Production, acceptability and microbiological evaluation of weaning food formulations

Processing and optimisation of complementary food blends from roasted pearl millet (Pennisetum glaucum) and soybean (Glycine max) using response surface modeling

Adequate nutrition is vital during infancy but the high cost of supplemented infant formulae has forced inhabitants of Central and West Africa to depend solely on low-nutrient gruels. Response Surface modelling was used to process a complementary food from roasted pearl millet and Soybean flour. A central composite design was adopted to study the effects of feed composition X1 (5.86-34.14%) and roasting temperature X2 (126-154 °C) on the micronutrients, functional, and sensory profiles of the different blends. The responses were significantly (p < 0.05) affected by the independent factors. For the vitamins in mg/100 g, the thiamin, riboflavin, folate, and β-carotene content ranged from 0.17-0.33, 24-53.50, 1.32-2.29, and 7-22.98, respectively. For the minerals in mg/100 g, the zinc, calcium, potassium, and iron content ranged from 0.35-0.54, 39.5-62.75, 1.2-1.8, and 0.017-0.18, respectively. The viscosity, bulk density, swelling capacity, water absorption capacity, and pH ranged from 1577.5-942.5 cP, 0.74-0.79 g/cm3, 0.10-0.30 ml/g, 1.2-1.4 ml/g, and 4.70-5.70, respectively. The sensory scores were rated highly by the panelists. The optimum processing conditions with a desirability of 0.50 gave 29.28% and 130.39 °C feed composition and roasting temperature, respectively.

Pyrosequencing scrutiny of bacterial and fungal communities in two Sudanese sorghum-based fermented foods

Purpose

Several fermented foods are produced from sorghum flour in Africa, especially in the dryland regions where it is the principal crop. It is important to explore the microbial communities in these foods to improve their quality and organoleptic properties. In this study, the bacterial and fungal communities of two popular sorghum-based fermented foods in Sudan (kisra and hulumur) were analyzed, for the first time, using a culture-independent method of next-generation sequencing.

Methods

Fermented doughs for kisra and hulumur production were prepared according to the traditional approach, and then the bacterial and fungal communities were investigated using high-throughput sequencing.

Results

Firmicutes and Proteobacteria phyla were the predominant bacteria in both fermented doughs. At the genus level, the bacterial community was dominated by lactic acid bacteria, primarily Lactobacillus and Pediococcus, which represented 95.7% and 72% of the bacterial population in kisra and hulumur, respectively. Next, acetic acid bacteria (Gluconobacter and Acetobacter) were subdominant in hulumur. The fungal community was more heterogeneous among the fermented doughs. Zygomycota (85.5%) comprised the major phylum in kisra fermented dough, whereas Ascomycota (99.5%) was predominant in hulumur. The major fungal genera, Rhizopus, Alternaria, Penicillium, Gibberella, Lasiodiplodia, and Aspergillus, were extremely varied between the fermented doughs.

Conclusion

Exploration of kisra and hulumur microbial community structure will expand the knowledge about their microbiota to manipulate the microbial community and improve their quality and organoleptic properties using different microbial recipes.

Effects of fermentation and malt addition on the physicochemical properties of cereal based complementary foods in Ethiopia

Complementary foods (CFs) in Ethiopia are characterised by bulkiness, and poor nutrient density as these foods are primarily made of starchy staples. Meanwhile, several modification techniques are available to improve the quality of the starch-based CFs. The objective of this study was to examine the effect of fermentation time and malt concentration on cereal-based CFs in Ethiopia, intending to improve the nutrient density and reduce dietary bulkiness. Oats, barley and teff flours, with added malt at different concentrations (0, 2 and 5%), were spontaneously fermented for 0, 24 and 48 h. The physical, chemical and sensory properties of the fermented CFs flour were evaluated. The protein, fat, fibre, energy, phytate, tannin, bulk density, water absorption capacity (WAC) and viscosity ranged between 8.12–16.82%, 1.63–4.55%, 1.58–5.96%, 359.33–380.26kcal/100g, 18.63–175.07mg/100g, 0.84–42.89mg/100g, 0.66–0.99 g/ml, 61.33–143.12%, 235cP-1016.33cP, respectively. For all the three kinds of cereal, fermentation for 24 h resulted in a better sensory quality regardless of the malt concentration. Crude fibre, crude fat, total carbohydrate, phytate, tannin, bulk density and viscosity of the three kinds of cereal were significantly reduced due to the interaction of fermentation and addition of malt. Conversely, crude protein and calorific value were significantly increased by the interaction. Addition of 2% malt and fermentation of the cereal flours for 24 h increased energy density and palatability, reduced dietary bulkiness and viscosity of CFs, which in turn will increase food intake by infants and young children.

Composition and Origin of the Fermentation Microbiota of Mahewu, a Zimbabwean Fermented Cereal Beverage

Mahewu is a fermented cereal beverage produced in Zimbabwe. This study determined the composition and origin of mahewu microbiota. The microbiota of mahewu samples consisted of 3 to 7 dominant strains of lactobacilli and two strains of yeasts. Enterobacteriaceae were not detected. Candida glabrata was present in high cell counts from samples collected in summer but not from samples collected in winter. Millet malt is the only raw ingredient used in the production of mahewu and is a likely source of fermentation microbiota; therefore, malt microbiota was also analyzed by culture-dependent and high-throughput 16S rRNA gene sequencing methodologies. Millet malt contained 8 to 19 strains of Enterobacteriaceae, lactobacilli, bacilli, and very few yeasts. Strain-specific quantitative PCR assays were established on the basis of the genome sequences of Lactobacillus fermentum FUA3588 and FUA3589 and Lactobacillus plantarum FUA3590 to obtain a direct assessment of the identity of strains from malt and mahewu. L. fermentum FUA3588 and FUA3589 were detected in millet malt, demonstrating that millet malt is a main source of mahewu microbiota. Strains which were detected in summer were not detected in samples produced at the same site in winter. Model mahewu fermentations conducted with a 5-strain inoculum consisting of lactobacilli, Klebsiella pneumoniae, and Cronobacter sakazakii demonstrated that lactobacilli outcompete Enterobacteriaceae, which sharply decreased in the first 24 h. In conclusion, mahewu microbiota is mainly derived from millet malt microbiota, but minor components of malt microbiota rapidly outcompete Enterobacteriaceae and Bacillus species during fermentation.IMPORTANCE This study provides insight into the composition and origin of the microbiota of mahewu and the composition of millet malt microbiota. Fermentation microbiota are often hypothesized to be derived from the environment, but the evidence remains inconclusive. Our findings confirm that millet malt is the major source of mahewu microbiota. By complementing culture methods with high-throughput sequencing of 16S rRNA amplicons and strain-specific quantitative PCR, this study provides evidence about the source of mahewu microbiota, which can inform the development of starter cultures for mahewu production. The study also documents the fate of Enterobacteriaceae during the fermentation of mahewu. There are concerns regarding the safety of traditionally prepared mahewu, and this requires in-depth knowledge of the fermentation process. Therefore, this study elucidated millet malt microbiota and identified cultures that are able to control the high numbers of Enterobacteriaceae that are initially present in mahewu fermentations.