Effects of infestation on the nutrient content and physiocochemical properties of two cowpea ( Vigna unguiculata) varieties

Two cowpea varieties (Ife-brown and Kano-white varieties) were used for the study. The effects of insect infestation on the chemical composition and physicochemical properties of these cowpea seeds were studied. The proximate composition, mineral content, total starch, total soluble sugars, bulk density, fat and water absorption capacities, viscosity, gelation capacity and emulsion properties of infested cowpea varieties were compared with those of uninfested cowpeas. Effects of infestation on nitrogen solubulity and on the protein fractions were also determined. lnfestation depleted the protein, starch and soluble sugar contents of cowpeas. Oil and water absorption capacities were increased while emulsification, foam and viscosity properties were reduced. The nitrogen solubility pattern was altered. Uninfested Kano-white cowpeas (UKW) possessed better foam properties than uninfested Ife-brown cowpeas (UFB). On the other hand, UFB had better emulsification properties than UKW.     

Potentials of Gum From <Emphasis Type="Italic">Detarium microcarpum</Emphasis> (DM) and <Emphasis Type="Italic">Mucuna flagellipes</Emphasis> (MF) Seeds as Raw Beef Burger Stabilizers

Raw beef burgers containing graded levels (0.25, 0.5, 0.75, and 1.0%) of polysaccharide gums extracted from Detarium microcarpum (DM) and Mucuna flagellipes (MF) were produced. Unstabilized beef burgers and beef burgers containing gum tragacanth (TR) were also produced simultaneously to serve as control. The raw beef burgers were evaluated for selected physicochemical and sensory properties so as to assess the stabilization potentials of DM and MF polysaccharide gums relative to the conventional TR. Beef burgers containing the polysaccharide gums had significantly (P<0.05) lower shrinkage, higher water holding capacity (WHC), and better stability under ambient conditions (27±1°C and RH 90.6%) then the unstabilized burgers. Among the stabilized burgers, DM gum burgers had lower (P0.05) shrinkage and higher WHC than MF and TR gums burgers. All the gum-stabilized beef burgers required 9–26% higher compression force indicating a less friable product than the unstabilized burgers. At 0.25 and 0.5% levels of gum incorporation DM gum burgers had comparable compression force with TR gum burgers and this was lower (P0.05) than the compression force of MF gum burgers. Sensory panel results indicated a lower score for finger feel in gum-stablized burgers than the unstabilized burgers. DM and TR gum burgers had comparable scores with TR gum burgers in all the sensory attributes tested. Overall acceptability score showed that all the gum-stabilized beef burgers were acceptable. It was evident from the study that polysaccharide gums from DM and MF seeds can serve as effective stabilizers in beef burgers without adverse effect on the quality of the product.     

Certain functional properties of gums derived from some lesser known tropical legumes (Afzelia africana,Detarium microcarpum andMucuna flagellipes)

Gum was extracted from some lesser known tropical legumes —Afzelia africana, Detarium microcarpum andMucuna flagellipes. The extracts were evaluated for some functional properties. At a constant shear rate the apparent viscosity of the gums was directly proportional to the gum concentration. At 2% concentration, the gum dispersions showed an apparent viscosity of 41.24, 115.05 and 145.14 cps forA. africana, D. microcarpum andM. flagellipes gums respectively, measured at 174/sec and 25±1°C with the NV sensor of Haaké rotovisko viscometer. All the gums were found to contain D-galactose as a major monosaccharide. In addition, the presence of D-mannose, and D-glucose were indicated in bothD. microcarpum andM. flagellipes while L-rhamnose, was indicated only inA. africana. A. africana showed significantly (p<0.05) lower water absorption capacity and gelation properties thanD. microcarpum andM. flagellipes. All the gums showed good emulsion properties. Emulsions ofM. flagellipes gum showed little response to pH changes whileA. africana andD. microcarpum gum showed better emulsion properties at acid pH than at alkaline pH.     

Effect of Detarium microcarpum (Dm) and Mucuna flagellipes (Mf) gums on the quality of white bread

Incorporation of Detarium Microcarpum (Dm) and Mucuna flagellipes (Mf) water soluble polysaccharides (gums) at 0.0 to 0.5% levels in wheat flour was studied to evaluate their effect on the rheological properties of wheat flour dough and white bread quality. At all levels of incorporation, there were increases (p 0.05) in water absorption of the dough. Doughs containing gums had higher (p 0.05) mixing tolerance index than the control. Set back viscosities decreased by 4.0 RVU and 9.0 RVU with increased levels of Dm and Mf gum incorporation, respectively. Significantly (p 0.05) higher oven spring occurred in all the gum substituted white bread when compared to the control. The 0.5% gum substituted breads had a significantly (p 0.05) higher sensory score for crumb grain, texture but lower (p<0.05) crumb firmness than the control as determined instrumentally. Textural analysis after 5 days storage revealed that Dm and Mf gums improved moisture retention properties of the bread and reduced crumb firming tendency.     

Effect of pre-dehulling treatments on the composition of seeds of the legumeAfzelia africana and its potential use in pastries

Flour was prepared from seeds ofAfzelia africana dehulled by different treatments and used to replace 10, 20, 30, 40 and 50% wheat flour in biscuits and doughnuts. The composition and water and oil absorption properties of the flour blends were evaluated. The biscuits and doughnuts made from each flour blend were evaluated organoleptically. The composite flour containing the highest proportion (50%) ofA. africana seed flour contained the highest levels of protein and fat, exhibited the highest water absorption property but the lowest oil absorption capacity. Sensory scores showed high overall acceptability for products with a 10–30% level of substitution.