共查询到18条相似文献，搜索用时 218 毫秒
1.
为探讨辐照处理对花生Ara h 2蛋白结构与致敏活性的影响,采用不同剂量60Co-γ辐照处理分离纯化所得到的花生过敏原Ara h 2蛋白,结合紫外扫描光谱、圆二色谱(CD)和聚丙烯酰胺凝胶电泳(SDS-PAGE)评估辐照处理后Ara h 2蛋白的结构变化,并用免疫印迹法和间接酶联免疫吸附法检测辐照处理后Ara h 2的抗原性变化。结果表明,60Co-γ辐照处理可以显著改变花生Ara h 2蛋白的构象,使其降解、发生交联。随着辐照剂量的增大,Ara h 2蛋白与抗体的结合能力呈逐渐下降趋势,且与蛋白紫外吸光度的增强和α-螺旋含量的降低呈现良好的相关性。当辐照剂量为10 kGy时,可基本破坏 Ara h 2 蛋白的结构和免疫活性。60Co-γ辐照处理可以有效降低花生过敏原 Ara h 2 蛋白的致敏性,这为花生脱敏技术的研究提供了新思路。 相似文献
2.
《核农学报》2019,(7)
为探讨辐照处理对花生Ara h 2蛋白结构与致敏活性的影响,采用不同剂量~(60)Co-γ辐照处理分离纯化所得到的花生过敏原Ara h 2蛋白,结合紫外扫描光谱、圆二色谱(CD)和聚丙烯酰胺凝胶电泳(SDS-PAGE)评估辐照处理后Ara h 2蛋白的结构变化,并用免疫印迹法和间接酶联免疫吸附法检测辐照处理后Ara h 2的抗原性变化。结果表明,~(60)Co-γ辐照处理可以显著改变花生Ara h 2蛋白的构象,使其降解、发生交联。随着辐照剂量的增大,Ara h 2蛋白与抗体的结合能力呈逐渐下降趋势,且与蛋白紫外吸光度的增强和α-螺旋含量的降低呈现良好的相关性。当辐照剂量为10 kGy时,可基本破坏Ara h 2蛋白的结构和免疫活性。~(60)Co-γ辐照处理可以有效降低花生过敏原Ara h 2蛋白的致敏性,这为花生脱敏技术的研究提供了新思路。 相似文献
3.
为研究辐照对鲈鱼过敏原生化性质、抗原性及二级结构的影响，本试验采用0、3、5、7、9 kGy剂量电子束辐照鲈鱼小清蛋白溶液及冻干粉，测定其浓度、浊度、疏水性、分子量和抗原性的变化，以及二级结构的含量。结果表明，随着辐照剂量增大，小清蛋白冻干粉及溶液的浓度降低，疏水性提高，浊度增加，过敏条带变浅，免疫印迹条带变浅，小清蛋白与抗体的结合能力减弱，抗原性降低；α-螺旋及无规则卷曲比例升高，β-折叠及β-转角变化不明显，二级结构被破坏。综上，电子束辐照使小清蛋白生化性质及结构发生了变化，有效降低了小清蛋白的抗原性，同时发现液态小清蛋白较固态对辐照更敏感。本研究结果为鲈鱼及其制品辐照消敏研究提供了理论依据。 相似文献
4.
5.
电子束辐照对美国红鱼杀菌保鲜效果的研究 总被引：1，自引：1，他引：0
以美国红鱼为对象,利用不同剂量电子束处理,对冷藏期内鱼肉菌落总数、总挥发性盐基氮（TVB-N）、过氧化值（POV）及鲜度指标K值进行测定,分析不同剂量电子束辐照对美国红鱼肉的杀菌效果及品质影响。结果表明：电子束辐照能有效降低美国红鱼肉的菌落总数,其中D10=161kGy,D=540kGy,冷藏期间辐照组样品菌落生长缓慢,且辐照剂量越大,杀菌效果越强;电子束处理后美国红鱼肉TVB-N值、POV均有不同程度增加,但在冷藏期内对照组TVB-N值、POV、K值的上升速度大于辐照组样品;辐照对美国红鱼肉感官影响不明显,但6kGy辐照组鱼肉色泽略微变红。综合考虑,美国红鱼肉经4kGy 电子束辐照,能有效杀灭其中的微生物,冷藏条件下保质期可达到14d,比对照延长5d左右。 相似文献
6.
为探明电子束辐照对醉泥螺的杀菌效果及辐照后醉泥螺感官品质与蛋白质营养价值的变化,为生食醉泥螺的辐照保鲜应用提供理论依据。以生食醉泥螺为研究材料,研究不同剂量电子束辐照对醉泥螺菌落总数、感官评分、蛋白质含量及其氨基酸组成的影响,并分析辐照后醉泥螺在冷藏和常温贮藏条件下的货架期变化。结果表明：1）经1～9 kGy剂量电子束辐照,醉泥螺的色泽和形态几乎没有变化,但7、9 kGy剂量组醉泥螺产生异味;2）辐照剂量越高,杀菌效果越好,当醉泥螺的初始菌落总数为1200 cfu/g时,菌落总数降至初始值10%所需的辐照剂量D10为3.46 kGy;3和5 kGy剂量的辐照对醉泥螺的抑菌效果明显,无论是冷藏还是常温贮藏,360 d内菌落总数均未超过5000 cfu/g;3）辐照对醉泥螺蛋白质含量无明显影响(P?0.05),不改变醉泥螺的限制性氨基酸种类,但经1、3、5 kGy辐照后,氨基酸总量、必需氨基酸总量及各必需氨基酸的氨基酸评分增加;4）结合电子束辐照对醉泥螺菌落总数及感官评分的影响,辐照剂量以3 kGy为宜,醉泥螺保质期冷藏条件下由对照组的5个月延长至12个月,常温条件下由对照组的不到1个月延长到3个月。该结果能为电子束辐照保鲜醉泥螺提供依据。 相似文献
7.
为探究高能电子束辐照对川产道地中药材杜仲叶品质的影响，本试验研究了不同辐照剂量（0、2、4、6、8 kGy）的高能电子束辐照对杜仲叶中的微生物含量、活性物质含量、高效液相色谱（HPLC）指纹图谱、色泽、水分和浸出物含量的影响。结果显示，电子束辐照能有效降低杜仲叶中需氧菌、霉菌和酵母菌总数；HPLC分析结果表明，不同辐照剂量对杜仲叶中的活性成分绿原酸、芦丁的影响不大，其含量变化与辐照剂量均无极显著线性相关性（P>0.01）；此外，不同电子束辐照剂量处理的杜仲叶指纹图谱相似度均大于0.90；随着辐照剂量的增加，杜仲叶色泽呈现先变浅再变深的变化，主要表现为a*、b*值先减小后增大；各辐照剂量下杜仲叶的水分、醇溶性浸出物含量均符合2020年版《中华人民共和国药典》规定。同时，2 kGy剂量的电子束辐照能有效降低杜仲叶微生物数量，且对活性成分含量和指纹图谱无显著影响。综上，2 kGy的电子束辐照剂量既能使杜仲叶微生物数量明显降低，又能够保障其品质。本研究结果为电子束辐照技术在杜仲叶贮藏中的应用提供了一定的参考依据。 相似文献
8.
辐照杀菌对鸡蛋蛋白液特性的影响 总被引：2，自引：0，他引：2
为了探明液态蛋蛋白液经辐照处理后有关特性的变化情况,为液态蛋的辐照杀菌技术应用提供试验依据。试验研究了不同辐照条件下鸡蛋蛋白液的pH值、色度、黏度、热变性、起泡性和乳化性的变化。试验表明,在辐照剂量0～3.0 kGy范围内随辐照剂量增大,蛋白液的pH值有所下降,但变化相对不大;蛋白液的黏度在辐照剂量0～0.4 kGy范围内随辐照剂量增大有较大下降,但剂量大于0.4 kGy 以后蛋白黏度随辐照剂量增大变化较小;蛋白液的色度随剂量增大无变化,但蛋液经加热凝固后,2.0 kGy以上剂量辐照组蛋白胶体颜色出现褐色,且随辐照剂量增大而加深;随辐照剂量增大,蛋白液起泡性能增强,但泡沫稳定性下降;随辐照剂量增大辐照后蛋白液的乳化性、乳化稳定性均下降。 相似文献
9.
为了研究电子束辐照处理对麦冬、大黄饮片灭菌的工艺及效果,以麦冬、大黄饮片为材料,研究不同剂量(0、2、4、6、8 kGy)电子束辐照对其微生物总数、理化指标、指纹图谱相似度及有效成分含量的影响。根据不同堆码厚度、辐照方式计算剂量不均匀度,优化麦冬、大黄饮片的电子束辐照加工工艺。结果表明,电子束辐照能明显降低麦冬、大黄饮片中的微生物数量;电子束辐照对麦冬饮片水分、水溶性浸出物及总灰分含量的变化无显著影响(P>0.05);电子束辐照有利于提高大黄饮片水溶性浸出物含量,对其干燥失重、总灰分变化无显著影响(P>0.05);辐照前后麦冬、大黄饮片的指纹图谱相似度均大于0.99,相对保留时间(RSD)均小于0.5%;不同剂量电子束辐照对麦冬、大黄饮片有效成分含量均无显著影响(P>0.05);剂量不均匀度与产品堆码厚度及辐照方式密切相关。综上,麦冬饮片适宜辐照剂量为2~8 kGy,大黄饮片适宜剂量为4~8 kGy,此剂量范围对麦冬、大黄饮片整体质量无显著影响。单面辐照时,麦冬饮片适宜堆码厚度为4 cm,大黄饮片适宜堆码厚度为4~6 cm;双面辐照时,麦冬饮片适宜堆码厚度为10 cm,大黄饮片适宜堆码厚度为14 cm。本研究为麦冬、大黄加工贮藏及电子束辐照在中药中的应用提供了理论依据与技术支持。 相似文献
10.
电子束辐照对大米营养和蒸煮品质的影响 总被引：2，自引：1，他引：1
为进一步发展、完善辐照杀虫灭菌技术应用于储粮方面的理论研究,该研究采用0、0.83、1.56、2.30、4.93kGy不同剂量的电子束辐照大米样品,考察其对大米品质的影响。结果表明:不同剂量的电子束辐照对大米的蛋白质含量、氨基酸的含量与组成无明显影响(p>0.05);随着辐照剂量的增加,大米的脂肪酸值、胶稠度升高(p<0.05),吸水率、膨胀率下降(p<0.05);电子束辐照对大米糊化温度的影响不明显(p>0.05),但显著降低大米的峰值黏度、衰减值、回生值(p<0.05),明显影响米饭的蒸煮品质(p<0.05),剂量为4.93kGy时蒸煮米饭出现明显的褐变。电子束辐照大米的剂量不宜超过2.30kGy,以0.83kGy的辐照剂量较佳,该研究结果将为储藏和进出口检疫中对大米进行辐照杀虫、灭菌时的剂量选择提供参考。 相似文献
11.
电子束辐照对素鸡杀菌效果及品质特性影响的研究 总被引：1，自引：0，他引：1
以素鸡为试验对象,研究电子束辐照对素鸡杀菌效果及其营养品质和感官品质的影响。结果表明,电子束辐照对素鸡的杀菌效果显著,D10=0．48kGy;8．8kGy以下电子束辐照对素鸡蛋白质、脂肪、脂肪酸、氨基酸的影响在5％水平上差异不显著,在水分含量方面差异显著;经8．8kGy电子束辐照处理的素鸡与对照素鸡相比,其感官品质未呈现显著差异。综合考虑,2．4kGy电子束辐照处理可以有效控制素鸡中的细菌而不影响其营养和感官品质,其货架期可达8d;电子束辐照素鸡的最高耐受剂量至少为8．8kGy。 相似文献
12.
Mondoulet L Paty E Drumare MF Ah-Leung S Scheinmann P Willemot RM Wal JM Bernard H 《Journal of agricultural and food chemistry》2005,53(11):4547-4553
Peanuts are one of the most common and severe food allergens. Nevertheless, the occurrence of peanut allergy varies between countries and depends on both the exposure and the way peanuts are consumed. Processing is known to influence the allergenicity of peanut proteins. The aim of this study was to assess the effect of thermal processing on the IgE-binding capacity of whole peanut protein extracts and of the major peanut allergens Ara h 1 and Ara h 2. Whole proteins, Ara h 1, and Ara h 2 were extracted and purified from raw, roasted and boiled peanuts using selective precipitation and multiple chromatographic steps, and were then characterized by electrophoresis and mass spectrometry. The immunoreactivity of whole peanut extracts and purified proteins was analyzed by the enzyme allergosorbent test (EAST) and EAST inhibition using the sera of 37 peanut-allergic patients. The composition of the whole protein extracts was modified after heat processing, especially after boiling. The electrophoretic pattern showed protein bands of low molecular weight that were less marked in boiled than in raw and roasted peanuts. The same low-molecular-weight proteins were found in the cooking water of peanuts. Whole peanut protein extracts obtained after the different processes were all recognized by the IgE of the 37 patients. The IgE-binding capacity of the whole peanut protein extracts prepared from boiled peanuts was 2-fold lower than that of the extracts prepared from raw and roasted peanuts. No significant difference was observed between protein extracts from raw and roasted peanuts. It is noteworthy that the proteins present in the cooking water were also recognized by the IgE of peanut-allergic patients. IgE immunoreactivity of purified Ara h 1 and Ara h 2 prepared from roasted peanuts was higher than that of their counterparts prepared from raw and boiled peanuts. The IgE-binding capacity of purified Ara h 1 and Ara h 2 was altered by heat treatment and in particular was increased by roasting. However, no significant difference in IgE immunoreactivity was observed between whole protein extracts from raw and roasted peanuts. The decrease in allergenicity of boiled peanuts results mainly from a transfer of low-molecular-weight allergens into the water during cooking. 相似文献
13.
Bernard H Mondoulet L Drumare MF Paty E Scheinmann P Thaï R Wal JM 《Journal of agricultural and food chemistry》2007,55(23):9663-9669
Numerous food allergens of plant origin belong to the 2S albumin family, including peanut Ara h 2. In addition to Ara h 2, several other conglutins related to 2S albumins are present in peanut seeds. We evaluated the allergenicity of different peanut conglutins as compared with Ara h 2. Several conglutins were isolated from the kernel, i.e. Ara h 2, a new isoform of Ara h 6 and its derived product, which is likely to be naturally formed during seed processing. Enzyme allergosorbent tests performed on sera of peanut allergic patients showed that more than 94% of 47 analyzed patients had positive IgE responses to Ara h 6 isoform and to its degradation product. Skin prick tests with the new isoform of Ara h 6 led to a positive response in seven out of the eight tested patients. Both enzyme allergosorbent tests and skin prick tests showed that the reactivity of Ara h 6 was similar to, or even higher than, that of Ara h 2, suggesting that the present isoform of Ara h 6 is as allergenic as Ara h 2. In addition the IgE response to the plant processed (i.e., hydrolyzed) Ara h 6 new isoform is equivalent to the IgE response to the native isoform. The IgE immunoreactivity is mostly abrogated by chemical reduction and denaturation of Ara h 6 isoforms, which underlined the importance of tertiary structure in Ara h 6 immunoreactivity. These results, and particularly the high correlation between anti-Ara h 2 and anti-Ara h 6 IgE responses, emphasise the major role of 2S albumins in peanut allergenicity. 相似文献
14.
van Boxtel EL van Beers MM Koppelman SJ van den Broek LA Gruppen H 《Journal of agricultural and food chemistry》2006,54(19):7180-7186
Ara h 1, a major peanut allergen, is known as a stable trimeric protein. Nevertheless, upon purification of native Ara h 1 from peanuts using only size exclusion chromatography, the allergen appeared to exist in an oligomeric structure, rather than as a trimeric structure. The oligomeric structure was independent of the salt concentration applied. Subjecting the allergen to anion exchange chromatography induced the allergen to dissociate into trimers. Ammonium sulfate precipitation did not bring about any structural changes, whereas exposing the allergen to hydrophobic interaction chromatography caused it to partly dissociate into trimers, with increasing amounts of trimers at higher ionic strengths. The (partial) dissociation into trimers led to a change in the tertiary structure of the monomeric subunits of the allergen, with the monomers in Ara h 1 oligomers having a more compact tertiary structure compared with the monomers in Ara h 1 trimers. As structural characteristics are important for a protein's allergenicity, this finding may imply a different allergenicity for Ara h 1 than previously described. 相似文献
15.
Confirmation of the allergenic peanut protein, Ara h 1, in a model food matrix using liquid chromatography/tandem mass spectrometry (LC/MS/MS) 总被引：1，自引：0，他引：1
Enzymatic digestion of total protein along with liquid chromatography/tandem mass spectrometry (LC/MS/MS) was used to confirm the presence of a major peanut allergen in food. Several peptides obtained from the enzymatic digestion of the most abundant peanut allergen, Ara h 1, were identified as specific peptide biomarkers for peanut protein. Using ice cream as a model food matrix, a method was developed for the detection of the allergen peptide biomarkers. A key component of the method was the use of molecular mass cutoff filters to enrich the Ara h 1 in the protein extracts. By applying the method to ice cream samples containing various levels of peanut protein, levels as low as 10 mg/kg of Ara h 1 could routinely be detected. This method provides an unambiguous means of confirming the presence of the peanut allergen, Ara h 1, in foods and can easily be modified to detect other food allergens. 相似文献
16.
宠物食品辐照灭菌及工艺剂量研究 总被引：4，自引：2，他引：2
本文以皮卷、绿爽洁牙骨、鸡肉排骨、鸡胸肉为试验材料,开展了宠物食品辐照灭菌工艺剂量的研究。结果表明：辐照剂量为4kGy时杀菌率达到了92%以上,辐照剂量为6 kGy时杀菌率已达99%以上,检测的各项微生物指标均符合国家食品卫生标准要求,10 kGy即可达到完全灭菌的效果。辐照前后4种样品中均未检出沙门氏菌。4～10 kGy辐照后,宠物食品中水分、脂肪、蛋白质、粗纤维、碳水化合物、矿质元素（除钙）及17种氨基酸的含量与对照相比差异均不显著,说明辐照对宠物食品的营养品质影响很小;在此剂量范围内,样品辐照前后的色泽、风味与滋味也没有明显变化。由此,确定宠物食品适宜的辐照工艺剂量范围为4～10 kGy。 相似文献
17.
Confirmation of peanut protein using peptide markers in dark chocolate using liquid chromatography-tandem mass spectrometry (LC-MS/MS) 总被引：1，自引：0，他引：1
Shefcheck KJ Callahan JH Musser SM 《Journal of agricultural and food chemistry》2006,54(21):7953-7959
Detection of peptides from the peanut allergen Ara h 1 by liquid chromatography-mass spectrometry (LC-MS) was used to identify and estimate total peanut protein levels in dark chocolate. A comparison of enzymatic digestion subsequent to and following extraction of Ara h 1 from the food matrix revealed better limits of detection (LOD) for the pre-extraction digestion (20 ppm) than for the postextraction digestion (50 ppm). Evaluation of LC-MS instruments and scan modes showed the LOD could be further reduced to 10 ppm via a triple-quadrupole and multiple-reaction monitoring. Improvements in extraction techniques combined with an increase in the amount of chocolate extracted (1 g) improved the LOD to 2 ppm of peanut protein. This method provides an unambiguous means of confirming the presence of the peanut protein in foods using peptide markers from a major allergen, Ara h 1, and can easily be modified to detect other food allergens. 相似文献
18.
van Boxtel EL van den Broek LA Koppelman SJ Vincken JP Gruppen H 《Journal of agricultural and food chemistry》2007,55(21):8772-8778
Mildly extracted peanut allergen Ara h 1 was previously reported to occur as an oligomeric complex. In this paper we describe how the protein in this oligomeric complex interacts noncovalently with phenolic compounds of the proanthocyanidin type. These interactions are being disrupted during anion exchange chromatography, resulting in the dissociation of the oligomeric Ara h 1 complex into protein trimers. By use of the known three-dimensional structure of beta-conglycinin, a soy protein homologous to Ara h 1, proline-rich regions were observed in silico on both faces of its trimeric structure, which are conserved in Ara h 1. These proline-rich regions could explain the binding of proanthocyanidins to Ara h 1 and the formation of multiple Ara h 1 trimer complexes. This was supported by the observation that the addition of peanut proanthocyanidins to trimeric Ara h 1 and to beta-conglycinin resulted in the formation of soluble oligomeric protein complexes. The structurally related legumin proteins do not contain such proline-rich regions on both sides of the protein, and proanthocyanidins were shown to have a lower affinity for legumin proteins from peanuts and soybeans (peanut allergen Ara h 3 and soy glycinin, respectively). Ara h 1 present as the oligomeric complex is assumed to be the representative form of the allergen in which it is consumed by humans. 相似文献