Influence of ripeness stage on the bioactive compounds' contents and antioxidant activities of Solanum anguivi Lam. fruits accessions.

Solanum anguivi Lam. fruits (SALF) possess bioactive compounds, such as phenolics, alkaloids, saponins, flavonoids, and vitamin C, that are beneficial for preventing oxidative stress-related diseases. It has been documented that ripeness stage influences the nutritional quality of fruits. However, there is limited information on the effect of the ripeness stages (unripe, yellow, orange and red) on the bioactive compounds' contents (BCC) and antioxidant activity (AA) of SALF. We investigated the effect of ripening on the BCC and AA of different SALF accessions. Spectrophotometry was used to determine SALF's total contents of phenolics, flavonoids, saponins, vitamin C, and AA and gravimetry for total alkaloids. The AA was determined as free radical scavenging activity (FRSC) and total antioxidant capacity (TAC). The total phenolics (7.6-22.6 mg gallic acid equivalent/g DW), flavonoids (1.3-4.1 mg quercetin equivalent (QE)/g DW), saponins (44.8-152.5 mg diosgenin equivalent/g DW), vitamin C (2.2-6.4 mg ascorbic acid equivalent/g DW), alkaloids (141.2-296.9 mg/g DW), FRSC (1.5-66.2 %) and TAC (0.1-14.2 mg QE/g DW) significantly differed among the ripeness stages. Fruits in the unripe stage were rich in phenolics, flavonoids, and AA; in the red stage in alkaloids and vitamin C; and in the orange stage, in saponins and flavonoids. The AA had strong positive correlations with total flavonoids and phenolics (r = 0.72 and 0.81, respectively) and a moderate negative correlation with total alkaloids (r = -0.67). Overall, unripe stage fruits had the highest AA and total phenolics and thus may have the highest health-promoting properties. Botanists and farmers may, therefore, focus on harvesting and trading SALF to markets/consumers while still unripe.

Influence of Drying Methods on Jackfruit Drying Behavior and Dried Products Physical Characteristics.

Drying processes including solar, oven, and refractance window were studied to determine their influence on the drying behavior of jackfruit slices and properties of resultant jackfruit powders. The loss of sample mass, converted to the ratio between the water content at time t and the initial water content (moisture ratio), was used as the experimental parameter for modelling drying processes. Fifteen thin layer drying models were fitted to the experimental data using nonlinear regression analysis. Based on the highest R 2 and lowest SEE values, the models that best fit the observed data were Modified Henderson and Pabis, Verma et al., and Hii et al. for RWD, oven, and solar drying, respectively. The effective moisture diffusivity coefficients were 5.11 × 10-9, 3.28 × 10-10, and 2.55 × 10-10 for RWD, oven and, solar drying, respectively. The solubility of freeze-dried jackfruit powder (75.7%) was not significantly different from the refractance window dried powder (73.2%) and was higher than oven-dried jackfruit powder (66.1%). Oven-dried jackfruit powder had a lower rehydration ratio and porosity. Differences in rehydration ratio and porosity under different drying methods could be explained by the microstructure. Fractal dimension (FD) and lacunarity were applied to study the structure and irregularities of jackfruit dried with the different methods. FD was significantly (P < 0.05) affected by the drying method. FD ranged from 1.809 to 1.837, while lacunarity ranged between 0.258 and 0.404.

Optimization of drying conditions for Jackfruit pulp using Refractance Window Drying technology.

Refractance window drying is a novel technology with high operational efficiency and high product quality retention compared with conventional drying methods. This study assessed the effect of refractance window dryer water temperature and pulp thickness on nutrient content and the antioxidant activity of jackfruit. Response surface methodology (RSM) was used to optimize the drying temperature and fruit pulp thickness. Optimal drying temperature and pulp thickness were found to be 93.4°C and 2.56 mm, respectively. The respective values for the response variables drying time (min), ascorbic acid (mg/100 g), antioxidant activity (mg/100 g AA equiv) and total carotenoid content (µg/g) were 60.47, 17.97, 82.34, and 13.34, respectively. Models for prediction of these values had R 2 values of .964, .980, .994, and .994, respectively, and nonsignificant lack of fit (p < .05). This indicates the suitability of the model in predicting the RWD operating conditions to produce quality dried jackfruit.

Production of organic flavor compounds by dominant lactic acid bacteria and yeasts from Obushera, a traditional sorghum malt fermented beverage.

Single and mixed starter cultures of lactic acid bacteria (LAB): Weissella confusa MNC20, Lactobacillus plantarum MNC21, Lactococcus lactis MNC24 and Lactobacillus fermentum MNC34 and yeasts: Issatchenkia orientalis MNC20Y and Saccharomyces cerevisiae MNC21Y were used to produce Obushera, a fermented sorghum beverage. Microbial counts, pH, sugars, organic acids, and volatile compounds in starter culture and spontaneous fermentations were monitored during 48 hrs. Maximum counts of LAB (8.4-9.4 log cfu g-1) and yeasts (7.5 ± 0.1 cfu g-1) starter cultures were attained in 6-48 hrs. Weissella confusa, Lc. lactis, and Lb. fermentum showed possible acid sensitivity while I. orientalis produced surface films. LAB starter cultures and their combinations with S. cerevisiae lowered pH from 5.83 to <4.5 (3.50-4.13) in a shorter time (12 hrs) than spontaneous fermentations (24 hrs). Lactococcus lactis and W. confusa metabolized glucose the fastest (p < .05) during the first 6 hrs. Lactobacillus fermentum, Lb. plantarum, and S. cerevisiae utilized glucose and maltose concurrently. Lactobacillus plantarum and S. cerevisiae additionally utilized fructose. S. cerevisiae metabolized sugars the fastest (p < .05) during the first 12-24 hrs. Lactobacillus plantarum and W. confusa produced the highest (p < .05) amounts of lactate (5.43 g kg-1) and diacetyl (9.5 mg kg-1), respectively. LAB also produced acetate, ethanol, acetaldehyde, acetone, and acetoin. Coculturing LAB with S. cerevisiae reduced (p < .05) lactate and diacetyl yield. Yeasts produced high amounts of acetaldehyde and methyl alcohols. Issatchenkia orientalis produced higher (p < .05) amounts of 2-methy-1-propanol and 3-methyl-1-butanol than S. cerevisiae. Combinations of LAB with S. cerevisiae produced a profile flavor compounds close to that of spontaneously fermented Obushera. These combinations can be adopted for controlled fermentation of Obushera and related fermented cereal products.

Determinants of anaemia among pregnant women in rural Uganda.

INTRODUCTION: In spite of intervention efforts, in Uganda, as in other developing countries, high levels of anaemia among pregnant women continue. Anaemia among women of reproductive age (15-49 years) is a matter of national concern. This study was carried out to assess determinants of anaemia in Kiboga district. METHODS: This was a single cross-sectional, descriptive survey. The anaemia status of the pregnant women was determined by measuring their haemoglobin levels. Possible determinant factors including socio-economic characteristics, knowledge, attitudes, practices and food intake were assessed using a structured questionnaire. RESULTS: Results showed that the prevalence of anaemia among pregnant women in Kiboga district was high enough (63.1%) to be described as a severe public health problem. The uptake and utilisation of the public-health intervention package to combat anaemia in pregnancy was low, with iron/folic acid supplementation at 13.2%, use of intermittent preventive treatment of malaria 45.4%, and use of de-worming medicines 14.5%. Women from households without a functional radio were 2.07 times more likely be anaemic (95%CI, 1.08-3.00) compared with women from households where there was a functional radio. There was little awareness and functional knowledge about anaemia among pregnant women. CONCLUSION: The high prevalence of anaemia observed in Kiboga district can be attributed to poverty and limited access to nutrition and health education information which lead to low uptake and utilization of the public-health intervention package to combat anaemia in pregnancy.

Formulation of a drinkable peanut-based therapeutic food for malnourished children using plant sources.

High ingredient costs continue to hamper local production of therapeutic foods (TFs). Development of formulations without milk, the most expensive ingredient, is one way of reducing cost. This study formulated a ready-to-drink peanut-based TF that matched the nutrient composition of F100 using plant sources. Three least cost formulations namely, A, B and C were designed using computer formulation software with peanuts, beans, sesame, cowpeas and grain amaranth as ingredients. A 100 g portion of the TF provided 101-111 kcal, 5 g protein and 5.3-6.5 g fat. Consumer acceptability hedonic tests showed that the products were liked (extremely and moderately) by 62-65% of mothers. These results suggest that nutrient dense TFs formulated from only plant sources have the potential to be used in the rehabilitation phase of the management of malnourished children after clinical testing.

The dominant microbial community associated with fermentation of Obushera (sorghum and millet beverages) determined by culture-dependent and culture-independent methods.

Obushera includes four fermented cereal beverages from Uganda namely: Obutoko, Enturire, Ekitiribita and Obuteire, whose microbial diversity has not hitherto been fully investigated. Knowledge of the microbial diversity and dynamics in these products is crucial for understanding their safety and development of appropriate starter cultures for controlled industrial processing. Culture-dependent and culture-independent techniques including denaturating gradient gel electrophoresis (DGGE) and mixed DNA sequencing of polymerase chain reaction (PCR) amplified ribosomal RNA genes were used to study the bacteria and yeast diversity of Obushera. The pH dropped from 6.0-4.6 to 3.5-4.0 within 1-2 days for Obutoko, Enturire and Obuteire whereas that of Ekitiribita decreased to 4.4 after 4 days. Counts of lactic acid bacteria (LAB) increased from 5.0 to 11.0 log cfug(-1) and yeasts increased from 3.4 to 7.1 log cfug(-1) while coliform counts decreased from 2.0 to <1 log cfug(-1) during four days of fermentation. LAB and yeast isolates were identified by rRNA gene sequence analysis. LAB isolates included: Enterococcus spp., Lactobacillus (Lb.) plantarum, Lb. fermentum, Lb. delbrueckii, Lactococcus lactis, Leuconostoc lactis, Streptococcus (S.) infantarius subsp. infantarius, Pediococcus pentosaceus and Weisella (W.) confusa. DGGE indicated predominance of S. gallolyticus, S. infantarius subsp. infantarius, Lb. fermentum, Lb. delbrueckii, W. confusa, Lb. reuteri, Fructobacillus spp., L. lactis and L. lactis. Yeast isolates included Clavispora lusitaniae, Cyberlindnera fabianii, Issatchenkia orientalis and Saccharomyces cerevisiae. DGGE indicated predominance of S. cerevisiae in Obutoko, Enturire and Obuteire and also detected Pichia spp. and I. orientalis in Obutoko. Obushera produced in the laboratory was initially dominated by Enterobacteriaceae and later by Lactococcus spp. Enterobacteriaceae and Bacillus spp. were also detected in Ekitiribita. Development of starters for Obushera may require combinations of LAB and S. cerevisiae for Obutoko, Enturire and Obuteire and LAB for Ekitiribita.

Influence of cofermentation by amylolytic Lactobacillus plantarum and Lactococcus lactis strains on the fermentation process and rheology of sorghum porridge.

Amylolytic lactic acid bacteria (ALAB) can potentially replace malt in reducing the viscosity of starchy porridges. However, the drawback of using ALAB is their low and delayed amylolytic activity. This necessitates searching for efficient ALAB and strategies to improve their amylolytic activity. Two ALAB, Lactobacillus plantarum MNC 21 and Lactococcus lactis MNC 24, isolated from Obushera, were used to ferment starches in MRS broth: sorghum, millet, sweet potato, and commercial soluble starch. The amylolytic activity of MNC 21 was comparable to that of the ALAB collection strain Lb. plantarum A6, while that of MNC 24 was extremely low. MNC 21, MNC 24, and their coculture were compared to A6 and sorghum malt for ability to ferment and reduce the viscosity of sorghum porridge (11.6% dry matter). ALAB and the coculture lowered the pH from 6.2 to <4.5 within 12 h, while malt as a carrier of wild starter took about 20 h. Coculturing increased lactic acid yield by 46% and 76.8% compared to the yields of MNC 21 and MNC 24 monocultures, respectively. The coculture accumulated significantly larger (P < 0.05) amounts of maltose and diacetyl than the monocultures. Sorghum malt control and the coculture hydrolyzed more starch in sorghum porridge than the monocultures. The coculture initiated changes in the rheological parameters storage modulus (G'), loss modulus (G″), phase angle (δ), and complex viscosity (η*) earlier than its constituent monocultures. The shear viscosity of sorghum porridge was reduced significantly (P < 0.05) from 1950 cP to 110 cP (malt), 281 cP (coculture), 382 cP (MNC 21), 713 cP (MNC 24), and 722 cP (A6). Coculturing strong ALAB with weak ALAB or non-ALAB can be exploited for preparation of nutrient-dense weaning foods and increasing lactic acid yield from starchy materials.

Effect of preparation conditions on protein secondary structure and biofilm formation of kafirin.

Various extraction and drying conditions for the isolation of kafirin from dry-milled, whole grain sorghum have been investigated, with a view to optimizing extraction of the protein for commercial food coatings and packaging films. The addition of sodium hydroxide to an aqueous ethanol extractant increased the yield and solubility of kafirin. Subsequent heat drying at 40 degrees C was shown to cause the kafirin to aggregate as indicated by an increase in intermolecular beta-sheets. Extraction of the flour using ethanol (70%, w/w) with 0.5% (w/w) sodium metabisulfite and 0.35% (w/w) sodium hydroxide at 70 degrees C followed by freeze-drying of the protein was found to produce a yield of 54% kafirin with good film-forming properties. The kafirin films were assessed for their sensory properties, tensile strength, strain, and water vapor permeability. Fourier transform infrared spectroscopy was used to study the secondary structure of the extracted kafirins. The best films were made with kafirin containing a large proportion of nativelike alpha-helical structures with little intermolecular beta-sheet content as indicated by the Fourier transform infrared reflectance peak intensity ratios associated with these secondary structures. The principal factor affecting the secondary structure of the protein appeared to be the temperature at which the protein was dried. Heat drying resulted in a greater proportion of intermolecular beta-sheets. Any industrial-scale extraction must therefore minimize protein aggregation and maximize native alpha-helical structures to achieve optimal film quality.