不同生产工艺对油茶籽油理化指标和脂质伴随物的影响

目的 研究油茶籽油加工过程中全生产工艺对油理化指标和脂质伴随物的影响。方法 首先收集不同预处理方式、不同制油工艺、不同精炼阶段生产的油茶籽油,其次对其酸价、过氧化值等质量指标、脂肪酸组成、生育酚、角鲨烯、甾醇等活性脂质伴随物进行检测,最后进行分析讨论。结果 热风和蒸汽预处理油茶籽对油茶籽油脂肪酸组成影响不大,可以使油中的多酚含量增加76.8%和59.8%,热风预处理会增加植物甾醇的含量。在制油环节,浸出工艺会大幅度增加油茶籽油的酸价、过氧化值,且有苯并[a]芘的产生,对油品影响严重。精炼结束后压榨油茶籽油的酸价下降了65.6%,能全部去除生产过程产生的苯并[a]芘,生育酚、甾醇、角鲨烯和多酚分别损失100%、46.57%、86.18%和79.19%。精炼工艺仅保留脱胶沉淀,不经脱色、脱酸脱臭和冬化等工序,油茶籽油的脂肪酸组成保持不变,过氧化值下降30.3%,也可全部去除苯并[a]芘,还可使生育酚、角鲨烯、多酚和甾醇等活性脂质伴随物的保留率达85%以上。结论 油茶籽油预处理和精炼工艺会影响油品质量,浸出油茶籽油较压榨油品质相差较大。在实际生产过程中可对各生产工艺进行优化以获得较高品质油茶籽油。     

不同脱酸工艺对红花籽油储藏品质的影响

为了选择合适的脱酸工艺,提高红花籽油的储藏品质,以脱胶红花籽油为原料,采用碱炼脱酸和超声波辅助乙醇萃取(UAEE)脱酸工艺制备脱酸红花籽油,并采用Schaal烘箱法进行加速氧化试验,比较加速氧化期间脱酸红花籽油的理化指标(酸值、过氧化值、p-茴香胺值)、脂质伴随物(α-生育酚、总酚、总甾醇)含量,以及体外抗氧化能力(DPPH、ABTS自由基清除能力),对比分析2种脱酸工艺对红花籽油储藏品质的影响,并预测货架期的差异。结果表明：随着储藏时间的延长,2种脱酸红花籽油的理化品质、脂质伴随物含量、体外抗氧化能力均呈下降趋势;与碱炼脱酸工艺相比,UAEE脱酸工艺制备的红花籽油储藏品质更优;2种脱酸红花籽油的氧化均符合一级氧化动力学反应,通过动力学方程预测20℃和25℃密封避光条件下,UAEE脱酸红花籽油的货架期分别约为28 d和27 d,而碱炼脱酸红花籽油的分别约为22 d和21 d。综上,与碱炼脱酸相比,UAEE脱酸能提升红花籽油的储藏品质,有利于延长红花籽油的货架期。     

基于微波预处理压榨文冠果油储藏期间的品质研究

利用Schaal烘箱法,研究测定了由微波预处理种仁冷榨制取的文冠果油储藏期间酸价、过氧化值、p-茴香胺值、生育酚含量、脂肪酸组成及含量的变化,评价了微波预处理对油脂氧化稳定性的影响,并对文冠果油理化指标进行了相关性分析。结果表明:文冠果油在储藏期间,过氧化值和K_(232)在前期快速增高,中期趋于平缓,后期又快速增长;酸价、p-茴香胺值及K_(270)则持续增长;生育酚含量与氧化诱导时间在前、后期快速降低,中期降低较缓慢;不饱和脂肪酸与饱和脂肪酸的比值降低;相关性分析表明文冠果油在储藏期间的氧化稳定性与生育酚含量及过氧化值、酸价、p-茴香胺值、K_(232)、K_(270)密切相关。此外,适当的微波预处理有助于增强文冠果油的氧化稳定性。     

精炼工艺对椰子油品质的影响

研究了精炼工艺对椰子油品质的影响。分析了毛椰油、碱炼油、脱色油、脱臭油的理化指标、脂肪酸、甘油酯组成和脂肪伴随物(甾醇、生育酚、多酚)的变化情况。结果表明:精炼工艺使椰子油的酸值、过氧化值显著降低,脂肪酸和甘油酯组成无显著变化;总甾醇、总生育酚和多酚含量显著降低,损失率分别为63.77%、68.03%、71.20%。综上表明,精炼能够显著影响油脂品质,需注重油脂适度加工技术的应用。     

大豆油食用期氧化稳定性的研究

以过氧化值、酸值和p-茴香胺值为评价指标,模拟大豆油家庭食用条件,研究充氮气、添加抗氧化剂(TBHQ)的大豆油(2.5L/桶)在3个月(6、7、8月)食用期内的品质变化规律.结果表明:在3个月的食用期内,2种处理方式下大豆油的过氧化值、酸值和p-茴香胺值均随着时间的延长逐渐增加,其中,过氧化值分别在第70、50 d达到质量安全值5.0 mmol/kg,酸值均小于质量安全值0.2 mg KOH/g,p-茴香胺值变化不大.与添加抗氧化剂相比,氮气储藏同样提高了大豆油的稳定性,氮气储藏可以成为大豆油的一种绿色储藏方法.     

化学和物理精炼工艺对葡萄籽油氧化劣变品质的影响

为了研究化学和物理精炼工艺对葡萄籽油氧化裂变品质的影响,分别采用化学和物理工艺精炼葡萄籽原油,探讨反式脂肪酸的变化规律,以及不同精炼阶段油脂的酸价、过氧化值、p-茴香胺值和VE含量变化。结果表明:葡萄籽油经化学精炼酸价降至(0.20±0.016)mg KOH/g,葡萄籽油的过氧化值和p-茴香胺值降低,反式脂肪酸质量分数增加至(0.36±0.001 4)%,VE损失了37%~43%。对葡萄籽原油进行物理精炼,240℃条件下真空脱酸6 h,酸价降至(0.19±0.029)mg KOH/g,过氧化值降低、p-茴香胺值升高,反式脂肪酸质量分数增至(0.91±0.001 3)%,VE损失了50.69%。比较得知,物理精炼过程相对于化学精炼对葡萄籽油品质的影响较大。     

大豆油和棕榈油煎炸薯条过程品质评价

为了对中包装的大豆油棕榈油煎炸专用调和油配方的开发和煎炸稳定性相关理化指标的选择提供参考,分别以一级大豆油、分提18℃棕榈油(一次精炼)及同批次的二次精炼18℃棕榈油为煎炸油,模拟薯条在180℃下高温煎炸32 h,对3种油品在煎炸过程中的酸值、过氧化值、p-茴香胺值、脂肪酸组成、极性组分含量、生育酚含量等理化指标进行了检测,并对18℃棕榈油中的风险因子,如PAH4、苯并(a)芘、3-氯丙醇酯(3-MCPDE)、反式脂肪酸含量进行了分析。结果表明：3种油品的酸值、过氧化值在煎炸过程中变化不明显,而p-茴香胺值、脂肪酸组成、极性组分含量在煎炸过程中变化比较明显;3种油品的生育酚氧化速度总体偏差不大;分提18℃棕榈油、二次精炼18℃棕榈油中的苯并(a)芘、反式脂肪酸含量均随煎炸时间延长呈缓慢升高的趋势;二次精炼18℃棕榈油的3-MCPDE在未煎炸时远高于分提18℃棕榈油的,3-MCPDE在煎炸初期降解剧烈,最终达到平衡;分提18℃棕榈油与二次精炼18℃棕榈油在煎炸稳定性方面没有明显区别,二次精炼不仅损失了部分有益的微量营养成分(如生育酚),还伴生出新的风险因子,如增加了3-MCPDE、反式脂...     

精炼工艺对元宝枫籽油品质的影响

为了对元宝枫籽油的精炼提供指导,分析了精炼过程中元宝枫籽油的基本理化指标、脂肪酸和有益油脂伴随物（植物甾醇、生育酚）的变化情况。结果表明：随着精炼工序的进行,元宝枫籽油的酸值、过氧化值和氧化诱导期显著降低（p<0.05）,脂肪酸组成变化不显著（p>0.05）,植物甾醇和生育酚两种有益油脂伴随物的含量显著降低（p<0.05）,分别由毛油的950.3 mg/kg和1 107.4 mg/kg降至脱臭油的569.9 mg/kg和743.4 mg/kg,损失率分别为40.0%、32.9%。研究结果说明精炼能够显著影响元宝枫籽油的品质,应有效控制脱臭条件,尽量减少有益油脂伴随物的损失。     

黄油的烘焙稳定特性及其脂肪酸含量

为研究不同烘焙条件对黄油氧化稳定性的影响,以起酥油和棕榈油为对照,分析烘焙体系下黄油酸值、过氧化值、p-茴香胺值、全氧化值、生育酚含量及脂肪酸组成变化。结果表明,在不同烘焙条件下黄油具有较好的氧化稳定性。随着加热温度和时间的延长,起酥油与棕榈油的酸值显著增加（P<0.05）,黄油的酸值也呈上升趋势,在250 ℃趋于稳定（1.69 mg/g）。与起酥油和棕榈油相比,加热温度和时间对黄油的过氧化值影响不显著（P<0.05）,基本保持在0.8～0.92 meq/kg。起酥油和棕榈油的最大p-茴香胺值（23.5,24.7）均高于黄油（22.8）。全氧化值大小排序为起酥油>棕榈油>黄油。当温度升至250 ℃时,起酥油和棕榈油生育酚含量损失较多（77%,79%）,黄油相比于两者生育酚含量变化相对较少（72%）。3种烘焙油脂多不饱和脂肪酸含量均降低,黄油在180 ℃时降低最小（0.8%）,且均未发现反式脂肪。饱和脂肪酸与不饱和脂肪酸的比例增加时,油脂氧化稳定性降低。     

荤素分类煎炸对油脂品质的影响

为了延长煎炸油的使用寿命,有效降低成本,研究了荤素分类煎炸对油脂品质的影响。采用食材荤素分类及不分类煎炸并循环使用煎炸油,分析了两种煎炸方式下煎炸油的色泽、酸值、过氧化值、p-茴香胺值、极性组分含量的变化情况,并对比分析两种煎炸方式用油量。结果表明：采用荤素分类煎炸可以更好地抑制油脂色泽、酸值、p-茴香胺值及极性组分含量的增长速度;不分类煎炸油脂的色泽在煎炸2 d后无法用比色仪检测,分类煎炸7 d后油脂的色泽才接近不分类煎炸2 d的色泽;不分类煎炸的油脂酸值(KOH)在煎炸前3 d内急剧上升,由初始的0.09 mg/g增至1.30 mg/g,分类煎炸的油脂酸值(KOH)浮动较小,由初始的0.09 mg/g最高增加至0.62 mg/g;在煎炸7 d时,不分类煎炸的油脂p-茴香胺值由初始的4.0增加到38.0,分类煎炸的油脂p-茴香胺值由初始的4.0增加到15.0,不分类煎炸油脂的p-茴香胺值的增长速度是分类煎炸的近3倍;不分类煎炸,油脂极性组分含量在第1天内急剧上升,在第4天达到最高,为12.5%,后逐渐趋于平稳,分类煎炸,油脂极性组分含量在前3 d内均保持在8%左右,之后才有上升的趋势...     

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.     

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.     

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.     

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.     

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