Magazine et Edition

Volume 26 (2022): Edition 1 (June 2022)

Volume 25 (2021): Edition 2 (December 2021)

Volume 25 (2021): Edition 1 (June 2021)

Volume 24 (2020): Edition 2 (December 2020)

Volume 24 (2020): Edition 1 (June 2020)

Volume 23 (2019): Edition 2 (December 2019)

Volume 23 (2019): Edition 1 (June 2019)

Volume 22 (2018): Edition 2 (December 2018)

Volume 22 (2018): Edition 1 (August 2018)

Volume 21 (2017): Edition 2 (December 2017)

Volume 21 (2017): Edition 1 (June 2017)

Volume 20 (2016): Edition 2 (December 2016)

Volume 20 (2016): Edition 1 (June 2016)

Volume 19 (2015): Edition 2 (December 2015)

Volume 19 (2015): Edition 1 (July 2015)

Volume 18 (2014): Edition 2 (December 2014)

Volume 18 (2014): Edition 1 (June 2014)

Volume 17 (2013): Edition 2 (December 2013)

Volume 17 (2013): Edition 1 (June 2013)

Détails du magazine
Format
Magazine
eISSN
2344-150X
Première publication
30 Jul 2013
Période de publication
2 fois par an
Langues
Anglais

Chercher

Volume 22 (2018): Edition 2 (December 2018)

Détails du magazine
Format
Magazine
eISSN
2344-150X
Première publication
30 Jul 2013
Période de publication
2 fois par an
Langues
Anglais

Chercher

11 Articles
access type Accès libre

Nutritional Properties of Oils from Various Parts of Three Varieties of Pears Consumed in South East Nigeria

Publié en ligne: 03 Jan 2019
Pages: 3 - 12

Résumé

Abstract

This study evaluated the nutrient properties of parts of Dacryodes edulis (DE), Persea americana (PA) and Canarium schweinfurthii (CS) oils using standard methods. Pulp oils of DE and PA had the least moisture, melting point, acid, and saponification values. Occurrence of C10-12 fatty acids was between 0 and 1.46%, and C22-26 between 0 and 4.3%. Anthocyanins, epicatechin, and ribalinidine were undetected in CS seed oils, while oils from the pulp and peels of PA showed the highest amounts for catechins (57.73µg/ml) and kaempferol (57.91µg/ml) respectively. The pulp oils contained higher amounts of Na, K, Zn, Ca, vit A and D. This study has shown that the seed oils suits industrial needs, and the pulp oils for therapeutic purposes.

Mots clés

  • Physicochemical properties
  • phytochemicals
  • fatty acids
  • micronutrients
  • oil
access type Accès libre

Total Phenolic Content and Antioxidant Capacity of Different Parts of Cucumber (Cucumis sativus L.)

Publié en ligne: 03 Jan 2019
Pages: 13 - 20

Résumé

Abstract

The aims of this research were to estimate the polyphenol content and antioxidant capacity from different parts of cucumber. The antioxidant activity was investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP), total flavonoid and phenolic contents were estimated using aluminium chloride and Folin-Ciocalteau reagents assays, respectively. Our finding showed that the ethanolic peel extract contained the highest phenolic (23.08 mg GAE/g) and flavonoids (14.02 mg QE/g). Also, ethanolic peel extract demonstrated significantly (p<0.05) higher FRAP value. Pearson correlation revealed that there were positive correlations (p<0.01) between TPC and TFC with FRAP assay. These findings suggest that consumption of cucumber with peel may provide optimum health benefit than its peeled counterpart.

Mots clés

  • antioxidant capacity
  • cucumber
  • total phenolic content
  • total flavonoid content
access type Accès libre

Process Optimization for Dietary Fiber Production from Cassava Pulp Using Acid Treatment

Publié en ligne: 03 Jan 2019
Pages: 21 - 32

Résumé

Abstract

Cassava pulp, the side product of tapioca industry consists of starch and fiber as the major component. Acid treatment was employed in the conversion process of cassava pulp into dietary fiber to remove the starch component, to increase fiber content, and to modify the structure of fiber. This study purposed to obtain optimum process conditions (acid concentration, temperature, and reaction time) in the production of dietary fiber from cassava pulp. Process optimization was conducted using Response Surface Methodology (RSM) for maximizing Total Dietary Fiber (TDF), Water Holding Capacity (WHC) and Oil Holding Capacity (OHC) as the responses. The optimum process was gained at 6% H2SO4 concentration, 127°C, and 45 mins. Prediction values of TDF, WHC, and OHC were 100%, 10.47 g/g, and 3.60 g/g, respectively. Validation was carried out and resulted in TDF 96.95%, WHC 10.47 g/g, and OHC 3.55 g/g. Physicochemical properties of the resulting dietary fiber were significantly improved. The fiber structure has modified which characterized by the changes in morphology and crystallinity.

Mots clés

  • cassava pulp
  • dietary fiber
  • optimization
  • acid treatment
  • physicochemical properties
access type Accès libre

Cloning, Expression and Characterization of an Esterase Gene in a Metagenomic Library of Traditional Fermented Food

Publié en ligne: 03 Jan 2019
Pages: 33 - 41

Résumé

Abstract

Esterase is an industrial enzyme that is widely used in food, medicine, fine chemicals. The total genomic DNA was extracted from traditional fermented food in China to construct a metagenomic library that included a novel esterase gene (est_115). Sequence homology analysis showed that the highest homology with the carboxylester hydrolase from Pseudomonas lutea was 38%, indicating that esterase belongs to a new class of esterases. Then, an est_115 gene recombinant expression vector was constructed and expressed. The Est_115 had higher catalytic activity to p-nitrophenol ester, with a short acyl-carbon chain. The enzyme can maintain high catalytic activity and salt tolerance in 10%–18% NaCl, suggesting that this novel esterase can be used in processing food using high osmotic pressure.

Mots clés

  • Traditional food
  • metagenomics
  • esterase
  • cloning
  • properties
access type Accès libre

Effects of Stachyose on Synbiotic Yogurt Obtained from Goat Milk with Lactobacillus acidophilus and Lactobacillus casei

Publié en ligne: 03 Jan 2019
Pages: 43 - 50

Résumé

Abstract

Development of synbiotic yogurt having multiple health benefits has become a new trend. The purpose of this study was to obtain the optimum stachyose concentration of the goat yogurt fermented by probiotics including Lactobacillus acidophilus (LA) or Lactobacillus casei (LC) besides Streptococcus thermophilus and Lactobacillus bulgaricus by measuring pH, acidity, viable counts and the change of stachyose content. The optimal stachyose concentration of goat LA-yogurt and goat LC-yogurt were 0.4% and 0.8%. Under the above concentrations, the total bacteria number and the viable counts of LA were 2.02×109cfu/mL, 3×107cfu/mL, respectively; the total bacteria number and the viable counts of LC were 2.55×109cfu/mL, 2.53×108cfu/mL, respectively. The results indicate that stachyose can effectively improve the vitality and the viable counts of strains in goat yogurt.

Mots clés

  • stachyose
  • synbiotic yogurt
  • goat milk
  • viable counts
access type Accès libre

Improving Fermentation of Steamed Stalk to Feed Using Candida utilis and Pachysolen tannophilus

Publié en ligne: 03 Jan 2019
Pages: 51 - 58

Résumé

Abstract

In order to improve the protein content of straw feed and reduce the amount of nutrients added, in this paper, the cell wall structure of corn stalk was destroyed by thermophilic digestion and the polysaccharide was degraded into monosaccharide by complex enzyme, and then transformed into bacterial protein by double strain Candida utilis 1807 and Pachysolen tannophilus 1771 fermentation. Single factor experiments and orthogonal test were made to obtain the best process for the feed of double-bacteria synchronous fermentation of stalks. The optimum amount of each nutrient and the inoculation amounts of double bacteria (accounts for the percentage of the original dry straw quality): ammonium sulfate 6.79%, urea 2.72%, yeast powder 1.63%, magnesium sulfate 0.27%, Candida utilis 54.31% and Pachysolen tannophilus 54.31%; The operational parameters of fermentation process were: fermentation temperature 29°C, rotate speed 100 r/min and fermentation time 55 hours. The yield of stalk feed and crude protein was 82.04%, 23.33%, respectively. The crude protein content of stalk feed was 28.44%, which was 4.33 times of original dry stalk. The results showed that the multi-strain distribution and degradation of protein production provide important significance for corn straw bio-utilization.

Mots clés

  • corn stalk
  • complex enzymes
  • single-cell protein
access type Accès libre

Effects of Carbohydrates, Prebiotics and Salts on Survival of Saccharomyces boulardii During Freeze-Drying

Publié en ligne: 03 Jan 2019
Pages: 59 - 66

Résumé

Abstract

Saccharomyces boulardii, as a probiotic yeast, had been commonly used in food, medicine and feed to treat diarrhea in humans or livestock. However, there are few researches focusing on the preparation of its freeze-drying S.boulardii powder. In this study, the effect of carbohydrates (glucose, sucrose, maltose, fructose, lactose, mannose and trehalose), prebiotics (isomalto-oligosaccharide, xylo-oligosaccharide, raffinose, stachyose, inulin, galacto-oligosaccharide and fructo-oligosaccharide) and salts (NaHCO3, MgSO4, sodium glutamate, sodium ascorbate, and phosphate buffer) on the freeze-dried survival of S. boulardii were investigated to screen the cryoprotectant by using single factor experiments. As the result, trehalose and XOS had better protective effect, the survival rate was 23.72% and 20.70% respectively, the number of viable cells reached 0.91×1010 CFU/g and 0.85×1010 CFU/g respectively; the addition amount of NaHCO3 was 0.3%, the freeze-dried survival rate reached the maximum value of 12.92%. The phosphate buffer additive amount and the bacterial sludge weight were 0.8:1, the freeze-dried survival rate reached a maximum of 14.14%, the freeze-dried survival rate of sodium glutamate, sodium ascorbate and MgSO4 groups was increasing, reaching a maximum of 20.26%, 16.47% and 6.29% when the addition amount was 2%, 10%, 0.5%.

Mots clés

  • freeze-drying
  • protective agents
  • carbohydrates
  • prebiotics
  • salts
access type Accès libre

Optimization of Enset Fermentation in the Production of Kocho Using Response Surface Methodology

Publié en ligne: 03 Jan 2019
Pages: 67 - 75

Résumé

Abstract

Response surface methodology (RSM) was used for optimization of enset fermentation process. Two numerical (time and amount of starter culture) and one categorical variable (types of starter strain) was used for evaluation of sensory quality of kocho. The physicochemical properties, proximate composition and color of kocho product were also analyzed. It was found that the coefficient of determination (R2) of the response variables were greater than 80% described that high percentage of the variability was defined by the model. These findings revealed that fermentation time, amount of starter culture and types of starter strain affected the sensory attributes of kocho. The preferred sensory quality of kocho was produced using 2% L. plantarum as starter strain at 6 days of fermentation time.

Mots clés

  • D-optimal design
  • sensory analysis
  • physicochemical properties
  • color analysis
access type Accès libre

Application of the Simplex Method to Create A Weekly Menu Planner

Publié en ligne: 03 Jan 2019
Pages: 77 - 84

Résumé

Abstract

Organized meals for different groups - students, servicemen, employees working in specific businesses and organization of work - is invariably care for people’s health. An important task in this process is the preparation of menu plans that correspond to the norms for full, balanced and healthy nutrition for the respective age group and working conditions. They must provide the energy and nutrients necessary for the organism - proteins, carbohydrates, vitamins, fats (of animal and plant origin), etc. In some cases, menu planning must be consistent with the use of available food products or the use of interchangeable or similar foods. Problems arise when it comes to assessment and proving compliance with the quality and quantity standards of the products in the weekly menu plan. A commonly used solution is through the formal substitution of food products from the menu plan with the basic products defined by the norms. The mathematical model we offer creates an optimal solution that leaves minimal quantities of unchanged products.

Mots clés

  • simplex method
  • weekly menu
  • weekly menu planner
  • organized eating
access type Accès libre

Comparative Study of Liposoluble Vitamins and Fatty Acids from Sea Buckthorn Oil, Wheat Germ Oil and Fish Oil

Publié en ligne: 03 Jan 2019
Pages: 85 - 90

Résumé

Abstract

An important role in human nutrition is played by fats, both of plant and animal origin. Fats are a category of foods rich in liposoluble vitamins and fatty acids. They are widely used in nutrition, in cosmetics, in the content of creams as well as in pharmaceutical products, in the form of dietary supplements, such as capsules with oils rich in fatty acids and the addition of liposoluble vitamins. The objective of this paper was to study the content in vitamins and fatty oils of two vegetable oils (wheat germ and sea buckthorn oils) and an animal oil (fish oil). The results show that these oils are rich in liposoluble vitamins, omega-3 fatty acids and omega-6 fatty acids. Hence, these oils can be used successfully in daily nutrition as substitutes for synthetic vitamins.

Mots clés

  • wheat germ oil
  • sea buckthorn oil
  • fish oil
  • lipid-soluble vitamins
  • fatty acids
  • nutrition
access type Accès libre

Retraction

Publié en ligne: 03 Jan 2019
Pages: 91 - 91

Résumé

11 Articles
access type Accès libre

Nutritional Properties of Oils from Various Parts of Three Varieties of Pears Consumed in South East Nigeria

Publié en ligne: 03 Jan 2019
Pages: 3 - 12

Résumé

Abstract

This study evaluated the nutrient properties of parts of Dacryodes edulis (DE), Persea americana (PA) and Canarium schweinfurthii (CS) oils using standard methods. Pulp oils of DE and PA had the least moisture, melting point, acid, and saponification values. Occurrence of C10-12 fatty acids was between 0 and 1.46%, and C22-26 between 0 and 4.3%. Anthocyanins, epicatechin, and ribalinidine were undetected in CS seed oils, while oils from the pulp and peels of PA showed the highest amounts for catechins (57.73µg/ml) and kaempferol (57.91µg/ml) respectively. The pulp oils contained higher amounts of Na, K, Zn, Ca, vit A and D. This study has shown that the seed oils suits industrial needs, and the pulp oils for therapeutic purposes.

Mots clés

  • Physicochemical properties
  • phytochemicals
  • fatty acids
  • micronutrients
  • oil
access type Accès libre

Total Phenolic Content and Antioxidant Capacity of Different Parts of Cucumber (Cucumis sativus L.)

Publié en ligne: 03 Jan 2019
Pages: 13 - 20

Résumé

Abstract

The aims of this research were to estimate the polyphenol content and antioxidant capacity from different parts of cucumber. The antioxidant activity was investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP), total flavonoid and phenolic contents were estimated using aluminium chloride and Folin-Ciocalteau reagents assays, respectively. Our finding showed that the ethanolic peel extract contained the highest phenolic (23.08 mg GAE/g) and flavonoids (14.02 mg QE/g). Also, ethanolic peel extract demonstrated significantly (p<0.05) higher FRAP value. Pearson correlation revealed that there were positive correlations (p<0.01) between TPC and TFC with FRAP assay. These findings suggest that consumption of cucumber with peel may provide optimum health benefit than its peeled counterpart.

Mots clés

  • antioxidant capacity
  • cucumber
  • total phenolic content
  • total flavonoid content
access type Accès libre

Process Optimization for Dietary Fiber Production from Cassava Pulp Using Acid Treatment

Publié en ligne: 03 Jan 2019
Pages: 21 - 32

Résumé

Abstract

Cassava pulp, the side product of tapioca industry consists of starch and fiber as the major component. Acid treatment was employed in the conversion process of cassava pulp into dietary fiber to remove the starch component, to increase fiber content, and to modify the structure of fiber. This study purposed to obtain optimum process conditions (acid concentration, temperature, and reaction time) in the production of dietary fiber from cassava pulp. Process optimization was conducted using Response Surface Methodology (RSM) for maximizing Total Dietary Fiber (TDF), Water Holding Capacity (WHC) and Oil Holding Capacity (OHC) as the responses. The optimum process was gained at 6% H2SO4 concentration, 127°C, and 45 mins. Prediction values of TDF, WHC, and OHC were 100%, 10.47 g/g, and 3.60 g/g, respectively. Validation was carried out and resulted in TDF 96.95%, WHC 10.47 g/g, and OHC 3.55 g/g. Physicochemical properties of the resulting dietary fiber were significantly improved. The fiber structure has modified which characterized by the changes in morphology and crystallinity.

Mots clés

  • cassava pulp
  • dietary fiber
  • optimization
  • acid treatment
  • physicochemical properties
access type Accès libre

Cloning, Expression and Characterization of an Esterase Gene in a Metagenomic Library of Traditional Fermented Food

Publié en ligne: 03 Jan 2019
Pages: 33 - 41

Résumé

Abstract

Esterase is an industrial enzyme that is widely used in food, medicine, fine chemicals. The total genomic DNA was extracted from traditional fermented food in China to construct a metagenomic library that included a novel esterase gene (est_115). Sequence homology analysis showed that the highest homology with the carboxylester hydrolase from Pseudomonas lutea was 38%, indicating that esterase belongs to a new class of esterases. Then, an est_115 gene recombinant expression vector was constructed and expressed. The Est_115 had higher catalytic activity to p-nitrophenol ester, with a short acyl-carbon chain. The enzyme can maintain high catalytic activity and salt tolerance in 10%–18% NaCl, suggesting that this novel esterase can be used in processing food using high osmotic pressure.

Mots clés

  • Traditional food
  • metagenomics
  • esterase
  • cloning
  • properties
access type Accès libre

Effects of Stachyose on Synbiotic Yogurt Obtained from Goat Milk with Lactobacillus acidophilus and Lactobacillus casei

Publié en ligne: 03 Jan 2019
Pages: 43 - 50

Résumé

Abstract

Development of synbiotic yogurt having multiple health benefits has become a new trend. The purpose of this study was to obtain the optimum stachyose concentration of the goat yogurt fermented by probiotics including Lactobacillus acidophilus (LA) or Lactobacillus casei (LC) besides Streptococcus thermophilus and Lactobacillus bulgaricus by measuring pH, acidity, viable counts and the change of stachyose content. The optimal stachyose concentration of goat LA-yogurt and goat LC-yogurt were 0.4% and 0.8%. Under the above concentrations, the total bacteria number and the viable counts of LA were 2.02×109cfu/mL, 3×107cfu/mL, respectively; the total bacteria number and the viable counts of LC were 2.55×109cfu/mL, 2.53×108cfu/mL, respectively. The results indicate that stachyose can effectively improve the vitality and the viable counts of strains in goat yogurt.

Mots clés

  • stachyose
  • synbiotic yogurt
  • goat milk
  • viable counts
access type Accès libre

Improving Fermentation of Steamed Stalk to Feed Using Candida utilis and Pachysolen tannophilus

Publié en ligne: 03 Jan 2019
Pages: 51 - 58

Résumé

Abstract

In order to improve the protein content of straw feed and reduce the amount of nutrients added, in this paper, the cell wall structure of corn stalk was destroyed by thermophilic digestion and the polysaccharide was degraded into monosaccharide by complex enzyme, and then transformed into bacterial protein by double strain Candida utilis 1807 and Pachysolen tannophilus 1771 fermentation. Single factor experiments and orthogonal test were made to obtain the best process for the feed of double-bacteria synchronous fermentation of stalks. The optimum amount of each nutrient and the inoculation amounts of double bacteria (accounts for the percentage of the original dry straw quality): ammonium sulfate 6.79%, urea 2.72%, yeast powder 1.63%, magnesium sulfate 0.27%, Candida utilis 54.31% and Pachysolen tannophilus 54.31%; The operational parameters of fermentation process were: fermentation temperature 29°C, rotate speed 100 r/min and fermentation time 55 hours. The yield of stalk feed and crude protein was 82.04%, 23.33%, respectively. The crude protein content of stalk feed was 28.44%, which was 4.33 times of original dry stalk. The results showed that the multi-strain distribution and degradation of protein production provide important significance for corn straw bio-utilization.

Mots clés

  • corn stalk
  • complex enzymes
  • single-cell protein
access type Accès libre

Effects of Carbohydrates, Prebiotics and Salts on Survival of Saccharomyces boulardii During Freeze-Drying

Publié en ligne: 03 Jan 2019
Pages: 59 - 66

Résumé

Abstract

Saccharomyces boulardii, as a probiotic yeast, had been commonly used in food, medicine and feed to treat diarrhea in humans or livestock. However, there are few researches focusing on the preparation of its freeze-drying S.boulardii powder. In this study, the effect of carbohydrates (glucose, sucrose, maltose, fructose, lactose, mannose and trehalose), prebiotics (isomalto-oligosaccharide, xylo-oligosaccharide, raffinose, stachyose, inulin, galacto-oligosaccharide and fructo-oligosaccharide) and salts (NaHCO3, MgSO4, sodium glutamate, sodium ascorbate, and phosphate buffer) on the freeze-dried survival of S. boulardii were investigated to screen the cryoprotectant by using single factor experiments. As the result, trehalose and XOS had better protective effect, the survival rate was 23.72% and 20.70% respectively, the number of viable cells reached 0.91×1010 CFU/g and 0.85×1010 CFU/g respectively; the addition amount of NaHCO3 was 0.3%, the freeze-dried survival rate reached the maximum value of 12.92%. The phosphate buffer additive amount and the bacterial sludge weight were 0.8:1, the freeze-dried survival rate reached a maximum of 14.14%, the freeze-dried survival rate of sodium glutamate, sodium ascorbate and MgSO4 groups was increasing, reaching a maximum of 20.26%, 16.47% and 6.29% when the addition amount was 2%, 10%, 0.5%.

Mots clés

  • freeze-drying
  • protective agents
  • carbohydrates
  • prebiotics
  • salts
access type Accès libre

Optimization of Enset Fermentation in the Production of Kocho Using Response Surface Methodology

Publié en ligne: 03 Jan 2019
Pages: 67 - 75

Résumé

Abstract

Response surface methodology (RSM) was used for optimization of enset fermentation process. Two numerical (time and amount of starter culture) and one categorical variable (types of starter strain) was used for evaluation of sensory quality of kocho. The physicochemical properties, proximate composition and color of kocho product were also analyzed. It was found that the coefficient of determination (R2) of the response variables were greater than 80% described that high percentage of the variability was defined by the model. These findings revealed that fermentation time, amount of starter culture and types of starter strain affected the sensory attributes of kocho. The preferred sensory quality of kocho was produced using 2% L. plantarum as starter strain at 6 days of fermentation time.

Mots clés

  • D-optimal design
  • sensory analysis
  • physicochemical properties
  • color analysis
access type Accès libre

Application of the Simplex Method to Create A Weekly Menu Planner

Publié en ligne: 03 Jan 2019
Pages: 77 - 84

Résumé

Abstract

Organized meals for different groups - students, servicemen, employees working in specific businesses and organization of work - is invariably care for people’s health. An important task in this process is the preparation of menu plans that correspond to the norms for full, balanced and healthy nutrition for the respective age group and working conditions. They must provide the energy and nutrients necessary for the organism - proteins, carbohydrates, vitamins, fats (of animal and plant origin), etc. In some cases, menu planning must be consistent with the use of available food products or the use of interchangeable or similar foods. Problems arise when it comes to assessment and proving compliance with the quality and quantity standards of the products in the weekly menu plan. A commonly used solution is through the formal substitution of food products from the menu plan with the basic products defined by the norms. The mathematical model we offer creates an optimal solution that leaves minimal quantities of unchanged products.

Mots clés

  • simplex method
  • weekly menu
  • weekly menu planner
  • organized eating
access type Accès libre

Comparative Study of Liposoluble Vitamins and Fatty Acids from Sea Buckthorn Oil, Wheat Germ Oil and Fish Oil

Publié en ligne: 03 Jan 2019
Pages: 85 - 90

Résumé

Abstract

An important role in human nutrition is played by fats, both of plant and animal origin. Fats are a category of foods rich in liposoluble vitamins and fatty acids. They are widely used in nutrition, in cosmetics, in the content of creams as well as in pharmaceutical products, in the form of dietary supplements, such as capsules with oils rich in fatty acids and the addition of liposoluble vitamins. The objective of this paper was to study the content in vitamins and fatty oils of two vegetable oils (wheat germ and sea buckthorn oils) and an animal oil (fish oil). The results show that these oils are rich in liposoluble vitamins, omega-3 fatty acids and omega-6 fatty acids. Hence, these oils can be used successfully in daily nutrition as substitutes for synthetic vitamins.

Mots clés

  • wheat germ oil
  • sea buckthorn oil
  • fish oil
  • lipid-soluble vitamins
  • fatty acids
  • nutrition
access type Accès libre

Retraction

Publié en ligne: 03 Jan 2019
Pages: 91 - 91

Résumé

Planifiez votre conférence à distance avec Sciendo