Isolation and characterization of a major allergen in kiwi fruit

 The isolation of an important allergen in kiwi fruit (Actinidia chinensis) by ion-exchange chromatography (IEC) and micropreparative SDS-PAGE followed by electroelution is reported. The purity of the allergen was analysed by SDS-PAGE and immunoblotting with sera from patients who have an allergy to kiwi. The allergen was shown to have a molecular weight of 43 kDa by SDS-PAGE/immunoblotting and an isoelectric point of approximately 6.9 as estimated by IEC. In accordance with World Health Organization nomenclature, this allergen is called Act c 2. By immunoblot inhibition it was shown that epitopes from different allergens in kiwi fruit are also located on Act c 2. N-terminal amino acid sequencing of 17 amino acid residues did not reveal homology with the major allergens in birch pollen (Bet v 1), apple (Mal d 1) or with other proteins of allergenic plant foods. In addition, the isoelectric point of a 67-kDa allergen in kiwi fruit was estimated to be 7.4 by IEC, but micropreparative isolation of this allergen failed because of its very low content in the fruit. Received: 14 April 1997     

猕猴桃籽油的抗氧化稳定性研究

用Schaal烘箱法研究了三种抗氧化剂及增效剂对猕猴桃籽油的抗氧化性能，结果表明：特丁基对苯二酚（TBHQ）的抗氧化性能最好，抗坏血酸和柠檬酸均是TBHQ的良好增效剂，二者都能显著提高TBHQ的抗氧化性能，选用TBHQ、BHT与抗坏血酸作为猕猴桃籽油的抗氧化剂，可使猕猴桃籽油在20℃下的贮藏时间从2个月延到16-18个月。     

Identification and characterisation of allergens related to Bet v I,the major birch pollen allergen,in apple,cherry, celery and carrot by two-dimensional immunoblotting and N-terminal microsequencing

Low temperature extracts taken from Granny Smith and Braeburn apples, cherries, celery and carrots were separated by two-dimensional electrophoresis. Bet v I, the major birch pollen allergen, related allergens in apple, cherry, celery and carrot extracts were detected by means of two-dimensional immunoblotting with patients' sera containing IgE antibodies specific to Bet v I, a rabbit polyclonal antiserum raised against Bet v I , and two Bet v I specific mouse monoclonal antibodies. The major cross-reacting allergen spots were observed with molecular weights/isoelectric points of 18.0 kDa/pI 5.5 for apple (Granny Smith and Braeburn) and 18.0 kDa/pI 5.8 for cherry, 15.5 kDa/pI 4.4–4.6 for celery and 16.0 kDa/pI 4.4 for carrot extract. Additional antibody reactivities with certain isoprotein spots were observed, which may indicate the presence of Bet v I-related epitopes on these proteins. Based on the first 15 N-terminal amino acid residues, the major allergen spots revealed 53% sequence identity between Bet v I and the Granny Smith apple allergen, 50% between Braeburn apple allergen and Bet v I , 67% between Bet v I and the cherry allergen, and 40 and 28% for celery and carrot, respectively. Furthermore, the N-terminal sequences showed identities ranging from 40% (apple/cherry) to 66% (celery) with PcPR l-l, a pathogenesis-related protein in parsley.     

几种主要产地猕猴桃的果籽营养成分比较

对湘西野生猕猴桃、湘西米良1号猕猴桃、陕西秦美猕猴桃、贵州中华猕猴桃的果籽含量及其营养成分进行分析对比。结果表明：湘西米良1号猕猴桃果籽含量及其粗脂肪、亚麻酸、微量元素硒含量均高于其它产地，但亚油酸含量低于其它产地；不同产地猕猴桃果籽Vc与氨基酸含量差别不大，贵州中华猕猴桃果籽VE最高。     

猕猴桃根提取物保健功能研究进展

介绍猕猴桃根的主要活性成分甾体及萜类物质、多糖类物质、大黄素、矿物质和微量元素；阐述猕猴桃根保健功能的研究和应用进展；着重介绍了猕猴桃根的抗肿瘤、抗氧化、降酶保肝、免疫调节作用，对其开发利用前号进行了分析和展望。     

猕猴桃籽油加热氧化性能的研究

目的与方法：为开发利用猕猴桃籽油，探索其加工生产性能；系统测定不同温度及加热时间下猕猴桃籽油的酸价、碘价、过氧化值（POV）；结果：温度对碘价的影响非常显著，但短时间加热对酸价影响不大；对POV加热温度则在65℃以下较好。猕猴桃籽油的加工应在65℃以下，同时加工过程应添加抗氧化剂和阻聚剂，防止猕猴桃籽油发生氧化、聚合等反应。     

超高压对鲜切猕猴桃果片多聚半乳糖醛酸酶及品质的影响

采用超高压处理对鲜切猕猴桃片进行保鲜,研究了超高压处理对贮藏期间多聚半乳糖醛酸酶活性、果片硬度、可溶性果胶和VC含量的影响。研究结果表明:猕猴桃片采用600MPa压力、30℃下加压10min后,在4℃条件下贮藏9d,与未超高压处理的对照组相比,超高压处理的鲜切猕猴桃片多聚半乳糖醛酸酶活性较低,果片硬度、可溶性果胶含量、VC含量和可溶性果胶变化不显著;600MPa超高压处理可通过抑制多聚半乳糖醛酸酶活性而维持果片硬度,同时可有效控制VC的损失。     

速冻猕猴桃生产线中耐高渗酵母的分离鉴定

目的旨在明确污染速冻猕猴桃产品加工环节中主要的高渗酵母种类,并且研究污染菌种的耐渗特性,从而在加工中能够预防性地识别和控制高渗酵母污染。方法对酵母基因组5.8S rDNA-ITS区或26S rDNA的D1/D2区两个保守区域进行扩增和测序,确定分离筛选的高渗酵母的种属信息和分布。测定部分菌株在2%、50%、60%(m:V)葡萄糖浓度下的OD600,确定耐糖特性。同时,测定部分菌株在2%和50%(m:V)糖浓度下的产气量。结果在速冻猕猴桃加工环境中共分离筛选到33株高渗酵母,分属于10个酵母种。其中,Hanseniaspora uvarum、Hanseniaspora opuntiae、Candida intermedia和Candida tropicalis是发生频次高的耐高渗酵母种。Lodderomyces elongisporus和Debaryomyces hansenii耐渗性强,能够耐受60%(m:V)葡萄糖;Hanseniaspora opuntiae和Metschnikowia pulcherrima在高糖培养基中产气量大。结论速冻猕猴桃加工车间中分离到潜在污染性的耐高渗酵母,尤其是车间空气中存在多种耐高渗酵母,因此需要加强加工过程中的卫生管理,增加预防性的杀菌措施,保证速冻猕猴桃加工过程的质量安全。     

The effect of a kiwi fruit based solution on meat traits in beef m. semimembranosus (topside)

The effectiveness of a kiwi fruit based solution for improving the tenderness of beef m. semimembranosus and the effect on colour stability was studied. Three treatments were applied; (1) injection with the solution, (2) injection with water and (3) no injection. All samples were packaged using a SmartShape™ prototype and aged for 1 or 14 days. There was a significant effect (P < 0.001) of the kiwi fruit solution on shear force, with no difference between samples injected with water and those not injected. For compression of the samples no fixed effects were significant (P > 0.05). Samples not injected (control) were the darkest (lowest L* values) with no difference between samples injected with water and those injected with kiwi fruit solution. Injected samples had lower a* (redness) values than non-injected samples. In general the samples not injected had higher ratio (630/580 nm) values indicating less formation of metmyoglobin.     

Isolation and characterization of natural Ara h 6: evidence for a further peanut allergen with putative clinical relevance based on resistance to pepsin digestion and heat

Peanut allergy is a significant health problem because of its prevalence and the potential severity of the allergic reaction. The characterization of peanut allergens is crucial to the understanding of the mechanism of peanut allergy. Recently, we described cloning of the peanut allergen Ara h 6. The aim of this study was isolation and further characterization of nAra h 6. We purified nAra h 6 from crude peanut extract using gel filtration and anion exchange chromatography. The preparation was further characterized by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) with subsequent immunoblotting. Stability of nAra h 6 was studied by an in vitro digestibility assay as well as by resistance against thermal processing. Sequencing of nAra h 6 identified the N-terminal amino acid sequence as MRRERGRQGDSSS. Further results clearly demonstrated stability of nAra h 6 against pepsin digestion and heating. Immunoglobulin G (IgE) binding analysis and its biological activity shown by RBL 25/30-test of natural Ara h 6 supported the importance of this peanut allergen. Investigation of nAra h 6 revealed evidence for a further peanut allergen with putative clinical relevance based on resistance to pepsin digestion and heat.     

Molecular and immunological characterization of Mus a 5 allergen from banana fruit

Scope Banana fruit has become an important cause of fruit allergy in the recent years. Among the five registered IUIS allergens, Mus a 1 and Mus a 2 have been characterized in detail. In this study, molecular characterization and evaluation of the allergenic properties of β‐1,3‐glucanase from banana (Musa acuminata), denoted as Mus a 5, were performed Methods and results The gene of Mus a 5 was cloned and sequenced. The obtained cDNA revealed a novel Mus a 5 isoform with an open reading frame encoding a protein of 340 amino acids comprising a putative signal peptide of 28 amino acid residues. By MALDI‐TOF analysis Mus a 5 isolated from banana fruit revealed a molecular mass of 33451±67 Da. Two Mus a 5 isoforms (pI 7.7 and 8.0) were detected by 2D immunoblot with an identical N‐terminal sequence. By mass fingerprint, 76 and 83% of the primary structure was confirmed for the two mature Mus a 5 isoforms, respectively. IgE reactivity to Mus a 5 was found in 74% of patients sensitized to banana fruit. Upregulation of basophil activation markers CD63 and CD203c was achieved with Mus a 5 in a concentration‐dependent manner Conclusion Mus a 5 is a functional allergen and a candidate for the component‐resolved allergy diagnosis of banana allergy.     

Determination of aflatoxins in food using LC/MS/MS

 A liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometric method is described for the determination of aflatoxins B₁, B₂, G₁ and G₂ in food with the use of aflatoxin M₁ as an internal standard. The method works well with matrices such as those of figs and peanuts, but there are problems with spices, due to limitations of the clean-up method used. Received: 15 October 1997     

番茄猕猴桃复合果蔬饮料的研制

以番茄和猕猴桃为原料,研制番茄猕猴桃复合果蔬饮料。探讨了番茄汁、猕猴桃汁、蔗糖和柠檬酸添加量对饮料加工品质的影响。在单因素试验基础上,应用Box-Bohnken响应面技术对番茄猕猴桃复合果蔬饮料加工工艺进行了优化,获得了最优的工艺参数,即番茄汁29%、猕猴桃汁29%、蔗糖10%、柠檬酸1.2%。最优条件下模型预测产品评分为97.69,验证试验结果（96.18±0.40,n=6）与模型预测结果接近。     

Comparison between two commercial ELISAs and a culture procedure for the detection of Listeria spp.

 The efficiency of two commercial enzyme-linked immunosorbent assays (ELISAs), the Oxoid Listeria rapid test and the Tecra Listeria visual immunoassay for the detection of Listeria spp. was compared with that of a culture method. Of the 60 samples examined by ELISA and the culture procedure, Listeria was detected and confirmed by culture in 20, 34 and 44 samples by the Tecra, Oxoid and microbiological methods, respectively. The overall sensitivity of the Tecra and Oxoid tests was 50% and 93%, respectively. Both ELISAs had a specificity of 100%. The efficiency of the Oxoid test was 95%, while that of the Tecra assay was 67%. Differences in the results of the Oxoid test and those of the culture method were not statistically significant; however, the differences between the results of the Tecra assay and the culture procedure were significant. The Oxoid test was less labour intensive, less time consuming and easier to perform than the Tecra assay. It was concluded that the Oxoid test is a good alternative method to the culture procedures when screening for the presence of Listeria spp. in foods, especially when a large number of samples have to be analysed. Received: 24 June 1997     

Comparison between two commercial ELISAs and a culture procedure for the detection of Listeria spp.

 The efficiency of two commercial enzyme-linked immunosorbent assays (ELISAs), the Oxoid Listeria rapid test and the Tecra Listeria visual immunoassay for the detection of Listeria spp. was compared with that of a culture method. Of the 60 samples examined by ELISA and the culture procedure, Listeria was detected and confirmed by culture in 20, 34 and 44 samples by the Tecra, Oxoid and microbiological methods, respectively. The overall sensitivity of the Tecra and Oxoid tests was 50% and 93%, respectively. Both ELISAs had a specificity of 100%. The efficiency of the Oxoid test was 95%, while that of the Tecra assay was 67%. Differences in the results of the Oxoid test and those of the culture method were not statistically significant; however, the differences between the results of the Tecra assay and the culture procedure were significant. The Oxoid test was less labour intensive, less time consuming and easier to perform than the Tecra assay. It was concluded that the Oxoid test is a good alternative method to the culture procedures when screening for the presence of Listeria spp. in foods, especially when a large number of samples have to be analysed. Received: 24 June 1997     

奇异果芦荟悬浮饮料的研制

研究了以奇异果和芦荟为主要原料的新型复合悬浮饮料的制作工艺,对加工过程中稳定剂的选择进行了探讨,并运用正交试验确定了产品的最佳配方和生产工艺,研制出风味良好的复合悬浮饮料。     

水果过敏原定量方法研究进展

随着水果消费种类与数量的增加以及相关花粉过敏的大流行,水果过敏问题日益凸显。水果过敏的预防与诊治对过敏原定量方法的灵敏度、精确性和稳健性提出了更高的要求。本文首先简述了水果过敏及其免疫学机制,对常见水果已鉴定的过敏原分子进行了蛋白家族汇总,介绍了5个主要蛋白家族（PR-10蛋白家族、类甜蛋白、非特异性脂质转移蛋白、抑制蛋白和几丁质酶）的生化性质和相关临床症状。其次,对水果过敏原定量应用最多的酶联免疫吸附法(enzyme-linked immunosorbent assay, ELISA)和液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)进行综述,分析了二者的优缺点及其在水果过敏原定量检测中的应用。最后,总结了水果过敏原定量的研究现状,并结合新兴技术指出未来研究方向,为水果过敏的临床诊断与防治提供参考。     

液态法猕猴桃醋生产及其醋酸饮料的研制

以秦美猕猴桃为原料，探讨液态法猕猴桃醋生产及其醋酸饮料的研制。结果表明，采用液态法生产的猕猴桃醋具有成熟猕猴桃的果香，酸味柔和，适宜调配醋酸饮料。通过单因素试验和正交试验确定猕猴桃醋酸饮料优化配方为：100ml猕猴猕醋酸饮料中含猕猴桃醋27ml、甜昧剂4．3mg、苹果酸27．0mg、柠檬酸15．9mg、姜汁12ml、乳酸钙51mg、食盐41.5mg、甜蜜素31mg、乙基麦芽酚5mg。     

铅对儿童健康的危害及猕猴桃促进排铅机理

阐述了儿童铅污染现状、铅代谢特点、铅对儿童健康的危害及儿童铅中毒的预防与控制措施,探讨了猕猴桃中的VC、硒、果胶、粗纤维等营养成分的促进排铅机理,表明猕猴桃是目前较为理想的一种天然排铅果品。     

Endogenous formaldehyde level of foods and its biological significance

 Formaldehyde was measured in different food samples based on its reaction with hydralazine to form s-triazolo-(3,4-α)-phthalazine(Tri-P). Formaldehyde reacts with hydralazine under mild acidic conditions to form Tri-P. The reaction products were separated by reversed-phase, high-performance liquid chromatography. The method of sample preparation and chromatography are reviewed and the analytical method validated. Using the discussed methods we measured formaldehyde levels in 23 animals and 22 vegetable and fruit samples. Formaldehyde levels were one and a half times higher in vegetable samples compared to meat samples. Received: 23 December 1996 / Revised version: 17 March 1997