Christian Picq

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.

Determination of expression and activity of genes involved in starch metabolism in Lactobacillus plantarum A6 during fermentation of a cereal-based gruel

Traditional fermented gruels prepared from cereals are widely used for complementary feeding of young children in Africa and usually have a low energy density. The amylase activity of some lactic acid bacteria (LAB) helps increase the energy content of gruels through partial hydrolysis of starch, thus enabling the incorporation of more starchy material while conserving the desired semi-liquid consistency for young children. Even if this ability is mainly related to the production of alpha-amylase (E.C. 3.2.1.1), in a recent molecular screening, genes coding for enzymes involved in starch metabolism were detected in the efficient amylolytic LAB Lactobacillus plantarum A6: alpha-glucosidase (E.C. 3.2.1.20), neopullulanase (E.C. 3.2.1.135), amylopectin phosphorylase (E.C. 2.4.1.1) and maltose phosphorylase (E.C. 2.4.1.8). The objective of this study was to investigate the expression of these genes in a model of starchy fermented food made from pearl millet (Pennisetum glaucum). Transcriptional and enzymatic analyses were performed during the 18-h fermentation period. Liquefaction was mainly caused by an extracellular alpha amylase encoded by the amyA gene specific to the A6 strain among L. plantarum species and found in both Lactobacillus amylovorus and Lactobacillus manihotivorans. The second most active enzyme was neopullulanase. Other starch metabolizing enzymes were less often detected. The dynamic detection of transcripts of gene during starch fermentation in pearl millet porridge suggests that the set of genes we investigated was not expressed continuously but transiently.

Iron Contamination during In-Field Milling of Millet and Sorghum

Nutritionally, contaminant iron in foods may lead to overestimation of the satisfaction of iron requirement while iron deficiencies remain a widespread health problem. Iron contamination was measured in millet and sorghum grains after decortication and in-field milling using different equipments in Burkina Faso. Total iron content did not change significantly after decortication, probably due to a balance between losses resulting from the removal of iron-rich peripheral parts and contamination. Total iron contents increased significantly after mechanical milling irrespective of whether iron or corundum grindstones were used. Contamination was highly variable, ranging from 3 to 6 mg iron/100 g DM, and was mainly due to wear of the milling equipment. After in vitro digestion of traditional cereal dishes prepared with iron-contaminated or uncontaminated flours, the contaminant iron was found mainly in the insoluble fraction. Only in sorghum was a small proportion (4%) bioaccessible, showing that contaminant iron has poor nutritional interest.

Recipes and nutritional value of dishes prepared from green-leafy vegetables in an urban district of Antananarivo (Madagascar)

Abstract The recipes of 50 multi-ingredient dishes consumed by the population in an urban district were noted down. The nutritional value was determined as well as the cook value of the dishes in order to evaluate the severity of the thermal treatment. The recipes were simple and involved steps such as boiling, mixing, and cutting. Fibre contents were rather low except when the leaf stems were included. All the dishes had very high β-carotene content (15.8–25.0 mg/100 g dry matter) and retinol activity equivalent (RAE) (1.3–2.3 mg RAE/100 g dry matter) because of the high proportion of fresh leafy vegetables (from 41.2% to 58.8% of the total dry matter of the ingredients). When meat was added to the preparation, the micronutrient content (iron, zinc, and retinol) was not increased significantly. In three dishes, a positive correlation was found between the thermal treatment severity and the 13-cis-β-carotene amount.

Rapid quantification of iron content in fish sauce and soy sauce: a promising tool for monitoring fortification programs.

Background In a number of Southeast Asian countries and China, fish sauce and soy sauce produced at the industrial level are fortified with iron. Unfortunately, the food producers and regulatory agencies implementing fortification programs do not always have the capacity to monitor the programs on an ongoing basis. Objective To assess a new portable device for the quantitative measurement of iron content of fortified sauces that could be used to control fortification levels. Methods The linearity, detection limits, and inter- and intraassay variability of this device were assessed on fish sauce and soy sauce fortified with ferrous sulfate, ferrous fumarate, and sodium iron ethylenediaminetetraacetate (NaFeEDTA); the accuracy of the results was determined by comparing them with the results obtained by atomic absorption spectrophotometry. Results Measurements required a minimum incubation time of 1 hour for iron sulfate or iron fumarate and 24 hours for NaFeEDTA. Linearity of the results ranged from 2 to 10 mg iron/L for ferrous sulfate or ferrous fumarate and from 1 to 10 mg iron/L for NaFeEDTA, implying the need for proper dilution, as the iron contents of fortified sauce are usually in the range of 150 to 1,000 mg/L. Depending on incubation time, iron compounds, and sauces, the coefficient of variation (CV) of intraassay precision was between 1.5% and 7.6% and the CV of interassay precision was between 2.9% and 7.4%. Comparison with results from atomic absorption spectrophotometry showed high agreement between both methods, with R = 0.926 and R = 0.935 for incubation times of 1 hour and 24 hours, respectively. The Bland—Altman plots showed limits of agreement between the two methods of ± 70 mg/L in the range of fortification levels tested (100 to 500 mg/L). Conclusions This device offers a viable method for field monitoring of iron fortification of soy and fish sauces after incubation times of 1 hour for ferrous sulfate or ferrous fumarate and 24 hours for NaFeEDTA.

Determining Factors of Lipophilic Micronutrient Bioaccessibility in Several Leafy Vegetables

Micronutrient deficiencies are still a public health issue in least developed countries. Promoting diet diversification is a promising strategy. Numerous fruits and vegetables are rich in micronutrients, but some of these compounds are poorly bioaccessible. The objective of this study was to identify the biochemical determinants of the micronutrient bioaccessibility in leaves. The contents in cell walls, pectins, tannins, and proteins of the leafy vegetables were assessed, and correlations with the micronutrient bioaccessibitity were explored. The leafy vegetables have interesting nutritional profiles with noticeable amounts in protein, provitamin A (β-carotene), and α-tocopherol for some species. Their cell wall contents greatly varied from 3.4 to 8.7 g/100 g as well as their pectin percentages. Only the perilla and drumstick leaves contained condensed tannins. In fresh leaves, the contents in bioaccessible carotenoids were low. The correlation study highlighted that the carotenoid bioaccessibility was negatively correlated to the pectin contents of the leaves.

Adequacy of Some Locally Produced Complementary Foods Marketed in Benin, Burkina Faso, Ghana, and Senegal

Adequate complementary foods are needed to help reduce the high prevalence of stunting in children in many Low and Middle Income Countries (LMICs). We assessed the availability, affordability, and nutrient adequacy of imported and locally produced processed cereal-based blends (PCBBs), marketed as complementary food for young children in Benin, Burkina Faso, Ghana, and Senegal. In total, 19 local producers and 275 points of sale in the four countries were surveyed to evaluate the quantities and accessibility of PCBBs. In addition, 32 PCBBs were analysed for their nutritional composition and packaging information. The results showed that only 7 out of 32 PCBBs could be classified as nutritionally satisfactory. Access to the products was insufficient in all surveyed settings. At the points of sale, the PCBB market was dominated by imported products, even though two out of four imported PCBBs were not nutritionally satisfactory. Imported PCBBs were two to three times more expensive than locally produced PCBBs. Labelling of the PCBBs was inadequate in many aspects. Technical support should be offered to local PCBB producers to ensure the adequate formulation and supply of an appropriate vitamin and mineral premix. The development of national specific regulations on PCBB composition and labelling is strongly recommended in these countries.

Effects of cooking and food matrix on estimated mineral bioavailability in Mloukhiya, a Mediterranean dish based on jute leaves and meat

Traditional Mediterranean plant-based dishes could allow tackling malnutrition while preserving the cultural heritage. To determine the effect of the cooking method on mineral bioavailability, the content in minerals and chelators of Mloukhiya, a Mediterranean dish based on jute leaves (Corchorus olitorius) that contains also meat, was monitored during the whole cooking process. Mineral bioaccessibility was assessed by measuring in vitro dialyzability. Model equation was also used to estimate mineral bioavailability. Comparison of Mloukhiya samples collected at different cooking time points showed that the dish total mineral content did not change despite the exchanges between sauce and meat during cooking. However, iron bioavailability decreased, because 58% of heme iron was degraded after 5h of cooking and non-heme iron showed poor bioaccessibility (1.2%), mainly due to its high content of phenolic compounds. The bioaccessibility of other minerals (zinc, calcium, magnesium and potassium) was high, indicating that the food matrix had no or little effect. The mineral bioavailability values predicted by using mathematical models were of the same order of magnitude as the bioaccessibility values.