6 research outputs found
Alterations in fruit and vegetable β-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers
This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on β-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and β-carotene by spectrophotometery at 450nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (
Changes In Physico-Chemical Properties And Flavour Compounds During Fermentation Of Different Obushera (Sorghum And Millet) Beverages
Four types of Obushera, a fermented millet or sorghum beverage:
Ekitiribita,Obuteire, Obutoko and Enturire were analyzed for their
physico-chemical properties, sugars, organic acids and volatile
compounds during fermentation. Standard chemical methods were used to
determine the physico-chemical properties of Obushera. The organic
acids, carbohydrates, glucose, fructose and maltose were analyzed by
high-performance liquid chromatography. The pH of all Obushera varied
between 4.00±0.10 and 4.42±0.11 after 4 days of fermentation.
The pH of Obuteire, Obutoko and Enturire dropped below 4.5 within one
day of fermentation. Acidity ranged between 0.13% (Ekitiribita) to
1.33% (Enturire) after 4 days of fermentation. Dry matter decreased and
varied between 5.4 and 22% after 4 days of fermentation. Fermentation
resulted into a 20 40% reduction of dry matter in Obutoko,
Obuteire and Enturire. Enturire had the highest dry matter content and
decreased from 22% to 13%. Fermentation resulted in an apparent
increase in protein concentration (5.7 12.3%). Flavour compounds
identified included sugars, organic acids, aldehydes, ketones, alcohols
and esters. Enturire contained the highest (p <0.05) concentrations
of most flavor compounds. Sugars (maltose, glucose and fructose) were
reduced during fermentation. The predominant organic acids detected
were lactate, acetate and succinate and increased with fermentation
time. Alcohols identified in Obushera were ethanol, 3-methyl-1-butanol,
2-methyl- 1-propanol and 2-methyl-1-butanol and increased during
fermentation. Ethanol was the predominating alcohol reaching a maximum
of 0.8-1.0% (Obuteire and Obutoko) and 4.5% in Enturire during
fermentation. The aldehydes detected in Obushera were acetaldehyde,
2-methyl-1-propanal, 2-methyl-1-butanal and 3-methyl-1-butanal and
varied from 0.1 mg kg-1 to 6.8 ± 1.2 mg kg-1. Diacetyl, acetoin
and 2,3 pentanedione were the ketones identified in Obushera. Esters
detected in Obushera included ethyl lactate, ethyl acetate, ethyl
butyrate and isobutyl acetate. Significantly higher (p <0.05)
amounts of esters were detected in Enturire than in the other types of
Obushera. Principal Component analysis, grouped Obushera into three
categories (Ekitiribita, Obuteire/Obutoko and Enturire) based on
flavour profile differences