Christèle Icard-Vernière

Enzyme activities of lactic acid bacteria from a pearl millet fermented gruel ( ben-saalga ) of functional interest in nutrition

Lactic acid bacteria responsible for the fermentation of a pearl-millet based fermented gruel, ben-saalga, were investigated for enzyme activity in relation with the nutritional characteristics of gruels used as complementary foods for young children. Thirty pre-selected LAB from a set of 155 isolates were characterized principally for their ability to produce amylase, phytase and alpha-galactosidase. Two Lactobacillus plantarum strains (4.4 and 6.1) and three Lactobacillus fermentum strains (11.11.2, 3.7, 7.4) able to produce one or more of these enzymes were selected. Only weak amylase activity was found in the two Lactobacillus plantarum strains. alpha-amylase activity was associated with cells and was lower than 0.05 Ceralpha Units/ml. Phytase activity was detected in all five strains and was linked to the cell. The highest phytase activity was found in Lb. plantarum 4.4 and 6.1 (348.7 +/- 17.4U/ml and 276.3 +/- 51.4U/ml, respectively) and Lb. fermentum 7.4. (276.3 +/- 13.2U/ml). All strains displayed a cell-linked alpha-galactosidase activity. In a medium containing 2% glucose, the highest cellular activity was found in Lb. fermentum 3.7 (1441.1 +/- 133.7U/ml) and Lb. plantarum 4.4 (1223.1 +/- 148.3U/ml) after 6h of fermentation in the presence of stachyose, and in Lb. plantarum 4.4 (763.3 +/- 23.5U/ml) and Lb. fermentum 7.4 (346.7 +/- 14.8U/ml) after 24h of fermentation with raffinose. These results are consistent with previous observations showing that phytates and alpha-galactooligosaccharides decreased during the natural lactic acid fermentation of pearl millet slurries, and that partial starch hydrolysis can be performed by endogenous microflora provided a pre-gelatinisation step is included in the process.

Potential of amylolytic lactic acid bacteria to replace the use of malt for partial starch hydrolysis to produce African fermented pearl millet gruel fortified with groundnut

Fermentation and starch hydrolysis of a pre-cooked pearl millet-groundnut (MG) slurry inoculated with amylolytic lactic acid bacteria (ALAB) or by back slopping was investigated as a substitute for the addition of malt to prepare infant gruels. The ALAB collection strain Lb. plantarum A6, and the endogenous microflora provided by back slopping were more efficient in acidifying and partially hydrolysing starch in the MG slurry than Lb. plantarum 6.1, isolated from the traditional process in Burkina Faso. Large amounts of maltotriose and maltotetraose accumulated in slurry fermented by strain A6. No accumulation of maltose was observed, which could be an advantage to prevent the growth of microbial contaminants such as yeasts. Starch hydrolysis in the MG slurry inoculated with strain A6 or by back slopping enabled preparation of high-energy density gruels (84.7+/-4.4 and 80.4+/-23.8 kcal/100 g of gruel, respectively) of liquid consistency. However variability was higher with back slopping.

Changes in iron, zinc and chelating agents during traditional African processing of maize: Effect of iron contamination on bioaccessibility

The effect of the different unit operations of processing traditionally used to produce four maize foods commonly consumed in Africa on the nutritional composition of the products was investigated, using Benin as a study context. The impact of the processes on lipid, fibre, phytate, iron and zinc contents varied with the process. The lowest IP6/Fe and IP6/Zn molar ratios, the indices used to assess Fe and Zn bioavailability were obtained in mawè, a fermented dough. Analysis of maize products highlighted a significant increase in iron content after milling, as a result of contamination by the equipment used. Evaluation of iron bioaccessibility by in vitro enzymatic digestion followed by dialysis revealed that the iron contamination, followed by lactic acid fermentation, led to a considerable increase in bioaccessible iron content. Extrinsic iron supplied to food products by the milling equipment could play a role in iron intake in developing countries.

Consumption pattern, biochemical composition and nutritional value of fermented pearl millet gruels in Burkina Faso

Ben-kida and ben-saalga are popular pearl-millet-based fermented gruels in Burkina Faso. A survey of 318 households in Ouagadougou (Burkina Faso) showed that they are often used as complementary food for young children. Pearl millet and gruels, sampled in 48 production units, were analysed for proximate composition, factors reducing nutrient bioavailability (phytate, insoluble fibres and iron-binding phenolic compounds), α-galactosides, sugars, total lactic acid and d-lactic acid, zinc and iron contents. The effects of processing of pearl millet into fermented gruel are discussed. Both positive effects (e.g. a decrease in factors reducing nutrient bioavailability or α-galactosides) and undesirable effects (e.g. considerable lipid, protein, iron and zinc losses) were observed. Lactic acid was produced during processing and d(−)-lactate was detected in all samples. The gruels had very low energy density, even after addition of sugar, and low lipid, protein and mineral contents, well below recommendations for complementary foods.

Nutrient intakes from complementary foods consumed by young children (aged 12–23 months) from North Wollo, northern Ethiopia: the need for agro-ecologically adapted interventions

OBJECTIVE To characterize current feeding practices and to evaluate the adequacy of energy and nutrient intakes of young children in subsistence farming rural households in North Wollo, Ethiopia. DESIGN A cross-sectional study examining sociodemographic status, anthropometry, breast-feeding and complementary feeding practices using two in-home non-consecutive 24 h recalls. SETTINGS Two rural villages in the highlands and lowlands of Gobalafto district, North Wollo. SUBJECTS Seventy-six young children aged 12-23 months, thirty-nine from the lowlands and thirty-seven from the highlands. RESULTS About 33% of the children, ~46% in the highlands and 24% in the lowlands (P=0.05), were stunted. Complementary diets were low in animal products, fruits and vegetables. Cereals and legumes were the major sources of energy, protein, Ca, Fe, Zn and vitamin A. Legumes with potentially toxic components (grass pea, broad beans) and low nutrient-dense beverages such as tea were frequently consumed. Intakes of energy, Ca, Zn, vitamin A and vitamin C from complementary foods were below WHO recommendations assuming average breast-milk intakes. In contrast, Fe and protein intakes and densities met WHO recommendations. Although vitamin C intakes and densities were higher (P<0.05) for the lowlands, they remained far below WHO recommendations. CONCLUSIONS Interventions promoting the WHO guiding principles for complementary feeding practices and behaviours that take the agro-ecological contexts into account are needed here. Furthermore, specific recommendations should be formulated to discourage the consumption of grass pea, broad beans and low nutrient-dense beverages such as tea.

Anthropometric and Micronutrient Status of School-Children in an Urban West Africa Setting: A Cross-Sectional Study in Dakar (Senegal)

Background Urban areas in West Africa are not immune to undernutrition with recent urbanization and high food prices being important factors. School children often have a poor nutritional status, potentially affecting their health and schooling performance. Yet, generally school children do not benefit from nutrition programs. The objective of the study was to assess the anthropometric and micronutrient status of children from state schools in the Dakar area. Methods School children (n = 604) aged from 5 to 17 y (52.5% girls, 47.5% ≥10 y) were selected through a two-stage random cluster sample of children attending urban primary state schools in the Dakar area (30 schools × 20 children). The prevalence of stunting (height-for-age<−2 z-scores) and thinness (BMI-for-age<−2 z-scores, WHO 2006, and three grades of thinness corresponding to BMI of 18.5, 17.0 and 16.0 kg/m2 in adults) were calculated from weight and height. Hemoglobin, plasma concentrations of ferritin (FER), transferrin receptors (TfR), retinol binding protein (RBP), and zinc, and urinary iodine concentrations were measured. Correction factors were used for FER and RBP in subjects with inflammation determined with C-reactive protein and α1-acid-glycoprotein. Results 4.9% of children were stunted, 18.4% were thin, 5.6% had severe thinness (BMI-for-age<−3 z-scores). Only one child had a BMI-for-age>2 z-scores. Prevalence of anemia, iron deficiency and iron deficiency anemia was 14.4%, 39.1% and 10.6% respectively. 3.0% had vitamin A deficiency, 35.9% a marginal vitamin A status, and 25.9% zinc deficiency. Urinary iodine was <50 µg/L in 7.3% of children and ≥200 µg/L in 22.3%. The prevalence of marginal vitamin A, zinc deficiency, high TfR was significantly higher in boys than in girls (P<0.05). Height-for-age and retinol were significantly lower in participants ≥10 y and <10 y respectively. Conclusion Undernutrition, especially thinness, iron and zinc deficiencies in school children in the Dakar area requires special targeted nutrition interventions.

Influence of flour blend composition on fermentation kinetics and phytate hydrolysis of sourdough used to make injera.

The influence of cereal blends, teff-white sorghum (TwS), barley-wheat (BW) and wheat-red sorghum (WrS), on fermentation kinetics during traditional fermentation of dough to prepare injera, an Ethiopian traditional fermented pancake, was investigated in samples collected in households. Barley malt was used with BW and WrS flours. WrS- and BW-injera sourdough fermentations were characterised by a transient accumulation of glucose and maltose and a two-step fermentation process: lactic acid fermentation and alcoholic fermentation with ethanol as the main end product. Only transient accumulation of glucose was observed in TwS-injera, and equimolar concentrations of lactic acid and ethanol were produced simultaneously. Final α-galactoside concentrations were low in all sourdoughs. Phytic acid (IP6) was completely hydrolyzed in WrS and BW-injeras probably due to the combined action of endogenous malt and microbial phytases. Only 28% IP6 hydrolysis was observed in TwS injera. Ways to improve IP6 hydrolysis in TwS-injera need to be investigated.

Fermentation by Amylolytic Lactic Acid Bacteria and Consequences for Starch Digestibility of Plantain, Breadfruit, and Sweet Potato Flours

UNLABELLED The potential of tropical starchy plants such as plantain (Musa paradisiaca), breadfruit (Artocarpus communis), and sweet potato (Ipomoea batatas) for the development of new fermented foods was investigated by exploiting the capacity of some lactic acid bacteria to hydrolyze starch. The amylolytic lactic acid bacteria (ALAB) Lactobacillus plantarum A6 and Lactobacillus fermentum Ogi E1 were able to change the consistency of thick sticky gelatinized slurries of these starchy fruits and tubers into semiliquid to liquid products. Consequently, a decrease in apparent viscosity and an increase in Bostwick flow were observed. These changes and the production of maltooligosaccharides confirmed starch hydrolysis. Sucrose in sweet potato was not fermented by strain A6 and poorly fermented by strain Ogi E1, suggesting possible inhibition of sucrose fermentation. In all 3 starchy plants, rapidly digestible starch (RDS) was higher than slowly digestible starch (SDS) and resistant starch (RS) represented between 17% and 30% dry matter (DM). The digestibility of plantain was not affected by fermentation, whereas the RDS content of breadfruit and sweet potato decreased and the RS content increased after fermentation. PRACTICAL APPLICATION The characteristics resulting from different combinations of gluten free starchy plants (plantain, breadfruit, sweet potato) and amylolytic lactic acid bacteria (ALAB) offer opportunities to develop new functional fermented beverages, mainly for breadfruit and sweet potato, after further investigation of their formulation, sensory attributes, nutritional, and prebiotic characteristics.

Enzymatic degradation of phytate, polyphenols and dietary fibers in Ethiopian injera flours: effect on iron bioaccessibility.

The effect of removing phytate (IP6), iron-binding polyphenols, and dietary fibers on iron bioaccessibility in wheat-red sorghum (WrS) and teff-white sorghum (TwS) flour blends used in Ethiopia to make injera, a fermented pancake, was evaluated through the application of exogenous enzymes. Phytase treatment led to >90% reduction in IP6 and to an IP6:Fe molar ratio <1, but iron bioaccessibility was not improved (P > 0.05). Phytase + xylanase + cellulase (P + X + C) treatment increased iron bioaccessibility in TwS (non-detectableto1.6%) and WrS (1.9-3.2%), whereas phytase + polyphenol oxidase (P + PPO) treatment only showed improvement in the TwS blend. P + X + C + PPO treatment of the WrS blend increased the soluble non-dialysable iron fraction (6.7%) more than P + PPO treatment (3.9%). Although responses to enzyme treatments and iron bioaccessibility were matrix dependent, a positive effect of dietary fiber hydrolysis with X + C was obtained, irrespective of the blend. Dietary fibers had a negative effect on iron bioaccessibility independent of phytates.

A Higher Proportion of Iron-Rich Leafy Vegetables in a Typical Burkinabe Maize Meal Does Not Increase the Amount of Iron Absorbed in Young Women

Food-to-food fortification can be a promising approach to improve the low dietary iron intake and bioavailability from monotonous diets based on a small number of staple plant foods. In Burkina Faso, the common diet consists of a thick, cereal-based paste consumed with sauces composed of mainly green leaves, such as amaranth and jute leaves. Increasing the quantity of leaves in the sauces substantially increases their iron concentration. To evaluate whether increasing the quantity of leaves in sauces would provide additional bioavailable iron, an iron absorption study in 18 young women was conducted in Zurich, Switzerland. Burkinabe composite test meals consisting of the maize paste tô accompanied by an iron-improved amaranth sauce, an iron-improved jute sauce, or a traditional amaranth sauce were provided as multiple meals twice a day for 2 consecutive days. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. Mean fractional iron absorption from maize paste consumed with an iron-improved amaranth sauce (4.9%) did not differ from the same meal consumed with an iron-improved jute sauce (4.9%; P = 0.9), resulting in a similar quantity of total iron absorbed (679 vs. 578 μg; P = 0.3). Mean fractional iron absorption from maize paste accompanied by a traditional amaranth sauce (7.4%) was significantly higher than that from the other 2 meal types (P < 0.05), but the quantity of total iron absorbed was similar (591 μg; P = 0.4 and 0.7, respectively). A food-to-food fortification approach based on an increase in leafy vegetables does not provide additional bioavailable iron, presumably due to the high phenolic compound concentration of the leaves tested. Alternative measures, such as adding iron absorption enhancers to the sauces, need to be investigated to improve iron nutrition from Burkinabe maize meals.