Restituto Tocmo | University of Wisconsin-Madison (original) (raw)
Papers by Restituto Tocmo
Journal of Functional Foods
Hydrogen sulphide (H2S), viewed as a deadly environmental pollutant, is now intensively research... more Hydrogen sulphide (H2S), viewed as a deadly environmental pollutant, is now intensively
researched as the third gaseous signalling molecule, ubiquitously present and with a myriad
of physiological functions.We studied garlic (Allium sativum L.) scapes, the underexplored
yet widely consumed “flower stalks” of garlic, for their organosulphide constituents and H2Sreleasing
activity. Oils obtained from pH-adjusted (pH 3.0–9.0) puree contained 15
organosulphides that showed sensitivity to the pH values of the processing media. Disulphides
are significantly higher in the oil obtained at basic pH while trisulphides and cyclic
organosulphides weremuch higher in the oils isolated at the acidic to weakly acidic pH values.
A cell-based fluorescent method was used to quantify the H2S-releasing capacity, expressed
as diallyl trisulphide equivalents (DATS-E in mmol DATS/g). DATS-E values significantly
increased with increasing concentrations of trisulphides and tetrasulphides but showed inverse
relationship with the increase in disulphides concentration. Common cooking method of
stir-frying resulted in loss of more than 96% of the organosulphides and the oil obtained
had an 85-fold lower DATS-E value.
Journal of Functional Foods
Blanched and unblanched garlic were fermented using L. plantarum for investigation of organosulph... more Blanched and unblanched garlic were fermented using L. plantarum for investigation of organosulphide
profiles, hydrogen sulphide-releasing activity, pH, titratable activity and microbial growth. Both raw
and blanched garlic preparations allowed growth of L. plantarum with corresponding lowering of pH
below 4.0 and an increase in titratable acidity from an initial value of less 0.05% to 0.3 and 0.5%, respectively.
Fermentation, alone, decreased allicin and vinyl dithiins, but increased the concentration of DATS.
The H2S-releasing activity, expressed as DATS-E (mmol DATS/g oil), of raw-fermented (2.91) garlic was
not significantly different to that of raw (4.74) garlic, but values in blanched (0.41) and blanchedfermented
(0.71) samples significantly decreased. Reductions in DATS-E values in blanched and
blanched-fermented garlic corresponded well with the negative effect of blanching on the organosulphide
concentrations of the products. Fermentation with L. plantarum retains H2S-releasing activity by
increasing DATS, despite notable losses in allicin and allicin transformation products.
Data in Brief
This articlecontainsexperimentaldataontheidentification and quantification oftheorganosulfides o... more This articlecontainsexperimentaldataontheidentification and
quantification oftheorganosulfides onboiledgarlicextracts.Data
included arerelatedtotheresearcharticle “Boiling enrichesthe
linear polysulfides andthehydrogensulfide-releasing activityof
garlic” (R. Tocmo,Y.Wu,D.Liang,V.Fogliano,D.Huang,2016)[1].
CharacterizationwascarriedoutbyGC–MS andHPLC.Dose-
response curvesobtainedfromthecell-basedH2S-releasing
capacity assayofallicintransformationproducts,namelyvinyl
dithiins andajoenearealsoincluded.DATS-Evalueswerecalcu-
lated fromthesedose-responsecurvestoquantifythecontribution
of theindividualpolysulfides totheH2S-releasing capacityof
boiled extracts.
Comprehensive Reviews in Food Science and Food Safety
The occurrence of Listeria monocytogenes in ready-to-eat (RTE) fish products is well documented a... more The occurrence of Listeria monocytogenes in ready-to-eat (RTE) fish products is well documented and represents
an important food safety concern. Contamination of this pathogen in vacuum-packed (VP) smoked fish products at levels
greater than the RTE food limit (100 CFU/g) has been traced to factors such as poor sanitary practices, contaminated
processing environments, and temperature abuse during prolonged storage in retail outlets. Intervention technologies
including physical, biological, and chemical techniques have been studied to control transmission of L. monocytogenes to
these products. High-pressure processing, irradiation, and pulsed UV-light treatment have shown promising results. Potential
antilisterial effects of some sanitizers and combined chemical preservatives have also been demonstrated. Moreover,
the concept of biopreservation, use of bioactive packaging, and a combination of different intervention technologies, as
in the hurdle concept, are also under consideration. In this review, the prevalence, routes of contamination, and potential
intervention technologies to control transmission of L. monocytogenes in VP smoked fish products are discussed.
Food Chemistry
Stinky beans (Parkia speciosa) were hydrodistilled and solvent-extracted and the oil obtained was... more Stinky beans (Parkia speciosa) were hydrodistilled and solvent-extracted and the oil obtained was analyzed
by GC–MS/FID. Nine cyclic and one acyclic organosulfides were identified comprising 36% of total
volatiles. Solvent extracts contained significantly (p < 0.05) higher total organosulfides (680 ppm) as
compared to distilled oil (444 ppm). The concentrations of organosulfides are highly dependent on the
pH values of the matrix, with control sample (pH 5.40) giving the highest total organosulfides
(424 ppm) followed by that of pH 7.0 (234 ppm), pH 9.0 (195 ppm), and pH 3.0 (152 ppm). The
H2S-releasing capacity, expressed as diallyl trisulfide equivalents (DATS-E in mmol DATS/g), corresponded
well with the differences in organosulfide concentrations as affected by pH with control having
the highest value (24.35) followed pH 7.0 (7.27), pH 9.0 (3.27), and pH 3.0 (1.80). We conclude that stinky
bean oil is a potent H2S-releasing agent that could have health-beneficial properties.
Food Chemistry
Garlic is rich in polysulfides, and some of them can be H2S donors. This study was conducted to e... more Garlic is rich in polysulfides, and some of them can be H2S donors. This study was conducted to explore
the effect of cooking on garlic’s organopolysulfides and H2S-releasing activity. Garlic bulbs were crushed
and boiled for a period ranging from 3 to 30 min and the solvent extracts were analyzed by GC–MS/FID
and HPLC. A cell-based assay was used to measure the H2S-releasing activity of the extracts. Results
showed that the amounts of allyl polysulfides increased in crushed garlic boiled for 6–10 min; however,
prolonging the thermal treatment to 20 or 30 min decreased their concentrations. Data of the
H2S-releasing activity, expressed as diallyl trisulfide equivalents (DATS-E), parallel this trend, being
significantly higher at 6 and 10 min boiling. Our results showed enhancement of H2S-releasing activity
upon moderate boiling, suggesting that shorter cooking time may maximize its health benefits as a
dietary source of natural H2S donors.
Journal of Agricultural and Food Chemistry
There is a growing account of the health benefits of H2S as an endogenous cell-signaling molecule... more There is a growing account of the health benefits of H2S as an endogenous cell-signaling molecule. H2S from organic polysulfides, in particular, is increasingly gaining attention for their beneficial effects to cardiovascular health. Here, we studied shallot as a potential dietary source of organic polysulfides and examined the effects of processing conditions on its polysulfide profiles. Boiling, autoclaving, and freeze-drying were tested on whole and crushed shallot bulbs, analyzing their effect on the yield of organosulfides. Seventeen organosulfides, including disulfides, trisulfides, and cyclic polysulfides, were identified. Significant differences in the quantitative and qualitative profiles of organosulfides in the hydrodistilled and solvent extracted oils were observed. Freeze-drying retained the majority of the organosulfides, but the whole-autoclaved and whole-boiled shallots lost more than 95% of their organic polysulfides. Crushed-boiled and crushed-autoclaved shallot lost 76-80% of their organosulfides, likely due to the thermal sensitivity of these compounds. The organosulfide profiles are sensitive to the pH values of the processing media. In general, disulfides increased at basic pH (pH 9.0) while trisulfides and cyclic organosulfides are much higher at the acidic to neutral pH values (pH 3.0-5.0). Our results provide important information on the effects of processing conditions that are relevant for optimizing extraction of organosulfides from shallot for further studies evaluating their H2S-releasing activity.
Journal of Functional Foods, 2015
Hydrogen sulphide (H2S) is a gaseous signalling molecule with multiple biological functions in th... more Hydrogen sulphide (H2S) is a gaseous signalling molecule with multiple biological functions in the human body. Previous research demonstrates that diallyl trisulphide (DATS) and diallyl disulphide (the two major compounds of garlic oil) can be metabolized to generate H2S in biological conditions and modulate cell signalling. In this paper, a fluorescent method for quantification of H2S releasing capacity in cell lines was developed. MCF-7 cells in 96 well plate were incubated with a H2S probe BCu for 3 h, then treated with H2S donors for 2 h, which would be metabolized by the cells and produce H2S. The resulting H2S was captured by the probe and turn on its fluorescence, which was measured with a microplate reader. Linear dose response could be established between organosulphur concentration and fluorescence intensity, and the H2S releasing capacity of a sample was determined by comparing the slope of the regression curve with that of a DATS standard obtained in parallel. With this method, the H2S releasing capacity of ten organosulphur rich fruits and vegetables (garlic, red onion, yellow onion, scallion, shallot, leek, spring onion, Chinese chives, durian, and stinky beans) were evaluated and ranked. Stinky beans (a vegetable from Southeast Asia) topped the ranking with very high H2S releasing capacity, followed by garlic and yellow onion. Our work provides new thinking on the health benefits of organosulphur-rich foods.
Journal of Functional Foods, 2017
The slow hydrogen sulphide (H2S) releasing compound S-allyl glutathione disulfide (GSSA) from gar... more The slow hydrogen sulphide (H2S) releasing compound S-allyl glutathione disulfide (GSSA) from garlic, which can release H2S via α carbon substitution, showed anti-aging effects on the chronological lifespan (CLS) of yeast Saccharomyces cerevisiae. Hormesis was observed, showing lifespan extension at nanomolar concentrations (100–200 nM), whereas at high concentration (1 mM) toxicity were observed. A possible explanation therefore might be the beneficial properties of the recently discovered gasotransmitter hydrogen sulfide (H2S). Yet, 2-vinyl-4H-1,3-dithiin (2-VDT) and 3-vinyl-4H-1,2-dithiin (3-VDT) from garlic appeared both inactive in terms of prolonging the lifespan of yeast. While for 2-VDT these findings seem reasonable since it cannot release H2S, for 3-VDT the contrary was expected as H2S releasing properties were observed. The underlying mechanism of H2S release of 3-VDT was proposed to be a similar α carbon substitution-like observed for GSSA.
Measurement of Antioxidant Activity & Capacity: Recent Trends and Applications, First Edition. Edited by Resat Apak, Esra Capanoglu, and Fereidoon Shahidi., 2018
Frontiers in Nutrition
Foods that are rich in organosulfides are highly regarded for their broad range of functions in d... more Foods that are rich in organosulfides are highly regarded for their broad range of functions
in disease prevention and health promotion since ancient time yet modern scientific study,
particularly clinical studies could not agree with traditional wisdom. One of the complexities
is due to the labile nature of organosulfides, which are often transformed to different
structures depending on the processing conditions. The recent evidence on polysulfides
as H2S donors may open up a new avenue for establishing structure and health promotion
activity relationship. To put this development into perspective, we carried out a review on
the recent progress on the chemistry and biochemistry of organopolysulfides with emphasis
on their cardioprotective property. First, we briefly surveyed the foods that are rich in
polysulfides and their structural diversity. This is followed by in-depth discussion on the
chemical transformations of polysulfides under various processing conditions.We further
reviewed the potential action mechanisms of polysulfides in cardioprotection through: (a)
hydrogen sulfide releasing activity; (b) radical scavenging activity; and (c) activity in enzyme
inhibition and intervention of gene regulation pathways. Based on the literature trend, we
can conclude that the emerging concept of organopolysulfides as naturally occurring H2S
donors is intriguing and warrants further research to establish the structure and activity
relationship of the organopolysulfides as H2S donors.
Journal of Functional Foods
Hydrogen sulphide (H2S), viewed as a deadly environmental pollutant, is now intensively research... more Hydrogen sulphide (H2S), viewed as a deadly environmental pollutant, is now intensively
researched as the third gaseous signalling molecule, ubiquitously present and with a myriad
of physiological functions.We studied garlic (Allium sativum L.) scapes, the underexplored
yet widely consumed “flower stalks” of garlic, for their organosulphide constituents and H2Sreleasing
activity. Oils obtained from pH-adjusted (pH 3.0–9.0) puree contained 15
organosulphides that showed sensitivity to the pH values of the processing media. Disulphides
are significantly higher in the oil obtained at basic pH while trisulphides and cyclic
organosulphides weremuch higher in the oils isolated at the acidic to weakly acidic pH values.
A cell-based fluorescent method was used to quantify the H2S-releasing capacity, expressed
as diallyl trisulphide equivalents (DATS-E in mmol DATS/g). DATS-E values significantly
increased with increasing concentrations of trisulphides and tetrasulphides but showed inverse
relationship with the increase in disulphides concentration. Common cooking method of
stir-frying resulted in loss of more than 96% of the organosulphides and the oil obtained
had an 85-fold lower DATS-E value.
Journal of Functional Foods
Blanched and unblanched garlic were fermented using L. plantarum for investigation of organosulph... more Blanched and unblanched garlic were fermented using L. plantarum for investigation of organosulphide
profiles, hydrogen sulphide-releasing activity, pH, titratable activity and microbial growth. Both raw
and blanched garlic preparations allowed growth of L. plantarum with corresponding lowering of pH
below 4.0 and an increase in titratable acidity from an initial value of less 0.05% to 0.3 and 0.5%, respectively.
Fermentation, alone, decreased allicin and vinyl dithiins, but increased the concentration of DATS.
The H2S-releasing activity, expressed as DATS-E (mmol DATS/g oil), of raw-fermented (2.91) garlic was
not significantly different to that of raw (4.74) garlic, but values in blanched (0.41) and blanchedfermented
(0.71) samples significantly decreased. Reductions in DATS-E values in blanched and
blanched-fermented garlic corresponded well with the negative effect of blanching on the organosulphide
concentrations of the products. Fermentation with L. plantarum retains H2S-releasing activity by
increasing DATS, despite notable losses in allicin and allicin transformation products.
Data in Brief
This articlecontainsexperimentaldataontheidentification and quantification oftheorganosulfides o... more This articlecontainsexperimentaldataontheidentification and
quantification oftheorganosulfides onboiledgarlicextracts.Data
included arerelatedtotheresearcharticle “Boiling enrichesthe
linear polysulfides andthehydrogensulfide-releasing activityof
garlic” (R. Tocmo,Y.Wu,D.Liang,V.Fogliano,D.Huang,2016)[1].
CharacterizationwascarriedoutbyGC–MS andHPLC.Dose-
response curvesobtainedfromthecell-basedH2S-releasing
capacity assayofallicintransformationproducts,namelyvinyl
dithiins andajoenearealsoincluded.DATS-Evalueswerecalcu-
lated fromthesedose-responsecurvestoquantifythecontribution
of theindividualpolysulfides totheH2S-releasing capacityof
boiled extracts.
Comprehensive Reviews in Food Science and Food Safety
The occurrence of Listeria monocytogenes in ready-to-eat (RTE) fish products is well documented a... more The occurrence of Listeria monocytogenes in ready-to-eat (RTE) fish products is well documented and represents
an important food safety concern. Contamination of this pathogen in vacuum-packed (VP) smoked fish products at levels
greater than the RTE food limit (100 CFU/g) has been traced to factors such as poor sanitary practices, contaminated
processing environments, and temperature abuse during prolonged storage in retail outlets. Intervention technologies
including physical, biological, and chemical techniques have been studied to control transmission of L. monocytogenes to
these products. High-pressure processing, irradiation, and pulsed UV-light treatment have shown promising results. Potential
antilisterial effects of some sanitizers and combined chemical preservatives have also been demonstrated. Moreover,
the concept of biopreservation, use of bioactive packaging, and a combination of different intervention technologies, as
in the hurdle concept, are also under consideration. In this review, the prevalence, routes of contamination, and potential
intervention technologies to control transmission of L. monocytogenes in VP smoked fish products are discussed.
Food Chemistry
Stinky beans (Parkia speciosa) were hydrodistilled and solvent-extracted and the oil obtained was... more Stinky beans (Parkia speciosa) were hydrodistilled and solvent-extracted and the oil obtained was analyzed
by GC–MS/FID. Nine cyclic and one acyclic organosulfides were identified comprising 36% of total
volatiles. Solvent extracts contained significantly (p < 0.05) higher total organosulfides (680 ppm) as
compared to distilled oil (444 ppm). The concentrations of organosulfides are highly dependent on the
pH values of the matrix, with control sample (pH 5.40) giving the highest total organosulfides
(424 ppm) followed by that of pH 7.0 (234 ppm), pH 9.0 (195 ppm), and pH 3.0 (152 ppm). The
H2S-releasing capacity, expressed as diallyl trisulfide equivalents (DATS-E in mmol DATS/g), corresponded
well with the differences in organosulfide concentrations as affected by pH with control having
the highest value (24.35) followed pH 7.0 (7.27), pH 9.0 (3.27), and pH 3.0 (1.80). We conclude that stinky
bean oil is a potent H2S-releasing agent that could have health-beneficial properties.
Food Chemistry
Garlic is rich in polysulfides, and some of them can be H2S donors. This study was conducted to e... more Garlic is rich in polysulfides, and some of them can be H2S donors. This study was conducted to explore
the effect of cooking on garlic’s organopolysulfides and H2S-releasing activity. Garlic bulbs were crushed
and boiled for a period ranging from 3 to 30 min and the solvent extracts were analyzed by GC–MS/FID
and HPLC. A cell-based assay was used to measure the H2S-releasing activity of the extracts. Results
showed that the amounts of allyl polysulfides increased in crushed garlic boiled for 6–10 min; however,
prolonging the thermal treatment to 20 or 30 min decreased their concentrations. Data of the
H2S-releasing activity, expressed as diallyl trisulfide equivalents (DATS-E), parallel this trend, being
significantly higher at 6 and 10 min boiling. Our results showed enhancement of H2S-releasing activity
upon moderate boiling, suggesting that shorter cooking time may maximize its health benefits as a
dietary source of natural H2S donors.
Journal of Agricultural and Food Chemistry
There is a growing account of the health benefits of H2S as an endogenous cell-signaling molecule... more There is a growing account of the health benefits of H2S as an endogenous cell-signaling molecule. H2S from organic polysulfides, in particular, is increasingly gaining attention for their beneficial effects to cardiovascular health. Here, we studied shallot as a potential dietary source of organic polysulfides and examined the effects of processing conditions on its polysulfide profiles. Boiling, autoclaving, and freeze-drying were tested on whole and crushed shallot bulbs, analyzing their effect on the yield of organosulfides. Seventeen organosulfides, including disulfides, trisulfides, and cyclic polysulfides, were identified. Significant differences in the quantitative and qualitative profiles of organosulfides in the hydrodistilled and solvent extracted oils were observed. Freeze-drying retained the majority of the organosulfides, but the whole-autoclaved and whole-boiled shallots lost more than 95% of their organic polysulfides. Crushed-boiled and crushed-autoclaved shallot lost 76-80% of their organosulfides, likely due to the thermal sensitivity of these compounds. The organosulfide profiles are sensitive to the pH values of the processing media. In general, disulfides increased at basic pH (pH 9.0) while trisulfides and cyclic organosulfides are much higher at the acidic to neutral pH values (pH 3.0-5.0). Our results provide important information on the effects of processing conditions that are relevant for optimizing extraction of organosulfides from shallot for further studies evaluating their H2S-releasing activity.
Journal of Functional Foods, 2015
Hydrogen sulphide (H2S) is a gaseous signalling molecule with multiple biological functions in th... more Hydrogen sulphide (H2S) is a gaseous signalling molecule with multiple biological functions in the human body. Previous research demonstrates that diallyl trisulphide (DATS) and diallyl disulphide (the two major compounds of garlic oil) can be metabolized to generate H2S in biological conditions and modulate cell signalling. In this paper, a fluorescent method for quantification of H2S releasing capacity in cell lines was developed. MCF-7 cells in 96 well plate were incubated with a H2S probe BCu for 3 h, then treated with H2S donors for 2 h, which would be metabolized by the cells and produce H2S. The resulting H2S was captured by the probe and turn on its fluorescence, which was measured with a microplate reader. Linear dose response could be established between organosulphur concentration and fluorescence intensity, and the H2S releasing capacity of a sample was determined by comparing the slope of the regression curve with that of a DATS standard obtained in parallel. With this method, the H2S releasing capacity of ten organosulphur rich fruits and vegetables (garlic, red onion, yellow onion, scallion, shallot, leek, spring onion, Chinese chives, durian, and stinky beans) were evaluated and ranked. Stinky beans (a vegetable from Southeast Asia) topped the ranking with very high H2S releasing capacity, followed by garlic and yellow onion. Our work provides new thinking on the health benefits of organosulphur-rich foods.
Journal of Functional Foods, 2017
The slow hydrogen sulphide (H2S) releasing compound S-allyl glutathione disulfide (GSSA) from gar... more The slow hydrogen sulphide (H2S) releasing compound S-allyl glutathione disulfide (GSSA) from garlic, which can release H2S via α carbon substitution, showed anti-aging effects on the chronological lifespan (CLS) of yeast Saccharomyces cerevisiae. Hormesis was observed, showing lifespan extension at nanomolar concentrations (100–200 nM), whereas at high concentration (1 mM) toxicity were observed. A possible explanation therefore might be the beneficial properties of the recently discovered gasotransmitter hydrogen sulfide (H2S). Yet, 2-vinyl-4H-1,3-dithiin (2-VDT) and 3-vinyl-4H-1,2-dithiin (3-VDT) from garlic appeared both inactive in terms of prolonging the lifespan of yeast. While for 2-VDT these findings seem reasonable since it cannot release H2S, for 3-VDT the contrary was expected as H2S releasing properties were observed. The underlying mechanism of H2S release of 3-VDT was proposed to be a similar α carbon substitution-like observed for GSSA.
Measurement of Antioxidant Activity & Capacity: Recent Trends and Applications, First Edition. Edited by Resat Apak, Esra Capanoglu, and Fereidoon Shahidi., 2018
Frontiers in Nutrition
Foods that are rich in organosulfides are highly regarded for their broad range of functions in d... more Foods that are rich in organosulfides are highly regarded for their broad range of functions
in disease prevention and health promotion since ancient time yet modern scientific study,
particularly clinical studies could not agree with traditional wisdom. One of the complexities
is due to the labile nature of organosulfides, which are often transformed to different
structures depending on the processing conditions. The recent evidence on polysulfides
as H2S donors may open up a new avenue for establishing structure and health promotion
activity relationship. To put this development into perspective, we carried out a review on
the recent progress on the chemistry and biochemistry of organopolysulfides with emphasis
on their cardioprotective property. First, we briefly surveyed the foods that are rich in
polysulfides and their structural diversity. This is followed by in-depth discussion on the
chemical transformations of polysulfides under various processing conditions.We further
reviewed the potential action mechanisms of polysulfides in cardioprotection through: (a)
hydrogen sulfide releasing activity; (b) radical scavenging activity; and (c) activity in enzyme
inhibition and intervention of gene regulation pathways. Based on the literature trend, we
can conclude that the emerging concept of organopolysulfides as naturally occurring H2S
donors is intriguing and warrants further research to establish the structure and activity
relationship of the organopolysulfides as H2S donors.