Marc Meurens - Academia.edu (original) (raw)
Papers by Marc Meurens
Journal of Agricultural and Food Chemistry, 2004
From a nutritional point of view, cereal lipids include valuable molecules, such as essential fat... more From a nutritional point of view, cereal lipids include valuable molecules, such as essential fatty acids, phytosterols, and fat-soluble vitamins. Spelt (Triticum spelta L.) is an alternative hulled bread cereal mostly grown in Belgium, where it is mainly intended for animal feed but should increasingly be used for human consumption. The present research focused on phytosterol quantification by LC/APCI-MS 2 in saponified wholemeal extracts of 16 dehulled spelt and 5 winter wheat (Triticum aestivum L.) varieties grown in Belgium during 2001-2002 at the same location. Glycosylated sterols and free and formerly esterified sterols could be determined in saponified extracts. Results show that the mean phytosterol content is comparable in both cereals (whereas other lipids, such as oleic and linoleic acids, are increased in spelt wholemeal): spelt extract has, on average, 527.7 µg of free and esterified sterols g -1 of wholemeal and 123.8 µg of glycosylated sterols g -1 of wholemeal versus 528.5 and 112.6 µg‚g -1 in winter wheat (values not corrected for recoveries). This is the first report on the application and validation of an LC/MS 2 method for the quantification of phytosterols in spelt and winter wheat.
Talanta, 2004
Negative effects on wine quality and productivity caused by stuck and sluggish fermentations can ... more Negative effects on wine quality and productivity caused by stuck and sluggish fermentations can be reduced significantly, if such problems are detected early through periodic chemical analysis. Infrared spectroscopy (IR) has been used successfully for monitoring fermentations, since many compounds can be measured quickly from a single sample without prior treatment. Nevertheless, few applications of this technology in large scale winemaking have been reported, and these do not cover the entire fermentation from must to finished wine. In this work, we developed IR calibrations for analyzing the fermenting must at any stage of fermentation. The calibration model was obtained with multivariable partial least squares and proved effective for analyzing Cabernet Sauvignon fermentations for glucose, fructose, glycerol, ethanol, and the organic acids; malic, tartaric, succinic, lactic, acetic, and citric. Upon external validation we found an average relative predictive error of 4.8%. Malic acid showed the largest relative predictive error (8.7%). In addition, external validation found that insufficient data for these calibrations made the analysis of fermenting musts using other grape varieties less reliable.
The assessment of the glycemic index (GI) seems to be an important parameter to take into account... more The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 ± 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was si...
Journal of Cereal Science, 2004
Journal of Cereal Science, 2003
Phytosterol analysis and characterization in spelt (Triticum aestivum ssp. spelta L.) and wheat (... more Phytosterol analysis and characterization in spelt (Triticum aestivum ssp. spelta L.) and wheat (T. aestivum L.) lipids by LC/APCI-MS q
Journal of Cereal Science, 2002
Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method i... more Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method in whole ground spelt (Triticum aestivum ssp. spelta L.) and hexaploid winter wheat (T. aestivum) samples. Ninety-one samples of spelt and 78 samples of winter wheat were analysed in the present study. The available material is representative of the wide variability found in spelt
Journal of Agricultural and Food Chemistry, 1996
... 10%, respectively. Six genuine virgin olive oil samples, differing in their chemicalcompositi... more ... 10%, respectively. Six genuine virgin olive oil samples, differing in their chemicalcomposition, were selected from a set of 1428 European samples. The best ... Oliveoil fluorescence is related to oil composition. Here it is shown ...
Journal of Agricultural and Food Chemistry, 2009
The potential of Fourier transform (FT)-Raman spectroscopy to quantify the total conjugated linol... more The potential of Fourier transform (FT)-Raman spectroscopy to quantify the total conjugated linoleic acid (CLA) content was evaluated to find a technique for the routine control of CLA synthesis by chemical procedures. The calibration and validation samples were obtained by photoisomerization of linoleic acid contained in soybean oil. The catalyst was iodine (I(2)), and the light source was the green line (514.5 nm) of an argon ion laser. The criteria to select the best partial least-squares (PLS) calibration model were a low standard error of prediction (SEP), a high correlation coefficient (R), and the selection of relevant variables of the Raman spectrum to reduce spectral interferences. The total CLA content of the 22 samples ranged from 0.05 to 3.28% of total lipids. The best PLS calibration model was obtained with three optimal factors, a SEP of 0.22, and a R of 0.97. This calibration model was obtained after baseline correction of the CC stretching region (1642-1680 cm(-1)), which contained sufficient spectral information for reliable CLA quantification.
Journal of Agricultural and Food Chemistry, 2004
From a nutritional point of view, cereal lipids include valuable molecules, such as essential fat... more From a nutritional point of view, cereal lipids include valuable molecules, such as essential fatty acids, phytosterols, and fat-soluble vitamins. Spelt (Triticum spelta L.) is an alternative hulled bread cereal mostly grown in Belgium, where it is mainly intended for animal feed but should increasingly be used for human consumption. The present research focused on phytosterol quantification by LC/APCI-MS 2 in saponified wholemeal extracts of 16 dehulled spelt and 5 winter wheat (Triticum aestivum L.) varieties grown in Belgium during 2001-2002 at the same location. Glycosylated sterols and free and formerly esterified sterols could be determined in saponified extracts. Results show that the mean phytosterol content is comparable in both cereals (whereas other lipids, such as oleic and linoleic acids, are increased in spelt wholemeal): spelt extract has, on average, 527.7 µg of free and esterified sterols g -1 of wholemeal and 123.8 µg of glycosylated sterols g -1 of wholemeal versus 528.5 and 112.6 µg‚g -1 in winter wheat (values not corrected for recoveries). This is the first report on the application and validation of an LC/MS 2 method for the quantification of phytosterols in spelt and winter wheat.
Journal of Agricultural and Food Chemistry, 2005
The detection of the presence of refined hazelnut oil in refined olive oil at low percentages is ... more The detection of the presence of refined hazelnut oil in refined olive oil at low percentages is still a challenge with the current official standards. FT-Raman and FT-MIR spectroscopies have been used to determine the level of detection of the presence of hazelnut oil in olive oil. Spectroscopic analysis has been made not only with the entire oil but also with its unsaponifiable matter. Univariate and multivariate statistical models have been designed with this objective. This study shows that a complete discrimination between olive and hazelnut oils is possible and that adulteration can be detected if the presence of hazelnut oil in olive oil is >8% and if the blends are of Turkish olive and hazelnut oils. The limit of detection is higher when the blends are of edible oils from diverse geographical origins.
Journal of Agricultural and Food Chemistry, 2008
The determination of conjugated linoleic acids (CLA) in cow milk fat was studied by using UV (210... more The determination of conjugated linoleic acids (CLA) in cow milk fat was studied by using UV (210-250 nm) and Fourier transform (FT)-Raman (900-3400 cm (-1)) spectroscopy in order to determine the best spectrophotometric technique for routine analysis of milk fat. A collection of 57 milk fat samples was randomly divided into two sets, a calibration set and a validation set, representing two-thirds and one-third of the samples, respectively. All calculations were performed on the calibration set and then applied to the validation set. The CLA content ranged from 0.56 to 4.70%. A comparison of various spectral pretreatments and different multivariate calibration techniques, such as partial least-squares (PLS) and multiple linear regression (MLR), was done. This paper shows that UV spectroscopy is as reliable as FT-Raman spectroscopy to monitor CLA in cow milk fat. The best calibration for FT-Raman was given by a PLS model of seven factors with a standard error of prediction (SEP) of 0.246. For UV spectroscopy, PLS models were also better than MLR models. The most robust PLS model was constructed with only one factor and with SEP=0.288.
Journal of Agricultural and Food Chemistry, 2005
The nutritional value of breadmaking cereal spelt (Triticum aestivum ssp. spelta) is said to be h... more The nutritional value of breadmaking cereal spelt (Triticum aestivum ssp. spelta) is said to be higher than that of common wheat (Triticum aestivum ssp. vulgare), but this traditional view is not substantiated by scientific evidence. In an attempt to clarify this issue, wholemeal and milling fractions (sieved flour, fine bran, and coarse bran) from nine dehulled spelt and five soft winter wheat samples were compared with regard to their lipid, fatty acid, and mineral contents. In addition, tocopherol (a biochemical marker of germ) was measured in all wholemeals, whereas phytic acid and phosphorus levels were determined in fine bran and coarse bran samples after 1 month of storage. Results showed that, on average, spelt wholemeals and milling fractions were higher in lipids and unsaturated fatty acids as compared to wheat, whereas tocopherol content was lower in spelt, suggesting that the higher lipid content of spelt may not be related to a higher germ proportion. Although milling fractionation produced similar proportions of flour and brans in spelt and wheat, it was found that ash, copper, iron, zinc, magnesium, and phosphorus contents were higher in spelt samples, especially in aleurone-rich fine bran and in coarse bran. Even though phosphorus content was higher in spelt than in wheat brans, phytic acid content showed the opposite trend and was 40% lower in spelt versus wheat fine bran, which may suggest that spelt has either a higher endogenous phytase activity or a lower phytic acid content than wheat. The results of this study give important indications on the real nutritional value of spelt compared to wheat. Moreover, they show that the Ca/Fe ratio, combined with that of oleate/palmitate, provides a highly discriminating tool to authenticate spelt from wheat flours and to face the growing issue of spelt flour adulteration. Finally, they suggest that aleurone differences, the nature of which still needs to be investigated, may account for the differential nutrient composition of spelt and wheat.
Journal of Agricultural and Food Chemistry, 2005
The collective term "conjugated linoleic acid&am... more The collective term "conjugated linoleic acid" or "CLA" generally refers to a mixture of conjugated positional and geometric isomers of linoleic (cis-9,cis-12-octodecadienoic) acid. In nature, these isomers are mainly formed in the rumen by biohydrogenation of polyunsaturated fatty acids. This study concerns a first trial of CLA determination in cow's milk fat by Raman spectroscopy. The spectra of pure cis-9-oleic, cis-9,cis-12-linoleic, cis-9,trans-11-linoleic, and trans-10,cis-12-linoleic acids have been examined in comparison with the spectra of selected milk-fat samples containing between 0 and 3% of CLA. The trial of CLA determination by Raman spectroscopy on cow milk fat has reached its objective with the two following results. First, the examination of the Raman spectra allows to identify three specific Raman signals of the chemical bonds associated to the cis,trans conjugated C=C in the rumenic and trans-10,cis-12-octodecadienoic acids at 1652, 1438, and 3006 cm(-1). Second, the calibration of Raman spectrometer for the CLA determination has indicated that these three specific signals suit very well for the accurate and reliable measurement of CLA concentration in milk fat. To our knowledge, the present study is the first successful attempt to determine the CLA content of milk fat by a spectrophotometric method.
Food Chemistry, 2007
The assessment of the glycemic index (GI) seems to be an important parameter to take into account... more The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 ± 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was similar to that of wheat bread. However, in order to avoid more inter-individual variability, our data supports the importance to propose standardised carbohydrate content for the last meal before evaluating the GI of food.
Chemometrics and Intelligent Laboratory Systems, 2004
Spectrophotometric data often comprise a great number of numerical components or variables that c... more Spectrophotometric data often comprise a great number of numerical components or variables that can be used in calibration models. When a large number of such variables are incorporated into a particular model, many difficulties arise, and it is often necessary to reduce the number of spectral variables. This paper proposes an incremental (Forward -Backward) procedure, initiated using an entropy-based criterion (mutual information), to choose the first variable. The advantages of the method are discussed; results in quantitative chemical analysis by spectrophotometry show the improvements obtained with respect to traditional and nonlinear calibration models. D
Chemometrics and Intelligent Laboratory Systems, 2004
Data from spectrophotometers form spectra that are sets of a great number of exploitable variable... more Data from spectrophotometers form spectra that are sets of a great number of exploitable variables in quantitative chemical analysis; calibration models using chemometric methods must be established to exploit these variables. In order to design these calibration models which are specific to each analyzed parameter, it is advisable to select a reduced number of spectral variables. This paper presents a new incremental method (step by step) for the selection of spectral variables, using linear regression or neural networks, and based on an objective validation (external) of the calibration model; this validation is carried out on data that are independent from those used during calibration. The advantages of the method are discussed and highlighted, in comparison to the current calibration methods used in quantitative chemical analysis by spectrophotometry. D
Vibrational spectroscopy, 1996
Fourier transform infrared spectra of 75 biopsies from 55 cases of breast carcinoma were studied ... more Fourier transform infrared spectra of 75 biopsies from 55 cases of breast carcinoma were studied in comparison with histo-morphometry. The spectra of carcinomatous tissues are very different from those of normal tissues. There are evident correlations between the ...
Applied Spectroscopy, 1994
NIR reflectance spectra of 110 cryostat sections of carcinomatous tissue and 114 cryostat section... more NIR reflectance spectra of 110 cryostat sections of carcinomatous tissue and 114 cryostat sections of normal surrounding fibro-glandular tissue from 10 cases of breast cancer, identified by a classical pathology method, were scanned between 1100 and 2500 nm by a grating spectrometer in reflectance mode. Four wavelength intervals (1208-1242, 1746-1788, 2012-2048 and 2326-2368 nm) were found to be different for normal and carcinomatous tissues. In each interval, the second-derivative spectra of normal tissue showed a similar pattern with several characteristic peaks. In order to test the capacity of NIR spectroscopy in discriminating between normal and carcinomatous breast samples, 104 tissue sections from five additional cases were scanned prior to microscopic examination. The diagnostic prediction of NIR spectroscopy coincided exactly with the histology diagnosis for all the samples. Moreover, the presence of even a minute quantity of cancer infiltration can be detected by NIR spectroscopy, in total accordance with the microscopical observation. Therefore, the results of our experiments allow us to consider that NIR spectroscopy might become, with feasible improvements, an accurate, rapid, and reliable method for detecting breast cancer.
Applied Spectroscopy, 1990
Applied Spectroscopy, 2000
One hundred and four edible oil and fat samples from 18 different sources, either vegetable (Braz... more One hundred and four edible oil and fat samples from 18 different sources, either vegetable (Brazil nut, coconut, corn, sun ower, wal-nut, virgin olive, peanut, palm, canola, soybean, sun ower) or ani-mal (tallow and hydrogenated sh), have been analyzed by high- ...
Journal of Agricultural and Food Chemistry, 2004
From a nutritional point of view, cereal lipids include valuable molecules, such as essential fat... more From a nutritional point of view, cereal lipids include valuable molecules, such as essential fatty acids, phytosterols, and fat-soluble vitamins. Spelt (Triticum spelta L.) is an alternative hulled bread cereal mostly grown in Belgium, where it is mainly intended for animal feed but should increasingly be used for human consumption. The present research focused on phytosterol quantification by LC/APCI-MS 2 in saponified wholemeal extracts of 16 dehulled spelt and 5 winter wheat (Triticum aestivum L.) varieties grown in Belgium during 2001-2002 at the same location. Glycosylated sterols and free and formerly esterified sterols could be determined in saponified extracts. Results show that the mean phytosterol content is comparable in both cereals (whereas other lipids, such as oleic and linoleic acids, are increased in spelt wholemeal): spelt extract has, on average, 527.7 µg of free and esterified sterols g -1 of wholemeal and 123.8 µg of glycosylated sterols g -1 of wholemeal versus 528.5 and 112.6 µg‚g -1 in winter wheat (values not corrected for recoveries). This is the first report on the application and validation of an LC/MS 2 method for the quantification of phytosterols in spelt and winter wheat.
Talanta, 2004
Negative effects on wine quality and productivity caused by stuck and sluggish fermentations can ... more Negative effects on wine quality and productivity caused by stuck and sluggish fermentations can be reduced significantly, if such problems are detected early through periodic chemical analysis. Infrared spectroscopy (IR) has been used successfully for monitoring fermentations, since many compounds can be measured quickly from a single sample without prior treatment. Nevertheless, few applications of this technology in large scale winemaking have been reported, and these do not cover the entire fermentation from must to finished wine. In this work, we developed IR calibrations for analyzing the fermenting must at any stage of fermentation. The calibration model was obtained with multivariable partial least squares and proved effective for analyzing Cabernet Sauvignon fermentations for glucose, fructose, glycerol, ethanol, and the organic acids; malic, tartaric, succinic, lactic, acetic, and citric. Upon external validation we found an average relative predictive error of 4.8%. Malic acid showed the largest relative predictive error (8.7%). In addition, external validation found that insufficient data for these calibrations made the analysis of fermenting musts using other grape varieties less reliable.
The assessment of the glycemic index (GI) seems to be an important parameter to take into account... more The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 ± 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was si...
Journal of Cereal Science, 2004
Journal of Cereal Science, 2003
Phytosterol analysis and characterization in spelt (Triticum aestivum ssp. spelta L.) and wheat (... more Phytosterol analysis and characterization in spelt (Triticum aestivum ssp. spelta L.) and wheat (T. aestivum L.) lipids by LC/APCI-MS q
Journal of Cereal Science, 2002
Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method i... more Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method in whole ground spelt (Triticum aestivum ssp. spelta L.) and hexaploid winter wheat (T. aestivum) samples. Ninety-one samples of spelt and 78 samples of winter wheat were analysed in the present study. The available material is representative of the wide variability found in spelt
Journal of Agricultural and Food Chemistry, 1996
... 10%, respectively. Six genuine virgin olive oil samples, differing in their chemicalcompositi... more ... 10%, respectively. Six genuine virgin olive oil samples, differing in their chemicalcomposition, were selected from a set of 1428 European samples. The best ... Oliveoil fluorescence is related to oil composition. Here it is shown ...
Journal of Agricultural and Food Chemistry, 2009
The potential of Fourier transform (FT)-Raman spectroscopy to quantify the total conjugated linol... more The potential of Fourier transform (FT)-Raman spectroscopy to quantify the total conjugated linoleic acid (CLA) content was evaluated to find a technique for the routine control of CLA synthesis by chemical procedures. The calibration and validation samples were obtained by photoisomerization of linoleic acid contained in soybean oil. The catalyst was iodine (I(2)), and the light source was the green line (514.5 nm) of an argon ion laser. The criteria to select the best partial least-squares (PLS) calibration model were a low standard error of prediction (SEP), a high correlation coefficient (R), and the selection of relevant variables of the Raman spectrum to reduce spectral interferences. The total CLA content of the 22 samples ranged from 0.05 to 3.28% of total lipids. The best PLS calibration model was obtained with three optimal factors, a SEP of 0.22, and a R of 0.97. This calibration model was obtained after baseline correction of the CC stretching region (1642-1680 cm(-1)), which contained sufficient spectral information for reliable CLA quantification.
Journal of Agricultural and Food Chemistry, 2004
From a nutritional point of view, cereal lipids include valuable molecules, such as essential fat... more From a nutritional point of view, cereal lipids include valuable molecules, such as essential fatty acids, phytosterols, and fat-soluble vitamins. Spelt (Triticum spelta L.) is an alternative hulled bread cereal mostly grown in Belgium, where it is mainly intended for animal feed but should increasingly be used for human consumption. The present research focused on phytosterol quantification by LC/APCI-MS 2 in saponified wholemeal extracts of 16 dehulled spelt and 5 winter wheat (Triticum aestivum L.) varieties grown in Belgium during 2001-2002 at the same location. Glycosylated sterols and free and formerly esterified sterols could be determined in saponified extracts. Results show that the mean phytosterol content is comparable in both cereals (whereas other lipids, such as oleic and linoleic acids, are increased in spelt wholemeal): spelt extract has, on average, 527.7 µg of free and esterified sterols g -1 of wholemeal and 123.8 µg of glycosylated sterols g -1 of wholemeal versus 528.5 and 112.6 µg‚g -1 in winter wheat (values not corrected for recoveries). This is the first report on the application and validation of an LC/MS 2 method for the quantification of phytosterols in spelt and winter wheat.
Journal of Agricultural and Food Chemistry, 2005
The detection of the presence of refined hazelnut oil in refined olive oil at low percentages is ... more The detection of the presence of refined hazelnut oil in refined olive oil at low percentages is still a challenge with the current official standards. FT-Raman and FT-MIR spectroscopies have been used to determine the level of detection of the presence of hazelnut oil in olive oil. Spectroscopic analysis has been made not only with the entire oil but also with its unsaponifiable matter. Univariate and multivariate statistical models have been designed with this objective. This study shows that a complete discrimination between olive and hazelnut oils is possible and that adulteration can be detected if the presence of hazelnut oil in olive oil is >8% and if the blends are of Turkish olive and hazelnut oils. The limit of detection is higher when the blends are of edible oils from diverse geographical origins.
Journal of Agricultural and Food Chemistry, 2008
The determination of conjugated linoleic acids (CLA) in cow milk fat was studied by using UV (210... more The determination of conjugated linoleic acids (CLA) in cow milk fat was studied by using UV (210-250 nm) and Fourier transform (FT)-Raman (900-3400 cm (-1)) spectroscopy in order to determine the best spectrophotometric technique for routine analysis of milk fat. A collection of 57 milk fat samples was randomly divided into two sets, a calibration set and a validation set, representing two-thirds and one-third of the samples, respectively. All calculations were performed on the calibration set and then applied to the validation set. The CLA content ranged from 0.56 to 4.70%. A comparison of various spectral pretreatments and different multivariate calibration techniques, such as partial least-squares (PLS) and multiple linear regression (MLR), was done. This paper shows that UV spectroscopy is as reliable as FT-Raman spectroscopy to monitor CLA in cow milk fat. The best calibration for FT-Raman was given by a PLS model of seven factors with a standard error of prediction (SEP) of 0.246. For UV spectroscopy, PLS models were also better than MLR models. The most robust PLS model was constructed with only one factor and with SEP=0.288.
Journal of Agricultural and Food Chemistry, 2005
The nutritional value of breadmaking cereal spelt (Triticum aestivum ssp. spelta) is said to be h... more The nutritional value of breadmaking cereal spelt (Triticum aestivum ssp. spelta) is said to be higher than that of common wheat (Triticum aestivum ssp. vulgare), but this traditional view is not substantiated by scientific evidence. In an attempt to clarify this issue, wholemeal and milling fractions (sieved flour, fine bran, and coarse bran) from nine dehulled spelt and five soft winter wheat samples were compared with regard to their lipid, fatty acid, and mineral contents. In addition, tocopherol (a biochemical marker of germ) was measured in all wholemeals, whereas phytic acid and phosphorus levels were determined in fine bran and coarse bran samples after 1 month of storage. Results showed that, on average, spelt wholemeals and milling fractions were higher in lipids and unsaturated fatty acids as compared to wheat, whereas tocopherol content was lower in spelt, suggesting that the higher lipid content of spelt may not be related to a higher germ proportion. Although milling fractionation produced similar proportions of flour and brans in spelt and wheat, it was found that ash, copper, iron, zinc, magnesium, and phosphorus contents were higher in spelt samples, especially in aleurone-rich fine bran and in coarse bran. Even though phosphorus content was higher in spelt than in wheat brans, phytic acid content showed the opposite trend and was 40% lower in spelt versus wheat fine bran, which may suggest that spelt has either a higher endogenous phytase activity or a lower phytic acid content than wheat. The results of this study give important indications on the real nutritional value of spelt compared to wheat. Moreover, they show that the Ca/Fe ratio, combined with that of oleate/palmitate, provides a highly discriminating tool to authenticate spelt from wheat flours and to face the growing issue of spelt flour adulteration. Finally, they suggest that aleurone differences, the nature of which still needs to be investigated, may account for the differential nutrient composition of spelt and wheat.
Journal of Agricultural and Food Chemistry, 2005
The collective term "conjugated linoleic acid&am... more The collective term "conjugated linoleic acid" or "CLA" generally refers to a mixture of conjugated positional and geometric isomers of linoleic (cis-9,cis-12-octodecadienoic) acid. In nature, these isomers are mainly formed in the rumen by biohydrogenation of polyunsaturated fatty acids. This study concerns a first trial of CLA determination in cow's milk fat by Raman spectroscopy. The spectra of pure cis-9-oleic, cis-9,cis-12-linoleic, cis-9,trans-11-linoleic, and trans-10,cis-12-linoleic acids have been examined in comparison with the spectra of selected milk-fat samples containing between 0 and 3% of CLA. The trial of CLA determination by Raman spectroscopy on cow milk fat has reached its objective with the two following results. First, the examination of the Raman spectra allows to identify three specific Raman signals of the chemical bonds associated to the cis,trans conjugated C=C in the rumenic and trans-10,cis-12-octodecadienoic acids at 1652, 1438, and 3006 cm(-1). Second, the calibration of Raman spectrometer for the CLA determination has indicated that these three specific signals suit very well for the accurate and reliable measurement of CLA concentration in milk fat. To our knowledge, the present study is the first successful attempt to determine the CLA content of milk fat by a spectrophotometric method.
Food Chemistry, 2007
The assessment of the glycemic index (GI) seems to be an important parameter to take into account... more The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 ± 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was similar to that of wheat bread. However, in order to avoid more inter-individual variability, our data supports the importance to propose standardised carbohydrate content for the last meal before evaluating the GI of food.
Chemometrics and Intelligent Laboratory Systems, 2004
Spectrophotometric data often comprise a great number of numerical components or variables that c... more Spectrophotometric data often comprise a great number of numerical components or variables that can be used in calibration models. When a large number of such variables are incorporated into a particular model, many difficulties arise, and it is often necessary to reduce the number of spectral variables. This paper proposes an incremental (Forward -Backward) procedure, initiated using an entropy-based criterion (mutual information), to choose the first variable. The advantages of the method are discussed; results in quantitative chemical analysis by spectrophotometry show the improvements obtained with respect to traditional and nonlinear calibration models. D
Chemometrics and Intelligent Laboratory Systems, 2004
Data from spectrophotometers form spectra that are sets of a great number of exploitable variable... more Data from spectrophotometers form spectra that are sets of a great number of exploitable variables in quantitative chemical analysis; calibration models using chemometric methods must be established to exploit these variables. In order to design these calibration models which are specific to each analyzed parameter, it is advisable to select a reduced number of spectral variables. This paper presents a new incremental method (step by step) for the selection of spectral variables, using linear regression or neural networks, and based on an objective validation (external) of the calibration model; this validation is carried out on data that are independent from those used during calibration. The advantages of the method are discussed and highlighted, in comparison to the current calibration methods used in quantitative chemical analysis by spectrophotometry. D
Vibrational spectroscopy, 1996
Fourier transform infrared spectra of 75 biopsies from 55 cases of breast carcinoma were studied ... more Fourier transform infrared spectra of 75 biopsies from 55 cases of breast carcinoma were studied in comparison with histo-morphometry. The spectra of carcinomatous tissues are very different from those of normal tissues. There are evident correlations between the ...
Applied Spectroscopy, 1994
NIR reflectance spectra of 110 cryostat sections of carcinomatous tissue and 114 cryostat section... more NIR reflectance spectra of 110 cryostat sections of carcinomatous tissue and 114 cryostat sections of normal surrounding fibro-glandular tissue from 10 cases of breast cancer, identified by a classical pathology method, were scanned between 1100 and 2500 nm by a grating spectrometer in reflectance mode. Four wavelength intervals (1208-1242, 1746-1788, 2012-2048 and 2326-2368 nm) were found to be different for normal and carcinomatous tissues. In each interval, the second-derivative spectra of normal tissue showed a similar pattern with several characteristic peaks. In order to test the capacity of NIR spectroscopy in discriminating between normal and carcinomatous breast samples, 104 tissue sections from five additional cases were scanned prior to microscopic examination. The diagnostic prediction of NIR spectroscopy coincided exactly with the histology diagnosis for all the samples. Moreover, the presence of even a minute quantity of cancer infiltration can be detected by NIR spectroscopy, in total accordance with the microscopical observation. Therefore, the results of our experiments allow us to consider that NIR spectroscopy might become, with feasible improvements, an accurate, rapid, and reliable method for detecting breast cancer.
Applied Spectroscopy, 1990
Applied Spectroscopy, 2000
One hundred and four edible oil and fat samples from 18 different sources, either vegetable (Braz... more One hundred and four edible oil and fat samples from 18 different sources, either vegetable (Brazil nut, coconut, corn, sun ower, wal-nut, virgin olive, peanut, palm, canola, soybean, sun ower) or ani-mal (tallow and hydrogenated sh), have been analyzed by high- ...