Romdhane Karoui - Academia.edu (original) (raw)

Papers by Romdhane Karoui

Critical Reviews in Food Science and Nutrition, 2015

Although being one of the most vulnerable and perishable products, fish and other seafoods provid... more Although being one of the most vulnerable and perishable products, fish and other seafoods provide a wide range of health-promoting compounds. Recently, the growing interest of consumers in food quality and safety issues has contributed to the increasing demand for sensitive and rapid analytical technologies. Several traditional physicochemical, textural, sensory, and electrical methods have been used to evaluate freshness and authentication of fish and other seafood products. Despite the importance of these standard methods, they are expensive and time-consuming, and often susceptible to large sources of variation. Recently, spectroscopic methods and other emerging techniques have shown great potential due to speed of analysis, minimal sample preparation, high repeatability, low cost, and, most of all, the fact that these techniques are noninvasive and nondestructive and, therefore, could be applied to any on-line monitoring system. This review describes firstly and briefly the basic principles of multivariate data analysis, followed by the most commonly traditional methods used for the determination of the freshness and authenticity of fish and other seafood products. A special focus is put on the use of rapid and nondestructive techniques (spectroscopic techniques and instrumental sensors) to address several issues related to the quality of these products. Moreover, the advantages and limitations of each technique is reviewed and some perspectives are also given.

Food and Bioprocess Technology, 2012

ABSTRACT The potential of spectroscopic (i.e. mid-infrared and front-face fluorescence) and physi... more ABSTRACT The potential of spectroscopic (i.e. mid-infrared and front-face fluorescence) and physicochemical methods combined with chemometric tools was investigated for discriminating Emmental cheeses produced in different regions of France. A total of 20 French Emmental cheeses belonging to different brand products were studied. When principal component analysis was applied separately to each used technique, the discrimination of cheeses was not satisfactory. Therefore, common components and specific weight analysis was applied to the whole data sets: the second common component (q 2), discriminating cheeses of producer C from the others, expressed 78 and 23 % of the inertia of the vitamin A and tryptophan, respectively. On the contrary, the third common component (q 3), discriminating cheeses as a function of their ripening time and/or their manufacturing process procedure, expressed 15, 30, and 16 % of the inertia of the 3,000–2,800, 1,700–1,500 and 1,500–900 cm−1 spectral region. The infrared and fluorescence spectral patterns allowed molecular interpretation and identification of Emmental cheeses according to their both manufacturing process and brand products.

Food and Bioprocess Technology, 2015

ABSTRACT This paper presents a study on sponge cakes produced at the pilot scale and monitored du... more ABSTRACT This paper presents a study on sponge cakes produced at the pilot scale and monitored during ageing (i.e. 1, 3, 6, 9, 16 and 20 day(s)) by different analytical techniques: nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Results from NMR showed that the spin–lattice relaxation time (T 1), measured on the crumb part, decreased from day 1 to day 16 while the spin–spin relaxation time (T 2) increased throughout the whole storage time (i.e. 1 to 20 day(s)). Based on the analysis of the state of water, TGA allowed to establishing a kinetic profile of retrogradation degree of starch contained in sponge cakes. This approach evidenced that the evolution of the sponge cakes freshness and staling closely depends on the dynamic of the water in the crumb during ageing. These results were supported by DSC thermograms exhibiting a variation of three main endotherms detected in sponge cakes at −15, +5 and +45 °C throughout ageing. The enthalpy changes of these endotherms reflected the evolution of chemical and physical reactions occurring in the sponge cakes during storage. The analysis of the endotherm enthalpy change at 45 °C allowed to determine the time τ (i.e. τ ≈ 9 days) corresponding to the apparition of amylopectin crystallites that could be considered as a reference time to separate fresh sponge cakes from the aged ones.

Soil Biology, 2009

Soils vary with depth due to their variable physical and chemical properties, topography, slope a... more Soils vary with depth due to their variable physical and chemical properties, topography, slope and origin. The ability to classify soil samples into three different depths (0–30, 30–60 and 60–90 cm) was investigated using visible (Vis) and near infrared (NIR) spectra. A fibre-type, Vis–NIR spectrophotometer from Zeiss (Zeiss Corona 1.7 visnir fibre, Germany) (306.5–1,710.9 nm) was used to measure light

Food and Bioprocess Technology, 2007

The objective of this study was to assess the potential of front-face fluorescence spectroscopy f... more The objective of this study was to assess the potential of front-face fluorescence spectroscopy for differentiating between two genotypes (Comisana and Sicilo–Sarde) of ewe’s milk collected during lactation period. Physico-chemical analyses and fluorescence spectra were performed on milk samples during the first 15 weeks of lactation period. Regarding fluorescence spectra, aromatic amino acids and nucleic acids (AAA+NA), tryptophan, and vitamin A

Food and Bioprocess Technology, 2008

ABSTRACT

Food and Bioprocess Technology, 2010

The present review gives an overview of the use of fluorescence spectroscopy (i.e., conventional,... more The present review gives an overview of the use of fluorescence spectroscopy (i.e., conventional, excitation–emission matrix, and synchronous fluorescence) for determining changes in food products and their quality during technological process and storage. From the present review, it was shown that fluorescence spectroscopy is able to determine several properties (functional, composition, nutritional) without the use of chemical reagents. This is

Food and Bioprocess Technology, 2010

... Sucrose was dissolved in date juice (total soluble solid varied between 19.03 and 24.70 °Brix... more ... Sucrose was dissolved in date juice (total soluble solid varied between 19.03 and 24.70 °Brix) in order to obtain a 55 °Brix solution at 25 °C. It ... Carbohydrate content was estimated by the difference of mean values, 100 − (Sum of percentages of moisture, ash, proteins and ...

Food and Bioprocess Technology, 2010

The drying of pomegranate seeds was investigated at 40°C, 50°C and 60°C with air velocity of 2 m/... more The drying of pomegranate seeds was investigated at 40°C, 50°C and 60°C with air velocity of 2 m/s. Prior to drying, seeds were osmodehydrated in 55°Brix sucrose solution for 20 min at 50°C. The drying kinetics and the effects of osmotic dehydration (OD) and air-drying temperature on antioxidant capacity, total phenolics, colour and texture were determined. Analysis of variance revealed that OD and air-drying temperature have a significant influence on the quality of seeds. Both anthocyanin and total phenolic contents decreased when air-drying temperature increased. The radical diphenylpicril-hydrazyl activity showed the lowest antioxidant activity at 60°C. Both chromatic parameters (L*, C* and h°) and browning index were affected by drying temperatures, which contributed to the discolouring of seeds. The final product has 22%, 20% and 16% of moisture; 0.630, 0.478 and 0.414 of a w ; 151, 141 and 134 mg gallic acid equivalent/100 g fresh matter (FM) of total phenolics; 40, 24, 20 mg/100 g FM of anthocyanins and 46%, 39% and 31% of antioxidant activity, for drying temperatures of 40°C, 50°C and 60°C, respectively. In view of these results, the temperature of 40°C is recommended as it has the lowest impact on the quality parameters of the seeds. Differential scanning calorimetry data provided complementary information on the mobility changes of water during drying. Glass transition temperature (Tg′) depends on moisture content and as consequence, on drying conditions. In fact, Tg′ of seeds dried at 60°C (Tg′=−21°C) was higher than those dried at 50°C (Tg′=−28°C) or 40°C (Tg′=−31°C) and osmodehydrated seeds (Tg′=−34°C). During OD and drying process, the texture of seeds changed. The thickness of seeds shrank by 55% at 60°C.

Sensing and Instrumentation for Food Quality and Safety, 2007

As a part of the project for detecting bruises on Golden Delicious apple using vision system, the... more As a part of the project for detecting bruises on Golden Delicious apple using vision system, the present paper shows a method that could separate the stem-end/calyx regions from the true bruises by combining the information of hyperspectral reflectance and fluorescence images. The images were scanned between 400 nm and 1,000 nm with a hyperspectral imaging system. Different light sources were constructed

Journal of Microbiological Methods, 2004

Thirty Pseudomonas spp. strains isolated from milk, water, cheese centre and cheese surface in tw... more Thirty Pseudomonas spp. strains isolated from milk, water, cheese centre and cheese surface in two traditional workshops manufacturing raw milk St. Nectaire cheese were characterised by fluorescence spectroscopy and Biolog metabolic profiling. Factorial discriminant analysis (FDA) of the two data sets revealed clear linkages between groups of isolates. In the first workshop, milk could be incriminated as the sole source of cheese contamination. In the second one, milk and cheese centre isolates were found similar but surface cheese contaminants could be linked to a secondary contamination originating from water. Thus, it is possible to characterise, differentiate and trace Pseudomonas spp. strains using the fluorescence and metabolic profiling techniques. In addition, the two data sets were found highly correlated by canonical correlation analysis (CCA). Fluorescence spectroscopy however showed several advantages because of its low cost and processing speed.

Journal of Agricultural and Food Chemistry, 2006

The potential of intrinsic fluorescence spectroscopy was investigated for differentiating between... more The potential of intrinsic fluorescence spectroscopy was investigated for differentiating between processed grains (flours, pasta, and semolinas) of different wheat cereal products. A total of 59 samples (e.g., 20 complete Kamut, semicomplete Kamut, and soft wheat flours, 28 pasta, and 11 semolinas manufactured from complete Kamut, semicomplete Kamut, and hard wheat flours) were analyzed by front-face fluorescence spectroscopy. Tryptophan fluorescence spectra were scanned between 305 and 400 nm on samples following excitation at 290 nm. The principal component analysis (PCA) performed on flour spectra clearly differentiated complete Kamut and semicomplete Kamut samples from those produced from complete and semicomplete soft wheat flours. The PCA performed on pasta spectra discriminated samples manufactured from complete Kamut and complete hard wheat flours from those made with semicomplete Kamut and semicomplete hard wheat flours. The best discrimination was obtained from tryptophan spectra recorded on semolinas since the four groups were well discriminated. Correct classification amounting to 61.9% was obtained for pasta spectra. A better classification was obtained for flour and semolina spectra since correct classification amounted to 86.7% and 87.9%, respectively. Front-face fluorescence spectroscopy has the potential to be a rapid, low-cost, and efficient method for the authentication of cereal products.

Journal of Agricultural and Food Chemistry, 2013

In the present study, sponge cakes, produced at the pilot scale, were monitored during aging (i.e... more In the present study, sponge cakes, produced at the pilot scale, were monitored during aging (i.e., 1, 3, 6, 9, 16, and 20 days) by three different analytical techniques. For the texture analyzer, the hardness and elasticity of crumb cakes were found to significantly increase and decrease, respectively, throughout aging. Color parameters (L*, a*, and b*) showed only slight change throughout aging, and a high correlation (R(2) = 0.88) was observed between the whiteness and the yellowness. Tryptophan fluorescence spectra (excitation, 290 nm; emission, 305-490 nm) recorded on cakes exhibited three maxima located at 382, 435, and 467 nm that were attributed to maximum emission of tryptophan (382 nm) and fluorescent Maillard reaction products (435 and 467 nm). The principal component analysis (PCA) applied to the tryptophan spectra allowed a clear discrimination of cakes aged for 1, 3, and 6 days from those aged for 9, 16, and 20 days. Finally, canonical correlation analysis (CCA) performed on the textural and tryptophan fluorescence spectral data sets showed that the two groups of variables were highly correlated because the squared canonical coefficients for canonical variates were 0.99, indicating that cake texture determined at the macroscopic level by texture analyzer is a reflection of its structure at the molecular level determined by fluorescence spectroscopy.

Journal of Agricultural and Food Chemistry, 2005

The potential of front-face fluorescence spectroscopy for the authentication of unifloral and pol... more The potential of front-face fluorescence spectroscopy for the authentication of unifloral and polyfloral honey types (n ) 57 samples) previously classified using traditional methods such as chemical, pollen, and sensory analysis was evaluated. Emission spectra were recorded between 280 and 480 nm (excit: 250 nm), 305 and 500 nm (excit: 290 nm), and 380 and 600 nm (excit: 373 nm) directly on honey samples. In addition, excitation spectra (290-440 nm) were recorded with the emission measured at 450 nm. A total of four different spectral data sets were considered for data analysis. After normalization of the spectra, chemometric evaluation of the spectral data was carried out using principal component analysis (PCA) and linear discriminant analysis (LDA). The rate of correct classification ranged from 36% to 100% by using single spectral data sets (250, 290, 373, 450 nm) and from 73% to 100% by combining these four data sets. For alpine polyfloral honey and the unifloral varieties investigated (acacia, alpine rose, honeydew, chestnut, and rape), correct classification ranged from 96% to 100%. This preliminary study indicates that front-face fluorescence spectroscopy is a promising technique for the authentication of the botanical origin of honey. It is nondestructive, rapid, easy to use, and inexpensive. The use of additional excitation wavelengths between 320 and 440 nm could increase the correct classification of the less characteristic fluorescent varieties.

International Journal of Food Science & Technology, 2007

Frozen fish usually have a much lower market price than fresh fish, hence, adulteration could occ... more Frozen fish usually have a much lower market price than fresh fish, hence, adulteration could occur. This paper focuses on the use of mid-infrared (MIR) spectroscopy combined with chemometric tools to determine whether fish has been frozen-thawed. A total of twenty-four fish samples (fresh fish (n ¼ 12) and frozenthawed fish (n ¼ 12)) were investigated. The principal component analysis and the factorial discriminant analysis were applied to the three spectral regions in the MIR of 3000-2800 cm )1 , 1700-1500 cm )1 and 1500-900 cm )1 . Within the 1500-900 cm )1 spectral region, correct classification (CC) of 100% and 75% was observed for the calibration and validation spectra, respectively. Improved classification was obtained from the 3000-2800 cm )1 spectral region, with CC of 100% and 87.5% of the calibration and validation spectra, respectively. It can be concluded that the 3000-2800 cm )1 and 1500-900 cm )1 spectral regions may provide useful fingerprints allowing the differentiation between fresh and frozen-thawed fish. These regions can be considered as a reliable indicator of fish freshness.

International Journal of Food Properties, 2007

ABSTRACT

International Journal of Food Properties, 2014

ABSTRACT The present study was aimed to investigate the potential of multispectral images coupled... more ABSTRACT The present study was aimed to investigate the potential of multispectral images coupled with chemometric tools (PLSDA and PLS-R) for: (1.) discriminating different French blue veined cheeses belonging to four brand products (Fourme d’Ambert, Fourme de Montbrison, Bleu d’Auvergne, and Bleu des Causses) and (2.) predicting some of physicochemical (pH, ash, dry matter, total nitrogen, water soluble nitrogen, Ca2+, Na+, Cl−, and P) and rheological properties (softening and dropping points). The results obtained showed that multispectral imaging system applied to anisotropic blue cheeses succeeded to: (1.) discriminate cheeses based on their blue veins features in spite of the visual similarity of their structure and appearance with percentage of correct classification varying between 30 and 100%; and (2.) predict selected parameters (i.e., Ca2+, Cl−, WSN, dropping, and softening points) since R 2cv ≥ 0.62 and RPD ≥ 1.62 were obtained. Moreover, the predictive results suggested that the image texture of cheese was strongly related to its physicochemical composition and rheological characteristics (softening and dropping points).

International Dairy Journal, 2005

The potential of mid-infrared and intrinsic fluorescence spectroscopies was investigated for dete... more The potential of mid-infrared and intrinsic fluorescence spectroscopies was investigated for determining the geographic origin of different hard cheeses. Mid-infrared (1700–1500cm−1 region), fluorescence emission spectra, following excitation at 250 and 290nm, and fluorescence excitation spectra following emission at 410nm were recorded directly on cheese samples. Twelve experimental hard cheeses were made using identical and controlled cheese-making conditions with milks originating

International Dairy Journal, 2003

... this technique is to predict membership of an individual cheese sample to a qualitative group... more ... this technique is to predict membership of an individual cheese sample to a qualitative group ([Robert, Devaux, & Bertrand (1996 ... that tan δ increased with increased levels of moisture and proteolysis, in agreement with previous findings ([Messens, De Walle, Arevalo, Dewettinck ...

Critical Reviews in Food Science and Nutrition, 2015

Although being one of the most vulnerable and perishable products, fish and other seafoods provid... more Although being one of the most vulnerable and perishable products, fish and other seafoods provide a wide range of health-promoting compounds. Recently, the growing interest of consumers in food quality and safety issues has contributed to the increasing demand for sensitive and rapid analytical technologies. Several traditional physicochemical, textural, sensory, and electrical methods have been used to evaluate freshness and authentication of fish and other seafood products. Despite the importance of these standard methods, they are expensive and time-consuming, and often susceptible to large sources of variation. Recently, spectroscopic methods and other emerging techniques have shown great potential due to speed of analysis, minimal sample preparation, high repeatability, low cost, and, most of all, the fact that these techniques are noninvasive and nondestructive and, therefore, could be applied to any on-line monitoring system. This review describes firstly and briefly the basic principles of multivariate data analysis, followed by the most commonly traditional methods used for the determination of the freshness and authenticity of fish and other seafood products. A special focus is put on the use of rapid and nondestructive techniques (spectroscopic techniques and instrumental sensors) to address several issues related to the quality of these products. Moreover, the advantages and limitations of each technique is reviewed and some perspectives are also given.

Food and Bioprocess Technology, 2012

ABSTRACT The potential of spectroscopic (i.e. mid-infrared and front-face fluorescence) and physi... more ABSTRACT The potential of spectroscopic (i.e. mid-infrared and front-face fluorescence) and physicochemical methods combined with chemometric tools was investigated for discriminating Emmental cheeses produced in different regions of France. A total of 20 French Emmental cheeses belonging to different brand products were studied. When principal component analysis was applied separately to each used technique, the discrimination of cheeses was not satisfactory. Therefore, common components and specific weight analysis was applied to the whole data sets: the second common component (q 2), discriminating cheeses of producer C from the others, expressed 78 and 23 % of the inertia of the vitamin A and tryptophan, respectively. On the contrary, the third common component (q 3), discriminating cheeses as a function of their ripening time and/or their manufacturing process procedure, expressed 15, 30, and 16 % of the inertia of the 3,000–2,800, 1,700–1,500 and 1,500–900 cm−1 spectral region. The infrared and fluorescence spectral patterns allowed molecular interpretation and identification of Emmental cheeses according to their both manufacturing process and brand products.

Food and Bioprocess Technology, 2015

ABSTRACT This paper presents a study on sponge cakes produced at the pilot scale and monitored du... more ABSTRACT This paper presents a study on sponge cakes produced at the pilot scale and monitored during ageing (i.e. 1, 3, 6, 9, 16 and 20 day(s)) by different analytical techniques: nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Results from NMR showed that the spin–lattice relaxation time (T 1), measured on the crumb part, decreased from day 1 to day 16 while the spin–spin relaxation time (T 2) increased throughout the whole storage time (i.e. 1 to 20 day(s)). Based on the analysis of the state of water, TGA allowed to establishing a kinetic profile of retrogradation degree of starch contained in sponge cakes. This approach evidenced that the evolution of the sponge cakes freshness and staling closely depends on the dynamic of the water in the crumb during ageing. These results were supported by DSC thermograms exhibiting a variation of three main endotherms detected in sponge cakes at −15, +5 and +45 °C throughout ageing. The enthalpy changes of these endotherms reflected the evolution of chemical and physical reactions occurring in the sponge cakes during storage. The analysis of the endotherm enthalpy change at 45 °C allowed to determine the time τ (i.e. τ ≈ 9 days) corresponding to the apparition of amylopectin crystallites that could be considered as a reference time to separate fresh sponge cakes from the aged ones.

Soil Biology, 2009

Soils vary with depth due to their variable physical and chemical properties, topography, slope a... more Soils vary with depth due to their variable physical and chemical properties, topography, slope and origin. The ability to classify soil samples into three different depths (0–30, 30–60 and 60–90 cm) was investigated using visible (Vis) and near infrared (NIR) spectra. A fibre-type, Vis–NIR spectrophotometer from Zeiss (Zeiss Corona 1.7 visnir fibre, Germany) (306.5–1,710.9 nm) was used to measure light

Food and Bioprocess Technology, 2007

The objective of this study was to assess the potential of front-face fluorescence spectroscopy f... more The objective of this study was to assess the potential of front-face fluorescence spectroscopy for differentiating between two genotypes (Comisana and Sicilo–Sarde) of ewe’s milk collected during lactation period. Physico-chemical analyses and fluorescence spectra were performed on milk samples during the first 15 weeks of lactation period. Regarding fluorescence spectra, aromatic amino acids and nucleic acids (AAA+NA), tryptophan, and vitamin A

Food and Bioprocess Technology, 2008

ABSTRACT

Food and Bioprocess Technology, 2010

The present review gives an overview of the use of fluorescence spectroscopy (i.e., conventional,... more The present review gives an overview of the use of fluorescence spectroscopy (i.e., conventional, excitation–emission matrix, and synchronous fluorescence) for determining changes in food products and their quality during technological process and storage. From the present review, it was shown that fluorescence spectroscopy is able to determine several properties (functional, composition, nutritional) without the use of chemical reagents. This is

Food and Bioprocess Technology, 2010

... Sucrose was dissolved in date juice (total soluble solid varied between 19.03 and 24.70 °Brix... more ... Sucrose was dissolved in date juice (total soluble solid varied between 19.03 and 24.70 °Brix) in order to obtain a 55 °Brix solution at 25 °C. It ... Carbohydrate content was estimated by the difference of mean values, 100 − (Sum of percentages of moisture, ash, proteins and ...

Food and Bioprocess Technology, 2010

The drying of pomegranate seeds was investigated at 40°C, 50°C and 60°C with air velocity of 2 m/... more The drying of pomegranate seeds was investigated at 40°C, 50°C and 60°C with air velocity of 2 m/s. Prior to drying, seeds were osmodehydrated in 55°Brix sucrose solution for 20 min at 50°C. The drying kinetics and the effects of osmotic dehydration (OD) and air-drying temperature on antioxidant capacity, total phenolics, colour and texture were determined. Analysis of variance revealed that OD and air-drying temperature have a significant influence on the quality of seeds. Both anthocyanin and total phenolic contents decreased when air-drying temperature increased. The radical diphenylpicril-hydrazyl activity showed the lowest antioxidant activity at 60°C. Both chromatic parameters (L*, C* and h°) and browning index were affected by drying temperatures, which contributed to the discolouring of seeds. The final product has 22%, 20% and 16% of moisture; 0.630, 0.478 and 0.414 of a w ; 151, 141 and 134 mg gallic acid equivalent/100 g fresh matter (FM) of total phenolics; 40, 24, 20 mg/100 g FM of anthocyanins and 46%, 39% and 31% of antioxidant activity, for drying temperatures of 40°C, 50°C and 60°C, respectively. In view of these results, the temperature of 40°C is recommended as it has the lowest impact on the quality parameters of the seeds. Differential scanning calorimetry data provided complementary information on the mobility changes of water during drying. Glass transition temperature (Tg′) depends on moisture content and as consequence, on drying conditions. In fact, Tg′ of seeds dried at 60°C (Tg′=−21°C) was higher than those dried at 50°C (Tg′=−28°C) or 40°C (Tg′=−31°C) and osmodehydrated seeds (Tg′=−34°C). During OD and drying process, the texture of seeds changed. The thickness of seeds shrank by 55% at 60°C.

Sensing and Instrumentation for Food Quality and Safety, 2007

As a part of the project for detecting bruises on Golden Delicious apple using vision system, the... more As a part of the project for detecting bruises on Golden Delicious apple using vision system, the present paper shows a method that could separate the stem-end/calyx regions from the true bruises by combining the information of hyperspectral reflectance and fluorescence images. The images were scanned between 400 nm and 1,000 nm with a hyperspectral imaging system. Different light sources were constructed

Journal of Microbiological Methods, 2004

Thirty Pseudomonas spp. strains isolated from milk, water, cheese centre and cheese surface in tw... more Thirty Pseudomonas spp. strains isolated from milk, water, cheese centre and cheese surface in two traditional workshops manufacturing raw milk St. Nectaire cheese were characterised by fluorescence spectroscopy and Biolog metabolic profiling. Factorial discriminant analysis (FDA) of the two data sets revealed clear linkages between groups of isolates. In the first workshop, milk could be incriminated as the sole source of cheese contamination. In the second one, milk and cheese centre isolates were found similar but surface cheese contaminants could be linked to a secondary contamination originating from water. Thus, it is possible to characterise, differentiate and trace Pseudomonas spp. strains using the fluorescence and metabolic profiling techniques. In addition, the two data sets were found highly correlated by canonical correlation analysis (CCA). Fluorescence spectroscopy however showed several advantages because of its low cost and processing speed.

Journal of Agricultural and Food Chemistry, 2006

The potential of intrinsic fluorescence spectroscopy was investigated for differentiating between... more The potential of intrinsic fluorescence spectroscopy was investigated for differentiating between processed grains (flours, pasta, and semolinas) of different wheat cereal products. A total of 59 samples (e.g., 20 complete Kamut, semicomplete Kamut, and soft wheat flours, 28 pasta, and 11 semolinas manufactured from complete Kamut, semicomplete Kamut, and hard wheat flours) were analyzed by front-face fluorescence spectroscopy. Tryptophan fluorescence spectra were scanned between 305 and 400 nm on samples following excitation at 290 nm. The principal component analysis (PCA) performed on flour spectra clearly differentiated complete Kamut and semicomplete Kamut samples from those produced from complete and semicomplete soft wheat flours. The PCA performed on pasta spectra discriminated samples manufactured from complete Kamut and complete hard wheat flours from those made with semicomplete Kamut and semicomplete hard wheat flours. The best discrimination was obtained from tryptophan spectra recorded on semolinas since the four groups were well discriminated. Correct classification amounting to 61.9% was obtained for pasta spectra. A better classification was obtained for flour and semolina spectra since correct classification amounted to 86.7% and 87.9%, respectively. Front-face fluorescence spectroscopy has the potential to be a rapid, low-cost, and efficient method for the authentication of cereal products.

Journal of Agricultural and Food Chemistry, 2013

In the present study, sponge cakes, produced at the pilot scale, were monitored during aging (i.e... more In the present study, sponge cakes, produced at the pilot scale, were monitored during aging (i.e., 1, 3, 6, 9, 16, and 20 days) by three different analytical techniques. For the texture analyzer, the hardness and elasticity of crumb cakes were found to significantly increase and decrease, respectively, throughout aging. Color parameters (L*, a*, and b*) showed only slight change throughout aging, and a high correlation (R(2) = 0.88) was observed between the whiteness and the yellowness. Tryptophan fluorescence spectra (excitation, 290 nm; emission, 305-490 nm) recorded on cakes exhibited three maxima located at 382, 435, and 467 nm that were attributed to maximum emission of tryptophan (382 nm) and fluorescent Maillard reaction products (435 and 467 nm). The principal component analysis (PCA) applied to the tryptophan spectra allowed a clear discrimination of cakes aged for 1, 3, and 6 days from those aged for 9, 16, and 20 days. Finally, canonical correlation analysis (CCA) performed on the textural and tryptophan fluorescence spectral data sets showed that the two groups of variables were highly correlated because the squared canonical coefficients for canonical variates were 0.99, indicating that cake texture determined at the macroscopic level by texture analyzer is a reflection of its structure at the molecular level determined by fluorescence spectroscopy.

Journal of Agricultural and Food Chemistry, 2005

The potential of front-face fluorescence spectroscopy for the authentication of unifloral and pol... more The potential of front-face fluorescence spectroscopy for the authentication of unifloral and polyfloral honey types (n ) 57 samples) previously classified using traditional methods such as chemical, pollen, and sensory analysis was evaluated. Emission spectra were recorded between 280 and 480 nm (excit: 250 nm), 305 and 500 nm (excit: 290 nm), and 380 and 600 nm (excit: 373 nm) directly on honey samples. In addition, excitation spectra (290-440 nm) were recorded with the emission measured at 450 nm. A total of four different spectral data sets were considered for data analysis. After normalization of the spectra, chemometric evaluation of the spectral data was carried out using principal component analysis (PCA) and linear discriminant analysis (LDA). The rate of correct classification ranged from 36% to 100% by using single spectral data sets (250, 290, 373, 450 nm) and from 73% to 100% by combining these four data sets. For alpine polyfloral honey and the unifloral varieties investigated (acacia, alpine rose, honeydew, chestnut, and rape), correct classification ranged from 96% to 100%. This preliminary study indicates that front-face fluorescence spectroscopy is a promising technique for the authentication of the botanical origin of honey. It is nondestructive, rapid, easy to use, and inexpensive. The use of additional excitation wavelengths between 320 and 440 nm could increase the correct classification of the less characteristic fluorescent varieties.

International Journal of Food Science & Technology, 2007

Frozen fish usually have a much lower market price than fresh fish, hence, adulteration could occ... more Frozen fish usually have a much lower market price than fresh fish, hence, adulteration could occur. This paper focuses on the use of mid-infrared (MIR) spectroscopy combined with chemometric tools to determine whether fish has been frozen-thawed. A total of twenty-four fish samples (fresh fish (n ¼ 12) and frozenthawed fish (n ¼ 12)) were investigated. The principal component analysis and the factorial discriminant analysis were applied to the three spectral regions in the MIR of 3000-2800 cm )1 , 1700-1500 cm )1 and 1500-900 cm )1 . Within the 1500-900 cm )1 spectral region, correct classification (CC) of 100% and 75% was observed for the calibration and validation spectra, respectively. Improved classification was obtained from the 3000-2800 cm )1 spectral region, with CC of 100% and 87.5% of the calibration and validation spectra, respectively. It can be concluded that the 3000-2800 cm )1 and 1500-900 cm )1 spectral regions may provide useful fingerprints allowing the differentiation between fresh and frozen-thawed fish. These regions can be considered as a reliable indicator of fish freshness.

International Journal of Food Properties, 2007

ABSTRACT

International Journal of Food Properties, 2014

ABSTRACT The present study was aimed to investigate the potential of multispectral images coupled... more ABSTRACT The present study was aimed to investigate the potential of multispectral images coupled with chemometric tools (PLSDA and PLS-R) for: (1.) discriminating different French blue veined cheeses belonging to four brand products (Fourme d’Ambert, Fourme de Montbrison, Bleu d’Auvergne, and Bleu des Causses) and (2.) predicting some of physicochemical (pH, ash, dry matter, total nitrogen, water soluble nitrogen, Ca2+, Na+, Cl−, and P) and rheological properties (softening and dropping points). The results obtained showed that multispectral imaging system applied to anisotropic blue cheeses succeeded to: (1.) discriminate cheeses based on their blue veins features in spite of the visual similarity of their structure and appearance with percentage of correct classification varying between 30 and 100%; and (2.) predict selected parameters (i.e., Ca2+, Cl−, WSN, dropping, and softening points) since R 2cv ≥ 0.62 and RPD ≥ 1.62 were obtained. Moreover, the predictive results suggested that the image texture of cheese was strongly related to its physicochemical composition and rheological characteristics (softening and dropping points).

International Dairy Journal, 2005

The potential of mid-infrared and intrinsic fluorescence spectroscopies was investigated for dete... more The potential of mid-infrared and intrinsic fluorescence spectroscopies was investigated for determining the geographic origin of different hard cheeses. Mid-infrared (1700–1500cm−1 region), fluorescence emission spectra, following excitation at 250 and 290nm, and fluorescence excitation spectra following emission at 410nm were recorded directly on cheese samples. Twelve experimental hard cheeses were made using identical and controlled cheese-making conditions with milks originating

International Dairy Journal, 2003

... this technique is to predict membership of an individual cheese sample to a qualitative group... more ... this technique is to predict membership of an individual cheese sample to a qualitative group ([Robert, Devaux, & Bertrand (1996 ... that tan δ increased with increased levels of moisture and proteolysis, in agreement with previous findings ([Messens, De Walle, Arevalo, Dewettinck ...