简述大蒜的食疗保健及防腐保鲜作用

大蒜具有很高的食疗保健价值。大蒜素是大蒜的主要功能成分,研究表明,大蒜素对多种细菌、真菌、病毒均具有抑制和杀灭作用,被称为"天然广谱植物杀菌素"。本文简述了大蒜素的形成、保健功能、杀菌机理及其在食品防腐保鲜中的主要应用。     

Isolation of Garlic Bioactives by Pressurized Liquid and Subcritical Water Extraction

Garlic (Allium sativum L.) is widely used in various food products and traditional medicine. Besides unique taste and flavour, it is well known for its chemical profile and bioactive potential. The aim of this study was to apply subcritical water extraction (SWE) and pressurized liquid extraction (PLE) for the extraction of bioactive compounds from the Ranco genotype of garlic. Moreover, PLE process was optimized using response surface methodology (RSM) in order to determine effects and optimize ethanol concentration (45–75%), number of cycles (1–3), extraction time (1–3 min) and temperature (70–110 °C) for maximized total phenols content (TP) and antioxidant activity evaluated by various in vitro assays. Furthermore, temperature effect in SWE process on all responses was evaluated, while allicin content (AC), as a major organosulphur compound, was determined in all samples. Results indicated that PLE provided tremendous advantage over SWE in terms of improved yield and antioxidant activity of garlic extracts. Therefore, high-pressure processes could be used as clean and green procedures for the isolation of garlic bioactives.     

大蒜素包埋球对MBR混合液可滤性影响解析

本研究采用大蒜素为原料,将其包埋在海藻酸钠中,制成大蒜素包埋球(allicin entrapping beads, AEBs)并投加至膜生物反应器(membrane bioreactor, MBR)中,以探讨大蒜素的群体淬灭(quorum quenching, QQ)效应对MBR污泥混合液可滤性的影响。实验结果表明：QQ作用对污泥混合液性质影响显著,对MBR污染物去除影响较小;混合液中胞外聚合物(extracellular polymeric substances, EPS)和溶解性微生物代谢产物(soluble microbial products, SMP)含量降低;通过对修正污染指数(modified fouling index, MFI)检测表明,QQ可提高污泥混合液可滤性,该指标与胞外多糖浓度紧密相关。     

提取大蒜有效成分--有机硫化物

文中研究了用乙醚萃取法提取大蒜中的有机硫化物,采用了正交实验方法考查了操作条件对提取物得率的影响,确定了影响产物得率的主要因素为酶解温度、酶解pH值、酶解时间、加水量以及离心pH值。确定了最佳提取条件为:酶解温度25℃,酶解pH值7.0,酶解时间60min,加水量100mL,离心pH值32。实验还发现二次萃取可以减少产物的流失.     

Inclusion of the allicin mimic S-p-tolyl t-butylthiosulphinate in β-cyclodextrin

Allicin, the active thiosulphinate present in freshly crushed garlic, has potent antimicrobial activity but is chemically labile. As part of a study aimed at producing stable allicin analogues as potential antimicrobial agents, the allicin mimic S-p-tolyl t-butylthiosulphinate was synthesised and complexed with β-cyclodextrin (β-CD). The inclusion complex, β-CD·S-p-tolyl t-butylthiosulphinate·12.5H₂O, was characterised by thermal analysis techniques (HSM, TG, DSC), powder X-ray diffraction and single-crystal X-ray diffraction. The inclusion complex is dimeric (space group C222₁) with the guest disordered over three positions. Within each β-CD molecule of the dimer, each disordered guest component is located in the host cavity with the t-butyl group protruding slightly from the primary hydroxyl side, while the phenyl ring is situated near the secondary hydroxyl side and the thiosulphinate moiety is centrally located within the host cavity. Stereoselectivity of guest inclusion is implicit in the disordered model, which reflects a 2:1 ratio of S- and R-enantiomers in the β-CD cavity.     

高效液相色谱法测定蒜油中大蒜素的含量

目的:建立高效液相色谱法测定蒜油中的大蒜素含量。方法:蒜油样品经正己烷溶液溶解,采用C18色谱柱(4.6mm×250mm,5um),以乙腈∶水∶四氢呋喃(68∶30∶2)为流动相,流速1.0mL/min,柱温:25℃,用紫外检测器在225nm波长下测定蒜油中大蒜素含量。结果:大蒜素在16.0～80.0ug/mL质量浓度范围内具有良好线性关系(r=0.9998),最低检出限为2ng/mL,在低、中、高3个水平下的加标回收率为98.4%～99.1%,相对标准偏差(RSD%)为0.29%～0.73%。结论:该方法前处理操作简便、灵敏度高、适用范围广。     

无臭蒜素与玉米胚芽油的制取及其在化妆品中的应用

论述了无臭蒜素与玉米胚芽油的制取,探讨了无臭蒜素与玉米胚芽油的保健功效及其在化妆品中的应用。     

大蒜的食疗价值及其深加工制品的研制

分析了大蒜的营养成分及食用药用价值,阐述了大蒜臭味产生的分子机理及脱臭方法,介绍了脱臭蒜素复合饮料等系列产品的加工技术。     

保健食品中大蒜素色谱检测方法的研究

以固体类、液体类、半固体类3类保健食品为研究对象,建立了气相色谱法测定保健食品中大蒜素的主要功效成分二烯丙基三硫醚(DATS)、二烯丙基二硫醚(DADS)含量的检测方法。考察了不同提取溶剂、提取方式、提取温度、提取时间的影响,并对3类保健食品样品进行高低两水平的加标回收实验。试样以丙酮水溶液(体积比8∶2)恒温水浴(超声)提取,经PEG-20M色谱柱(30 m×0.32 mm×0.5μm)分离,氢火焰离子化检测器(FID)测定,内标法计算含量。DATS与DADS的检出限分别为5.0、1.5 mg/kg,加标回收率分别为91%~109%、91%~108%。重复性RSD为2.6%~3.1%,再现性RSD为4.1%~8.4%。将该法与HPLC相比较,结果无显著性差异。该方法简便快速,结果准确可靠,适用于多种保健食品中大蒜素含量的检测。