Sittiwat Lertsiri - Academia.edu (original) (raw)

Papers by Sittiwat Lertsiri

Acta horticulturae, Mar 1, 2005

To investigate the pro-oxidative activity of nutmeg, safflower, and lemongrass, methanolic extrac... more To investigate the pro-oxidative activity of nutmeg, safflower, and lemongrass, methanolic extracts of each were incubated with bovine serum albumin (BSA) in the absence or presence of Fe 3+ /EDTA/H 2 O 2 , Fe 2+ /ascorbate, or Cu 2+ /H 2 O 2 at 37°C. The protein cleavage by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), protein and free amino groups contents were determined. As a result, BSA degradation was observed on SDS-PAGE. This corresponded with decrease in protein concentration and free amino group elevation in the reaction mixture. Such degradation was inhibited in the presence of mannitol, the hydroxyl radical scavenger, indicating that the pro-oxidative activity in these spices caused hydroxyl radical formation.

Journal of General and Applied Microbiology, 2004

Acinetobacter calcoaceticus LP009 is a lipase producer isolated from raw milk. It was classified ... more Acinetobacter calcoaceticus LP009 is a lipase producer isolated from raw milk. It was classified as a psychrotroph since its optimum growth was found at 15°C, and yet, it could also grow at 30°C (Pratungdejkul and Dharmsthiti, 2000). Heat-labile lipase is useful for some applications mainly in food manufacture in which high temperatures during processing may destroy texture, flavor and aroma, and heat-labile lipase can be easily inactivated at a relatively low temperature (Margesin and Schinner, 1994). In our recent study, A. calcoaceticus LP009 lipase was found to be efficient in digesting palm oil (Pratungdejkul and Dharmsthiti, 2000). Products from palm oil hydrolysis are useful in many applications, which are more valuable than the oil itself. In this study, palm oil hydrolysis by A. calcoaceticus LP009 lipase was carried out. In the first part, a medium suitable for growth and lipase production was developed. The enzyme produced was analyzed for general properties and lipolysis on palm oil. Quantitative analysis of monoglyceride was carried out on HPLC and the fatty acid composition of monoglyceride was determined using gas chromatography mass spectrometry (GC-MS). Lipase production from A. calcoaceticus LP009 (LP009) in LB medium (48-h cultivation at 15°C) was formerly found to be best induced by 1% Tween-80 (Pratungdejkul and Dharmsthiti, 2000). Therefore, a complex medium, MMPT, for A. calcoaceticus lipase (Lip009) production was formulated based on MMP, which was composed of 0.1% (NH 4) 2 SO 4 , 40 mg ml Ϫ1 MgSO 4 , 4 mg ml Ϫ1 FeSO 4 in 2% buffer solution [7.3% Na 2 HPO 4 , 3.2% KH 2 PO 4 , pH 7.2] (Lotrakul and Dharmsthiti, 1997) plus 1% Tween-80. LP009 was found to be incapable of metabolizing glucose (Table 1) while the addition of maltose or lactose to MMPT did not promote higher growth or lipase production than that without them. However, whey, which contained lactose as a major sugar constituent, did promote high Lip009 production. Thus, the effect of protein, another major component in whey, was tested. It was shown that MMPT in the presence of peptone, either with or without whey, resulted in remarkably higher lipase production. This indicated that LP009 used the amino acid as its carbon source for growth. Cultivation of LP009 in MMPT with 1% of various kinds of amino acids revealed that leucine and asparagine gave the highest lipase production per cell (Table 2). However, in terms of total productivity, monosodium glutamate (MSG) gave the highest lipase activity. Therefore, MSG was determined to be the best carbon source for LP009 since it supported the highest growth and lipase production from the bacteria. Optimum concentration of MSG was at 1%. Medium containing 1% MSG gave approximately 1.5 time

Acta horticulturae, Mar 1, 2005

Twenty methanolic extracts from Thai spice powder (anise, cardamom, chilli, Chinese key, cinnamon... more Twenty methanolic extracts from Thai spice powder (anise, cardamom, chilli, Chinese key, cinnamon, clove, coriander, cumin, deeplee, dill, fennel, galangal, kencur, lemongrass, ginger, nutmeg, oregano, pepper, safflower, and turmeric) were screened for pro-oxidative activity using a lecithin-liposome model system. The oxidative stress was induced by four systems: (I) non-metal induction; (II) FeCl 3 /H 2 O 2 /EDTA; (III) FeSO 4 /ascorbate; and (IV) CuSO 4 /H 2 O 2. Of these spices, safflower, lemongrass, and nutmeg extracts showed the pro-oxidative activity observed by thiobarbituric acid reactive substance elevation. Since pro-oxidation were metal dependent, hydroxyl radical formation was investigated by monitoring fluorescence products from benzoate hydroxylation. The formation of hydroxyl radical was confirmed with the fluorescence detected and the suppression due to addition of mannitol, a hydroxyl radical scavenger.

Journal of Chromatography A, Apr 1, 1994

ABSTRACT

Bioscience, Biotechnology, and Biochemistry, 1998

ABSTRACT

Lwt - Food Science and Technology, 2017

Lwt - Food Science and Technology, 2017

Data in Brief, Aug 1, 2020

Crude extracts of fresh Dendrobium Sonia 'Earsakul' orchid flowers (DSE) were prepared using micr... more Crude extracts of fresh Dendrobium Sonia 'Earsakul' orchid flowers (DSE) were prepared using microwave assisted extraction (MAE; using household microwave oven) and hot water extraction (HWE; at constant 80 °C). The obtained DSEs were measured their absorbance at λ max of 543 and 583 nm and determined their total monomeric anthocyanin contents (TAC). Mathematical models of MAE of Dendrobium Sonia 'Earsakul' orchid flower were constructed using response surface methodology-Box-Behnken design. Studied parameters included flower to water ratio, microwave power, and extraction time, with absorbance at λ max as response. The data generated were 1) visible spectrum (40 0-70 0 nm) of DSE; 2) absorbance values at λ max and 3) TAC of DSEs obtained from various extraction conditions of MAE and HWE; 4) linear equations describing correlations between TAC and absorbance at λ max of DSEs; and 5) mathematical models of MAE of Dendrobium Sonia 'Earsakul' orchid.

Food and Chemical Toxicology, 2008

Acrylamide in Thai curry cooked in coconut milk was investigated using ion trap LC-ESI-MS/MS. The... more Acrylamide in Thai curry cooked in coconut milk was investigated using ion trap LC-ESI-MS/MS. The transitions of m/z 72 > 55 and 86 > 58 were monitored in multiple reaction monitoring mode for identification and quantification. A linear response was found for the acrylamide standard in the range of 400-30,000 pg, with correlation coefficients (r) greater than 0.99. The limit of detection (s/n = 3) and limit of quantification (s/n = 9) were 400 and 1200 pg, respectively. Sample preparation was performed by means of solvent extraction, giving recovery of 92-108% with relative standard deviation less than 10%. Thirty Thai curry samples were analyzed and found acrylamide at concentration in the range of less than 60-606 ng/g dry weight. Acrylamide was formed in solely heated coconut milk at 121 degrees C. Changes in 5-(hydroxymethyl)-2-furfuraldehyde, fructose, glucose and glutamic acid contents in coconut milk during heat treatment were observed as progress parameters for the Maillard reaction. Moreover, acrylamide was determined in equimolar model system of glutamic acid with glucose or fructose (1mM), and yielded acrylamide, approximately 0.1% and 0.06% (w/w), respectively.

Process Biochemistry, Jul 1, 2005

ABSTRACT The effect of glycation on properties of thermostable glucoamylase was studied by incuba... more ABSTRACT The effect of glycation on properties of thermostable glucoamylase was studied by incubating purified glucoamylase with maltodextrin at 60 °C. Glycation occurred during the incubation and was assessed by 5-(hydroxymethyl)-2-furfuraldehyde (HMF) released from acid hydrolysis of the glycated protein. Stability and kinetic parameters of the glycated glucoamylase and the intact enzyme were compared. The glycated enzyme was more resistant to the heat but glycation did not strongly affect pH stability and pI value significantly. In the presence of maltose as substrate, the Km value of the glucoamylase glycated by maltodextrin was lower than that of the intact enzyme. This indicated a greater affinity of the glycated enzyme for maltose. In the presence of maltodextrin as substrate, glycation led to increases in the rate of hydrolytic reaction. Moreover, glycation resulted in a higher efficiency of glucoamylase to convert the substrate into glucose. This might be due to a greater conformational flexibility of the glycated glucoamylase.

Journal of Food Measurement and Characterization, Jul 19, 2014

An analytical method has been developed for the separation of glyoxal (Go), methylglyoxal (MGo), ... more An analytical method has been developed for the separation of glyoxal (Go), methylglyoxal (MGo), and dimethylglyoxal (DMGo) by MEKC using stilbenediamine (SD) as derivatizing reagent, separation time 6.5 min, SDS as micellar medium at pH 8, and sodium tetraborate (0.1 M) as buffer. Uncoated fused‐silica capillary, effective length 50 cm×75 μm id; applied voltage 20 kV and photodiode array detection, were used. Calibration was linear within 0.02–150 μg/mL with detection limits 3.5–5.8 ng/mL. Go and MGo, observed for diabetic and healthy volunteers, were within 0.098–0.193 μg/mL Go and 0.106–0.245 μg/mL MGo with RSD 1.6–3.5 and 1.7–3.4%, respectively, in diabetics against 0.016–0.046 μg/mL Go and 0.021–0.066 μg/mL MGo with RSDs 1.5–3.5 and 1.4–3.6%, respectively, in healthy volunteers. Go and MGo in diabetics were also measured by standard addition and DMGo as an internal standard. Additives do not contribute significantly to Go and MGo matrix.

Biochimica Et Biophysica Acta - General Subjects, Dec 1, 1995

Hydroperoxide formation during Maillard reaction (amino-carbonyl reaction) was investigated using... more Hydroperoxide formation during Maillard reaction (amino-carbonyl reaction) was investigated using luminol-chemiluminescence-high performance liquid chromatography (CL-HPLC). From the equimolar reaction mixture of 1 M fl-alanine/D-glucose in phosphate buffer (pH 8.0) at 95°C, two hydroperoxides and H20 2 were detected as chemiluminescent products in CL-HPLC, and the yields were proportional to the browning development. One of these hydroperoxides was isolated and identified as 3-hydroxy-5-hydroperoxy-2methyl-5,6-dihydropyran-4-one (HMDP, pyrone hydroperoxide) by fast atom bombardment mass spectrometry. The HMDP formation was also confirmed in L-lysine/D-glucose and in bovine serum albumin/D-glucose with the physiological incubation at 37°C for 4 days and 3 wk, respectively. Incubation at 37°C of human plasma containing 5.5-25.0 mM of o-glucose for 60 h showed the glucose concentration-dependent formation of HMDP (10-35/xM of H 202 equivalence). The HMDP was negative to thiobarbituric acid reaction and was degraded by peroxidases such as horseradish peroxidase, Athromyces ramosus peroxidase, heated cytochrome c, and microperoxidase. The results strongly suggested the formation of such hydroperoxide even in biological Maillard reaction termed as glycation, and implied its contribution in pathogenesis and oxidative lesions associated with hyperglycemia.

Journal of Food Quality, Apr 1, 2013

ABSTRACT Sensory descriptive analysis was performed on 52 Thai fish sauce samples by 15 trained p... more ABSTRACT Sensory descriptive analysis was performed on 52 Thai fish sauce samples by 15 trained panelists, with an intention to explore the aroma profiles and to correlate with their total nitrogen (TN) contents, which is conventionally used as a general standard for commercial product grading. Thai fish sauce aroma characteristics could be exemplified through eight descriptive attributes. Sweet, meaty and cheesy odors presented overall characteristics of Thai fish sauce, while salty and anchovy‐like odors were noticeably perceived due to their high intensity in fish sauce. Aroma intensity of three attributes including sour, shrimp paste‐like and fishy odors could categorize Thai fish sauce samples into two groups, i.e., high‐TN and low‐TN groups. This categorization was also observed when rating scores of the intensity of these eight odor attributes were applied on principal component analysis (PCA). Moreover, total volatile basic‐nitrogen and pH of the samples were applied on PCA to better explain the contribution of aroma attributes to fish sauce products. Practical ApplicationsThailand is a major producer of fish sauce; hence, varieties of product qualities are available in the market. Generally, the products are graded in accordance to its total nitrogen (TN) content. However, manufacturers could distinguish the product quality based on its aroma profile. On the other hand, prices of products are based on TN and their characteristic aroma that consumers can perceive. The finding in this study would be applicable to fish sauce quality standardization based on aroma profiles that are correlated to conventional TN grading, as well as conservation of product authenticity.

international food research journal, 2014

Eight native Thai plant rarely studied were extracted by using distilled water and 95% ethanol th... more Eight native Thai plant rarely studied were extracted by using distilled water and 95% ethanol then were investigated for their total phenolics, free radical scavenging, metal chelating and five antibacterial capacities. Five bacteria consisted of one gram-negative (Esherichia coli) and four gram-positive (Stapphylococcus aureus, Stapphylococcus epidermidis, Bacillus cereus and Bacillus subtilis). Significant difference was observed among solvent extractions used and the plant species. The aqueous extracts gave higher antioxidant abilities but lower antibacterial capacities than the ethanol ones. Principle component analysis (PCA) revealed that the free radical scavenging was correlated to the total phenolics. Among the eight species, S. gratum extracts showed the strongest free radical scavenging ability, while, C. harmandiana showed the strongest chelating capacity. The G. cowa extracts were exception in antibacterial capacities because their activities against all the test bacter...

Annu Rep ICBiotech, 1998

TOP > J-EAST > List of Journal Titles (A) > Annu Reports ICBiotech (1998) > Kinetic M... more TOP > J-EAST > List of Journal Titles (A) > Annu Reports ICBiotech (1998) > Kinetic Modeling of Lactic Acid Fermentation from Sago Starch Using Lactococcus lactis IO-1. ... Kinetic Modeling of Lactic Acid Fermentation from Sago Starch Using Lactococcus lactis IO-1. ... Title;Kinetic Modeling of Lactic Acid Fermentation from Sago Starch Using Lactococcus lactis IO-1. ... Copyright (c) 2006-2007 Japan Science and Technology Agency. All Rights Reserved.

Lwt - Food Science and Technology, 2016

Foods

Organic heme iron in the form of heme iron polypeptide (HIP) is a bioavailable form of iron that ... more Organic heme iron in the form of heme iron polypeptide (HIP) is a bioavailable form of iron that can be used for dietary supplements. However, one practical challenge with HIP is that the quality of HIP prepared with different batches of raw material could lead to HIP products with inconsistent characteristics. In this study, skipjack tuna blood, a by-product in canned tuna industry, was converted to HIP at different degrees of enzymatic hydrolysis. The variation in HIP physical–chemical characteristics from different batches was evaluated, including composition, solubility, and molecular weight distribution. It was found that the batch variation had no effect on HIP composition and solubility; however, the degree of hydrolysis (DH) and the size of peptides that interact with heme greatly influenced HIP solubility at pH 2. Tuna-HIP with a low DH (DH, 8%) had 1.76-fold greater solubility than tuna-HIP with a high DH (DH, 32%). High-performance liquid chromatography (HPLC) revealed th...

Journal of Applied Polymer Science, 2016

ABSTRACTThis article was aimed at preparation and characterization of drug delivery carriers made... more ABSTRACTThis article was aimed at preparation and characterization of drug delivery carriers made from biodegradable polyhydroxyalkanoates (PHAs) for slow release of tetracycline (TC) for periodontal treatment. Four PHA variants; polyhydroxybutyrate (PHB), poly(hydroxybutyrate‐co‐hydroxyvalerate) with 5, 12, and 50% hydroxyvalerate were used to formulate TC‐loaded PHA microspheres by double emulsion‐solvent evaporation method. We also compared the effect of different molecular weight (Mw) of polyvinyl alcohol (PVA) acting as surface stabilizer on particle size, drug loading, encapsulation efficiency, and drug release profile. The TC‐loaded PHA microspheres exhibited microscale and nanoscale spherical morphology under scanning electron microscopy. Among formulations, TC‐loaded PHB:low Mw PVA demonstrated the highest TC loading with slow release behavior. Our results showed that the release rate from PHA microspheres was influenced by both the type of PHA and Mw of PVA stabilizer. Las...

Acta horticulturae, Mar 1, 2005

To investigate the pro-oxidative activity of nutmeg, safflower, and lemongrass, methanolic extrac... more To investigate the pro-oxidative activity of nutmeg, safflower, and lemongrass, methanolic extracts of each were incubated with bovine serum albumin (BSA) in the absence or presence of Fe 3+ /EDTA/H 2 O 2 , Fe 2+ /ascorbate, or Cu 2+ /H 2 O 2 at 37°C. The protein cleavage by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), protein and free amino groups contents were determined. As a result, BSA degradation was observed on SDS-PAGE. This corresponded with decrease in protein concentration and free amino group elevation in the reaction mixture. Such degradation was inhibited in the presence of mannitol, the hydroxyl radical scavenger, indicating that the pro-oxidative activity in these spices caused hydroxyl radical formation.

Journal of General and Applied Microbiology, 2004

Acinetobacter calcoaceticus LP009 is a lipase producer isolated from raw milk. It was classified ... more Acinetobacter calcoaceticus LP009 is a lipase producer isolated from raw milk. It was classified as a psychrotroph since its optimum growth was found at 15°C, and yet, it could also grow at 30°C (Pratungdejkul and Dharmsthiti, 2000). Heat-labile lipase is useful for some applications mainly in food manufacture in which high temperatures during processing may destroy texture, flavor and aroma, and heat-labile lipase can be easily inactivated at a relatively low temperature (Margesin and Schinner, 1994). In our recent study, A. calcoaceticus LP009 lipase was found to be efficient in digesting palm oil (Pratungdejkul and Dharmsthiti, 2000). Products from palm oil hydrolysis are useful in many applications, which are more valuable than the oil itself. In this study, palm oil hydrolysis by A. calcoaceticus LP009 lipase was carried out. In the first part, a medium suitable for growth and lipase production was developed. The enzyme produced was analyzed for general properties and lipolysis on palm oil. Quantitative analysis of monoglyceride was carried out on HPLC and the fatty acid composition of monoglyceride was determined using gas chromatography mass spectrometry (GC-MS). Lipase production from A. calcoaceticus LP009 (LP009) in LB medium (48-h cultivation at 15°C) was formerly found to be best induced by 1% Tween-80 (Pratungdejkul and Dharmsthiti, 2000). Therefore, a complex medium, MMPT, for A. calcoaceticus lipase (Lip009) production was formulated based on MMP, which was composed of 0.1% (NH 4) 2 SO 4 , 40 mg ml Ϫ1 MgSO 4 , 4 mg ml Ϫ1 FeSO 4 in 2% buffer solution [7.3% Na 2 HPO 4 , 3.2% KH 2 PO 4 , pH 7.2] (Lotrakul and Dharmsthiti, 1997) plus 1% Tween-80. LP009 was found to be incapable of metabolizing glucose (Table 1) while the addition of maltose or lactose to MMPT did not promote higher growth or lipase production than that without them. However, whey, which contained lactose as a major sugar constituent, did promote high Lip009 production. Thus, the effect of protein, another major component in whey, was tested. It was shown that MMPT in the presence of peptone, either with or without whey, resulted in remarkably higher lipase production. This indicated that LP009 used the amino acid as its carbon source for growth. Cultivation of LP009 in MMPT with 1% of various kinds of amino acids revealed that leucine and asparagine gave the highest lipase production per cell (Table 2). However, in terms of total productivity, monosodium glutamate (MSG) gave the highest lipase activity. Therefore, MSG was determined to be the best carbon source for LP009 since it supported the highest growth and lipase production from the bacteria. Optimum concentration of MSG was at 1%. Medium containing 1% MSG gave approximately 1.5 time

Acta horticulturae, Mar 1, 2005

Twenty methanolic extracts from Thai spice powder (anise, cardamom, chilli, Chinese key, cinnamon... more Twenty methanolic extracts from Thai spice powder (anise, cardamom, chilli, Chinese key, cinnamon, clove, coriander, cumin, deeplee, dill, fennel, galangal, kencur, lemongrass, ginger, nutmeg, oregano, pepper, safflower, and turmeric) were screened for pro-oxidative activity using a lecithin-liposome model system. The oxidative stress was induced by four systems: (I) non-metal induction; (II) FeCl 3 /H 2 O 2 /EDTA; (III) FeSO 4 /ascorbate; and (IV) CuSO 4 /H 2 O 2. Of these spices, safflower, lemongrass, and nutmeg extracts showed the pro-oxidative activity observed by thiobarbituric acid reactive substance elevation. Since pro-oxidation were metal dependent, hydroxyl radical formation was investigated by monitoring fluorescence products from benzoate hydroxylation. The formation of hydroxyl radical was confirmed with the fluorescence detected and the suppression due to addition of mannitol, a hydroxyl radical scavenger.

Journal of Chromatography A, Apr 1, 1994

ABSTRACT

Bioscience, Biotechnology, and Biochemistry, 1998

ABSTRACT

Lwt - Food Science and Technology, 2017

Lwt - Food Science and Technology, 2017

Data in Brief, Aug 1, 2020

Crude extracts of fresh Dendrobium Sonia 'Earsakul' orchid flowers (DSE) were prepared using micr... more Crude extracts of fresh Dendrobium Sonia 'Earsakul' orchid flowers (DSE) were prepared using microwave assisted extraction (MAE; using household microwave oven) and hot water extraction (HWE; at constant 80 °C). The obtained DSEs were measured their absorbance at λ max of 543 and 583 nm and determined their total monomeric anthocyanin contents (TAC). Mathematical models of MAE of Dendrobium Sonia 'Earsakul' orchid flower were constructed using response surface methodology-Box-Behnken design. Studied parameters included flower to water ratio, microwave power, and extraction time, with absorbance at λ max as response. The data generated were 1) visible spectrum (40 0-70 0 nm) of DSE; 2) absorbance values at λ max and 3) TAC of DSEs obtained from various extraction conditions of MAE and HWE; 4) linear equations describing correlations between TAC and absorbance at λ max of DSEs; and 5) mathematical models of MAE of Dendrobium Sonia 'Earsakul' orchid.

Food and Chemical Toxicology, 2008

Acrylamide in Thai curry cooked in coconut milk was investigated using ion trap LC-ESI-MS/MS. The... more Acrylamide in Thai curry cooked in coconut milk was investigated using ion trap LC-ESI-MS/MS. The transitions of m/z 72 > 55 and 86 > 58 were monitored in multiple reaction monitoring mode for identification and quantification. A linear response was found for the acrylamide standard in the range of 400-30,000 pg, with correlation coefficients (r) greater than 0.99. The limit of detection (s/n = 3) and limit of quantification (s/n = 9) were 400 and 1200 pg, respectively. Sample preparation was performed by means of solvent extraction, giving recovery of 92-108% with relative standard deviation less than 10%. Thirty Thai curry samples were analyzed and found acrylamide at concentration in the range of less than 60-606 ng/g dry weight. Acrylamide was formed in solely heated coconut milk at 121 degrees C. Changes in 5-(hydroxymethyl)-2-furfuraldehyde, fructose, glucose and glutamic acid contents in coconut milk during heat treatment were observed as progress parameters for the Maillard reaction. Moreover, acrylamide was determined in equimolar model system of glutamic acid with glucose or fructose (1mM), and yielded acrylamide, approximately 0.1% and 0.06% (w/w), respectively.

Process Biochemistry, Jul 1, 2005

ABSTRACT The effect of glycation on properties of thermostable glucoamylase was studied by incuba... more ABSTRACT The effect of glycation on properties of thermostable glucoamylase was studied by incubating purified glucoamylase with maltodextrin at 60 °C. Glycation occurred during the incubation and was assessed by 5-(hydroxymethyl)-2-furfuraldehyde (HMF) released from acid hydrolysis of the glycated protein. Stability and kinetic parameters of the glycated glucoamylase and the intact enzyme were compared. The glycated enzyme was more resistant to the heat but glycation did not strongly affect pH stability and pI value significantly. In the presence of maltose as substrate, the Km value of the glucoamylase glycated by maltodextrin was lower than that of the intact enzyme. This indicated a greater affinity of the glycated enzyme for maltose. In the presence of maltodextrin as substrate, glycation led to increases in the rate of hydrolytic reaction. Moreover, glycation resulted in a higher efficiency of glucoamylase to convert the substrate into glucose. This might be due to a greater conformational flexibility of the glycated glucoamylase.

Journal of Food Measurement and Characterization, Jul 19, 2014

An analytical method has been developed for the separation of glyoxal (Go), methylglyoxal (MGo), ... more An analytical method has been developed for the separation of glyoxal (Go), methylglyoxal (MGo), and dimethylglyoxal (DMGo) by MEKC using stilbenediamine (SD) as derivatizing reagent, separation time 6.5 min, SDS as micellar medium at pH 8, and sodium tetraborate (0.1 M) as buffer. Uncoated fused‐silica capillary, effective length 50 cm×75 μm id; applied voltage 20 kV and photodiode array detection, were used. Calibration was linear within 0.02–150 μg/mL with detection limits 3.5–5.8 ng/mL. Go and MGo, observed for diabetic and healthy volunteers, were within 0.098–0.193 μg/mL Go and 0.106–0.245 μg/mL MGo with RSD 1.6–3.5 and 1.7–3.4%, respectively, in diabetics against 0.016–0.046 μg/mL Go and 0.021–0.066 μg/mL MGo with RSDs 1.5–3.5 and 1.4–3.6%, respectively, in healthy volunteers. Go and MGo in diabetics were also measured by standard addition and DMGo as an internal standard. Additives do not contribute significantly to Go and MGo matrix.

Biochimica Et Biophysica Acta - General Subjects, Dec 1, 1995

Hydroperoxide formation during Maillard reaction (amino-carbonyl reaction) was investigated using... more Hydroperoxide formation during Maillard reaction (amino-carbonyl reaction) was investigated using luminol-chemiluminescence-high performance liquid chromatography (CL-HPLC). From the equimolar reaction mixture of 1 M fl-alanine/D-glucose in phosphate buffer (pH 8.0) at 95°C, two hydroperoxides and H20 2 were detected as chemiluminescent products in CL-HPLC, and the yields were proportional to the browning development. One of these hydroperoxides was isolated and identified as 3-hydroxy-5-hydroperoxy-2methyl-5,6-dihydropyran-4-one (HMDP, pyrone hydroperoxide) by fast atom bombardment mass spectrometry. The HMDP formation was also confirmed in L-lysine/D-glucose and in bovine serum albumin/D-glucose with the physiological incubation at 37°C for 4 days and 3 wk, respectively. Incubation at 37°C of human plasma containing 5.5-25.0 mM of o-glucose for 60 h showed the glucose concentration-dependent formation of HMDP (10-35/xM of H 202 equivalence). The HMDP was negative to thiobarbituric acid reaction and was degraded by peroxidases such as horseradish peroxidase, Athromyces ramosus peroxidase, heated cytochrome c, and microperoxidase. The results strongly suggested the formation of such hydroperoxide even in biological Maillard reaction termed as glycation, and implied its contribution in pathogenesis and oxidative lesions associated with hyperglycemia.

Journal of Food Quality, Apr 1, 2013

ABSTRACT Sensory descriptive analysis was performed on 52 Thai fish sauce samples by 15 trained p... more ABSTRACT Sensory descriptive analysis was performed on 52 Thai fish sauce samples by 15 trained panelists, with an intention to explore the aroma profiles and to correlate with their total nitrogen (TN) contents, which is conventionally used as a general standard for commercial product grading. Thai fish sauce aroma characteristics could be exemplified through eight descriptive attributes. Sweet, meaty and cheesy odors presented overall characteristics of Thai fish sauce, while salty and anchovy‐like odors were noticeably perceived due to their high intensity in fish sauce. Aroma intensity of three attributes including sour, shrimp paste‐like and fishy odors could categorize Thai fish sauce samples into two groups, i.e., high‐TN and low‐TN groups. This categorization was also observed when rating scores of the intensity of these eight odor attributes were applied on principal component analysis (PCA). Moreover, total volatile basic‐nitrogen and pH of the samples were applied on PCA to better explain the contribution of aroma attributes to fish sauce products. Practical ApplicationsThailand is a major producer of fish sauce; hence, varieties of product qualities are available in the market. Generally, the products are graded in accordance to its total nitrogen (TN) content. However, manufacturers could distinguish the product quality based on its aroma profile. On the other hand, prices of products are based on TN and their characteristic aroma that consumers can perceive. The finding in this study would be applicable to fish sauce quality standardization based on aroma profiles that are correlated to conventional TN grading, as well as conservation of product authenticity.

international food research journal, 2014

Eight native Thai plant rarely studied were extracted by using distilled water and 95% ethanol th... more Eight native Thai plant rarely studied were extracted by using distilled water and 95% ethanol then were investigated for their total phenolics, free radical scavenging, metal chelating and five antibacterial capacities. Five bacteria consisted of one gram-negative (Esherichia coli) and four gram-positive (Stapphylococcus aureus, Stapphylococcus epidermidis, Bacillus cereus and Bacillus subtilis). Significant difference was observed among solvent extractions used and the plant species. The aqueous extracts gave higher antioxidant abilities but lower antibacterial capacities than the ethanol ones. Principle component analysis (PCA) revealed that the free radical scavenging was correlated to the total phenolics. Among the eight species, S. gratum extracts showed the strongest free radical scavenging ability, while, C. harmandiana showed the strongest chelating capacity. The G. cowa extracts were exception in antibacterial capacities because their activities against all the test bacter...

Annu Rep ICBiotech, 1998

TOP > J-EAST > List of Journal Titles (A) > Annu Reports ICBiotech (1998) > Kinetic M... more TOP > J-EAST > List of Journal Titles (A) > Annu Reports ICBiotech (1998) > Kinetic Modeling of Lactic Acid Fermentation from Sago Starch Using Lactococcus lactis IO-1. ... Kinetic Modeling of Lactic Acid Fermentation from Sago Starch Using Lactococcus lactis IO-1. ... Title;Kinetic Modeling of Lactic Acid Fermentation from Sago Starch Using Lactococcus lactis IO-1. ... Copyright (c) 2006-2007 Japan Science and Technology Agency. All Rights Reserved.

Lwt - Food Science and Technology, 2016

Foods

Organic heme iron in the form of heme iron polypeptide (HIP) is a bioavailable form of iron that ... more Organic heme iron in the form of heme iron polypeptide (HIP) is a bioavailable form of iron that can be used for dietary supplements. However, one practical challenge with HIP is that the quality of HIP prepared with different batches of raw material could lead to HIP products with inconsistent characteristics. In this study, skipjack tuna blood, a by-product in canned tuna industry, was converted to HIP at different degrees of enzymatic hydrolysis. The variation in HIP physical–chemical characteristics from different batches was evaluated, including composition, solubility, and molecular weight distribution. It was found that the batch variation had no effect on HIP composition and solubility; however, the degree of hydrolysis (DH) and the size of peptides that interact with heme greatly influenced HIP solubility at pH 2. Tuna-HIP with a low DH (DH, 8%) had 1.76-fold greater solubility than tuna-HIP with a high DH (DH, 32%). High-performance liquid chromatography (HPLC) revealed th...

Journal of Applied Polymer Science, 2016

ABSTRACTThis article was aimed at preparation and characterization of drug delivery carriers made... more ABSTRACTThis article was aimed at preparation and characterization of drug delivery carriers made from biodegradable polyhydroxyalkanoates (PHAs) for slow release of tetracycline (TC) for periodontal treatment. Four PHA variants; polyhydroxybutyrate (PHB), poly(hydroxybutyrate‐co‐hydroxyvalerate) with 5, 12, and 50% hydroxyvalerate were used to formulate TC‐loaded PHA microspheres by double emulsion‐solvent evaporation method. We also compared the effect of different molecular weight (Mw) of polyvinyl alcohol (PVA) acting as surface stabilizer on particle size, drug loading, encapsulation efficiency, and drug release profile. The TC‐loaded PHA microspheres exhibited microscale and nanoscale spherical morphology under scanning electron microscopy. Among formulations, TC‐loaded PHB:low Mw PVA demonstrated the highest TC loading with slow release behavior. Our results showed that the release rate from PHA microspheres was influenced by both the type of PHA and Mw of PVA stabilizer. Las...