。煎炸过程中色泽变化较慢,极性组分超过27%限量的时间为67 h,酸价由(0.18±0.05) mg/g增加至(3.53±0.10) mg/g,羰基价由(9.42±0.12) meq/kg增加至(36.0±0.14) meq/kg,过氧化值和苯并(α)芘没有明显的变化趋势,丙烯酰胺未检出;与河北地区常用于煎炸的三级棉籽油46 h的煎炸寿命和较高的羰基价、过氧化值和苯并(α)芘相比,配制的煎炸调和油的煎炸寿命延长了18 h,稳定性提高了37%,煎炸薯条的平均含油率为18%煎炸感官效果好,可以作为一种新型煎炸调和油。     

煎炸不同食材的花生油中极性组分与氧化甘三酯聚合物含量的相关性研究

利用花生油分别对油条、薯条、鸡翅、豆腐4种食材进行32 h连续煎炸,对每隔2 h所取煎炸油样进行极性组分、氧化甘三酯聚合物含量的检测,并与不加任何食材的空白煎炸油脂进行对比,分析研究花生油连续煎炸不同食材过程中极性组分、氧化甘三酯聚合物及其他指标的综合变化。结果表明:随煎炸时间的延长,煎炸油中极性组分、氧化甘三酯聚合物含量升高,煎炸油酸值升高、色泽加深,反式脂肪酸含量升高,经32 h连续深度煎炸,油条、薯条、鸡翅、豆腐、空白5种煎炸油中极性组分从初始的3.34%分别增至32.98%、30.61%、15.50%、29%、47.02%,其中油条、薯条、鸡翅、空白煎炸油中极性组分含量分别在32、24、30、16 h时超出27%的国标限量。氧化甘油三酯聚合物含量从初始的0.43%分别增至18.97%、23.68%、6.52%、16.92%、38.83%。煎炸油中极性组分与氧化甘油三酯聚合物含量间存在极显著的线性相关(P0.01),R2分别为0.996 4、0.993 7、0.9972、0.974 0、0.991 2。经32 h连续煎炸,5种煎炸油的酸值从初始的0.17 (mgKOH/g)的分别增至7.15、2.24、2.39、2.75、2.18(mg KOH/g);反式酸含量从初始的0.17%增加至0.34%、0.28%、0.39%、0.38%、3.54%。     

鲮鱼油炸过程中棕榈油指标的变化与控制

本研究对鲮鱼油炸过程中棕榈油指标的变化进行了感官及理化分析,并采用"Dalsorb吸附剂+板框过滤"的方法,对油炸后的棕榈油进行处理。结果表明:随着油炸时间的延长,棕榈油色泽逐渐加深、流动性及透明度逐渐变差,并且有大量鱼渣出现;棕榈油的酸价、羰基价、极性组分随油炸时间的延长不断增大(酸价由初始0.06 mg KOH/g上升至2.34 mg KOH/g,羰基价由初始3.64meq/kg上升至17.70 meq/kg,极性组分由初始3.07%上升至15.1%),过氧化值的变化无明显规律;其中酸价、极性组分变化更接近国标上限,可优先做为评价指标,但考虑到极性组分检测时间长的原因,建议在线监控以酸价指标为主。采用"Dalsorb吸附剂+板框过滤"的方法,能够明显的降低煎炸后棕榈油的酸价指标(酸价由2.36 mg KOH/g下降至1.50 mg KOH/g),对羰基价和极性组分的处理效果不明显。     

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.