Physicochemical, Structural, and Functional Properties of Fructans from Single-Clove Garlic and Multiclove Garlic: A Comparison.

This study aimed to compare the structural features and functional properties of polysaccharides from single-clove garlic (SGPs) and multiclove garlic (MGPs) and to establish their structure-function relationships. Both SGPs and MGPs were identified as fructans consisting mainly of →1)-ß-d-Fruf (2→ and →6)-ß-d-Fruf (2→ residues but differed in average molecular weights (6.76 and 5.40 kDa, respectively). They shared similar thermodynamic properties, X-ray diffraction patterns, and high gastrointestinal digestive stability. These two purified fructans could dose-dependently scavenge free radicals, reduce oxidized metals, and effectively alleviate metronidazole-induced oxidative stress and CuSO4-induced inflammation in zebrafish via inhibiting the overexpression of inflammation-related proteins and cytokines. SGPs showed lower free radical scavenging activity in vitro than MGPs but higher antioxidant and anti-inflammatory activities in vivo. Taken together, the molecular weight was the main structural difference between the two garlic fructans of different varieties, which is a potential reason for their differences in biological activities.

Ultrasound-Assisted Extraction of Paeonol from Moutan Cortex: Purification and Component Identification of Extract.

Moutan Cortex (MC) is a traditional Chinese medicine that contains abundant medicinal components, such as paeonol, paeoniflorin, etc. Paeonol is the main active component of MC. In this study, paeonol was extracted from MC through an ultrasound-assisted extraction process, which is based on single-factor experiments and response surface methodology (RSM). Subsequently, eight macroporous resins of different properties were used to purify paeonol from MC. The main components of the purified extract were identified by ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS/MS). The results indicate the optimal parameters are as follows: liquid-to-material ratio 21:1 mL/g, ethanol concentration 62%, ultrasonic time 31 min, ultrasonic temperature 36 °C, ultrasonic power 420 W. Under these extraction conditions, the actual yield of paeonol was 14.01 mg/g. Among the eight tested macroporous resins, HPD-300 macroporous resin was verified to possess the highest adsorption and desorption qualities. The content of paeonol increased from 6.93% (crude extract) to 41.40% (purified extract) after the HPD-300 macroporous resin treatment. A total of five major phenolic compounds and two principal monoterpene glycosides were characterized by comparison with reference compounds. These findings will make a contribution to the isolation and utilization of the active components from MC.

Quality Improvement of Garlic Paste by Whey Protein Isolate Combined with High Hydrostatic Pressure Treatment.

Garlic, one of the most popular spices and medical herbs, has a unique pungent flavor and taste. Conventional homogenization and thermal treatment commonly lead to flavor and color deterioration in garlic paste, because allicin is highly susceptible to degradation and reaction. The present study was to investigate the effects of whey protein isolate (WPI) and different levels of high hydrostatic pressure (HHP, 200, 300, 400, 500, and 600 MPa) on the quality of garlic paste. Results showed that the addition of WPI in the homogenization of garlic significantly prevented green discoloration. Furthermore, WPI plus HHP under 500 MPa could better protect the color of garlic paste. Higher pressure (600 MPa) led to WPI aggregation, resulting in higher green color chroma of garlic paste. GC-MS results revealed that the application of WPI and HHP in garlic paste increased the relative level of pungent flavor compounds and decreased those of unpleasant odor compounds. The correlation analysis results revealed that WPI efficiently prevented garlic green discoloration, which is attributed to the thiol group in WPI exchanging the sulfonyl groups in allicin. In consideration of the microbial load, flavor and color quality of garlic paste, the optimal processing conditions were found at 500 MPa for 5 min with 2% WPI addition, extending shelf life to 25 days.

Garlic polysaccharide-Cr (III) complexes with enhanced in vitro and in vivo hypoglycemic activities.

This study aimed to prepare a complex of Cr (III) and garlic polysaccharides (GPs) and evaluate the in vitro and in vivo hypoglycemic activities of GPs and GP-Cr (III) complexes. The chelation of GPs with Cr (III) increased molecular weight, modified crystallinity, and altered morphological characteristics, through targeting the OH of hydroxyl groups and involving the C-O/O-C-O structure. The GP-Cr (III) complex had a higher thermal stability over 170-260 °C and higher stability throughout the gastrointestinal digestion. In vitro, the GP-Cr (III) complex exhibited a significantly stronger inhibitory effect against α-glucosidase compared with the GP. In vivo, the GP-Cr (III) complex at a high dose (4.0 mg Cr/kg body weight) generally had a higher hypoglycemic activity than the GP in (pre)-diabetic mice induced by a high-fat and high-fructose diet, based on indices like body weight, blood glucose levels, glucose tolerance, insulin resistance, insulin sensitivity, blood lipid levels, and hepatic morphology and function. Therefore, GP-Cr (III) complexes could be a potential Cr (III) supplement with an enhanced hypoglycemic activity.

Preparation and characterization of garlic polysaccharide-Zn (II) complexes and their bioactivities as a zinc supplement in Zn-deficient mice.

This study explored the potential of garlic polysaccharides (GPs) as a carrier for synthesizing GP-Zn (II) complexes to supplement Zn. According to the response surface analysis, the optimal preparation conditions were: mass ratio of GPs to Zn2+ 1:0.21, temperature 53 °C, pH 5.9 and time 148.75 min, with the maximum chelation rate of 90.11%. The chelation of GPs and Zn2+ involved O-H/C-O/O-C-O groups, increased crystallinity and altered absorption peaks of circular dichroism spectra, with a higher thermal stability, particle size and negative zeta potential. Compared with inorganic zinc salts, supplementation of GP-Zn (II) complexes showed enhance zinc supplementation effects in Zn-deficient mice model: increased body weight, organ index and Zn (II) levels in serum and liver, enhanced Superoxidedismutase (SOD) activity and alkaline phosphatase activity, decreased NO content and Malondialdehyde (MDA) content and improved colon and testicular morphology. Therefore, GP-Zn (II) complex can be used as a potential zinc supplement for Zn-deficient individuals.

Pumpkin Skin Polysaccharide-Zn(II) Complex: Preparation, Characterization, and Suppression of Inflammation in Zebrafish.

In this study, pumpkin (Cucurbita moschata) skin polysaccharide-zinc(II) (PSP-Zn) complex was successfully prepared. The structure and physicochemical properties of PSP and PSP-Zn were analyzed. The anti-inflammatory activity of PSP and PSP-Zn was investigated in zebrafish larvae induced by copper sulphate. PSP and PSP-Zn consisted of rhamnose, arabinose, galactose, glucose, and galacturonic acid. The molecular weight (Mw) of PSP and PSP-Zn were 3.034 × 106 and 3.222 × 106 Da, respectively. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) analysis results suggested that the chemical modification of zinc might occur through hydroxyl groups of PSP. The PSP-Zn complex had lamellar texture, smooth surface morphology, and larger particle size. X-ray Diffraction (XRD) analysis revealed that both PSP and PSP-Zn were semi-crystalline substances. PSP-Zn solution showed superior stability in a weak acid and alkaline environment, especially at pH = 6.0. Moreover, PSP and PSP-Zn showed a good inhibitory effect on inflammation cells in zebrafish. Real-time quantitative polymerase chain reaction (RT-PCR) result suggested that the anti-inflammatory mechanism of PSP and PSP-Zn were through downregulation of the expression of nitric oxide synthase 2b (nos2b), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and nuclear factor-kappa B2 (NF-κB2). The present study indicated that PSP-Zn is expected to be a safe and efficient novel zinc supplement with anti-inflammatory activity.

Bioactive polysaccharides and oligosaccharides from garlic (Allium sativum L.): Production, physicochemical and biological properties, and structure-function relationships.

Garlic is a common food, and many of its biological functions are attributed to its components including functional carbohydrates. Garlic polysaccharides and oligosaccharides as main components are understudied but have future value due to the growing demand for bioactive polysaccharides/oligosaccharides from natural sources. Garlic polysaccharides have molecular weights of 1 × 103 to 2 × 106  Da, containing small amounts of pectins and fructooligosaccharides and large amounts of inulin-type fructans ((2→1)-linked ß-d-Fruf backbones alone or with attached (2→6)-linked ß-d-Fruf branched chains). This article provides a detailed review of research progress and identifies knowledge gaps in extraction, production, composition, molecular characteristics, structural features, physicochemical properties, bioactivities, and structure-function relationships of garlic polysaccharides/oligosaccharides. Whether the extraction processes, synthesis approaches, and modification methods established for other non-garlic polysaccharides are also effective for garlic polysaccharides/oligosaccharides (to preserve their desired molecular structures and bioactivities) requires verification. The metabolic processes of ingested garlic polysaccharides/oligosaccharides (as food ingredients/dietary supplements), their modes of action in healthy humans or populations with chronic conditions, and molecular/chain organization-bioactivity relationships remain unclear. Future research directions related to garlic polysaccharides/oligosaccharides are discussed.

Effect of blend oil on the volatile aroma profile and storage quality of garlic paste.

The aim of this study was to evaluate the effect of edible oil on the volatile aroma profile and storage quality of garlic paste, and to explore the underlying mechanisms. The administration of blend oil at 40 °C in a garlic to oil ratio of 1.8 had a higher overall acceptance by affective sensory test. Compared with the original garlic paste, the sensory aroma profile of the oil-immersed garlic paste was characterized by suppressed pungency, garlic scent and garlic odor, and enhanced oil scent. SPME-GC-MS and HS-GC-IMS showed that the application of blend oil caused great changes in the level of some compounds, which could explain its role in the oil-immersed garlic paste. Furthermore, the blend oil also reduced the growth rate of the total number of colonies and browning intensity, and inhibited the loss of allicin. Therefore, the application of blend oil in garlic paste improved the sensory aroma and delayed the deterioration of the product quality.

Structural characterization and antioxidant activities of one neutral polysaccharide and three acid polysaccharides from Ziziphus jujuba cv. Hamidazao: A comparison.

A neutral polysaccharide (HJP-1a) and three acid polysaccharides (HJP-2, HJP-3 and HJP-4) were obtained from Z. jujuba cv. Hamidazao. HJP-1a was mainly composed of arabinose and galactose in a ratio of 56.9:20.0, with an average molecular weight of 3.115 × 104 g/mol. HJP-2, HJP-3 and HJP-4 were homogeneous heteropolysaccharides mainly containing galacturonic acid, arabinose and galactose, with average molecular weights of 4.590 × 104, 6.986 × 104 and 1.951 × 105 g/mol, respectively. Structural characterization indicated that the backbone of HJP-3 appeared to be mainly composed of →4)-α-d-GalpA (1→ and →2,4)-α-l-Rhap (1→ residues with some branches consisting of →5)-α-l-Araf (1→ residues and terminals of T-α-l-Araf (1→ and T-ß-d-Galp residues. The four purified fractions displayed dose-dependent radical scavenging activity on ABTS+ radicals and reducing capacity, as well as excellent protective effect on H2O2-induced HepG2 cells and metronidazole-damaged zebrafish embryos, especially HJP-2 in vitro and HJP-1a in vivo. Therefore, the polysaccharides from Z. jujuba cv. Hamidazao could be used as a potential antioxidant in functional foods.

Evaluation of degradation of pigments formed during garlic discoloration in different pH.

The specific chemical bond changes of green pigment formed in garlic discoloration were investigated in our study. Multiple analysis methods were used in the degradation of pigment, including ultraviolet-visible (UV-Vis) spectrophotometry, attenuated total reflection Fourier transform infrared (ATR-FTIR) and Fourier transform infrared near infrared (FT-NIR). Green pigments were treated at 40 °C for 7 days in the pH range of 5.0-8.0. Principal component analysis of the ATR-FTIR and FT-NIR spectra indicated the similarities and differences during pigment degradation. It was found that the degradation degree of green pigments in a solution with pH 5.0 was the lowest. Changes in the absorptions of CO, COO-, CN, CN, OCOCH, COC, COOH, and NH bonds vibrations are attributed to the decomposition of the pigments. The absorption at 5170 cm-1 (NH bond first overtone) and 4871 cm-1 (OCH stretching) correlated to pigment degradation were confirmed by FT-NIR spectra. One proposed pathway of the pigment decomposition was explored.

Effect of blanching and freezing on the physical properties, bioactive compounds, and microstructure of garlic (Allium sativum L.).

The aim of this work was to evaluate the impact of blanching on the physical properties of frozen garlic cloves and to explore the relationship between quality changes and microstructure. A short-term blanching treatment (100 °C  for 45 s, 90 °C  for 45 s, and 80 °C  for 60 s) before freezing did not affect the total organosulfur compound content. In a preliminary research, blanching conditions were determined to be 100 °C  for 45 to 80 s. Under these conditions, peroxidase was inactivated, but organosulfur compounds were retained. Mechanical and color tests showed a damaging effect of blanching and freezing on frozen garlic blanched for 60 and 80 s at 100 °C . Compared to frozen fresh garlic, frozen garlic treated by blanching for 45 s at 100 °C  retained 2871.49 ± 200.24 µg/g of allicin, although 81.83% of peroxidase was inactivated; browning and hardness improved by 49.97 and 48.01%, respectively. According to scanning electron microscopy, significant damage to the microstructure was observed in both frozen fresh garlic and frozen garlic after 60 s and 80 s of blanching at 100 °C . Moreover, 1 H low-field nuclear magnetic resonance (LF-NMR) indicated that blanching for 60 s and 80 s induced an increase in free water in garlic tissues, resulting in further damage after freezing. As peroxidase was efficiently inactivated, the microstructure and organosulfur compounds were better preserved, and blanching treatment at 100 °C  for 45 s before freezing is a potential method for obtaining frozen garlic with high sensory and nutritional qualities. PRACTICAL APPLICATION: Freezing helps to overcome challenges associated with growing seasons and the deterioration of garlic during storage. After frozen garlic is thawed, it is prone to some undesirable changes, such as enzymatic browning and softening. Minimal blanching (45 s at 100 °C ) pretreatment can help to maintain the bioactive compounds of garlic and prevent texture and color deterioration caused by freezing directly.

Formation, nutritional value, and enhancement of characteristic components in black garlic: A review for maximizing the goodness to humans.

Black garlic (BG) is essentially a processed food and obtained through the transformation of fresh garlic (FG) (Allium sativum L.) via a range of chemical reactions (including the Maillard reaction) and microbial fermentation. This review provides the up-to-date knowledge of the dynamic and complicated changes in major components during the conversion of FG to BG, including moisture, lipids, carbohydrates (such as sugars), proteins, organic acids, organic sulfur compounds, alkaloids, polyphenols, melanoidins, 5-hydroxymethylfurfural, vitamins, minerals, enzymes, and garlic endophytes. The obtained evidence confirms that BG has several advantages over FG in certain product attributes and biological properties (especially antioxidant activity), and the factors affecting the quality of BG include the type and characteristics of FG and processing technologies and methods (especially pretreatments, and processing temperature and humidity). The interactions among garlic components, and between garlic nutrients and microbes, as well as the interplay between pretreatment and main manufacturing process, all determine the sensory and nutritional qualities of BG. Before BG is marketed as a novel snack or functional food, more research is required to fill the knowledge gaps related to quantitative monitoring of the changes in metabolites (especially those taste-active and/or biological-active substances) during BG manufacturing to maximize BG's antioxidant, anticancer, antiobesity, anti-inflammatory, immunostimulatory, anti-allergic, hepatoprotective, cardioprotective and oxidative stress-/hangover syndrome-reducing functions, and beneficial effects on memory/nervous systems. Assessments of the quality, efficacy, and safety of BG should be performed considering the impacts of BG production conditions, postproduction handling, and intake methods.

Effects and mechanism of free amino acids on browning in the processing of black garlic.

BACKGROUND: Black garlic is produced by heating raw garlic at a high temperature for a long time without any additives. The thermal processing induces many chemical reactions, such as the Maillard reaction, which causes the color change from white to dark brown. Garlic contains a variety of amino acids, and the effect of each amino acid on browning is not fully understood. This work investigated the effect and mechanism of free amino acids on the browning of black garlic using model solutions containing garlic neutral polysaccharide, hydrolyzed garlic neutral polysaccharide, fructose, and free amino acids. RESULTS: A significant increase in reducing sugar was detected when garlic neutral polysaccharide was heated with glycine. The browning intensity of garlic neutral polysaccharide-glycine model solution was obviously higher after heating at 80 °C compared with that of garlic neutral polysaccharide solution. The model solution containing histidine had the greatest browning degree. The histidine model has a stable pH value, and almost no 5-hydroxymethylfurfural (5-HMF) was detected. CONCLUSION: Amino acid can promote the breaking of the garlic neutral polysaccharide chain and can react with the fructose generated to form browning. Histidine has the greatest effect on the browning, because histidine could eliminate the inhibiting effect of organic acid on Maillard reaction due to the buffer ability, and histidine had high reactivity in the late stage of Maillard reaction. © 2019 Society of Chemical Industry.

Simultaneous Determination of Oleanolic Acid and Ursolic Acid by in Vivo Microdialysis via UHPLC-MS/MS Using Magnetic Dispersive Solid Phase Extraction Coupling with Microwave-Assisted Derivatization and Its Application to a Pharmacokinetic Study of Arctiumlappa L. Root Extract in Rats.

Simultaneous detection of oleanolic acid and ursolic acid in rat blood by in vivo microdialysis can provide important pharmacokinetics information. Microwave-assisted derivatization coupled with magnetic dispersive solid phase extraction was established for the determination of oleanolic acid and ursolic acid by liquid chromatography tandem mass spectrometry. 2'-Carbonyl-piperazine rhodamine B was first designed and synthesized as the derivatization reagent, which was easily adsorbed onto the surface of Fe3O4/graphene oxide. Simultaneous derivatization and extraction of oleanolic acid and ursolic acid were performed on Fe3O4/graphene oxide. The permanent positive charge of the derivatization reagent significantly improved the ionization efficiencies. The limits of detection were 0.025 and 0.020 ng/mL for oleanolic acid and ursolic acid, respectively. The validated method was shown to be promising for sensitive, accurate, and simultaneous determination of oleanolic acid and ursolic acid. It was used for their pharmacokinetics study in rat blood after oral administration of Arctiumlappa L. root extract.

Characterization of microbial community structure and metabolic potential using Illumina MiSeq platform during the black garlic processing.

Black garlic is a distinctive garlic deep-processed product made from fresh garlic at high temperature and controlled humidity. To explore microbial community structure, diversity and metabolic potential during the 12days of the black garlic processing, Illumina MiSeq sequencing technology was performed to sequence the 16S rRNA V3-V4 hypervariable region of bacteria. A total of 677,917 high quality reads were yielded with an average read length of 416bp. Operational taxonomic units (OTU) clustering analysis showed that the number of species OTUs ranged from 148 to 1974, with alpha diversity increasing remarkably, indicating the high microbial community abundance and diversity. Taxonomic analysis indicated that bacterial community was classified into 45 phyla and 1125 distinct genera, and the microbiome of black garlic samples based on phylogenetic analysis was dominated by distinct populations of four genera: Thermus, Corynebacterium, Streptococcus and Brevundimonas. The metabolic pathways were predicted for 16S rRNA marker gene sequences based on Kyoto Encyclopedia of Genes and Genomes (KEGG), indicating that amino acid metabolism, carbohydrate metabolism and membrane transport were important for the black garlic fermentation process. Overall, the study was the first to reveal microbial community structure and speculate the composition of functional genes in black garlic samples. The results contributed to further analysis of the interaction between microbial community and black garlic components at different stages, which was of great significance to study the formation mechanism and quality improvement of black garlic in the future.

Semi-Preparative Separation of 10 Caffeoylquinic Acid Derivatives Using High Speed Counter-Current Chromatogaphy Combined with Semi-Preparative HPLC from the Roots of Burdock (Arctium lappa L.).

Burdock roots are healthy dietary supplements and a kind of famous traditional Chinese medicine, which contains large amounts of caffeoylquinic acid derivatives. However, little research has been reported on the preparative separation of these compounds from burdock roots. In the present study, a combinative method of HSCCC and semi-preparative HPLC was developed for the semi-preparative separation of caffeoylquinic acid derivatives from the burdock roots. The ethyl acetate extract of burdock roots was first fractionated by MCI macroporous resin chromatography and give three fractions (Fr. 1-3) from the elution of 40% methanol. Then, these three fractions (120 mg) were separately subjected to HSCCC for purification with the solvent system composed of petroleum ether-ethyl acetate-methanol-water at different volume ratios, and the mixtures were further purified by semi-preparative HPLC. As a result, a total of eight known caffeoylquinic acid derivatives including 3-O-caffeoylquinic acid (32.7 mg, 95.7%), 1,5-O- dicaffeoylquinic acid (4.3 mg, 97.2%), 3-O-caffeoylquinic acid methyl ester (12.1 mg, 93.2%), 1,3-O-dicaffeoylquinic acid (42.9 mg, 91.1%), 1,5-O-dicaffeoyl-3-O-(4-maloyl)-quinic acid (4.3 mg, 84.5%), 4,5-O-dicaffeoylquinic acid (5.3 mg, 95.5%), 1,5-O-dicaffeoyl-3-O-succinylquinic acid (8.7 mg, 93.4%), and 1,5-O-dicaffeoyl-4-O-succinylquinic acid (1.7 mg, 91.8%), and two new compounds were obtained. The new compounds were 1,4-O-dicaffeoyl-3-succinyl methyl ester quinic acid (14.6 mg, 96.1%) and 1,5-O-dicaffeoyl-3-O-succinyl methyl ester quinic acid (3.1 mg, 92.6%), respectively. The research indicated that the combination of HSCCC and semi-preparative HPLC is a highly efficient approach for preparative separation of the instability and bioactive caffeoylquinic acid derivatives from natural products.

A Strategy for Preparative Separation of 10 Lignans from Justicia procumbens L. by High-Speed Counter-Current Chromatography.

Ten compounds, including three lignan glycosides and seven lignans, were purified from Justicia procumbens L. in 8 h using an efficient strategy based on high-speed counter-current chromatography (HSCCC). The two-phase solvent system composed of petroleum-ethyl acetate-methanol-H2O (1:0.7:1:0.7, v/v) was firstly employed to separate the crude extract (320 mg), from which 19.3 mg of justicidin B (f), 10.8 mg of justicidin A (g), 13.9 mg of 6'-hydroxyjusticidin C (h), 7.7 mg of justicidin E (i), 6.3 mg of lignan J1 (j) were obtained with 91.3 mg of enriched mixture of compounds a-e. The enriched mixture (91.3 mg) was further separated using the solvent system consisting of petroleum-ethyl acetate-methanol-H2O (3:3.8:3:3.8, v/v), yielding 12.1 mg of procumbenoside E (a); 7.6 mg of diphyllin-1-O-ß-d-apiofuranoside (b); 7.4 mg of diphyllin (c); 8.3 mg of 6'-hydroxy justicidin B (d); and 7.9 mg of diphyllin acetyl apioside (e). The purities of the 10 components were all above 94%, and their structures were identified by NMR and ESI-MS spectra. The results demonstrated that the strategy based on HSCCC for the separation of lignans and their glycosides was efficient and rapid.

Large-scale separation of alkaloids from Corydalis bungeana Turcz. by pH-zone-refining counter-current chromatography.

pH-Zone-refining counter-current chromatography (pH-zone-refining CCC) was successfully applied for the large-scale separation of alkaloids from Corydalis bungeana. The crude extract was separated by a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water (5:5:2:8, v/v) where triethylamine (10 mM) was added to the upper organic stationary phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase as a displacer. As a result, 285 mg of protopine, 86 mg of corynoloxine, 430 mg of coryno1ine, and 115 mg of acetylcorynoline were obtained from 3.0 g of crude extract in a one-step separation. The purities of these compounds were 99.1%, 98.3%, 99.0% and 98.5%, respectively, as determined by HPLC. The chemical structures of these isolated compounds were confirmed by ESI-MS, ¹H-NMR and ¹³C-NMR.

Studies on purification of allicin by molecular distillation.

BACKGROUND: With recent improvements in living standards, people have been giving more consideration to the healthcare effects of foods. In this respect, allicin, which is the most important organosulfur compound in garlic and plays a key role in physiological function, has been receiving much attention. RESULTS: Allicin obtained from garlic by supercritical CO(2) extraction was purified by molecular distillation (MD). The effects of operating conditions such as absolute pressure (AP), distillation temperature (DT) and feed flow rate (FFR) on allicin purity and yield were studied. The optimal AP, DT and FFR levels in first-stage MD were found to be 200 Pa, 50 °C and 15 mL min(-1) respectively. After three stages of MD the contents of allicin, diallyl disulfide (DADS) and diallyl trisulfide (DATS) were 68.04, 9.19 and 5.91% (w/w) respectively. CONCLUSION: This study has provided a safe and effective method for the purification of allicin.