American Journal of Food Technology1557-45711557-458XAcademic Journals Inc.10.3923/ajft.2007.502.511AnuonyeJ.C. BadifuG.I.O. InyangC.U. AkpapunamM.A. OdumuduC.U. MbajikaV.I. 6200726The effect of extrusion variables on the protein dispersibility
index and tyrpsin inhibitor activity of blends of acha and soybean were
studied using response surface analysis. Soybean flour was mixed with
acha flour at 0, 12.5, 25, 37.5 and 50% levels of substitution. Moisture
content of the mixtures was adjusted to 15, 20, 25, 30 and 35%. Extrusion
was carried out in a single screw Brabender extruder by adjusting the
screw speed from 90 to 120, 150, 180 and 210 rpm and barrel temperature
from 100 to 125, 150, 175 and 200°C following a 4-variable central
composite rotatable response surface design. Protein dispersibility index
and trypsin inhibitor activity of raw and extruded blends were evaluated.
Raw acha, soybean flour and raw acha/soybean flour blends had PDI
of 86.84, 91.84 and 74.27%, respectively compared to extrudate PDI which
ranged from 3.77-8.70%. Blending decreased the protein dispersibility
index of the raw flours while extrusion cooking significantly improved
the protein dispersibility. For TIA, the results showed that TIA of extrudates
ranged from 4.0-46.1 units, compared to the raw samples (64.5 units for
raw soybean). The results showed that extrusion cooking reduced TIA by
about (70.33-97.40%) with feed moisture and barrel temperature exerting
the greatest influence on extrudate TIA. The decrease in TIA corresponded
to increased protein dispersibility of extrudate samples.]]>Aguilera, J.M. and E.W. Lusas,198663239243AOAC.,198414th Edn.,pp: 522-533pp: 522-533Camire, M.E., A. Camire and K. Krumhar,1990293557Cheftel, J.C.,19841984pp: 1-15pp: 1-15Del Valle, F.R., M. Escobedo, M.J. Munoz, R. Ortega and H. Bourges,1983Prosopis juliftora).]]>48914919FAO,1985Harper, J.M.,1980Vol. 1,pp: 1-3pp: 1-3Harper, J.M. and G.R. Jasen,198512797Iwe, M.O. and P.O. Ngoddy,200024453463Iwe, M.O.,200055169184Iwe, M.O., D.J. van Zuilichem, P.O. Ngoddy and D.J. Winlarmmers,2001347175Iwe, M.O.,20031st Edn.,Iwe, M.O., D.J. Van Zuilichem, W. Stolp and P.O. Ngoddy,200462143150Keshun, L.,19991999pp: 409418Kwon-Ndung, E.H. and S.M. Misari,2000pp: 71-76pp: 71-76Leslie, L.R. and A.W. Dale,1990Vol. 3,Liener, I.E.,1994343167Lorenz, K., G.R. Jansen and J.M. Harper,198025161162Meyers, H.R.,1976Mullen, K. and D.M. Ennis,1979337481Osho, S.M. and K. Dashiell,19951995pp: 151156Philips, R.D., M.S. Chinnan and L.G. Mendoza,1983in vitro digestibility and nitrogen solubility of cowpea flour.]]>4818631867Poel, A.F., J. Blonk, D.J. van Zuilichem and M.G. van Oort,1990Phaseolus vulgaris L.) and effects on protein quality.]]>53215228Rackis, J.J., J.E. McGhee and A.N. Booth,1976528591Tanteeratarm, K. and K.E. Weingartner,19981998pp: 419-422pp: 419-422Tayeb, J., G. del Valle, C. Barres and V. Bruno,19921992pp: 41-70pp: 41-70Tsen, C.C., E.P. Farrel, W.J. Hoover and P.R. Crowdley,197520413418Victor, J.T. and D.B. James,1991Digitaria exilis) grain.]]>56561563Wilmot, B.W. and A.I. Nelson,19981998pp: 149-157pp: 149-157