紫外光降解黄曲霉毒素B1技术对小油坊花生油食用安全性的影响

模拟黄曲霉毒素B_1紫外光降解技术,研究不同紫外照射剂量下花生油中酸价、过氧化值、脂肪酸组成、苯并(a)芘、黄曲霉毒素B_1等品质及安全性指标的变化。结果表明:在紫外光照射强度800~1 600μW/cm~2范围内,花生油除过氧化值略有上升,其他指标基本无变化。小油坊使用紫外光降解设备时应尽量减少辐照时间,防止因花生油过氧化值增加超出国家标准要求范围,带来新的食品安全隐患。     

紫外LED冷光降解黄曲霉毒素B1技术对花生油品质影响的研究

目的考察紫外LED冷光降解黄曲霉毒素B_1(AFB_1)对花生油品质的影响。方法通过测定紫外LED冷光照射前后脂肪酸、酸价、过氧化值的变化来初步评价对花生油脂肪酸的影响。结果经紫外LED冷光技术处理的花生油,其脂肪酸组成及含量变化,酸价和过氧化值的变化均无显著性差异(P0.05),对花生油的品质影响不大。结论黄曲霉毒素降解机(紫外LED冷光技术)基本对花生油品质无影响,为花生油加工企业的实际生产提供一定的参考。     

利用紫外光降解花生油中黄曲霉毒素B1

目的评价紫外光照射对花生油中黄曲霉毒素B_1(AFB_1)的降解效果以及油品质的安全性的影响。方法采用波长为365 nm,功率100 W的紫外灯设备对花生油中的AFB_1进行照射处理后,分别利用高效液相色谱(HPLC)对花生油中的AFB_1的含量,滴定法对过氧化值,Ranciment法对氧化稳定性以及气相色谱法(GC)对不饱和脂肪酸的含量进行跟踪测定。结果结果表明,随着紫外照射时间的延长,花生油中黄曲霉毒素的含量逐渐降低,在25 min内降解率可达90%,过氧化值、不饱和脂肪酸的含量以及氧化稳定性这些品质指标数值均无明显变化。结论紫外光照射脱毒技术不仅对花生油中的AFB_1有很好的降解效果,并且对油品质无显著影响。     

紫外处理对黄曲霉毒素B1及花生油品质的影响

以花生油为原料,采用紫外辐照处理花生油以降解其中的黄曲霉毒素B1,并探究其对花生油品质的影响。结果表明,紫外辐照处理能显著降低花生油中的黄曲霉毒素B1含量。紫外辐照处理对花生油的过氧化值、酸值的影响会因花生油的氧化程度不同而有所差异,当花生油的过氧化值在8 mmol/kg时,进行紫外辐照处理后,花生油的酸值、过氧化值变化幅度较大;当花生油较新鲜,酸值、过氧化值较低时,经紫外辐照处理后花生油的酸值、过氧化值变化幅度不大;色泽、碘值、铅、总砷、脂肪酸、反式脂肪酸没有变化,折光指数、磷脂也无明显变化,维生素E则有一定程度的减少。     

60Co辐照降解花生油中黄曲霉毒素B1及对花生油品质的影响

以市售花生油为原料,选取酸值、过氧化值、碘值、维生素E和反式脂肪酸作为检测指标,研究不同辐照剂量下60Co辐照对花生油中黄曲霉毒素B1(AFB1)降解率及对花生油品质的影响。结果表明:在食品辐照所限定的剂量内,60Co辐照可以有效地减少AFB1残留,且花生油的各项理化指标变化均未超出国家标准。60Co辐照不仅对降解AFB1有效,而且对花生油品质和安全性无显著影响。     

紫外照射条件及花生油的铺展厚度对花生油中黄曲霉毒素B1含量的影响

以黄曲霉毒素B1(Aflatoxin B1,AFB1)含量为50μg/kg的花生油为原料,254 nm的紫外灯为光源,通过调节紫外照射强度、照射时间以及花生油的铺展厚度,研究不同条件下紫外照射对花生油中AFB1含量的影响.研究结果表明,紫外照射能显著降低花生油中AFB1含量,其残留量与照射强度和照射时间成正比,与油的铺...     

紫外LED冷光技术对花生油中黄曲霉毒素B1降解效果的研究

以10种黄曲霉毒素B1(AFB_1)含量不同的花生油为样品,采用紫外LED冷光照射花生油,探究紫外LED冷光技术对花生油中AFB_1的降解效果。结果表明:紫外LED冷光照射能有效降低花生油中AFB_1的含量,随着紫外照射时间的延长,花生油中AFB_1含量呈逐渐降低的趋势;当样品中AFB_1含量小于等于650μg/kg,紫外LED冷光照射时间120 s,可达到国家标准要求的花生油中AFB_1含量不超过20μg/kg的要求;而当样品中AFB_1含量大于650μg/kg,需延长其照射时间(样品3照射时间1 200 s),才可达到国家标准要求的花生油中AFB_1含量不超过20μg/kg的要求;相同的照射时间(60 s)下,在3 500～450μW/cm2的照射强度下,随照射强度的降低AFB_1降解率降低。花生油经紫外LED冷光照射后,其酸价、过氧化值没有显著的变化。     

5S压榨工艺对花生油综合品质的影响

以花生为原料,研究5S压榨花生油挥发性风味成分、VE、VD3、甾醇微量成分、抗氧化稳定性及黄曲霉毒素B1去除情况,分析压榨工艺对花生油风味、营养及安全等综合品质的影响。结果表明:5S压榨花生油的挥发性风味成分主要为吡嗪、吡啶、呋喃等含氮、氧杂环化合物。其中吡嗪类化合物含量最高,占总鉴定化合物的33.09%。与浸出花生油相比,5S压榨花生油中甾醇、VE、VD3含量较高,诱导时间更长,抗氧化稳定性更好,且紫外降解去除黄曲霉毒素B1安全有效。     

不同制油工艺及去除红衣对花生黄曲霉毒素的影响

研究不同制油工艺对花生黄曲霉毒素迁移的影响以及去除红衣对花生黄曲霉毒素削减的影响。结果表明:采用溶剂浸提法制取花生油时,约3%的黄曲霉毒素B1(AFB1)和黄曲霉毒素B2(AFB2)迁移至油中,而剩下的97%迁移至粕中;采用水酶法制取花生油过程中,约10%的AFB1、0. 1%的AFB2迁移至油中,AFB1、AFB2分别有69. 25%、77. 70%迁移至液相中;采用压榨法制取花生油时,AFB1、AFB2有约10%迁移至油中,剩下的约90%迁移至饼中;当花生仁中黄曲霉毒素含量较低时,去除红衣对其削减率影响较大;而当黄曲霉毒素含量较高时,去除红衣对其削减率影响较小。     

等离子体处理对花生油品质的影响

研究采用低温射频等离子体技术处理花生油,处于激发态的等离子体可能会引起油脂的理化性质发生改变,因此以花生油中的酸价、碘价、过氧化值、维生素E、氧化稳定性和反式脂肪酸含量等作为检测指标,来评估低温射频等离子体去除黄曲霉毒素过程中对其对花生油品质的影响。实验结果表明,经100 W、200 W和300 W的等离子体处理花生油10 min后,花生油的酸价从0.87mg KOH/g分别减少到0.28、0.25和0.26,差异显著(p0.05)。碘价在10 min范围内的变化幅度不大,差异不显著(p0.05)。在实验所处理的范围内,花生油的过氧化值均未超出6 mmol/kg。通过高效液相色谱分析,等离子体对花生油中的维生素E和反式脂肪酸含量的影响较小。说明低温射频等离子体技术降解花生油中的AFB1的方法不仅安全、有效,而且也不会影响花生油的品质。     

紫外光下4种抗氧化剂在猪油中的抗氧化效果

旨在研究光照对油脂抗氧化剂抗氧化效果的影响。分别研究在254、365 nm波长光照射下,猪油中添加丁基羟基茴香醚(BHA)、2,6-二叔丁基-4-甲基苯酚(BHT)、特丁基对苯二酚(TBHQ)、没食子酸丙酯(PG)对其过氧化值、酸价、丙二醛值、共轭二烯类值、共轭三烯类值的影响。结果表明,与空白相比,在254 nm光照下,4种抗氧化剂抑制猪油过氧化值、酸价、丙二醛值、共轭二烯类值、共轭三烯类值的效果差异不显著(p>0.05);在365 nm光照下,BHA、BHT、PG抑制猪油过氧化值、酸价、共轭二烯类值、共轭三烯类值效果差异性不显著(p>0.05),抑制丙二醛效果差异极显著(p<0.01)。TBHQ抑制猪油酸价、共轭三烯类值效果差异不显著(p>0.05),抑制过氧化值、共轭二烯类值差异显著(p<0.05),抑制丙二醛效果差异性极显著(p<0.01)。由此说明,在254、365 nm光照射下,BHA、BHT、PG基本没有抗氧化效果,TBHQ的效果也不够理想。     

脂质氧化加速实验3种方法的比较分析

以猪背膘为实验对象,研究比较高温加热、反复冻融及紫外照射3种加速脂质氧化方法的效果.通过分析酸价、游离脂肪酸含量及组成、过氧化值(peroxide value,POV)、硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)值及脂质氧化产物等指标的变化情况,同时...     

Characterization of UV-peroxide killing of bacterial spores

Advantage is taken in many sterilization processes, especially for food packaging materials, of the synergy between H2O2 and UV irradiation for spore killing. The nature of the synergy is currently not well defined in terms of targets and mechanisms. We found that under some experimental conditions, the synergistic killing of spores of Bacillus megaterium ATCC 19213 appeared to be mainly UV-enhanced peroxide killing, while under other conditions, it appeared to be mainly peroxide-enhanced UV killing. Lethal combinations of H2O2 and UV irradiation for spores resulted in only modest increases in auxotrophic mutations among survivors, indicative of little DNA damage, in contrast to higher mutation levels after dry-heat damage at 115 degrees C. However, the combination of UV light and peroxide did lead to major inactivation of glucose 6-phosphate dehydrogenase, an enzyme that was used to monitor the damage to bacterial protein. Synergistic UV-H2O2 killing was reduced by agents such as pyruvate, thiosulfate, and iron or copper cations, which appeared to act at least in part by reacting chemically with H2O2, and was only slightly affected by the use of UV light at a wavelength of 222 nn rather than 254 nm. Hydrogen peroxide treatment can precede UV irradiation for synergistic killing by some hours with an interim of drying for spores of Bacillus subtilis A, a spore type used commonly for the validation of aseptic processes. Synergistic killing of dried spores or those in suspensions was accelerated at higher temperatures (50 degrees C) rather than at lower temperatures (25 degrees C).     

辐照对蚕蛹贮藏期品质特性的影响

以真空包装的蚕蛹为材料,经0、3、6 kGy 60Co-γ射线辐照后,在4 ℃条件下贮藏0～60 d,研究不同辐照剂量和不同贮藏时间（0、30、60 d）条件下蚕蛹的感官指标与品质的变化。结果表明：1）辐照蚕蛹的色度值、酸值、脂肪含量、微生物数量显著降低,硬度、咀嚼性、过氧化值显著升高;感官评分、蛋白质含量和弹性无显著变化。2）在贮藏期间,辐照蚕蛹的色度值、微生物数量随辐照剂量的增加而降低;硬度、咀嚼性、脂肪含量随剂量的增加而增加;过氧化值增加的幅度低于对照,且辐照剂量较高的处理增加幅度较为缓慢;酸值无明显变化。3）6 kGy辐照对蚕蛹具有显著的杀菌效果。由此可见,辐照改善了蚕蛹的贮藏品质,杀菌效果显著,有利于延长蚕蛹的保鲜期。     

紫外结合γ-氨基丁酸对鲜切香瓜品质的影响

为了探讨γ-氨基丁酸( γ-aminobutyric acid,GABA)和紫外辐照对鲜切香瓜贮藏品质的影响,本文研究了不同浓度GABA和不同紫外辐照时间对鲜切香瓜失重率、L*值、硬度、可溶性固形物（TSS）含量的影响,筛选出GABA的最佳处理浓度和紫外辐照的最佳时间,并比较了GABA、紫外辐照以及两者相结合对鲜切香瓜贮藏品质的影响。结果表明:不同浓度的GABA处理均能降低鲜切香瓜的失重率和TSS的含量,较好地保持其硬度和色泽,其中1% GABA处理的失重率和TSS含量最低,硬度和L*值最高;紫外处理不同时间能减缓鲜切香瓜的失重率和TSS含量的增加,其中5 min处理的失重率和TSS含量最低,L*值和硬度最高。根据失重率、TSS含量、硬度和L*值等指标,确定GABA的最佳处理浓度为1%,紫外辐照的最佳处理时间为5 min。紫外辐照5 min结合1% GABA的处理能有效减缓鲜切香瓜的失重率和可溶性固形物的积累,保持鲜切香瓜的色泽和硬度,并且还能延缓可滴定酸含量下降,保持较高的可溶性蛋白质的含量。因此,紫外辐照5 min结合1% GABA处理更能保持鲜切香瓜的贮藏品质。     

A comparison of single oxidants versus advanced oxidation processes as chlorine-alternatives for wild blueberry processing (Vaccinium angustifolium)

Advanced oxidation processes and single chemical oxidants were evaluated for their antimicrobial efficacy against common spoilage bacteria isolated from lowbush blueberries. Predominant bacterial flora were identified using biochemical testing with the assessment of relative abundance using non-selective and differential media. Single chemical oxidants evaluated for postharvest processing of lowbush blueberries included 1% hydrogen peroxide, 100 ppm chlorine, and 1 ppm aqueous ozone while advanced oxidation processes (AOPs) included combinations of 1% hydrogen peroxide/UV, 100 ppm chlorine/UV, and 1 ppm ozone/1% hydrogen peroxide/UV. Enterobacter agglomerans and Pseudomonas fluorescens were found to comprise 90-95% of the bacterial flora on lowbush blueberries. Results of inoculation studies reveal significant log reductions (p< or 5) in populations of E. agglomerans and P. fluorescens on all samples receiving treatment with 1% hydrogen peroxide, 1% hydrogen peroxide/UV, 1 ppm ozone, or a combined ozone/hydrogen peroxide/UV treatment as compared to chlorine treatments and unwashed control berries. Although population reductions approached 2.5 log CFU/g, microbial reductions among these treatments were not found to be significantly different (p< or 5) from each other despite the synergistic potential that should result from AOPs; furthermore, as a single oxidant, UV inactivation of inoculated bacteria was minimal and did not prove effective as a non-aqueous bactericidal process for fresh pack blueberries. Overall, results indicate that hydrogen peroxide and ozone, as single chemical oxidants, are as effective as AOPs and could be considered as chlorine-alternatives in improving the microbiological quality of lowbush blueberries.     

Oxidative consequences of UV irradiation on isolated milk proteins: Effects of hydrogen peroxide and bivalent metal ions

β-Casein (β-CN), β-lactoglobulin (β-LG), and α-lactalbumin (α-LA), were subjected to UV irradiation, alone or in the presence of hydrogen peroxide, hydrogen peroxide plus copper, or iron. Disappearance of tryptophan (Trp) was fastest for α-LA and slowest for β-CN. Hydrogen peroxide accelerated loss of Trp, while addition of iron did not further increase the speed of Trp reduction, but the addition of copper did. Oxidation products were higher for β-CN than for β-LG following UV irradiation alone or in the presence of hydrogen peroxide or hydrogen peroxide plus iron. In the presence of copper, oxidation rates were similar for both proteins. UV photo-oxidation caused the loss of the native polypeptides, the rate of this being faster for β-LG than for β-CN. These results are compatible with the concept that formation of dityrosine and N-formylkynurenine were favoured by mobility in the native protein.     

氢气对油脂过氧化值的影响研究

用对比实验的方法,在包装袋内充氢气及改变袋内氢气存留时间,研究了氢气对几种主要食用油脂及火腿肥膘在室内环境和紫外灯光照射下过氧化值(POV)的变化,发现氢气对油脂及其含油脂产品有较好的防止氧化酸败作用,能有效保证食品的质量品质,延长油脂及含油脂食品的保质时间。     

电子束辐照对松花粉脂质氧化及其品质的影响

以原松花粉为试材,研究电子束辐照对其杀菌效果、脂肪酶活力、脂质氧化性能和营养品质的影响,并分析了破壁松花粉在加速氧化过程中色泽、过氧化值和挥发性成分的变化。结果表明,电子束辐照可显著降低松花粉中微生物含量,且辐照剂量越大,杀菌效果越显著;菌落总数、霉菌酵母数和大肠菌群的D10值分别为2.20、1.95和1.84 kGy;随着辐照剂量的增加,松花粉中脂肪酶活力、类胡萝卜素含量和游离脂肪酸含量显著降低,过氧化值略有升高但总体仍处于较低水平,当辐照剂量为8 kGy时,脂肪酶灭活率为53.52%,类胡萝卜素保留率为60.81%,游离脂肪酸含量为1.38 mg/kg,过氧化值为0.46 meq/kg;此外,8 kGy剂量辐照对松花粉的基本营养成分及氨基酸含量无明显影响,在加速氧化过程中,破壁松花粉的色泽无明显变化,过氧化值、己醛和己酸含量增幅不大。表明8 kGy电子束辐照对松花粉营养品质影响不大,并能有效杀灭微生物,抑制脂质氧化,提高产品储藏稳定性。