Rice as staple food is the most important and valuable cereal crop in Cameroon, particularly in rural areas where poor population cannot afford to cook and eat at their convenience. With the outbreak of Nerica varieti...Rice as staple food is the most important and valuable cereal crop in Cameroon, particularly in rural areas where poor population cannot afford to cook and eat at their convenience. With the outbreak of Nerica varieties, it is important to evaluate and compare their nutritional and mineral properties to those of the local ones prior to their vulgarisation. Therefore, some nutritional and mineral properties of 4 Nerica and a local seeds varieties used in this study were harvested from control (T0), chemical fertilizer (TE), mycorrhiza (TM) applied plants, or their mixture (TEM). These seeds originating from Wakwa and/or Yagoua experimental sites were assessed and compared in a split-plot design (4 × 5) × 3 between treatments (4) and varieties (5). The local DIR-95 variety had values close to those of Nerica varieties in all the parameters assessed. Protein contents ranged from 17.66% - 24.35%, and was higher than those reported in rice samples elsewhere. All the studied varieties were classified as high amylose rice, and therefore, their textures in cooked form should be less sticky and harder, which is convenient to the diet behavior of many consumers. The relative low Fe content in Nerica rice suggest that these varieties may be resistant to Fe accumulation in seeds. The P, N, Mg contents were found to be more elevated in seeds harvested from mycorrhiza or chemical fertilizer applied plants, with Nerica seeds variety FKR62-N as the best of all in nutrients mineral and nutritional compositions. These results confirm varietal and site influences on proximate and mineral contents in the studied rice varieties.展开更多
Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sa...Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sauces, improvement of the swelling of maize and bean cakes) and in the process of decantation of traditional beer. In order to valorize these barks in dried form, study of the effect of drying temperature on the rheological properties of their gums was carried out. In this respect, the fresh barks were dried at 40℃, 50℃, 60℃, 70℃ and 80℃ and the viscosity of their extracts was measured. The drying kinetic of the barks showed two falling rate periods represented by two drying constants?k1 and k2. The absolute viscosity of the extracts decreased beyond drying temperatures higher than 70℃ and 80℃respectively for T cordifolia and B. Thermifolia. The decreasing viscosity is attributed mainly to a reorganization of polysaccharide chains. The temperatures range lower than 70℃ could be retained to dry the barks and to extract gums without deteriorating their properties.展开更多
The industrial production of most food and probiotic products often requires processing involving high temperatures and physiological stress causing loss of viability of probiotic microbial strains. The viability and ...The industrial production of most food and probiotic products often requires processing involving high temperatures and physiological stress causing loss of viability of probiotic microbial strains. The viability and stability of probiotic strains is a key determinant of their efficacy during administration in human and animal. Thermotolerance is actually a very important feature for probiotic undergoing industrial processing. This paper aimed at assessing the effect of some mineral salts on the thermotolerance and the probiotic properties of lactobacilli isolated from curded milk produced in Mezam Division, Cameroon. Lactobacilli were isolated by pour plate method on de Man Rogosa and Sharpe (MRS) agar. Lactobacilli were selected based on their ability to suppress in-vitro and in-vivo food borne pathogenic bacteria;Salmonella enterica serovar Enteridis and Esherichia coli. Inhibitory activities against these food borne pathogens were performed by disc diffusion method on Mueller Hinton agar. In-vivo inhibition of Salmonella was achieved using oral administration by gavage of (1.0 × 109 CFU/ml) of selected probiotic strain suspended in sterile water. Thermotolerance was assessed by measuring the survival rate of the strain after heating at various temperatures in the presence and absence of mineral salts. Resistance to bile was determined by measuring the survival rate of probiotics after incubation in the presence of oxgallbille and mineral salts. Two catalase negatives isolates were selected based on their capacity to exhibit inhibitory activities in-vitro and in-vivo against food borne pathogens. They were identified as strain of Lactobacillus casei (LS3) and Lactobacillus plantarum (LM4). These strains exhibited significant reduction (P Salmonella count in caeca swabs of infected chick model. The calcium and magnesium salts increased significantly (P < 0.05) the thermo-tolerance and resistance to bile of probiotic strains studied. These results suggested that calcium and magnesium could be used to monitor the viability of probiotic strains in probiotic products.展开更多
Biosurfactants are structurally diverse classes of amphiphilic molecules derived from microorganisms.They have various properties such as surface,emulsification,antibacterial,anti-adhesive,anti-biofilm,antioxidant act...Biosurfactants are structurally diverse classes of amphiphilic molecules derived from microorganisms.They have various properties such as surface,emulsification,antibacterial,anti-adhesive,anti-biofilm,antioxidant activity that can be used in many industrial fields.The interest in these molecules compared to their synthetic counterparts is due to their biodegradability,low toxicity,structural diversity,and stability over a wide range of pH,temperature,and salinity.Among biosurfactants,those derived from lactic acid bacteria(LAB)attracted attention nowadays due to the GRAS(Generally recognized as safe)status of these microorganisms.Biosurfactants production by LAB strains has been documented in several investigations,and they deal with the functionality and chemical nature of biosurfactants.LAB biosurfactants were mainly a complex mixture of proteinaceous compounds,glycolipids,glycoproteins,or glycolipopeptides.There are only a few studies reporting on the elucidation of the structure of LAB biosurfactants.Generally,biosurfactants’production process includes several unit operations starting from screening methods to the characterization of the biosurfactant compound.This review highlights the different techniques used in the screening of biosurfactants production by LAB,their extraction and purification processes,and their structural characterization and application in the food industry.展开更多
文摘Rice as staple food is the most important and valuable cereal crop in Cameroon, particularly in rural areas where poor population cannot afford to cook and eat at their convenience. With the outbreak of Nerica varieties, it is important to evaluate and compare their nutritional and mineral properties to those of the local ones prior to their vulgarisation. Therefore, some nutritional and mineral properties of 4 Nerica and a local seeds varieties used in this study were harvested from control (T0), chemical fertilizer (TE), mycorrhiza (TM) applied plants, or their mixture (TEM). These seeds originating from Wakwa and/or Yagoua experimental sites were assessed and compared in a split-plot design (4 × 5) × 3 between treatments (4) and varieties (5). The local DIR-95 variety had values close to those of Nerica varieties in all the parameters assessed. Protein contents ranged from 17.66% - 24.35%, and was higher than those reported in rice samples elsewhere. All the studied varieties were classified as high amylose rice, and therefore, their textures in cooked form should be less sticky and harder, which is convenient to the diet behavior of many consumers. The relative low Fe content in Nerica rice suggest that these varieties may be resistant to Fe accumulation in seeds. The P, N, Mg contents were found to be more elevated in seeds harvested from mycorrhiza or chemical fertilizer applied plants, with Nerica seeds variety FKR62-N as the best of all in nutrients mineral and nutritional compositions. These results confirm varietal and site influences on proximate and mineral contents in the studied rice varieties.
文摘Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sauces, improvement of the swelling of maize and bean cakes) and in the process of decantation of traditional beer. In order to valorize these barks in dried form, study of the effect of drying temperature on the rheological properties of their gums was carried out. In this respect, the fresh barks were dried at 40℃, 50℃, 60℃, 70℃ and 80℃ and the viscosity of their extracts was measured. The drying kinetic of the barks showed two falling rate periods represented by two drying constants?k1 and k2. The absolute viscosity of the extracts decreased beyond drying temperatures higher than 70℃ and 80℃respectively for T cordifolia and B. Thermifolia. The decreasing viscosity is attributed mainly to a reorganization of polysaccharide chains. The temperatures range lower than 70℃ could be retained to dry the barks and to extract gums without deteriorating their properties.
文摘The industrial production of most food and probiotic products often requires processing involving high temperatures and physiological stress causing loss of viability of probiotic microbial strains. The viability and stability of probiotic strains is a key determinant of their efficacy during administration in human and animal. Thermotolerance is actually a very important feature for probiotic undergoing industrial processing. This paper aimed at assessing the effect of some mineral salts on the thermotolerance and the probiotic properties of lactobacilli isolated from curded milk produced in Mezam Division, Cameroon. Lactobacilli were isolated by pour plate method on de Man Rogosa and Sharpe (MRS) agar. Lactobacilli were selected based on their ability to suppress in-vitro and in-vivo food borne pathogenic bacteria;Salmonella enterica serovar Enteridis and Esherichia coli. Inhibitory activities against these food borne pathogens were performed by disc diffusion method on Mueller Hinton agar. In-vivo inhibition of Salmonella was achieved using oral administration by gavage of (1.0 × 109 CFU/ml) of selected probiotic strain suspended in sterile water. Thermotolerance was assessed by measuring the survival rate of the strain after heating at various temperatures in the presence and absence of mineral salts. Resistance to bile was determined by measuring the survival rate of probiotics after incubation in the presence of oxgallbille and mineral salts. Two catalase negatives isolates were selected based on their capacity to exhibit inhibitory activities in-vitro and in-vivo against food borne pathogens. They were identified as strain of Lactobacillus casei (LS3) and Lactobacillus plantarum (LM4). These strains exhibited significant reduction (P Salmonella count in caeca swabs of infected chick model. The calcium and magnesium salts increased significantly (P < 0.05) the thermo-tolerance and resistance to bile of probiotic strains studied. These results suggested that calcium and magnesium could be used to monitor the viability of probiotic strains in probiotic products.
基金The current project was funded by the TWAS-CSIR,India,Postgraduate fellowship under grant number 3240293592.
文摘Biosurfactants are structurally diverse classes of amphiphilic molecules derived from microorganisms.They have various properties such as surface,emulsification,antibacterial,anti-adhesive,anti-biofilm,antioxidant activity that can be used in many industrial fields.The interest in these molecules compared to their synthetic counterparts is due to their biodegradability,low toxicity,structural diversity,and stability over a wide range of pH,temperature,and salinity.Among biosurfactants,those derived from lactic acid bacteria(LAB)attracted attention nowadays due to the GRAS(Generally recognized as safe)status of these microorganisms.Biosurfactants production by LAB strains has been documented in several investigations,and they deal with the functionality and chemical nature of biosurfactants.LAB biosurfactants were mainly a complex mixture of proteinaceous compounds,glycolipids,glycoproteins,or glycolipopeptides.There are only a few studies reporting on the elucidation of the structure of LAB biosurfactants.Generally,biosurfactants’production process includes several unit operations starting from screening methods to the characterization of the biosurfactant compound.This review highlights the different techniques used in the screening of biosurfactants production by LAB,their extraction and purification processes,and their structural characterization and application in the food industry.
