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Response surface methodology (with central composite rotatable design for k = 3) was used to investigate the product properties of extruded rice--cowpea groundnut blends in a single screw extruder. The combined effect of cowpea (0-20%), groundnut (0-10%), and feed moisture (14-48%) levels were used for formulation of the products. The product moisture, expansion ratio, bulk density and total colour change were studied using standard analytical methods. Well-expanded rice legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Increasing legume addition affected the various shades of colour in the product. Models developed for the indices gave [R.sup.2] values ranging from 52.8% (for the b-value) to 86.5% (for bulk density). The models developed suggested that the optimal process variables for the production of a puffed snack with an enhanced nutrition and spongy structure from a rice--cowpea--groundnut blend are low feed moisture of 14-20% and maximum additions of 20% cowpea and 10% groundnut. A lack-of-fit test showed no significance, indicating that the models adequately fitted the data.

The rheological and textural characteristics of Ga-kenkey are critical for consumer acceptability of the product. This work studied the effects of corn steep water pretreatment with potassium metabisulfite on the rheological properties of Ga-kenkey. The pasting properties of corn dough obtained from corn that was soaked in water treated with and without potassium metabisulfite were determined using the Brabender viscoamylograph. The viscoelastic properties of Ga-kenkey obtained from the sulfited and nonsulfited steeped corn were determined using the TAXT2i Texture Analyzer. There was no detectable residual sulfur dioxide in Ga-kenkey obtained from metabisulfite treated corn. Metabisulfite treatment of steep water did not significantly change the pasting temperature of corn dough (80.15-80.40 °C). However, viscosities of the pastes increased tremendously for dough obtained from corn that was steeped in metabisulfite treated water. In particular, while viscosity at 50-Hold for dough obtained from metabisulfite treated corn was 191BU, it was 140BU for dough obtained from nonmetabisulfite treated corn. The stress relaxation parameters indicated that Ga-kenkey obtained from corn that was steeped in metabisulfite treated water exhibited more pronounced elastic behavior (equilibrium modulus, Ee = 0.695 kPa) and were stiffer than that obtained from corn that was steeped in water without metabisulfite treatment (equilibrium modulus, Ee = 0.399 kPa). SEM showed that Ga-kenkey obtained from both soaking treatments had some amounts of native starch, but Ga-kenkey obtained from sulfited steep water showed a more compact microstructure with more extensive starch transformations than that obtained from nonsulfited steep water. Practical applications Kenkey is a staple food in Ghana, and its processing and sale provide employment to many people. The operations in this cottage industry need to be standardized and eventually industrialized. Consequently, the effects of key unit operations on product quality characteristics need to be rationalized and improved. In the traditional kenkey process, the corn steep water is typically discarded without further treatment. However, disposing large quantities of corn steep water without pretreatment will eventually raise environmental problems because of the foul smell. Steeping corn in dilute potassium metabisulfite will retard the growth of putrefactive organisms and prevent foul odor development in the steep water, but may affect the textural characteristics of Ga-Kenkey. [ABSTRACT FROM AUTHOR]

Pito is an alcoholic beverage obtained through a yeast ( Saccharomyces cerevisiae) fermentation of wort extracted from sorghum ( Sorghum bicolor L. Moench) malt. The malting conditions of sorghum are thought to influence the quality characteristics of the malt, and subsequently the quality of the pito obtained from it. Studies were carried out on a local sorghum cultivar grown in Ghana - chireh, to optimize the conditions for malting conditions for pito production in Ghana. A 33 full factorial experimental design was replicated with steeping times of 12, 16 and 22 h, germination times of 3, 4 and 5 days, and malt drying temperatures of 30, 40 and 50 °C as factors. Diastatic power, extract yield, attenuation limit and free amino nitrogen were determined. Germination duration significantly affected diastatic power and free amino nitrogen ( p < 0.001). Extract yield was also significantly influenced by germination duration ( p = 0.001). The germination time, steeping time and drying temperature had no significant effect on the attenuation limit. The optimal conditions for malting this specific cultivar grown in Ghana to obtain critical malt quality indices are 12.0-12.5 h steeping, 5 days of germination at 30 °C and drying at 40 °C. Free amino nitrogen levels in all treatments were higher than the minimum requirement for good yeast nutrition and fermentation. Copyright © 2015 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

ABSTRACT Response surface methodology was used to study the effect of extruder characteristics on product quality of rice-groundnut-cowpea extrudates using a single-screw extruder. The combined effect of cowpea (0-20%), groundnut (0-10%) and feed moisture (12.02-44.06%) were used to formulate the products. Product moisture, protein, fat, ash, bulk density, expansion ratio, water absorption capacity (WAC) and swelling capacity were determined. Well-expanded rice-legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Addition of legumes resulted in significant increases in protein, fat and ash contents of the rice-legume extrudates while increasing cowpea increased all the physico-functional properties. The models developed gave R2 values ranging from 64.01% (WAC at 70C) to 86.5% (bulk density) and suggested that the optimal process variables of low feed moisture (10-12%), cowpea level (20%) and groundnut level (10%) would produce ready-to-eat puffed snack with enhanced nutritive value and physico-functional properties from rice-groundnut-cowpea blend extrudates. PRACTICAL APPLICATIONS Rice constitutes a primary food for millions of people in sub-Saharan Africa, Asia and Latin America, where it forms a major source of proteins and calories in the diet of large segments of the population. However, its protein is 'incomplete' and is deficient in the essential amino acids such as lysine and methionine. Fortification with legumes (groundnut and cowpea) has shown to lead to improvement in the total protein quality and quantity. Extrusion cooking involves a high-temperature short-time process, whereby a single- or mixed-food material is modified through the unique combination of high temperature, pressure and shear forces causing large numbers of complex changes to the food. Extrusion cooking of the rice-groundnut-cowpea blends is expected to produce a convenient puffed snack food, ready-to-eat and breakfast cereal of high nutritional value, comprising of complementary proteins that have increased nutritional value and better product of physical and functional characteristics. [ABSTRACT FROM AUTHOR]