Joel Scher - Academia.edu (original) (raw)

Papers by Joel Scher

Drying Technology

ABSTRACT

Powder Technology, 2002

A good knowledge of powder flow properties is necessary to consider industrial application of a s... more A good knowledge of powder flow properties is necessary to consider industrial application of a system. Flowability is a complex combination of different parameters like size, shape or surface properties of particles. The goal of this study is to compare the impact of two drying techniques (freeze-drying and spray drying) on powder flowability in order to choose the most appropriate device. Powder is first studied at the particle level with size measurements and shape description. Then, the global behaviour is characterised by water content, water up-take and physicochemical analysis. Finally, the influences of two additives and of coating on powder flow properties have been investigated. The two powders obtained by spray and freeze-drying vary principally by the shape of the particles. Residual water content, moisturising capacity and surface properties are similar. In both cases, powder flowability is bad. Results obtained with the two additives show no improvement of powder flow properties. However, coating reduces the number of fine particles and, as a consequence, improves powder flowability with furthering particle motion. D

International Journal of Food Engineering

In this study, starches were extracted from two cultivars of local Irish potatos (Solanum tuberos... more In this study, starches were extracted from two cultivars of local Irish potatos (Solanum tuberosum,) and tree cultivars of local Cassava (Manihot esculanta). These starches and a commercial Irish potato starch (IPS), where characterized with respect to their physico-chemical and functional properties. Significant differences (P<0.05) were observed among starches as far as their proximate composition were concerned. The commercial starch showed the highest phosphorus content. The amylose content was observed to be significantly lower (P<0.05) in the cassava starches than in the local Irish potato starches. The highest (P<0.05) gelatinisation parameters were those of 2425 starch cultivar. Potato starch granules exhibited the largest granule size at 10, 50 and 90% diameter compared to those of cassava starches. Potato starches had wider particle size distribution compared to cassava starches. There were apparent differences, between species (Cassava and potatoes) with respect...

African Journal of Food, Agriculture, Nutrition and Development, 2005

Colloids and Surfaces B: Biointerfaces, 2015

Probiotic bacteria are routinely incorporated into dairy foods because of the health benefits the... more Probiotic bacteria are routinely incorporated into dairy foods because of the health benefits they can provide when consumed. In this work, the marked pH-dependence of the pili/EPS organization at the outer surface of Lactobacillus rhamnosus GG is characterized in detail by Single Cell Force Microscopy and cell electrophoretic mobility measurements analyzed according to formalisms for nanomechanical contact and soft particle electrokinetics, respectively. At pH 6.8, LGG pili are easily accessible by AFM tips functionalized with whey proteins for specific binding, while at pH 4.8 the collapsed EPS surface layer significantly immobilized the LGG pili. This resulted in their reduced accessibility to the specific whey-coated AFM tip, and to stronger whey protein-pili rupture forces. Thus, pili interactions with whey proteins are screened to an extent that depends on the pH-mediated embedment of the pili within the EPS layer.

Journal of Food Measurement and Characterization, 2015

ABSTRACT

The objective of this study was to evaluate the effects of tubers maturity stage on the physicoch... more The objective of this study was to evaluate the effects of tubers maturity stage on the physicochemical characteristics and thermal properties of Colocasia esculenta (Sosso ecotype) starches. Plantation was done in Chad, tropical area from May to February following a randomized design with 5 maturity stages (6, 7, 8, 9 and 10 months after planting) as the main treatments. The results showed significant increase in phosphorus content (from 113.99 to 145.64µg/100g), temperature (from 80.69 to 84.54°C) and enthalpy of gelatinization (from 13.24 to 16.27 J/g), water absorption capacity (from 140.11 to 304.48 %), solubility index (from 17.50 to 29.42%) and swelling index (from 115 to 135%). In addition the monomolecular moisture content (varying from 2.67 to 3.36 %) and the GAB constant C (varying from 11.73 to 113.22) exhibited significant increase with maturity. Furthermore, a significant decrease in amylose content (from 35.90 to 27.65%) was observed as the maturity increases. In conclusion and on the basis of the correlation observed, the changes in phosphorus and amylose composition of starch during growth seemed to play a role not only on the molecular structure of the starch granules, but also on its functionality.

Journal of Food Science and Technology, 2014

This e-offprint is for personal use only and shall not be self-archived in electronic repositorie... more This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

Colloids and surfaces. B, Biointerfaces, 2015

The surface composition of dairy powders prepared by mixing various amounts of micellar casein (M... more The surface composition of dairy powders prepared by mixing various amounts of micellar casein (MC), whey proteins isolate (WPI), lactose, and anhydrous milk fat (AMF) was investigated by XPS measurements. The use of matrices are generally accepted to transform surface atomic composition (i.e., C, O, N contents) into surface component composition (i.e., lactose, proteins, lipids). These atomic-based matrices were revisited and two new matrices based on the surface bond composition were developed. Surface compositions obtained from atomic and bond-based matrices were compared. A successful matrix allowing good correlations between XPS predicted and theoretical surface composition for powders free from fat was identified. Nevertheless, samples containing milk fat were found to present a possible segregation of components owing to the AMF overrepresentation on the surface. Supplementary analyses (FTIR, SEM) were carried out in order to investigate the homogeneity of the mixtures.

Advances in colloid and interface science, 2014

This review gives an overview of the importance of interactions occurring in dairy matrices betwe... more This review gives an overview of the importance of interactions occurring in dairy matrices between Lactic Acid Bacteria and milk components. Dairy products are important sources of biological active compounds of particular relevance to human health. These compounds include immunoglobulins, whey proteins and peptides, polar lipids, and lactic acid bacteria including probiotics. A better understanding of interactions between bioactive components and their delivery matrix may successfully improve their transport to their target site of action. Pioneering research on probiotic lactic acid bacteria has mainly focused on their host effects. However, very little is known about their interaction with dairy ingredients. Such knowledge could contribute to designing new and more efficient dairy food, and to better understand relationships between milk constituents. The purpose of this review is first to provide an overview of the current knowledge about the biomolecules produced on bacterial ...

Advances in food and nutrition research, 2013

Food powders are used in everyday life in many ways and offer technological solutions to the prob... more Food powders are used in everyday life in many ways and offer technological solutions to the problem of food production. The natural origin of food powders, diversity in their chemical composition, variability of the raw materials, heterogeneity of the native structures, and physicochemical reactivity under hydrothermal stresses contribute to the complexity in their behavior. Food powder agglomeration has recently been considered according to a multiscale approach, which is followed in the chapter layout: (i) at the particle scale, by a presentation of particle properties and surface reactivity in connection with the agglomeration mechanisms, (ii) at the mechanisms scale, by describing the structuration dynamics of agglomerates, (iii) at the process scale, by a presentation of agglomeration technologies and sensors and by studying the stress transmission mode in the powder bed, and finally (iv) by an integration of the acquired knowledge, thanks to a dimensional analysis carried out...

Journal of dairy science, 2007

A simplified method to study rehydration was used on different dairy powders. The method involved... more A simplified method to study rehydration was used on different dairy powders. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor. The changes of turbidity occurring during powder rehydration highlighted the rehydration stage, and the influence of the proteins' state on rehydration was clarified. Casein powders had a quick wetting time but very slow dispersion, making the total rehydration process time-consuming. On the other hand, whey powders were found to have poor wettability but demonstrated immediate dispersion after wetting. Mixing casein (80%) and whey (20%) before spray drying greatly improved rehydration time compared with casein powder; whereas mixing whey powder with casein powder at the same ratio after spray drying caused a dramatic deterioration in the rehydration properties. Moreover, agglomeration was found to significantly improve the rehydration time of whey protein powder and to slow down the rehydration time of casein p...

Journal of dairy science, 2005

A simplified method to study rehydration of dairy powders was developed for native phosphocaseina... more A simplified method to study rehydration of dairy powders was developed for native phosphocaseinate powder. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor under standardized conditions. The changes of turbidity occurring during powder rehydration highlighted several stages. These stages include particles wetting, and then swelling as the water penetrates into the powder bed, followed by a slow dispersion of the particles. With this tool, some technological effects on powder rehydration were analyzed. Ultrafiltrate incorporation to the casein concentrate before spray drying was found to greatly improve the rehydration, whereas mixing ultrafiltrate powder with casein powder after spray drying did not change the rehydration properties. The effect of granulation on powder rehydration stages was also investigated.

British Journal of Applied Science & Technology, 2015

Aims: This study was aimed at evaluating the effect of the method of processing on the antinutrie... more Aims: This study was aimed at evaluating the effect of the method of processing on the antinutrient content of flours made from Tacca leontopetaloides (Tacca) tubers. Study Design: Two experimental designs -the randomized block and the doehlert designs -were used in the study. Place and Duration of Study: The study was carried out in the Laboratoire d'ingenierie et Biomolecules of the University of Lorraine, France between September 2011 and May 2012. Methodology: Fresh tacca tubers were peeled, sliced and subjected to six different soaking and boiling conditions: unprocessed, 36 h soaking-4h boiling, 72h soaking, 4h boiling, 4h boiling-36 h soaking, 4h acid boiling, 4h alkaline boiling. Following the doehlert design, 9 treatments were obtained within the experimental domain of soaking (0 to 48h) and boiling time (3 to 5 h). The BJAST, 5(3): 258-269, 2015; Article no.BJAST.2015.025 259 slices were dried and ground into flours which were subsequently analyzed for their antinutrients content.

ABSTRACT Monitoring, understanding and improving rehydration of dairy powders

ABSTRACT The objective of this study was to examine the influence of high concentration of NaCI o... more ABSTRACT The objective of this study was to examine the influence of high concentration of NaCI on the secondary structure, hydrophobicity and opacity of Whey Protein Isolates (WPI) dispersions. Dispersions were studied at a constant protein concentration (5%) in high NaCl environments (from 0 to 6%). Protein dispersions were characterized as to their color and protein surface hydrophobicity. Additionally, changes in secondary structures upon salt increase were followed by Fourier Transform Infrared Spectroscopy (FTIR). The estimations of secondary structural elements from Amide III assignments were correlated to results obtained from Amide I. Upon salt increase, no differences in secondary structure were observed whereas the protein surface hydrophobicity related to the number of hydrophobic sites available decreased. Concurrently, color differences (ΔE) related to evolution of the protein dispersions containing variable NaCI concentration increased significantly.

Food and Bioprocess Technology, 2014

ABSTRACT The impact of thermal and chemical pretreatments on the physicochemical, rheological, an... more ABSTRACT The impact of thermal and chemical pretreatments on the physicochemical, rheological, and functional properties of sweet potato flour was investigated. The chemical pretreatment consisted in dipping peeled sweet potatoes in 1 % (w/v) calcium chloride (CaCl2), while the thermal pretreatment was achieved by blanching them in tap water at 90 °C for 1 min. Composition in flour moisture, protein, fat, non-reducing sugars, and starch was determined using standard methods. Particle size, color, gelatinization, and rheological properties were analyzed. The water absorption index (WAI) and water solubility index (WSI), as well as the swelling capacity (SC) and sorption isotherms, were determined. The reducing sugar content of sweet potato flour was slightly higher in CaCl2-pretreated (SSPCaCl2) samples than that in blanched (SSPB) and control (SSP) samples. However, the lightness of the SSPB sample was lower than that of the SSPCaCl2 and SSP samples. SSPCaCl2 sample had the higher value of enthalpy of gelatinization and elasticity modulus G′. The SC was higher in blanched samples. A slight increase in the constant of water binding energy (C BET) was observed after the CaCl2 treatment and a marked increase for the blanched sample. Owing to the differences induced by blanching and CaCl2 pretreatments, CaCl2-pretreated flour samples are more suitable for bread-making processes and can also be used in food formulations.

Cahiers de Nutrition et de Diététique, 2012

ABSTRACT Lactose maldigestion: Clinical presentation and treatment The lactose of dairy products ... more ABSTRACT Lactose maldigestion: Clinical presentation and treatment The lactose of dairy products is digested in the small intestine thanks to a membrane enzyme named lactase. For a large part of the world adult population, there is a decline in lactase activity and this leads to a partial malabsorption of the ingested lactose. In order to continue to consume dairy products and to avoid deficiency in calcium and vitamin D, several solutions can be considered. This is the case of yogurt that contains bacteria which have proven effective in lactose digestion. There are also processing aids that allow lactose hydrolysation or lactose remove from food products. Finally, dietary supplements can have a positive effect on lactose digestion if they are consumed at the same time of food products that contain lactose. All of these solutions are therefore intended to maintain the consumption of dairy products in people with lactose maldigestion.

Powder Technology, 2014

Powdered cocoa beverages are a class of instant foods that contain cocoa powder often mixed with ... more Powdered cocoa beverages are a class of instant foods that contain cocoa powder often mixed with high quantities of sugar. One of the desirable functional properties of these beverages is their aptitude to rehydration. Unfortunately, cocoa is a poorly dispersible powder and this is one of the reasons why sugar is added to the initial mix. The influence of sugar nature (sucrose or lactose), sugar size (30 or 480 μm) and sugar percentage (from 70 to 90%) on the rehydration properties at 20°C are investigated. Two techniques were tested and compared: classical static (Standards) and dynamic (Quicpic Analyser). It was concluded that the static method usually used for milk powder can correctly discriminate the influence of sugar nature and sugar percentage. The dynamic method was found to be an interesting complementary tool and allow a better sensibility than the static one. In addition, this dynamic method may be of interest to industrialists. Both, the possibility to obtain kinetics and "in situ" images of particles during rehydration are strongly interesting to interpret size changes.

Drying Technology

ABSTRACT

Powder Technology, 2002

A good knowledge of powder flow properties is necessary to consider industrial application of a s... more A good knowledge of powder flow properties is necessary to consider industrial application of a system. Flowability is a complex combination of different parameters like size, shape or surface properties of particles. The goal of this study is to compare the impact of two drying techniques (freeze-drying and spray drying) on powder flowability in order to choose the most appropriate device. Powder is first studied at the particle level with size measurements and shape description. Then, the global behaviour is characterised by water content, water up-take and physicochemical analysis. Finally, the influences of two additives and of coating on powder flow properties have been investigated. The two powders obtained by spray and freeze-drying vary principally by the shape of the particles. Residual water content, moisturising capacity and surface properties are similar. In both cases, powder flowability is bad. Results obtained with the two additives show no improvement of powder flow properties. However, coating reduces the number of fine particles and, as a consequence, improves powder flowability with furthering particle motion. D

International Journal of Food Engineering

In this study, starches were extracted from two cultivars of local Irish potatos (Solanum tuberos... more In this study, starches were extracted from two cultivars of local Irish potatos (Solanum tuberosum,) and tree cultivars of local Cassava (Manihot esculanta). These starches and a commercial Irish potato starch (IPS), where characterized with respect to their physico-chemical and functional properties. Significant differences (P<0.05) were observed among starches as far as their proximate composition were concerned. The commercial starch showed the highest phosphorus content. The amylose content was observed to be significantly lower (P<0.05) in the cassava starches than in the local Irish potato starches. The highest (P<0.05) gelatinisation parameters were those of 2425 starch cultivar. Potato starch granules exhibited the largest granule size at 10, 50 and 90% diameter compared to those of cassava starches. Potato starches had wider particle size distribution compared to cassava starches. There were apparent differences, between species (Cassava and potatoes) with respect...

African Journal of Food, Agriculture, Nutrition and Development, 2005

Colloids and Surfaces B: Biointerfaces, 2015

Probiotic bacteria are routinely incorporated into dairy foods because of the health benefits the... more Probiotic bacteria are routinely incorporated into dairy foods because of the health benefits they can provide when consumed. In this work, the marked pH-dependence of the pili/EPS organization at the outer surface of Lactobacillus rhamnosus GG is characterized in detail by Single Cell Force Microscopy and cell electrophoretic mobility measurements analyzed according to formalisms for nanomechanical contact and soft particle electrokinetics, respectively. At pH 6.8, LGG pili are easily accessible by AFM tips functionalized with whey proteins for specific binding, while at pH 4.8 the collapsed EPS surface layer significantly immobilized the LGG pili. This resulted in their reduced accessibility to the specific whey-coated AFM tip, and to stronger whey protein-pili rupture forces. Thus, pili interactions with whey proteins are screened to an extent that depends on the pH-mediated embedment of the pili within the EPS layer.

Journal of Food Measurement and Characterization, 2015

ABSTRACT

The objective of this study was to evaluate the effects of tubers maturity stage on the physicoch... more The objective of this study was to evaluate the effects of tubers maturity stage on the physicochemical characteristics and thermal properties of Colocasia esculenta (Sosso ecotype) starches. Plantation was done in Chad, tropical area from May to February following a randomized design with 5 maturity stages (6, 7, 8, 9 and 10 months after planting) as the main treatments. The results showed significant increase in phosphorus content (from 113.99 to 145.64µg/100g), temperature (from 80.69 to 84.54°C) and enthalpy of gelatinization (from 13.24 to 16.27 J/g), water absorption capacity (from 140.11 to 304.48 %), solubility index (from 17.50 to 29.42%) and swelling index (from 115 to 135%). In addition the monomolecular moisture content (varying from 2.67 to 3.36 %) and the GAB constant C (varying from 11.73 to 113.22) exhibited significant increase with maturity. Furthermore, a significant decrease in amylose content (from 35.90 to 27.65%) was observed as the maturity increases. In conclusion and on the basis of the correlation observed, the changes in phosphorus and amylose composition of starch during growth seemed to play a role not only on the molecular structure of the starch granules, but also on its functionality.

Journal of Food Science and Technology, 2014

This e-offprint is for personal use only and shall not be self-archived in electronic repositorie... more This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

Colloids and surfaces. B, Biointerfaces, 2015

The surface composition of dairy powders prepared by mixing various amounts of micellar casein (M... more The surface composition of dairy powders prepared by mixing various amounts of micellar casein (MC), whey proteins isolate (WPI), lactose, and anhydrous milk fat (AMF) was investigated by XPS measurements. The use of matrices are generally accepted to transform surface atomic composition (i.e., C, O, N contents) into surface component composition (i.e., lactose, proteins, lipids). These atomic-based matrices were revisited and two new matrices based on the surface bond composition were developed. Surface compositions obtained from atomic and bond-based matrices were compared. A successful matrix allowing good correlations between XPS predicted and theoretical surface composition for powders free from fat was identified. Nevertheless, samples containing milk fat were found to present a possible segregation of components owing to the AMF overrepresentation on the surface. Supplementary analyses (FTIR, SEM) were carried out in order to investigate the homogeneity of the mixtures.

Advances in colloid and interface science, 2014

This review gives an overview of the importance of interactions occurring in dairy matrices betwe... more This review gives an overview of the importance of interactions occurring in dairy matrices between Lactic Acid Bacteria and milk components. Dairy products are important sources of biological active compounds of particular relevance to human health. These compounds include immunoglobulins, whey proteins and peptides, polar lipids, and lactic acid bacteria including probiotics. A better understanding of interactions between bioactive components and their delivery matrix may successfully improve their transport to their target site of action. Pioneering research on probiotic lactic acid bacteria has mainly focused on their host effects. However, very little is known about their interaction with dairy ingredients. Such knowledge could contribute to designing new and more efficient dairy food, and to better understand relationships between milk constituents. The purpose of this review is first to provide an overview of the current knowledge about the biomolecules produced on bacterial ...

Advances in food and nutrition research, 2013

Food powders are used in everyday life in many ways and offer technological solutions to the prob... more Food powders are used in everyday life in many ways and offer technological solutions to the problem of food production. The natural origin of food powders, diversity in their chemical composition, variability of the raw materials, heterogeneity of the native structures, and physicochemical reactivity under hydrothermal stresses contribute to the complexity in their behavior. Food powder agglomeration has recently been considered according to a multiscale approach, which is followed in the chapter layout: (i) at the particle scale, by a presentation of particle properties and surface reactivity in connection with the agglomeration mechanisms, (ii) at the mechanisms scale, by describing the structuration dynamics of agglomerates, (iii) at the process scale, by a presentation of agglomeration technologies and sensors and by studying the stress transmission mode in the powder bed, and finally (iv) by an integration of the acquired knowledge, thanks to a dimensional analysis carried out...

Journal of dairy science, 2007

A simplified method to study rehydration was used on different dairy powders. The method involved... more A simplified method to study rehydration was used on different dairy powders. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor. The changes of turbidity occurring during powder rehydration highlighted the rehydration stage, and the influence of the proteins' state on rehydration was clarified. Casein powders had a quick wetting time but very slow dispersion, making the total rehydration process time-consuming. On the other hand, whey powders were found to have poor wettability but demonstrated immediate dispersion after wetting. Mixing casein (80%) and whey (20%) before spray drying greatly improved rehydration time compared with casein powder; whereas mixing whey powder with casein powder at the same ratio after spray drying caused a dramatic deterioration in the rehydration properties. Moreover, agglomeration was found to significantly improve the rehydration time of whey protein powder and to slow down the rehydration time of casein p...

Journal of dairy science, 2005

A simplified method to study rehydration of dairy powders was developed for native phosphocaseina... more A simplified method to study rehydration of dairy powders was developed for native phosphocaseinate powder. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor under standardized conditions. The changes of turbidity occurring during powder rehydration highlighted several stages. These stages include particles wetting, and then swelling as the water penetrates into the powder bed, followed by a slow dispersion of the particles. With this tool, some technological effects on powder rehydration were analyzed. Ultrafiltrate incorporation to the casein concentrate before spray drying was found to greatly improve the rehydration, whereas mixing ultrafiltrate powder with casein powder after spray drying did not change the rehydration properties. The effect of granulation on powder rehydration stages was also investigated.

British Journal of Applied Science & Technology, 2015

Aims: This study was aimed at evaluating the effect of the method of processing on the antinutrie... more Aims: This study was aimed at evaluating the effect of the method of processing on the antinutrient content of flours made from Tacca leontopetaloides (Tacca) tubers. Study Design: Two experimental designs -the randomized block and the doehlert designs -were used in the study. Place and Duration of Study: The study was carried out in the Laboratoire d'ingenierie et Biomolecules of the University of Lorraine, France between September 2011 and May 2012. Methodology: Fresh tacca tubers were peeled, sliced and subjected to six different soaking and boiling conditions: unprocessed, 36 h soaking-4h boiling, 72h soaking, 4h boiling, 4h boiling-36 h soaking, 4h acid boiling, 4h alkaline boiling. Following the doehlert design, 9 treatments were obtained within the experimental domain of soaking (0 to 48h) and boiling time (3 to 5 h). The BJAST, 5(3): 258-269, 2015; Article no.BJAST.2015.025 259 slices were dried and ground into flours which were subsequently analyzed for their antinutrients content.

ABSTRACT Monitoring, understanding and improving rehydration of dairy powders

ABSTRACT The objective of this study was to examine the influence of high concentration of NaCI o... more ABSTRACT The objective of this study was to examine the influence of high concentration of NaCI on the secondary structure, hydrophobicity and opacity of Whey Protein Isolates (WPI) dispersions. Dispersions were studied at a constant protein concentration (5%) in high NaCl environments (from 0 to 6%). Protein dispersions were characterized as to their color and protein surface hydrophobicity. Additionally, changes in secondary structures upon salt increase were followed by Fourier Transform Infrared Spectroscopy (FTIR). The estimations of secondary structural elements from Amide III assignments were correlated to results obtained from Amide I. Upon salt increase, no differences in secondary structure were observed whereas the protein surface hydrophobicity related to the number of hydrophobic sites available decreased. Concurrently, color differences (ΔE) related to evolution of the protein dispersions containing variable NaCI concentration increased significantly.

Food and Bioprocess Technology, 2014

ABSTRACT The impact of thermal and chemical pretreatments on the physicochemical, rheological, an... more ABSTRACT The impact of thermal and chemical pretreatments on the physicochemical, rheological, and functional properties of sweet potato flour was investigated. The chemical pretreatment consisted in dipping peeled sweet potatoes in 1 % (w/v) calcium chloride (CaCl2), while the thermal pretreatment was achieved by blanching them in tap water at 90 °C for 1 min. Composition in flour moisture, protein, fat, non-reducing sugars, and starch was determined using standard methods. Particle size, color, gelatinization, and rheological properties were analyzed. The water absorption index (WAI) and water solubility index (WSI), as well as the swelling capacity (SC) and sorption isotherms, were determined. The reducing sugar content of sweet potato flour was slightly higher in CaCl2-pretreated (SSPCaCl2) samples than that in blanched (SSPB) and control (SSP) samples. However, the lightness of the SSPB sample was lower than that of the SSPCaCl2 and SSP samples. SSPCaCl2 sample had the higher value of enthalpy of gelatinization and elasticity modulus G′. The SC was higher in blanched samples. A slight increase in the constant of water binding energy (C BET) was observed after the CaCl2 treatment and a marked increase for the blanched sample. Owing to the differences induced by blanching and CaCl2 pretreatments, CaCl2-pretreated flour samples are more suitable for bread-making processes and can also be used in food formulations.

Cahiers de Nutrition et de Diététique, 2012

ABSTRACT Lactose maldigestion: Clinical presentation and treatment The lactose of dairy products ... more ABSTRACT Lactose maldigestion: Clinical presentation and treatment The lactose of dairy products is digested in the small intestine thanks to a membrane enzyme named lactase. For a large part of the world adult population, there is a decline in lactase activity and this leads to a partial malabsorption of the ingested lactose. In order to continue to consume dairy products and to avoid deficiency in calcium and vitamin D, several solutions can be considered. This is the case of yogurt that contains bacteria which have proven effective in lactose digestion. There are also processing aids that allow lactose hydrolysation or lactose remove from food products. Finally, dietary supplements can have a positive effect on lactose digestion if they are consumed at the same time of food products that contain lactose. All of these solutions are therefore intended to maintain the consumption of dairy products in people with lactose maldigestion.

Powder Technology, 2014

Powdered cocoa beverages are a class of instant foods that contain cocoa powder often mixed with ... more Powdered cocoa beverages are a class of instant foods that contain cocoa powder often mixed with high quantities of sugar. One of the desirable functional properties of these beverages is their aptitude to rehydration. Unfortunately, cocoa is a poorly dispersible powder and this is one of the reasons why sugar is added to the initial mix. The influence of sugar nature (sucrose or lactose), sugar size (30 or 480 μm) and sugar percentage (from 70 to 90%) on the rehydration properties at 20°C are investigated. Two techniques were tested and compared: classical static (Standards) and dynamic (Quicpic Analyser). It was concluded that the static method usually used for milk powder can correctly discriminate the influence of sugar nature and sugar percentage. The dynamic method was found to be an interesting complementary tool and allow a better sensibility than the static one. In addition, this dynamic method may be of interest to industrialists. Both, the possibility to obtain kinetics and "in situ" images of particles during rehydration are strongly interesting to interpret size changes.