Pectinesterase (EC 3.1.1.11) was extracted and purified from papaya (Carica papaya L. var. exotic... more Pectinesterase (EC 3.1.1.11) was extracted and purified from papaya (Carica papaya L. var. exotica). The procedure adopted for purification resulted in an approximate 250-fold purification (784 units/mg protein) with a 45% recovery of the pectinesterase activity. The enzyme was eluted in a single peak after CM-Sephadex and Sephadex G-100 chromatography. The purified enzyme had a uniform specific activity throughout the final chromatographic peak. The enzyme preparation was confirmed to be of homogeneous state by gel filtration and non-denaturing polyacrylamide gel electrophoresis and it has a molecular weight of approximately 32 000 Da.
Twenty-eight different tea samples sold in the United States were evaluated using high-performanc... more Twenty-eight different tea samples sold in the United States were evaluated using high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) for their contamination with polycyclic aromatic hydrocarbons (PAHs). Many PAHs exhibit carcinogenic, mutagenic, and teratogenic properties and have been related to several kinds of cancer in man and experimental animals. The presence of PAHs in environmental samples such as water, sediments, and particulate air has been extensively studied, but food samples have received little attention. Eighteen PAHs congeners were analyzed, with percentage recovery higher than 85%. Contamination expressed as the sum of the 18 analyzed PAHs was between 101 and 1337 mg/kg on dry mass and the average contents in all of the 28 examined samples was 300 mg/kg on dry mass. Seven of the congeners were found in all samples with wide ranges of concentrations as follows: fluorene (7-48 mg/kg), anthracene (1-31 mg/kg), pyrene (1-970 mg/kg), benzo(a)anthracene (1-18 mg/kg) chrysene (17-365 mg/kg), benzo(a)pyrene (1-29 mg/kg), and indeno(1,2,3-cd)pyrene (4-119 mg/kg). The two most toxic congeners benzo(a)pyrene and dibenzo(a,h)anthracene
Journal of the Science of Food and Agriculture, 2002
... I Yusep,; S Jinap,; B Jamilah,; S Nazamid. Article first published online: 17 SEP 2002. ... H... more ... I Yusep,; S Jinap,; B Jamilah,; S Nazamid. Article first published online: 17 SEP 2002. ... How to Cite. Yusep, I., Jinap, S., Jamilah, B. and Nazamid, S. (2002), Influence of carboxypeptidases on free amino acid, peptide and methylpyrazine contents of under-fermented cocoa beans. ...
Journal of the Science of Food and Agriculture, 1998
The e †ect of nib roasting time and temperature on volatile component proÐles was studied using r... more The e †ect of nib roasting time and temperature on volatile component proÐles was studied using response surface methodology (RSM) which consisted two independent variables : time (5È65 min) and temperature (110È170¡C). A steam distillation extraction (SDE) method was used to extract and gas chromatographÈmass spectrometry equipped with an ICIS data system was used to identify the volatile compounds. Tetramethylpyrazine, trimethylpyrazine, phenethyl acetate, isoamyl acetate, 3-methylbutyl acetate, phenylacetaldehyde, benzaldehyde and 2-phenylethanol were present in all treatments. Pyrazine formation increased as roasting time and temperature were increased. The number of pyrazines increased from 4 to 11 and 25, respectively, when roasting, time was increased from 5 to 35 and 65 min at 140¡C. The unit area of esters increased (up to 1700È1800) when the roasting time was increased from 15 to 65 min (at 110È 120¡C). However, the unit area of carbonyls linearly decreased with an increasing roasting temperature at shorter time (5È25 min). The unit area of phenols was enormously reduced at the highest roasting temperature (160È170¡C) with longest roasting time (45È65 min) while that of alcohol slightly decreased as roasting time and temperature were increased. 1998 SCI. ( J Sci Food Agric 77, 441È448 (1998)
Journal of the Science of Food and Agriculture, 1998
Abstract A study on storage stability of durian leather was carried out at room temperature using... more Abstract A study on storage stability of durian leather was carried out at room temperature using four types of packaging materials—laminated aluminium foil (LAF), high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polypropylene (PP) films—for ...
Journal of the Science of Food and Agriculture, 2006
In this study fermented cocoa beans were dried in a direct solar dryer at three levels of loading... more In this study fermented cocoa beans were dried in a direct solar dryer at three levels of loading (20, 30 and 60 kg). Surface mouldiness was found to be heavy in the 60 kg treatment, with beans appearing blackish. All the dried beans were reasonably acceptable in terms of vinegary odour and weak in alcohol odour. Weak odour was also detected for the faecal, rancid and cheesy odours. The 60 kg treatment was rated strong for wet sock odour due to poor drying condition. A significant difference (P < 0.05) was found between the 60 kg treatment and the lower loading treatments for pH and titratable acidity. A cut test showed that the lower loading treatments resulted in a higher percentage of brown beans. The 20 kg treatment showed the highest cut test score, which is significantly different (P < 0.05) from the 60 kg treatment. Fermentation index also showed a tendency for lower loading treatments to have a higher index. No significant difference (P > 0.05) was found among the treatments in terms of cocoa, astringency, bitterness and sourness flavour notes. However, better flavour was observed for beans from the 20 kg treatment. No mouldy off flavour was found in any of the dried beans. Overall quality assessment showed that the 20 kg treatment was able to produce reasonably good-quality beans as compared to other loadings and therefore is recommended for the direct solar dryer.
Journal of the Science of Food and Agriculture, 2002
... Amin, I., Jinap, S., Jamilah, B., Harikrisna, K. and Biehl, B. (2002), Analysis of vicilin (7... more ... Amin, I., Jinap, S., Jamilah, B., Harikrisna, K. and Biehl, B. (2002), Analysis of vicilin (7S)-class globulin in cocoa cotyledons from various genetic origins. ... 4 Clapperton J F, Yow S T K, Chan J, Lim D H K, Lockwood G, Romanczyk L and Hammerstone J F, The contribution of ...
Journal of Liquid Chromatography & Related Technologies, 2009
Abstract A novel approach to identify compounds possessing adenosine A1 receptor binding activity... more Abstract A novel approach to identify compounds possessing adenosine A1 receptor binding activity in the leaves of O. stamineus was developed. O. stamineus extract is one of the components of a functional beverage used in Indonesia for the treatment of kidney ...
Journal of Liquid Chromatography & Related Technologies, 2009
... Zaidul Islam Sarker a , Irwandi Jaswir c &amp;amp;amp;amp;amp;amp; Robert Verpoorte b pag... more ... Zaidul Islam Sarker a , Irwandi Jaswir c &amp;amp;amp;amp;amp;amp; Robert Verpoorte b pages 214-224. ... J. Ethnopharm. 2008 , 119 , 680 – 685 . [CrossRef], [PubMed], [Web of Science ®]; 8. Hossain , MM ; Paul , N. ; Sohrab , MH ; Rahman , E. ; Rashid , MA Antibacterial activity of Vitex trifolia . ...
The optimum operating conditions for the extraction of cocoa butter from cocoa liquor using super... more The optimum operating conditions for the extraction of cocoa butter from cocoa liquor using supercritical carbon dioxide and the effect of sample particle size on cocoa butter extraction under optimized operating conditions were investigated. The optimization was conducted at 10-45 MPa and 35-75C, with extraction times of 1-12 h by response surface methodology. The effect of particle size was studied using cocoa liquor, ground cocoa nibs and crushed cocoa nibs with particle sizes of approximately 74 mm, 0.85-1 mm and 4-6 mm, respectively. The yield was analyzed for total fat content by gravimetric method and triacylglycerol (TAG) profile by high-performance liquid chromatography. The results showed higher yield of cocoa butter with higher values of pressure, temperature and extraction time. The optimum conditions for cocoa butter extraction were 45 MPa, 75C and 12 h. The smaller particle size produced a higher yield of cocoa butter. 1, were the major TAGs present in the extracted cocoa butter, with POS being the highest (>30%) for all treatments studied.
The effects of particle size, fermentation, roasting time and roasting temperature of cocoa nibs ... more The effects of particle size, fermentation, roasting time and roasting temperature of cocoa nibs on cocoa butter extraction using supercritical fluid technology were studied. The effect of particle size was studied using cocoa liquor (D = 0.074 mm), ground cocoa nib (D = 0.25-0.50 mm and 1.0-1.2 mm) and whole cocoa nibs at 35 MPa, 60°C and flow rate of 2 ml/min using supercritical carbon dioxide (SC-CO 2 ). The effect of degree of fermentation was studied using unfermented, partly fermented and fermented cocoa, whereas the effect of roasting using roasted and unroasted cocoa nibs. Fermentation and roasting studies were conducted under the same operation conditions as particle size study using SC-CO 2 but with ethanol (25% w/w) as cosolvent. Cocoa butter extracted from the three studies was analyzed for total fat content (%), triglycerides and fatty acid methyl ester. The results showed that the extraction yield was significantly increased by a reduction in particle size. The highest yield was also obtained using unfermented cocoa, roasted for 35 min and at 150°C. Generally, cocoa butter had similar triglycerides and fatty acid methyl ester composition at 5, 10 and 15 h extraction time. Glycerol-1,3dipalmitate-2-oleate (POP), glycerol-1-palmitate-2-oleate-3-stearate (POS), and glycerol-1,3-distearate-2-oleate (SOS) account for most of the triglycerides, with POS (42.52-46.44%) being the major component. Palmitic, stearic and oleic were the main fatty acids in the extracted cocoa butter, with stearic acid being the highest component (33.70-40.22%).
Supercritical fluid extraction (SFE) offers an alternative method to conventional extraction of f... more Supercritical fluid extraction (SFE) offers an alternative method to conventional extraction of fatty acids. SFE was developed for analytical application in the mid-1980s in response to the desire to reduce the use of organic solvents in the laboratory environment, and it is now becoming a standard method for the extraction, fractionation, refinement and deodorization of lipids or essential oils containing
Journal of the American Oil Chemists' Society, 2001
The effects of microwave heating on the cooling profiles of two vegetable oils (corn oil and soyb... more The effects of microwave heating on the cooling profiles of two vegetable oils (corn oil and soybean oil) were studied using differential scanning calorimetry (DSC) and compared to changes in chemical parameters. These oils were exposed for several periods of time to three controlled treatments: low-, medium-, and high-power settings, respectively. The DSC results were derived from the cooling curve of oils at a scanning rate of 5°C/min. The chemical analyses of the oils included peroxide value, anisidine value, free fatty acid content, iodine value, and C18:2/C16:0 peak area ratio. A statistical comparison was carried out between DSC and the chemical parameters. In general, correlations were good between these parameters. Likewise, the experimental data showed that, for a given microwave power setting, a good correlation existed between DSC curve parameters and heating periods. These results indicate that DSC can be used as an objective nonchemical, instrumental technique to monitor lipid oxidation in both traditionally heated and microwave-heated oils.
Journal of the American Oil Chemists' Society, 2001
A new analytical method was developed for the determination of aflatoxins in groundnut and ground... more A new analytical method was developed for the determination of aflatoxins in groundnut and groundnut cakes by Fourier transform infrared (FTIR) spectroscopy using horizontal attenuated total reflectance technique. Groundnut and groundnut cake samples were used in this study. The wavelengths were selected for the four types of aflatoxins-B 1 , B 2 , G 1 , and G 2 -and the standards prepared for each by spiking some clean sample with the aflatoxins in concentrations of 0-1200 parts per billion. A partial least square regression was used to derive the calibration models for each toxin. The coefficients of determination (R 2 ) of the calibration model were computed for the FTIR spectroscopy predicted values vs. actual values of aflatoxins in parts per billion. The R 2 was found to be 0.9911, 0.9859, 0.9986, and 0.9789 for aflatoxins B 1 , B 2 , G 1 , and G 2 , respectively. Standard errors of calibration for groundnut samples were found to be 1.80, 2.03, 1.42, and 2.05 for aflatoxins B 1 , B 2 , G 1 , and G 2 , respectively. Calibration models were validated with an independent set of samples. The R 2 of validation models were computed. The SD of the difference for repeatability of the FTIR method was found to be better than that of the chemical method. Based on the results obtained, FTIR spectroscopy can be a useful instrumental method for determining aflatoxins in oilseeds and oilseed cakes. With its speed and ease of data manipulation by computer software, it is a possible alternative to the standard wet chemical methods for a rapid and accurate routine determination of aflatoxin levels in food and feed.
Journal of the American Oil Chemists' Society, 2000
A study was conducted to investigate the oxidative behavior of various mixtures of rosemary, sage... more A study was conducted to investigate the oxidative behavior of various mixtures of rosemary, sage, and citric acid in a linoleic acid model system by oxygen consumption measurement and in a palm olein system by differential scanning calorimetry (DSC) analysis. Response surface methodology was used to optimize the use of the mixtures. Results showed that rosemary and sage were two important factors for the protective index (PI). The two antioxidants were highly significantly (P < 0.001) in influencing PI values. There was a significant (P < 0.01) synergistic effect between rosemary and sage on PI values. Citric acid was also found to be significant (P < 0.05) for PI. With respect to onset time (T o ), all three antioxidants were significant (P < 0.05). However, no significant interaction among antioxidants was found for T o . Mathematical models for both PI and T o could be developed with confidence. The R 2 values for PI and T o were 0.992 and 0.926, respectively. A combination of 0.078% rosemary, 0.067% sage and 0.037% citric acid was the optimal combination for PI, whereas a combination of 0.068% rosemary, 0.075% sage, and 0.039% citric acid was required to reach the optimal T o value.
Journal of the American Oil Chemists' Society, 2002
A new analytical method was developed for the determination of soap in palm and groundnut oils by... more A new analytical method was developed for the determination of soap in palm and groundnut oils by FTIR spectroscopy. Soap from 0 to 80 mg/kg oil was produced in situ in the oils by adding sodium hydroxide. The FTIR spectroscopy was with a sodium chloride transmission cell, and the partial least-squares statistical method was used to calibrate a model for each oil. The accuracy of the method was comparable to that of AOCS Method Cc17-95, with coefficients of determination (R 2 ) of 0.98 and 0.98 for both palm and groundnut oils. The standard errors of calibration were 1.84 and 1.36 for the two oils, respectively. The calibration models were cross-validated, and the R 2 of cross-validation and standard errors of cross validation were computed. The standard deviation of the difference for repeatability of the FTIR method was better than that for the chemical method used for determining soap in palm and groundnut oils. With its speed and ease of data manipulation by computer software, FTIR spectroscopy is a possible alternative to the standard wet chemical methods for rapid (2 min) and accurate routine determination of soap in chemically refined vegetable oils.
Journal of the American Oil Chemists' Society, 2001
Fourier transform infrared (FTIR) spectra of palm oil samples between 2900 and 2800 cm -1 and 180... more Fourier transform infrared (FTIR) spectra of palm oil samples between 2900 and 2800 cm -1 and 1800 and 1600 cm -1 were used to compare different multivariate calibration techniques for quantitative determination of their thiobarbituric acid-reactive substance (TBARS) content. Fifty spectra (in duplicate) of palm oil with TBARS values between 0 and 0.25 were used to calibrate models based on partial least squares (PLS) and principal components regression (PCR) analyses with different baselines. The methods were compared for the number of factors, coefficients of determination (R 2 ), and accuracy of estimation. The standard errors of prediction (SEP) were calculated to compare their predictive ability. The calibrated models generated three to eight factors, R 2 of 0.9414 to 0.9803, standard error of estimation (SEE) of 0.0063 to 0.0680, and SEP of 1.20 to 6.67.
Ž . In the present work, the influence of microwave power low-, medium-and high-power settings an... more Ž . In the present work, the influence of microwave power low-, medium-and high-power settings and heating time on lipid Ž . deterioration produced during the microwave heating of RBD palm olein RBDPO was evaluated. The changes in thermal O Ž . profiles by differential scanning calorimetry DSC were studied in comparison to the changes in chemical parameters. The DSC method was based on the cooling and melting curves of oils at a scanning rate of 5 ЊCrmin. The chemical evaluation of the oils was based on free fatty acid content, C18:2rC16:0 ratio, peroxide, iodine, and anisidine values. The DSC results were explained on the basis of the endo-or exothermic peak temperatures. A statistical comparative study was carried out on the DSC and chemical parameters. The results indicate that there is a good correlation between the DSC and chemical methods. Based on the results obtained, the DSC appears to be a useful instrumental method in monitoring the oxidation of microwave heated oils, and it may have the potential to replace the time-and chemical-consuming standard chemical methods. ᮊ Industrial rele¨ance: Microwave heating has become an essential tool in home meal preparation and in the institutional food service sector. Few studies exist on the influence of microwave heating on the composition and quality of edible oils especially refined-bleached-deodorized palm Ž . Ž olein RBDPO . Consequently the objective of this work was to investigate the effect of microwave heating in combination with microwave o . power and heating time on RBDPO . Exposing RBDPO to various microwave power settings and heating periods caused the formation of o o hydroperoxides and secondary oxidation products, hydrolysis of free fatty acids, decreased level of unsaturated fatty acids and iodine as well as changes in the differential scanning calorimeter cooling and melting parameters.
Pectinesterase (EC 3.1.1.11) was extracted and purified from papaya (Carica papaya L. var. exotic... more Pectinesterase (EC 3.1.1.11) was extracted and purified from papaya (Carica papaya L. var. exotica). The procedure adopted for purification resulted in an approximate 250-fold purification (784 units/mg protein) with a 45% recovery of the pectinesterase activity. The enzyme was eluted in a single peak after CM-Sephadex and Sephadex G-100 chromatography. The purified enzyme had a uniform specific activity throughout the final chromatographic peak. The enzyme preparation was confirmed to be of homogeneous state by gel filtration and non-denaturing polyacrylamide gel electrophoresis and it has a molecular weight of approximately 32 000 Da.
Twenty-eight different tea samples sold in the United States were evaluated using high-performanc... more Twenty-eight different tea samples sold in the United States were evaluated using high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) for their contamination with polycyclic aromatic hydrocarbons (PAHs). Many PAHs exhibit carcinogenic, mutagenic, and teratogenic properties and have been related to several kinds of cancer in man and experimental animals. The presence of PAHs in environmental samples such as water, sediments, and particulate air has been extensively studied, but food samples have received little attention. Eighteen PAHs congeners were analyzed, with percentage recovery higher than 85%. Contamination expressed as the sum of the 18 analyzed PAHs was between 101 and 1337 mg/kg on dry mass and the average contents in all of the 28 examined samples was 300 mg/kg on dry mass. Seven of the congeners were found in all samples with wide ranges of concentrations as follows: fluorene (7-48 mg/kg), anthracene (1-31 mg/kg), pyrene (1-970 mg/kg), benzo(a)anthracene (1-18 mg/kg) chrysene (17-365 mg/kg), benzo(a)pyrene (1-29 mg/kg), and indeno(1,2,3-cd)pyrene (4-119 mg/kg). The two most toxic congeners benzo(a)pyrene and dibenzo(a,h)anthracene
Journal of the Science of Food and Agriculture, 2002
... I Yusep,; S Jinap,; B Jamilah,; S Nazamid. Article first published online: 17 SEP 2002. ... H... more ... I Yusep,; S Jinap,; B Jamilah,; S Nazamid. Article first published online: 17 SEP 2002. ... How to Cite. Yusep, I., Jinap, S., Jamilah, B. and Nazamid, S. (2002), Influence of carboxypeptidases on free amino acid, peptide and methylpyrazine contents of under-fermented cocoa beans. ...
Journal of the Science of Food and Agriculture, 1998
The e †ect of nib roasting time and temperature on volatile component proÐles was studied using r... more The e †ect of nib roasting time and temperature on volatile component proÐles was studied using response surface methodology (RSM) which consisted two independent variables : time (5È65 min) and temperature (110È170¡C). A steam distillation extraction (SDE) method was used to extract and gas chromatographÈmass spectrometry equipped with an ICIS data system was used to identify the volatile compounds. Tetramethylpyrazine, trimethylpyrazine, phenethyl acetate, isoamyl acetate, 3-methylbutyl acetate, phenylacetaldehyde, benzaldehyde and 2-phenylethanol were present in all treatments. Pyrazine formation increased as roasting time and temperature were increased. The number of pyrazines increased from 4 to 11 and 25, respectively, when roasting, time was increased from 5 to 35 and 65 min at 140¡C. The unit area of esters increased (up to 1700È1800) when the roasting time was increased from 15 to 65 min (at 110È 120¡C). However, the unit area of carbonyls linearly decreased with an increasing roasting temperature at shorter time (5È25 min). The unit area of phenols was enormously reduced at the highest roasting temperature (160È170¡C) with longest roasting time (45È65 min) while that of alcohol slightly decreased as roasting time and temperature were increased. 1998 SCI. ( J Sci Food Agric 77, 441È448 (1998)
Journal of the Science of Food and Agriculture, 1998
Abstract A study on storage stability of durian leather was carried out at room temperature using... more Abstract A study on storage stability of durian leather was carried out at room temperature using four types of packaging materials—laminated aluminium foil (LAF), high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polypropylene (PP) films—for ...
Journal of the Science of Food and Agriculture, 2006
In this study fermented cocoa beans were dried in a direct solar dryer at three levels of loading... more In this study fermented cocoa beans were dried in a direct solar dryer at three levels of loading (20, 30 and 60 kg). Surface mouldiness was found to be heavy in the 60 kg treatment, with beans appearing blackish. All the dried beans were reasonably acceptable in terms of vinegary odour and weak in alcohol odour. Weak odour was also detected for the faecal, rancid and cheesy odours. The 60 kg treatment was rated strong for wet sock odour due to poor drying condition. A significant difference (P < 0.05) was found between the 60 kg treatment and the lower loading treatments for pH and titratable acidity. A cut test showed that the lower loading treatments resulted in a higher percentage of brown beans. The 20 kg treatment showed the highest cut test score, which is significantly different (P < 0.05) from the 60 kg treatment. Fermentation index also showed a tendency for lower loading treatments to have a higher index. No significant difference (P > 0.05) was found among the treatments in terms of cocoa, astringency, bitterness and sourness flavour notes. However, better flavour was observed for beans from the 20 kg treatment. No mouldy off flavour was found in any of the dried beans. Overall quality assessment showed that the 20 kg treatment was able to produce reasonably good-quality beans as compared to other loadings and therefore is recommended for the direct solar dryer.
Journal of the Science of Food and Agriculture, 2002
... Amin, I., Jinap, S., Jamilah, B., Harikrisna, K. and Biehl, B. (2002), Analysis of vicilin (7... more ... Amin, I., Jinap, S., Jamilah, B., Harikrisna, K. and Biehl, B. (2002), Analysis of vicilin (7S)-class globulin in cocoa cotyledons from various genetic origins. ... 4 Clapperton J F, Yow S T K, Chan J, Lim D H K, Lockwood G, Romanczyk L and Hammerstone J F, The contribution of ...
Journal of Liquid Chromatography & Related Technologies, 2009
Abstract A novel approach to identify compounds possessing adenosine A1 receptor binding activity... more Abstract A novel approach to identify compounds possessing adenosine A1 receptor binding activity in the leaves of O. stamineus was developed. O. stamineus extract is one of the components of a functional beverage used in Indonesia for the treatment of kidney ...
Journal of Liquid Chromatography & Related Technologies, 2009
... Zaidul Islam Sarker a , Irwandi Jaswir c &amp;amp;amp;amp;amp;amp; Robert Verpoorte b pag... more ... Zaidul Islam Sarker a , Irwandi Jaswir c &amp;amp;amp;amp;amp;amp; Robert Verpoorte b pages 214-224. ... J. Ethnopharm. 2008 , 119 , 680 – 685 . [CrossRef], [PubMed], [Web of Science ®]; 8. Hossain , MM ; Paul , N. ; Sohrab , MH ; Rahman , E. ; Rashid , MA Antibacterial activity of Vitex trifolia . ...
The optimum operating conditions for the extraction of cocoa butter from cocoa liquor using super... more The optimum operating conditions for the extraction of cocoa butter from cocoa liquor using supercritical carbon dioxide and the effect of sample particle size on cocoa butter extraction under optimized operating conditions were investigated. The optimization was conducted at 10-45 MPa and 35-75C, with extraction times of 1-12 h by response surface methodology. The effect of particle size was studied using cocoa liquor, ground cocoa nibs and crushed cocoa nibs with particle sizes of approximately 74 mm, 0.85-1 mm and 4-6 mm, respectively. The yield was analyzed for total fat content by gravimetric method and triacylglycerol (TAG) profile by high-performance liquid chromatography. The results showed higher yield of cocoa butter with higher values of pressure, temperature and extraction time. The optimum conditions for cocoa butter extraction were 45 MPa, 75C and 12 h. The smaller particle size produced a higher yield of cocoa butter. 1, were the major TAGs present in the extracted cocoa butter, with POS being the highest (>30%) for all treatments studied.
The effects of particle size, fermentation, roasting time and roasting temperature of cocoa nibs ... more The effects of particle size, fermentation, roasting time and roasting temperature of cocoa nibs on cocoa butter extraction using supercritical fluid technology were studied. The effect of particle size was studied using cocoa liquor (D = 0.074 mm), ground cocoa nib (D = 0.25-0.50 mm and 1.0-1.2 mm) and whole cocoa nibs at 35 MPa, 60°C and flow rate of 2 ml/min using supercritical carbon dioxide (SC-CO 2 ). The effect of degree of fermentation was studied using unfermented, partly fermented and fermented cocoa, whereas the effect of roasting using roasted and unroasted cocoa nibs. Fermentation and roasting studies were conducted under the same operation conditions as particle size study using SC-CO 2 but with ethanol (25% w/w) as cosolvent. Cocoa butter extracted from the three studies was analyzed for total fat content (%), triglycerides and fatty acid methyl ester. The results showed that the extraction yield was significantly increased by a reduction in particle size. The highest yield was also obtained using unfermented cocoa, roasted for 35 min and at 150°C. Generally, cocoa butter had similar triglycerides and fatty acid methyl ester composition at 5, 10 and 15 h extraction time. Glycerol-1,3dipalmitate-2-oleate (POP), glycerol-1-palmitate-2-oleate-3-stearate (POS), and glycerol-1,3-distearate-2-oleate (SOS) account for most of the triglycerides, with POS (42.52-46.44%) being the major component. Palmitic, stearic and oleic were the main fatty acids in the extracted cocoa butter, with stearic acid being the highest component (33.70-40.22%).
Supercritical fluid extraction (SFE) offers an alternative method to conventional extraction of f... more Supercritical fluid extraction (SFE) offers an alternative method to conventional extraction of fatty acids. SFE was developed for analytical application in the mid-1980s in response to the desire to reduce the use of organic solvents in the laboratory environment, and it is now becoming a standard method for the extraction, fractionation, refinement and deodorization of lipids or essential oils containing
Journal of the American Oil Chemists' Society, 2001
The effects of microwave heating on the cooling profiles of two vegetable oils (corn oil and soyb... more The effects of microwave heating on the cooling profiles of two vegetable oils (corn oil and soybean oil) were studied using differential scanning calorimetry (DSC) and compared to changes in chemical parameters. These oils were exposed for several periods of time to three controlled treatments: low-, medium-, and high-power settings, respectively. The DSC results were derived from the cooling curve of oils at a scanning rate of 5°C/min. The chemical analyses of the oils included peroxide value, anisidine value, free fatty acid content, iodine value, and C18:2/C16:0 peak area ratio. A statistical comparison was carried out between DSC and the chemical parameters. In general, correlations were good between these parameters. Likewise, the experimental data showed that, for a given microwave power setting, a good correlation existed between DSC curve parameters and heating periods. These results indicate that DSC can be used as an objective nonchemical, instrumental technique to monitor lipid oxidation in both traditionally heated and microwave-heated oils.
Journal of the American Oil Chemists' Society, 2001
A new analytical method was developed for the determination of aflatoxins in groundnut and ground... more A new analytical method was developed for the determination of aflatoxins in groundnut and groundnut cakes by Fourier transform infrared (FTIR) spectroscopy using horizontal attenuated total reflectance technique. Groundnut and groundnut cake samples were used in this study. The wavelengths were selected for the four types of aflatoxins-B 1 , B 2 , G 1 , and G 2 -and the standards prepared for each by spiking some clean sample with the aflatoxins in concentrations of 0-1200 parts per billion. A partial least square regression was used to derive the calibration models for each toxin. The coefficients of determination (R 2 ) of the calibration model were computed for the FTIR spectroscopy predicted values vs. actual values of aflatoxins in parts per billion. The R 2 was found to be 0.9911, 0.9859, 0.9986, and 0.9789 for aflatoxins B 1 , B 2 , G 1 , and G 2 , respectively. Standard errors of calibration for groundnut samples were found to be 1.80, 2.03, 1.42, and 2.05 for aflatoxins B 1 , B 2 , G 1 , and G 2 , respectively. Calibration models were validated with an independent set of samples. The R 2 of validation models were computed. The SD of the difference for repeatability of the FTIR method was found to be better than that of the chemical method. Based on the results obtained, FTIR spectroscopy can be a useful instrumental method for determining aflatoxins in oilseeds and oilseed cakes. With its speed and ease of data manipulation by computer software, it is a possible alternative to the standard wet chemical methods for a rapid and accurate routine determination of aflatoxin levels in food and feed.
Journal of the American Oil Chemists' Society, 2000
A study was conducted to investigate the oxidative behavior of various mixtures of rosemary, sage... more A study was conducted to investigate the oxidative behavior of various mixtures of rosemary, sage, and citric acid in a linoleic acid model system by oxygen consumption measurement and in a palm olein system by differential scanning calorimetry (DSC) analysis. Response surface methodology was used to optimize the use of the mixtures. Results showed that rosemary and sage were two important factors for the protective index (PI). The two antioxidants were highly significantly (P < 0.001) in influencing PI values. There was a significant (P < 0.01) synergistic effect between rosemary and sage on PI values. Citric acid was also found to be significant (P < 0.05) for PI. With respect to onset time (T o ), all three antioxidants were significant (P < 0.05). However, no significant interaction among antioxidants was found for T o . Mathematical models for both PI and T o could be developed with confidence. The R 2 values for PI and T o were 0.992 and 0.926, respectively. A combination of 0.078% rosemary, 0.067% sage and 0.037% citric acid was the optimal combination for PI, whereas a combination of 0.068% rosemary, 0.075% sage, and 0.039% citric acid was required to reach the optimal T o value.
Journal of the American Oil Chemists' Society, 2002
A new analytical method was developed for the determination of soap in palm and groundnut oils by... more A new analytical method was developed for the determination of soap in palm and groundnut oils by FTIR spectroscopy. Soap from 0 to 80 mg/kg oil was produced in situ in the oils by adding sodium hydroxide. The FTIR spectroscopy was with a sodium chloride transmission cell, and the partial least-squares statistical method was used to calibrate a model for each oil. The accuracy of the method was comparable to that of AOCS Method Cc17-95, with coefficients of determination (R 2 ) of 0.98 and 0.98 for both palm and groundnut oils. The standard errors of calibration were 1.84 and 1.36 for the two oils, respectively. The calibration models were cross-validated, and the R 2 of cross-validation and standard errors of cross validation were computed. The standard deviation of the difference for repeatability of the FTIR method was better than that for the chemical method used for determining soap in palm and groundnut oils. With its speed and ease of data manipulation by computer software, FTIR spectroscopy is a possible alternative to the standard wet chemical methods for rapid (2 min) and accurate routine determination of soap in chemically refined vegetable oils.
Journal of the American Oil Chemists' Society, 2001
Fourier transform infrared (FTIR) spectra of palm oil samples between 2900 and 2800 cm -1 and 180... more Fourier transform infrared (FTIR) spectra of palm oil samples between 2900 and 2800 cm -1 and 1800 and 1600 cm -1 were used to compare different multivariate calibration techniques for quantitative determination of their thiobarbituric acid-reactive substance (TBARS) content. Fifty spectra (in duplicate) of palm oil with TBARS values between 0 and 0.25 were used to calibrate models based on partial least squares (PLS) and principal components regression (PCR) analyses with different baselines. The methods were compared for the number of factors, coefficients of determination (R 2 ), and accuracy of estimation. The standard errors of prediction (SEP) were calculated to compare their predictive ability. The calibrated models generated three to eight factors, R 2 of 0.9414 to 0.9803, standard error of estimation (SEE) of 0.0063 to 0.0680, and SEP of 1.20 to 6.67.
Ž . In the present work, the influence of microwave power low-, medium-and high-power settings an... more Ž . In the present work, the influence of microwave power low-, medium-and high-power settings and heating time on lipid Ž . deterioration produced during the microwave heating of RBD palm olein RBDPO was evaluated. The changes in thermal O Ž . profiles by differential scanning calorimetry DSC were studied in comparison to the changes in chemical parameters. The DSC method was based on the cooling and melting curves of oils at a scanning rate of 5 ЊCrmin. The chemical evaluation of the oils was based on free fatty acid content, C18:2rC16:0 ratio, peroxide, iodine, and anisidine values. The DSC results were explained on the basis of the endo-or exothermic peak temperatures. A statistical comparative study was carried out on the DSC and chemical parameters. The results indicate that there is a good correlation between the DSC and chemical methods. Based on the results obtained, the DSC appears to be a useful instrumental method in monitoring the oxidation of microwave heated oils, and it may have the potential to replace the time-and chemical-consuming standard chemical methods. ᮊ Industrial rele¨ance: Microwave heating has become an essential tool in home meal preparation and in the institutional food service sector. Few studies exist on the influence of microwave heating on the composition and quality of edible oils especially refined-bleached-deodorized palm Ž . Ž olein RBDPO . Consequently the objective of this work was to investigate the effect of microwave heating in combination with microwave o . power and heating time on RBDPO . Exposing RBDPO to various microwave power settings and heating periods caused the formation of o o hydroperoxides and secondary oxidation products, hydrolysis of free fatty acids, decreased level of unsaturated fatty acids and iodine as well as changes in the differential scanning calorimeter cooling and melting parameters.
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Papers by Selamat Jinap