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Effect of Low Storage Temperature on Some of the Flavour Precursors in Garlic (Allium Sativum)
Abstract
Garlic (Allium sativum) cloves were stored at ambient temperature and 4 degrees C for periods up to six months to establish the effect of position of the individual clove within the bulb and of low storage temperature on the composition of several flavours precursors and other organic sulphur compounds, measured by gradient High Pressure Liquid Chromatography. Levels of alliin, gamma glutamyl allyl cysteine sulphoxide and gamma glutamyl isoallyl cysteine sulphoxide were statistically significantly higher in outer than in inner cloves. There was no statistically significant change in levels of alliin, the major flavour precursor, in cloves stored at 4 degrees C, remaining in the average range 17.5+/-3.8-39.1+/-7.5 mM. However, isoalliin increased significantly during storage at 4 degrees C, rising from an average 0.6+/-0.2 mM (outer cloves) -- 0.7+/-0.4 mM (inner cloves) to 7.1+/-1.7 mM (outer cloves) -- 4.1+/-0.7 mM (inner cloves). A decline in other sulphur-containing compounds, most likely to be the peptides gamma-glutamyl allylcysteine sulphoxide and gamma-glutamyl isoallylcysteine sulphoxide, occurred at the same time and possibly contributed to the increase in the flavour precursor compounds. The degree of chemical changes during storage will be of interest to the food and pharmaceutical industries.
... ACSOs were extracted after the chemical inhibition of alliinase by using OCMHA according to [8,15], with slight modifications. The entire extraction procedure was designed to eliminate the main source of variability caused by differences between individual garlic cloves and bulbs, which can be significant, as pointed out by some researchers [10,16]. Briefly, approximately 20 g of intact peeled garlic cloves (mixture from various bulbs and positions within those bulbs, duplicates for all samples) were placed into a laboratory blender. ...
... Although some samples had the highest ACSO content in their immature state, they almost regained their initial values by longterm storage due to the increase in isoalliin content. The observed increase in isoalliin content during cold storage is in good agreement with other research [16,19,20]. Ichikawa et al. [19] compared the influence of three different storage temperatures (−3, 4 and 23°C) on ACSO and γ-glutamylpeptides levels in garlic and after 150 days of storage, they reported the most significant increase (32-fold) at 4°C. ...
... Regarding the other ACSOs, Ichikawa et al. [19] reported a slight increase in alliin content during 150 days of storage at −3, 4 as well as 23°C, similarly to Hornickova et al. [17], who found an increase in alliin content by 30% on average after eight weeks' storage at 5°C. On the other hand, no significant changes in alliin content in garlic bulbs stored at 4°C for 180 days were observed by Hughes et al. [16]. In any case, all changes in ACSO content may alter the biological activity and sensory properties of garlic (higher ACSO content is preferred). ...
The composition of garlic (Allium sativum L.) may vary among cultivars and, moreover, change over time, thereby affecting both biological activity and flavour. Thus, it is important to identify the trends in the content of bioactive compounds in garlic, by reliable analytical methods. This study was focused on the key sulfur-containing compounds, S-alk(en)yl-l-cysteine sulfoxides (alliin, isoalliin, methiin, propiin), which were quantified by a fast liquid chromatography – tandem mass spectrometry (LC-MS/MS) method. Several garlic cultivars were monitored repeatedly within seven months: one month before harvest maturity; at harvest maturity; and after two and six months of storage. The results showed not only a high variability among individual cultivars, but also among samples of the same cultivar grown at different localities. During storage, a significant increase in isoalliin content (up to 54-fold after six months) occurred. Nevertheless, none of the cultivars showed significantly different properties compared to others, suggesting that many other factors affect garlic composition.
... Therefore, it is necessary to find a proper storage for garlic bulbs to maintain a high quality both for consumption and stock seeds. There are few studies on the effects of storage conditions to the garlic bulb qualities [7,8,9], however, proper storage condition for a local variety, such as Lumbu Kuning, is limited. The objective of this study was to examine the effect of storage temperature on the quality of garlic during storage. ...
... A number of the sprouting garlic bulbs were observed starting at 3 months after the storage at 7 ºC, whereas no bulb sprouting occurred from those stored at 0ºC and a room temperature. The bulb sprouting is associated with the increasing number of isoalliin during storage at low temperature as the result of the degradation of the γ-glutamyl peptides by an increased activity of a trans-peptidase stimulated following the breaking of dormancy [9]. Physically, the emergence of the sprouting is controlled mainly by external factors, such as a cool temperature (7 o C) [12]. ...
The quality of garlic bulbs may be deteriorated under storage. This work aimed to study the effect of storage temperature on the quality of garlic during storage. A local garlic variety, i.e. Lumbu Kuning was used in the study. The bulbs were collected from a farmer. After drying, the bulbs were subjected to different temperature storage conditions, i.e. 0°>C; 7°C (RH 50-70%, darkness), and a room temperature (29-31°C, RH 70-80%). The treated bulbs were stored for 6 months. The parameters observed were weight, numbers of empty and sprouted bulbs. The treatments were carried out in three replications (54-67 bulbs or 300 g per replicate). The results showed that the highest weight loss was found from the bulbs stored at 7°C (25.08%), followed those stored at the room temperature (18.76%) and 0°C (10.47%). The highest sprouting percentage occurred in those stored at 7°C (25.16%). The empty bulbs percentage was found for that garlic stored at 0°C and a room temperature were 6% and 13%, respectively. The study suggests that storage condition at 0°C is recommended for long-term storage of garlic bulbs.
... The oxidised isomers of GSAC (GSAC(O)) and GSPC (GSPC(O)) eluted significantly earlier than the parent compounds. Both compounds have been reported as being present in garlic by Yamazaki et al. 17 They were quantified by Hughes et al. 18 during a study of the changes in GSAC(O) and GSPC(O) in garlic bulbs and cloves due to storage conditions with concentrations for GSAC(O) being between 6.2 and 68 mmol kg À1 and between 27 and 202 mmol kg À1 for GSPC(O) with no indication of whether it was determined on a dry or fresh weight basis. 18 In our study the amount of GSPC(O) in the bulbs was lower than that of GSAC(O) in contrast to Hughes' findings (Table S5, ESI †). ...
... Both compounds have been reported as being present in garlic by Yamazaki et al. 17 They were quantified by Hughes et al. 18 during a study of the changes in GSAC(O) and GSPC(O) in garlic bulbs and cloves due to storage conditions with concentrations for GSAC(O) being between 6.2 and 68 mmol kg À1 and between 27 and 202 mmol kg À1 for GSPC(O) with no indication of whether it was determined on a dry or fresh weight basis. 18 In our study the amount of GSPC(O) in the bulbs was lower than that of GSAC(O) in contrast to Hughes' findings (Table S5, ESI †). Roots contained similar amounts of both compounds at the low and medium fertilization levels, but significantly more GSAC(O) than GSPC(O) at the high level (with a very high inter-plant variability in all cases). ...
Garlic (A. sativum) contains a large number of small sulphur (S)-containing metabolites, which are important for its taste and smell and vary with A. sativum variety and growth conditions. This...
... It has been well documented that the total content and relative proportions of the individual S-alk(en)ylcysteine sulfoxides in garlic are strongly affected by a number of genetic and environmental factors (e.g. climatic conditions, soil composition, irrigation, fertilisation, harvest date, etc.) (Randle & Lancaster 2002;Volk et al. 2004;Kamenetsky et al. 2005;Hughes et al. 2006;Ichikawa et al. 2006). However, the differences in S-alk(en)ylcysteine sulfoxide profiles of various garlic morphotypes have been so far studied only sporadically. ...
... Thus, the observed increase in the content of S-alk(en)ylcysteine sulfoxides can be attributed to the conversion of the corresponding γ-glutamyl dipeptides to sulfoxides rather than to the loss of water. Similar observations of a several-fold increase of isoalliin content in garlic cloves were also reported by Lawson et al. (1991), Hughes et al. (2006), and Ichikawa et al. (2006). This phenomenon has very important implications for food industry. ...
The contents of major S-alk(en)ylcysteine sulfoxides (namely alliin, methiin and isoalliin) were determined in a set of 58 various garlic genotypes (22 flowering plant morphotypes, 14 semi bolting plants and 22 scape absent morphotype plants), representing the garlic collection of the Allium gene bank in the Czech Republic. The plants were cultivated in four successive years (2005-2008) and analysed immediately after harvest and subsequently after eight weeks of storage at 5°C. The total content of the three cysteine derivatives in fresh samples varied considerably between 3.35 mg/g fresh weigh and 12.77 mg/g fresh weight, with the mean of 7.50 mg/g fresh weight and the average relative proportions of alliin/methiin/isoalliin of 83/16/1. Upon 8-week storage at 5°C, the average total amount of S-alk(en)ylcysteine sulfoxides increased by 30% to 9.75 mg/g fresh weight, with the alliin/methiin/isoalliin ratio changing to 82/14/4. The data obtained were statistically evaluated using linear discrimination analysis to distinguish the differences betweenthe years of harvest, between freshly harvested and stored samples, and between the individual morphotypes. While the year-to-year differences between the samples were statistically not very significant, the fresh and stored samples as well as the individual garlic morphotypes differed considerably in S-alk(en)ylcysteine sulfoxide content. Our results indicate that the content of S-alk(en)ylcysteine sulfoxides primarily depends on various genetic factors and post-harveststorage conditions, whereas the climatic conditions during the growth (e.g. temperature, irrigation) influence their level to a lesser extent. Various implications for the food and pharmaceutical industries are discussed.
... In garlic bulbs, the main flavor precursor is alliin, with fewer amounts of isoalliin and methiin (Lancaster and Boland 1990). The remaining OSCs in garlic are present as g-glutamyl peptides such as g-glutamyl allyl cysteine sulphoxide (g-GLUACSO), and g-glutamyl isoallyl cysteine sulphoxide (g-GLUisoACSO) (Hughes et al. 2006). When garlic tissue is damaged, the vacuolar enzyme alliinase rapidly hydrolyses the cytosolic ACSOs, including alliin, to form the thiosulfinates (which provide the characteristic flavor and odor), pyruvate and ammonia. ...
... In the present work, we have focused on the study of OSCs content changes during postharvest. Several studies have been carried out on the chemical changes occurring during storage of garlic bulbs (Lawson et al. 1991b;Hughes et al. 2006;Ichikawa et al. 2006). In addition, it is well known that garlic bulb storage has problems, such as sprouting and weight loss. ...
The aim of the present work was to evaluate the application of a physiological indicator as marker of allicin content during postharvest storage at different temperatures. Sureño INTA garlic cultivar was stored at room temperature (20C ± 3) and cold storage (0C ± 0.5). Samples were taken periodically and allicin, pyruvate content were analyzed and the sprout growth was measured through of the visual index of dormancy (VID). The results showed that regardless of storage temperature, allicin, pyruvate content and VID changed significantly during the period of the assay. For the conditions evaluated, the highest allicin content was observed at 50% and 100% VID. These facts suggest that VID may be a suitable tool to estimate allicin level during storage. PRACTICAL APLICATIONSThis work was addressed to resolve the problem of standardization of garlic subproducts according to their bioactive compounds levels. The information acquired is important for farmers and the food and phytotherapic industry in order to guarantee the adequate supply of garlic subproducts to the consumer. Therefore, we found that it is important to consider a physiological indicator as a tool to estimate the bioactive compound levels during postharvest storage.
... In garlic bulbs, the main flavor precursor is alliin, with fewer amounts of isoalliin and methiin (Lancaster and Boland 1990). The remaining OSCs in garlic are present as g-glutamyl peptides such as g-glutamyl allyl cysteine sulphoxide (g-GLUACSO), and g-glutamyl isoallyl cysteine sulphoxide (g-GLUisoACSO) (Hughes et al. 2006). When garlic tissue is damaged, the vacuolar enzyme alliinase rapidly hydrolyses the cytosolic ACSOs, including alliin, to form the thiosulfinates (which provide the characteristic flavor and odor), pyruvate and ammonia. ...
... In the present work, we have focused on the study of OSCs content changes during postharvest. Several studies have been carried out on the chemical changes occurring during storage of garlic bulbs (Lawson et al. 1991b;Hughes et al. 2006;Ichikawa et al. 2006). In addition, it is well known that garlic bulb storage has problems, such as sprouting and weight loss. ...
Garlic is a vegetable mainly agamically propagated, and it has been dispersed all around the world. Garlic cultivars have been classified in different ecophysiological groups (EG) according to their bulbing requirements. The variability in organosulfur composition (ACSOs), solids content (SC), pungency (PC) and antiplatelet activity (IAA) and the correlation among these traits in garlic clones belonging to three EG was studied. We found variability for ACSOs, SC, PC and IAA between clones belonging to different EG and also among clones belonging to the same EG. Cutivars EG III presented more variability than EG IV for ACSOs, thiosulfinates, allicin and PC, while for SC, EG IV was the most variable. The correlations found suggested that IAA observed was mainly due to organosulfur composition. Finally recommendations about the most suitable cultivars for fresh consumption, pharmaceutical and dehydration industry are made.
... In one study alliin increased to over twice its original concentration when garlic was stored for 83 d at ambient temperature (Bloem et al., 2011). In contrast, Hughes et al. (2006) found alliin remaining largely unchanged after 6 months of cold storage and Ichikawa et al. (2006) reported no significant changes from pre-storage levels in garlic stored at − 3 • C or 23 • C across 9 time points over 150 d storage. Ichikawa et al. (2006) did, however, report a significant increase in alliin concentration at 90, 120 and 150 d compared to pre-storage levels in the same garlic cultivar when stored at 4 • C. Differences may be therefore ascribed to temperature or cultivar effects. ...
Garlic (Allium sativum L.) has a long history of use as a culinary seasoning and source of health-promoting compounds. In particular organosulphur compounds derived from the action of alliinase on alliin are of interest for their antimicrobial action. Due to the seasonal nature of the garlic harvest, long-term storage is required to ensure year-round supply of high-quality bulbs. However, quality is known to deteriorate throughout storage, and storage regimes are aimed at maintaining culinary, not biochemical quality, posing challenges for biotech firms extracting high value products, such as alliinase, from garlic. Storage typically involves extended periods of up to 9 months at -1.5 °C. Here, quality parameters (disease incidence and moisture content) as well as biotechnological quality parameters (alliinase yield and activity) were measured, and correlated with gene expression and volatile organic compound (VOC) profiles comparing storage at -1.5 °C and 22 °C. The aim is to develop potential molecular markers for garlic quality assessment. Alliinase activity fell in the first 6 months of storage, with garlic stored at -1.5 °C losing more activity, however 22 °C stored garlic suffered higher spoilage after 12 months storage. Alliinase activity loss was not proportional to gene transcript levels, suggesting post-translational control. A total of 150 VOCs were detected across all samples using thermal desorption gas chromatography, time of flight mass spectrometry of intact garlic bulbs, the most abundant of which were organosulphur compounds. Storage temperature significantly affected the whole VOC profile and discrete profiles were detected from garlic cold-stored for different time periods. Using weighted correlation network analysis 17 VOCs were identified that correlated with storage time, six VOCs that were indicative for storage temperature and four VOCs (azulene, octanal, o-Xylene and 4-methylhexadecane) were significantly associated with alliinase activity.
... Growth and development, bulb quality, nutrient value and clove sprouting and decaying of garlic have been reported to be associated with environmental conditions as well as clove size (Bhandari et al., 2012). Several workers have reported that techniques applied during growth and development in field, pre-and post-harvest conditions, bulb/clove type and size may affect yield quantity and quality of bulbs or cloves as colour, taste, favour, weight, sprouting, decaying as a result of increased respiration Hughes et al., 2006). Hence, there is a great requirement to standardize the size of garlic cloves used for storage time and cultivation bulbs in order to increase effective garlic production. ...
Main goals of the present study were (1) to initially investigate the nutrient contents and bioactive compounds in the bulb and cloves of garlic, and (2) to study the growth parameter after planting. Garlic bulbs were firstly separated into three categories as pickled, big and small, while the big garlic cloves were also classified into three categories as big, small and central. Secondly, the garlic samples were analyzed before planting for their element profile, proline, soluble protein, free amino acid, β-carotene, lycopene, total phenolic, soluble sugars, SOD and α-amylase activities. Finally, the growth parameters were measured using the cultivated cloves and the pickled bulbs. According to the result, the highest soluble protein, N, phenolic, lycopene and α amylase activity (97.06 mg, 2.58%, 971 mg, 0.368 mg and 38.13 EU, respectively) were recorded in the biggest cloves. The highest proline, amino acid, glucose content (93.84 µmol, 23.54 mg, 230.89 mg, respectively) and K, P, S, Mg, Mn, Fe and Zn (21940 ppm, 7577 ppm, 12200 ppm, 504 ppm, 38.1ppm, 377,7ppm and 44.5 ppm, respectively) were found in the pickled bulb. The maximum level of β-carotene (0.282 mg), Ca, Cl and Sr (11260ppm, 818.7ppm and 47.9 ppm) were determined in the small bulbs. Based on the growth parameters of seedlings, the highest value of shoot and root length (39.12 cm and 24.11 cm respectively), the fresh weight of shoot and root (5.29 g and 4.54 g respectively) and dry weight of shoot and root (1.70 g and 1.24 g respectively) were noted with the big cloves. The results of the current study have indicated that the pickled cloves have higher macro and micro nutrients, proline, amino acid and glucose, while the big cloves of garlic have higher proline, phenolic, N%, lycopene and amylase activity. It can be said that the big cloves showed good value for the five bioactive compounds, but the pickled exhibited good value for the macro and micro element and glucose.
... Following the same pattern, storage at 23 ∘ C showed a significant increase in cyclo alliin compared to iso alliin and a decrease in GSPC. Beato et al. 36 reported degradation (49% loss) of the three -glutamyl peptides in blanched garlic stored for 365 days at room temperature whereas Hughes et al. 37 reported that when garlic was stored at 4 ∘ C for 168 day couldn't find any change in the alliin content. It was also observed that -glutamyl peptides were slowly degraded during the storage period with an increased activity of a transpeptidase that yielded the corresponding S-alk(en)yl-l-cysteine, isoalliin, etc. ...
BACKGROUND
This study highlights the effect of removing different plant parts on the biochemical changes in the garlic scape of cultivars G064 and G025 during controlled atmosphere storage (O2 = 2%–5%, CO2 = 3%–6%) at temperature = 0 ± 0.5 °C, Relative Humidity (RH) RH = 85%–95%, for 168 day. Total polyphenols (TP), total flavonoids (TF), the concentration of allicin, ethylene production and the antioxidant potential were evaluated and analyzed by using four different assays. Statistically significant differences were observed between different treatments.
RESULTS
Total polyphenols, allicin concentration, and ethylene production were the highest in G064, while the total flavonoid concentration was the highest in G025. Removing the top resulted in the highest levels of total polyphenols, total flavonoids, allicin, and ethylene in both cultivars. The antioxidant capacity was also significantly higher when the top was removed than with other treatments in both cultivars. 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH), hydroxyl radical scavenging activity (HRSC), ferric ion reducing antioxidant power (FRAP) and metal‐chelating capacity (MCC) were higher in cultivar G064 compared to G025.
CONCLUSION
Overall, the results suggest that the removing the tops of the scapes of G025 and G064 is the best treatment to maintain these biochemical changes. © 2018 Society of Chemical Industry
... Chemical changes in garlic during storage and processing [www.kyolic.com/research/truth-about-garlic/transformation-of-sulfur-compounds-in-garlic/] γ-Glutamylcysteines are reserve compounds and can be hydrolyzed and oxidized to form alliin, which accumulates naturally during storage of garlic bulbs at a low temperature (Hughes et al., 2006). After processing, such as cutting, crushing, chewing or dehydration, the vacuolar enzyme, alliinase, rapidly lyses the cytosolic cysteine sulfoxides (alliin) to form cytotoxic and odoriferous alkyl alkane-thiosulfinates such as allicin (Fig.2). ...
The protective effect of garlic extracts against cadmium toxicity was examined for the first time using “in ovo” model. As the egg must supply all the nutrients that the embryo needs to access for growth and development, the introducing “in ovo” additive compounds provides an ideal scenario for the testing their toxic effects and protectors efficacy without any external interference. The main studied topics were focused on the comparison of bioactive compounds in fresh and freeze drying garlic bulbs (Polish and Chinese) as well as leaves of wild bear's garlic. Moreover, the protective effect of various form of garlic against cadmium was studied and compared with separate sulfur compounds (reduced glutathione and N-acetylcysteine) efficacy in cadmium detoxification. Cadmium ions (6 µg/egg) and/or protectors were injected to the albumen of fertilized hens egg at 4th day of incubation. The e Three lysosomal hydrolases activity (N-acetyl-β-glucosaminidase, β-mannosidase and arylsulfatase) were used to detect cellular lysosomal damage caused by cadmium. It was shown that garlic supplementation to diet can protect consumer against toxic effect of cadmium present in food.
Key-words: food, cadmium, garlic, protectors, N-acetylcysteine, GSH, lysosomal hydrolase, in ovo model
Full pdf http://www.ibuk.pl/fiszka/149536/bioactive-components-of-garlic-and-their-effect-on-the-reduction-of-cadmium-toxicity-in-food.html
... Apesar de todos os estudos desenvolvidos em várias partes do mundo envolvendo a cultura do alho, há uma lacuna na literatura consultada acerca do conteúdo de substâncias bioativas em bulbos de alho durante o armazenamento pós-colheita. HUGHES et al. (2006) indicaram claramente a necessidade de um maior aprofundamento nas pesquisas enfocando essa questão. ...
The objective of the present research was to determine the content of functional compounds in garlic cloves of two Brazilian cultivars ('Caçador' and 'Peruano') one Chinese cultivar ('Jinxiang'), during the postharvest storage up to 60 days. The experiments were carried out in a completely randomized design, in a factorial scheme 3x5 (3 cultivars; 5 samplings times) with 3 replicates. Experimental unit was comprised by 10 garlic bulbs. Garlic bulbs were stored at 22±1°C and 70±2% RH and analyzed, every 15 days for allicin, phenolic compounds and antioxidant activity using the -carotene/linoleic acid method. In general, it was observed that functional compounds were altered in the garlic cultivars studied. The profile of the levels of allicin was not changed during the period of storage for the variety 'Caçador'. However, the profile was of bioactive degradation at 45 and 15 days of storage for 'Peruano' and 'Jinxiang' cultivars, respectively. The antioxidant potential measured by the system ?-carotene/ linoleic acid for cultivars 'Caçador' and 'Jinxiang' were higher than the 'Peruano' cultivar, at the beginning of the evaluation. The profile for all cultivars was of reduction of potential, and after 30 days these differences were no observed. Regarding the content of phenolic compounds it was observed that 'Jinxiang' showed higher levels than in the cultivars 'Peruano' and 'Caçador', at the beginning of the evaluation. All cultivars showed a significant increase from 15 days evaluation. Therefore, the garlic cultivars evaluated had antioxidant activity of compounds derived from organosulfur and phenolic compounds, which was modified with storage under refrigeration.
... Studies on the distribution of CSOs in Alliums show that they are found in a range of tissues, including leaf, bulb, root and flower scapes as well as in cell culture and callus tissues [4] . Studies on garlic cloves in storage indicate that they have the capacity to synthesise CSOs from other organosulphur containing compounds present in the cloves [13,14] . However, the origin of CSOs in the clove has to be considered in the context of the development of the whole plant. ...
The major flavour precursors in the genus Allium include alliin, isoalliin, proliin and methiin, members of the alkyl Cysteine Sulfoxide group (CSOs). The path of synthesis of alkyl Cysteine Sulphoxides, or flavour precursors, in the Alliums are still speculative. There are two proposed routes for alliin biosynthesis, one is from serine and allyl thiol while the other is from glutathione and an allyl source via glutamyl peptides.The addition of allyl thiol to differentiating garlic tissue cultures resulted in the appearance of detectable levels of both S-allyl cysteine and alliin and also demonstrated that S-allyl-cysteine was oxidised stereospecifically to alliin by garlic tissue cultures, indicating the presence of a specific oxidase in the cells. Although these reports provide good evidence that S-allyl cysteine can be converted to alliin by garlic tissue cultures, it does not indicate whether γ–glutamyl-S-allyl cysteine or S-allyl cysteine is the substrate for the oxidation in vivo. Several approaches have been combined to investigate the intermediates and enzymes involved in the biosynthetic pathways, which have allowed to build up, for the first time, a picture of the dynamic uptake, allocation and distribution of flavour precursors during the life cycle. This indicated that CSOs are remobilised to the new cloves in a late stage of development, following uptake of the bulk of sulphur by the plant. Studies involving feeding potential intermediates to garlic callus tissue, that generally lack flavour precursors, indicated that several alk(en)yl thiols could be converted to alk(en)yl cysteine and alk(en)yl cysteine sulphoxide by callus. This may indicate that synthase and oxidase enzyme(s) with broad substrate specificity may exist in Allium. Cysteine synthase (CS) and serine acetyltransferase (SAT) may play a role in flavour precursor biosynthesis. Alliinase is the enzyme that initiates the conversion of alliin to allicin and its derivatives. These results provide further insight into the biosynthetic pathway of garlic flavour compounds.
... Ayr›ca Yahudiler de sar›msakla yak›ndan ilgilenmifllerdir, d›fl yüzeyde, meyve etinden daha fazla miktarda bulunmas› ile birlikte depolama süresince isoallyl miktar› art›fl gösterirken, sülfür bilefliklerinin miktar› azalm›fl. Tat ve alliin miktar›ndaki de¤iflimler ise belirgin bulunmad›¤› belirtilmifltir(29).Kontrollü atmosfer, so¤uk depolama tekni¤inin yan› s›ra gelifltirilen bir teknik olmakla birlikte ürünün bulundu¤u ortamdaki atmosfer bileflimini de¤ifltirme esas›na dayan›r. Genellikle düflük O 2 yüksek CO 2 gaz kompozisyonlar› kullan›l›r. ...
Garlic (Allium sativum L.) has been used to treat many diseases as well as a food flavoring for many years. In the last twenty years, consumers' trend for foods which have high nutritional value and
therapeutic activity has led to an increase in the studies on nutritional value of garlic worldwide.The importance and necessity of the involvement of garlic in daily nutritional programs is emphasized
much more than ever in recent years as a result of its antibiotic, antioxidant and anti-carcinogenic properties. Garlic is a species which can be stored longer than other vegetables. In our country, garlic
can only be stored, often without cooling, at 0-5 °C, 60-70 % relative humidity for at least 3-4 months in warehouses. Today, no treatment is made in pre and post storage of garlic in Turkey. Storage of garlic
in controlled atmosphere and the modified atmosphere is commonly made with different irradiation, chemicals, and heat treatment in abroad. In this study, results of studies on the effect of pre and
postharvest treatments on the storage life and quality of garlic were reviewed.
... Similarly, from the study of Beato et al. (2012), it can be concluded that the three ␥-glutamyl peptides in pickled blanched garlic were significantly degraded during storage at room temperature (49% loss after 1 year of storage). However, Hughes et al. (2006) did not find a variation in the alliin content when garlic was stored for 6 months at 4 • C, but isoalliin increased significantly from 0.6 mM to 7.1 mM in the outer cloves. It is reasonable to argue that the ␥-glutamyl peptides were slowly degraded by an increased activity of a transpeptidase during storage to yield the corresponding S-alk(en)yl-l-cysteine, isoalliin, which increased during storage as also observed in our study. ...
The evaluation of the impact of postharvest processing and storage on the health benefits of vegetables is of great practical importance. Reports on their effect on the antioxidant capacity, polyphenol and S-alk(en)yl-l-cysteine sulfoxide (ACSO) content, i.e. isoalliin and methiin of the white shaft of leek (Allium ampeloprasum var. porrum), however, are limited. This study determined the levels of the antioxidant properties of leek from postharvest processing at the farm until refrigerated storage of 13 days at the consumer. Two cases were investigated, (1) leek sold as an entire plant and (2) leek with a large part of the green leaves removed, where the shafts are sold in a plastic package. The antioxidant capacity and the total content of phenolic compounds in the white shaft of the entire and packaged leek was stable during 13 days of refrigerated storage. A significant increase in the concentration of isoalliin was observed. Comparing the entire and processed/packaged leek, significant differences could be observed in antioxidant properties. The ACSO content in the white shaft of packaged leek was significant lower than the content in the white part of the entire leek. Therefore, the minimal processing step of cutting the green leaves and roots had an influence on the levels of antioxidant properties.
... From the study of Ceci et al. (1992), it was found that during the first 90 days of storage the activity of GTP in garlic changed only slightly. This was due to dormancy period of garlic (Hughes et al., 2006). In our study, during the first 80 days after harvest (60 days of storage) allicin content in each treatment did not differ from one another. ...
This research aims to find treatments to increase allicin content in garlic after harvesting. The harvested garlic was stored at various conditions, including room temperature (Tr1); 4-6°C and 60-70% RH (Tr2); 4-6°C and 80-90% RH (Tr3); 8-10°C and 60-70% RH (Tr4); 8-10°C and 80-90% RH (Tr5); room temperature for 90 days and following at 4-6°C for 30 days (Tr6) room temperature for 90 days following at 4-6°C and 80-90% RH for 30 days (Tr7). Allicin content and weight loss were measured every 20 days for 120 days. The results showed that the allicin content of garlic in all treatments has increased during storage. The garlic in each treatment had only 4-11% weight loss during storage for 120 days. The maximum allicin content was found in Tr3 after storing for 60 days (36.5 mM/g dry weight). After storage for 120 days, the allicin content in treatment 2, 3, 4, 5 and 7 was higher than that in treatment 1and 6. The allicin content in Tr7 increased quickly after transferring from room temperature to low temperature and high humidity.
... Similarly, from the study of Beato et al. (2012), it can be concluded that the three -glutamyl peptides in pickled blanched garlic were significantly degraded during storage at room temperature (49% loss after 1 year of storage). However, Hughes et al. (2006) did not find a variation in the alliin content when garlic was stored for 6 months at 4 @BULLET C, but isoalliin increased significantly from 0.6 mM to 7.1 mM in the outer cloves. It is reasonable to argue that the -glutamyl peptides were slowly degraded by an increased activity of a transpeptidase during storage to yield the corresponding S-alk(en)yl-l-cysteine, isoalliin, which increased during storage as also observed in our study. ...
Evaluating the effect of domestic cooking on the health benefits of vegetables has great practical importance. But only a limited number of reports provide information on the effect of these treatments on the antioxidant capacity, polyphenol and S-alk(en)yl-L-cysteine sulfoxide (ACSO, e.g. isoalliin and methiin) content of the white shaft and green leaves of leek (Allium ampeloprasum var. porrum).
In the present study, the antioxidant capacity of leek was highly influenced by cooking (blanching, boiling and steaming). Boiling had a negative effect on total phenolic content in the white shaft and green leaves. An obvious increase could be observed in the antioxidant capacity of the steamed green leaves, while steaming did not influence the polyphenolic content. Remarkably, blanching resulted in a slight increase in the ACSO content. Subjecting leek samples to a longer thermal treatment appeared to have a negative influence on the ACSO content in leek. Steaming was also responsible for a decrease in ACSOs. Methiin was less susceptible to heat treatment than isoalliin.
In general, steaming appeared to be responsible for better retention of the bioactive compounds present in leek compared with boiling.
... Similarly, from the study of Beato et al. (2012), it can be concluded that the three -glutamyl peptides in pickled blanched garlic were significantly degraded during storage at room temperature (49% loss after 1 year of storage). However, Hughes et al. (2006) did not find a variation in the alliin content when garlic was stored for 6 months at 4 @BULLET C, but isoalliin increased significantly from 0.6 mM to 7.1 mM in the outer cloves. It is reasonable to argue that the -glutamyl peptides were slowly degraded by an increased activity of a transpeptidase during storage to yield the corresponding S-alk(en)yl-l-cysteine, isoalliin, which increased during storage as also observed in our study. ...
Background:
Leek is grown for its thickened cylindrical white shaft made up of long leaf bases. Despite the potentially valuable nutritional profile of the green leaves, a large portion remains unused owing its restricted culinary applications. This large quantity of this plant biomass could be valorized given an adequate stabilization method. In this study, we examined leek fermentation with regard to antioxidant changes.
Results:
The oxygen radical absorbance capacity (ORAC) increased by 62% when the green leaves were fermented for 21 days, while 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity did not increase significantly. Fermentation resulted in an increase of endogenous polyphenolic compounds such as ferulic acid, astragalin, luteolin and naringenin. Moreover, fermentation stimulated the production of a series of polyphenolic compounds that were not present in the fresh leek. The flavour precursors in leek, i.e. methiin and isoalliin, were reduced by 91-93% and 100%, respectively, when spontaneous fermentation was allowed to occur on the white shaft and green leaves.
Conclusion:
Our results demonstrated that application of fermentation resulted in a higher ORAC value and polyphenol content of the leek plant, especially in the green leaves. These results indicate the nutritional relevance of fermentation, which hold promise as a stabilization technique.
... ' RESULTS AND DISCUSSION Garlic bulbs are generally stored for a period of time: when the postharvest temperature is between 20 and 30°C, garlic bulbs remain firm for about 60 days before they shrivel; at cool temperatures (5À18°C), dormancy is lost after 90À120 days and sprouting occurs, while under cold conditions (À1À0°C), bulbs remain stable for long periods. 26 Targeted S fertilization increases the content of bioactive compounds in onions and garlic. 16,20 Fertilization influenced the mineral composition too. ...
The most important active compound in garlic is alliin. Sulfur (S) fertilization was shown to significantly increase the alliin concentration in garlic cloves, while high nitrogen (N) levels had an adverse effect. The effect of graded N and S application on the storage life of garlic has been paid little attention so far. A bifactorial field trial with 4 levels of N and S was conducted in a randomized block design. At harvest, 40 bulbs per treatment were stored under terms comparable to the storage conditions in average households (20 °C, dry, and dim) for 83 days. Every 3 weeks, samples were analyzed for their alliin and water content. The alliin concentration in peeled garlic cloves increased during storage from on average 9.2 mg g(-1) dry weight at harvest to 21.4 mg g(-1) dry weight after 83 days of storage. S fertilization increased the alliin concentration by a factor of 2.3 from 11.4 mg g(-1) in the control treatment to 26.6 mg g(-1) dry weight at the highest S level of 45 kg ha(-1) after 83 days of storage. N fertilization decreased by a trend of the alliin content. Fertilizer rates had only a minor influence on water losses from bulbs at short-term storage. After 83 days of storage, water losses were by trend lower at higher S levels, and this relationship proved to be significant when no N was applied. Best quality in terms of high alliin contents was obtained during the entire storage time at an S level of at minimum 30 kg ha(-1) S if no N was applied. The results show that the physiological S demand of 15 kg ha(-1) S for optimum yield is lower than the S requirement of 30 kg ha(-1) S for a longer storage life.
Garlic (Allium sativum) is the most important plant species that richer for of sulphur-containing compounds (allysin, alliin), carbohydrates (saccharos, glycose), protein, fiber, free amino acids, enzymes, minerals, β-caroten and vitamins. Because of those properties it has been used to treat many diseases as well as a food flavoring for many years. Garlic can be consumed as dried, powder, juice of garlic, pure, volatile oil forms which prooducted from garlic bulp directly as well as freshly. However, taste of garlic, nutrients, chemical composition, colour and shape can be changed according to pre and postharvest treatments, storage life and conductions and preservation types. In this presentstudy, the effect of different preservation condition on cloves quality in Taşköprü garlic was evaluated by analyzing the chemical composition of garlic such as proline, free amino acids, total soluble proteins, β-caroten, total phenoloic compund and flavonoit, saccharose and total soluble carbohydrates amounts, level of lipid peroxadation (as malondialdehyde), APx, CAT and SOD activity. All analyses were performed in control group, stored in -18 °C and kept in pure oil, vinegar which contained 2% NaCl, and left for 10 mounths in dark and warm conduction. Based on the data, the proline, free amino acid, total flavonoit amount were the highest for the stored in vinegar, whereas total soluble protein, total phenoloic compound content and APx and SOD activity increased in the olive oil samples. The highest β-caroten, saccharose and total soluble carbohydrate value obtained from the samples kept in -18 °C; the highest CAT activity was found in the control group. Level of lipit peroxadation was lower in the cloves belonged -18 °C and vinegar but it was higher in others garlic samples.
Finaly, we have concluded that we can obtain different garlic products by using olive oil and vinegar in different concentrations. In addition, the results have shown that Taşköprü garlic have higher nutrients and antioxidant capacity.
Garlic has been reported to contain various organosurfur compounds which have antibiotic and anticarcinogenic properties and thus may reduce the possibility of cancer and chronic diseases. Garlic bulbs maintain dormancy for about 3 months after harvest at ambient temperature and then sprouting occurs. Garlic bulbs are stored at 0 C for 6 months and then moved to -4 similar to-2 degrees C to control sprouting and decay. Hot-air drying at 38 degrees C for 3-6 days is an essential pre-storage treatment to prevent frozen injury and sprouting. Recently, the steady growth in retail sales of fresh-cut produce has led to pre-peeled and crushed garlic products. During distribution and sale, unfavorable color changes like blueing and browning reduce the marketability of processed garlic product. Blueing in crushed garlic occurs when garlic bulb is stored under 15 degrees C for more than 3 months and the amount of 1-PeCSO increases enough to react with alliinase by disruption. Although organic acids and heat treatments are used to control blueing, better control methods need to be developed. Browning in crushed garlic is due to oxidation of phenolic compounds by polyphenol oxidase and it can be inhibited by pH adjustment with organic acids.
The influence of processing, with and without fermentation, on the contents of organosulfur compounds, namely, γ-glutamyl peptides, S-alk(en)yl-L-cysteine sulfoxides (ACSOs), and S-allyl-L-cysteine (SAC), in pickled blanched garlic was evaluated. For each processing type, the effect of the preservation method and storage time was also analyzed. Blanching in hot water (90 °C for 5 min) hardly affected the individual organosulfur compound content. The fermentation and packing steps negatively affected the levels of all compounds except for SAC. The content of this compound increased during storage at room temperature whereas γ-glutamyl peptides and ACSOs were degraded to various extents. The pasteurization treatment itself had no significant effect on the concentrations of organosulfur compounds. Use of the corresponding fermentation brine in the case of the fermented product in conjunction with refrigerated storage was found to be the best method to preserve the levels of organosulfur compounds in pickled garlic stored for up to one year.
The content of organosulfur compounds was determined in selected garlic cultivars grown at four locations in Andalusia, Spain. The organosulfur compounds studied were three γ-glutamyl peptides, namely, γ-l-glutamyl-S-(2-propenyl)-l-cysteine (GSAC), γ-l-glutamyl-S-(trans-1-propenyl)-l-cysteine (GSPC), and γ-l-glutamyl-S-methyl-l-cysteine (GSMC), and four cysteine sulfoxides (alliin, isoalliin, methiin, and cycloalliin). There was a significant effect of the location, cultivar, and garlic ecotype on individual organosulfur compound contents. Purple-type cultivars showed on average the highest contents of GSMC, GSAC, alliin, and methiin but the lowest isoalliin content. The impact of genotype was relatively high for GSAC, whereas this factor hardly contributed to the total variability in alliin and isoalliin content. Planting date had a significant effect on the content of alliin and isoalliin. Discriminant analysis evidenced the ability of organosulfur compounds to distinguish among garlic bulbs from different locations or ecotypes with 81 or 86% accuracy, respectively.
An understanding of temperature and photoperiod effect on garlic (A. sativum L.) growth and florogenesis might solve the enigma of garlic sterility and provide environmental tools for flowering regulation and fertility restoration. The effect of storage temperature and growth conditions on the interactive relationships between the developing vegetative and reproductive organs was studied. A long photoperiod for more than 2 weeks was required for both dormancy induction of the axillary buds and clove formation. In contrast, combination of low temperatures with short photoperiod resulted in sprouting of the axillary buds. Four phases were recognized in the florogenesis of garlic, including: transition of the apical meristem, scape elongation, inflorescence differentiation, and completion of floral development. In garlic accession #2091, meristem transition is autonomous and occurs in growing plants under a variety of storage and growth conditions. A long photoperiod triggers the initial elongation of the scape in post-transitional plants. The temperature effect was quantitative: low storage and growth temperatures combined with long photoperiod promoted scape elongation, whereas warm temperatures and long photoperiod promoted the translocation of reserves to the cloves, and the degeneration of the developing inflorescence. Differentiation of topsets followed flower formation and was dominated by and required lengthy exposure to long photoperiod. Hence, under short photoperiod with only short interruption of long photoperiod, normal development of fertile flowers occurred. We conclude that in bolting garlic genotypes, manipulation of the environment, both before and after planting, can regulate the development of flowers and regain fertility. Normal flowering cannot be achieved if any of the four developmental stages of florogenesis mentioned above is inhibited.
Garlic storage is important to provide product for fresh market and fresh peeled processing. Garlic bulbs (cv. California Late) and unpeeled cloves were stored in several experiments in air and CA (0.1, 0.5, 1% O2 in combination with 0, 5, 10, 15 and 20% CO2) at 0-1°C for up to 6 months. Quality changes, especially sprout growth, decay and discoloration, were reduced by CO2-containing atmospheres, but the low O2 atmospheres alone generally had little benefit. Storage of garlic with CO2 atmospheres >15% may lead to injury after 4-6 months. Fructan concentrations were similar among air and CA-stored bulbs, but notably decreased under 20% CO2. Thiosulfinate and pyruvate concentrations were generally maintained in CO2-containing atmospheres, but increased in air- and low O2- stored garlic that permitted sprout development. Alliin concentrations were generally stable during storage up to 6 months, but in some cases decreased significantly under CO2 atmospheres. For fresh peeled garlic, atmospheres of CO2 (5-15%) in air or in low O2 (1- 3%) were effective in retarding discoloration and decay at 5 and 10°C for 3 weeks.
One hundred forty-six volunteers were randomized to receive a placebo or an allicin-containing garlic supplement, one capsule daily, over a 12-week period between November and February. They used a five-point scale to assess their health and recorded any common cold infections and symptoms in a daily diary. The active-treatment group had significantly fewer colds than the placebo group (24 vs 65, P < .001). The placebo group, in contrast, recorded significantly more days challenged virally (366 vs 111, P < .05) and a significantly longer duration of symptoms (5.01 vs 1.52 days, P < .001). Consequently, volunteers in the active group were less likely to get a cold and recovered faster if infected. Volunteers taking placebo were much more likely to get more than one cold over the treatment period. An allicin-containing supplement can prevent attack by the common cold virus.
Although garlic has been used for its medicinal properties for thousands of years, investigations into its mode of action are relatively recent. Garlic has a wide spectrum of actions; not only is it antibacterial, antiviral, antifungal and antiprotozoal, but it also has beneficial effects on the cardiovascular and immune systems. Resurgence in the use of natural herbal alternatives has brought the use of medicinal plants to the forefront of pharmacological investigations, and many new drugs are being discovered. This review aims to address the historical use of garlic and its sulfur chemistry, and to provide a basis for further research into its antimicrobial properties.
Onion (Allium cepa L.) pungency changes during storage. To better understand these flavor changes, seven onion cultivars representing different storage duration, photoperiodic requirement, and flavor intensity were greenhouse grown and the bulbs stored for 3 or 6 months at 5 ± 3°C, 0.8 to 1.1 kPa vapor pressure deficit. Bulbs were evaluated using high-pressure liquid chromatography quantification for changes in S-alk(en)yl cysteine sulfoxide (ACSO) flavor precursors and γ-glutamyl peptide (γ-GP) biosynthetic intermediates before storage and monthly thereafter. Before and during storage, cultivars differed in total ACSO, (+) S-methyl-L-cysteine sulfoxide (MCSO), trans-(+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO), (+) propyI-L-cysteine sulfoxide (PCSO), S-2 carboxypropyl glutathione (2-CARB), and γ-L-glutamyl-S-(1-propenyl)-L-cysteine sulfoxide (γGPECSO) concentration. During storage MCSO generally decreased while PRENCSO increased in concentration for most cultivars. The linear increase in PRENCSO concentration during storage was accompanied by a linear decrease in γGPECSO concentration. While not measured in this study, these trends indicate γglutamyl transpeptidase activity throughout bulb storage. γ-Glutamyl transpeptidase was previously reported to be active only in the later stages of bulb storage or during bulb sprouting. Changes in ACSO and γ-GP compounds during storage did not follow previously reported changes during storage for enzymatically formed pyruvic acid (EPY) for these cultivars. To better understand what causes flavor changes in onions during storage, future investigations should include analysis of the enzymes involved in flavor development and ACSO hydrolysis products.
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Pulse-chase experiments with 35SO42− fed for 10 min to leaves of Allium cepa (onion), A. sativum (garlic) and 4 A. siculum showed that label appeared in γ-glutamyl peptides within 15 min, reached a maximum amount at 1 hr and had decreased by 6 hr. Label was not detected in free S-alk(en)yl-l-cysteine sulphoxides (flavour precursors) until 6 hr after pulse feeding, and then increased steadily for at least 24hr and for onions until day 3. It is concluded that glutathione, and γ-glutamyl peptides are intermediates in the biosynthetic pathway to flavour precursors in Allium spp.
Quantitative analysis of γ-glutamyl peptides in onion bulbs showed that γ-glutamyl trans-(+)-S-(1-propenyl)-l-cysteine sulphoxide (γ-glutamyl propenyl CSO) and S-2-carboxypropyl glutathione (2CPGTH) were absent prior to bulbing, and then at bulbing accumulated to levels of 2.1 and 0.4 mg g−1 fr. wt respectively. These levels were maintained throughout storage. The hydrolytic enzyme γ-glutamyl transpeptidase [EC 2.3.2.1] was of minimal activity in a stored bulb. During sprouting, activity increased ca five-fold. Levels of γ-glutamyl propenyl CSO and 2CPGTH decreased by 50% to 0.94 and 0.14 mg g−1 fr. wt respectively. These data support the hypothesis that the two major γ-glutamyl peptides function as storage compounds during the overwintering of onion bulbs.
Allicin, one of the active principles of freshly crushed garlic homogenates, has a variety of antimicrobial activities. Allicin in its pure form was found to exhibit i) antibacterial activity against a wide range of Gram-negative and Gram-positive bacteria, including multidrug-resistant enterotoxicogenic strains of Escherichia coli; ii) antifungal activity, particularly against Candida albicans; iii) antiparasitic activity, including some major human intestinal protozoan parasites such as Entamoeba histolytica and Giardia lamblia; and iv) antiviral activity. The main antimicrobial effect of allicin is due to its chemical reaction with thiol groups of various enzymes, e.g. alcohol dehydrogenase, thioredoxin reductase, and RNA polymerase, which can affect essential metabolism of cysteine proteinase activity involved in the virulence of E. histolytica.
The objective of this review is to examine briefly the medical uses of garlic throughout the ages and the role that it was considered to play in prevention and treatment of disease. Interest in the potential benefits of garlic has origins in antiquity and is one of the earliest documented examples of plants employed for treatment of disease and maintenance of health. Garlic was in use at the beginning of recorded history and was found in Egyptian pyramids and ancient Greek temples. There are Biblical references to garlic. Ancient medical texts from Egypt, Greece, Rome, China and India each prescribed medical applications for garlic. In many cultures, garlic was administered to provide strength and increase work capacity for laborers. Hippocrates, the revered physician, prescribed garlic for a variety of conditions. Garlic was given to the original Olympic athletes in Greece, as perhaps one of the earliest "performance enhancing" agents. It is of interest that cultures that developed without contact with one another came to similar conclusions about the efficacy of garlic. Modern science is tending to confirm many of the beliefs of ancient cultures regarding garlic, defining mechanisms of action and exploring garlic's potential for disease prevention and treatment.
The path of synthesis of alkyl cysteine sulphoxides, or flavour precursors, in the Alliums is still speculative. There are two proposed routes for alliin biosynthesis, one is from serine and allyl thiol while the other is from glutathione and an allyl source via gamma glutamyl peptides. The routes have been investigated by exposing undifferentiated callus cultures of garlic and onion to potential pathway intermediates. After a period of incubation of 2 days the callus was extracted, and analysed for flavour precursors and related compounds by HPLC. Standards of alliin, isoallin and propiin were synthesised and their identity confirmed by HPLC and NMR. Putative intermediates selected included the amino acids serine and cysteine, as well as more complex intermediates such as allylthiol, allyl cysteine and glutathione. Both garlic and onion tissue cultures were able to synthesize alliin following incubation with allylthiol, and cysteine conjugates such as allyl cysteine. The ability of the tissue cultures to form alliin from intermediates was compatible with the proposed routes of synthesis of alliin.
S-Alk(en)yl cysteine sulfoxides are odourless, non-protein sulfur amino acids typically found in members of the family Alliaceae and are the precursors to the lachrymatory and flavour compounds found in the agronomically important genus Allium. Traditionally, Allium species, particularly the onion (Allium cepa) and garlic (A. sativum), have been used for centuries in European, Asian and American folk medicines for the treatment of numerous human pathologies, however it is only recently that any significant progress has been made in determining their mechanisms of action. Indeed, our understanding of the role of Allium species in human health undoubtedly comes from the combination of several academic disciplines including botany, biochemistry and nutrition. During tissue damage, S-alk(en)yl cysteine sulfoxides are converted to their respective thiosulfinates or propanethial-S-oxide by the action of the enzyme alliinase (EC 4.4.1.4). Depending on the Allium species, and under differing conditions, thiosulfinates can decompose to form additional sulfur constituents including diallyl, methyl allyl, and diethyl mono-, di-, tri-, tetra-, penta-, and hexasulfides, the vinyldithiins and (E)- and (Z)-ajoene. Recent reports have shown onion and garlic extracts, along with several principal sulfur constituents, can induce phase II detoxification enzymes like glutathione-S-transferases (EC 2.5.1.18) and quinone reductase (QR) NAD(P)H: (quinine acceptor) oxidoreductase (EC 1.6.99.2) in mammalian tissues, as well as also influencing cell cycle arrest and apoptosis in numerous in vitro cancer cell models. Moreover, studies are also beginning to highlight a role of Allium-derived sulfur compounds in cardiovascular protection. In this review, we discuss the chemical diversity of S-alk(en)yl cysteine sulfoxide metabolites in the context of their biochemical and pharmacological mechanisms.
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