University of Khartoum

Protein Quality and Acceptability of Sorghum Flour Supplemented with Defatted Groundnut Flour as Influenced by Traditional Processing

Protein Quality and Acceptability of Sorghum Flour Supplemented with Defatted Groundnut Flour as Influenced by Traditional Processing

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Title: Protein Quality and Acceptability of Sorghum Flour Supplemented with Defatted Groundnut Flour as Influenced by Traditional Processing
Author: Ellhag,Mardia Eltahir
Abstract: Sorghum flour (SF) was supplemented with defatted groundnut flour (DGF); 15, 20 and 25% composite flours, their protein content, fractions and digestibility were determined. Supplementation significantly (P<0.05) increased protein content, fractions (albumin plus globulin) and the in vitro protein digestibility, whereas prolamin, glutelins and insoluble proteins significantly (P<0.05) decreased as a result of supplementation. The in vitro protein digestibility was 49.3, 64.6, 56.8, 60.1 and 62.5% for (SF), (GDF), and 15, 20 and 25% composite flours, respectively. Sorghum flour and the selected 20% composite flour(according to acceptability) were naturally fermented for 36 hr. Fermentation was found to significantly (P<0.05) increase the protein content, albumin plus globulin, G2 and G3-glutelin fractions and the in vitro protein digestibility, whereas it significantly (P<0.05) decreased prolamin and G1-glutelin fractions. The insoluble protein fluctuated throughout the fermentation time. The fermentation of 20% composite flour was found to increase protein content from 20.1 at 0 hr to 24.3 at 36 hr, albumin plus globulin from 64.7 at 0 hr to 70.2 at 36 hr, prolamin decreased from 15.0 at 0 hr to 11.6% at 36 hr, G1-glutelin decreased from 12.1 at 0 hr to 9.4 at 36 hr, G2-glutelin increased from 1.5 at 0 hr to 2.6% at 36 hr, G3-glutelin from 9.2 to 10.1% and insoluble protein from 0.4 at 0 hr to 0.8% at 36 hr of fermentation. The in vitro protein digestibility of 20% composite flour was 49.3, 75.2, 65.1, 74.0 and 68.2% for 0, 8, 16, 24 and 32 hr of fermentation, respectively. Cooking was found to reduce the nutritive value of sorghum and the 20% composite flour significantly (P<0.05) the protein content of the former from 8.8 to 7.4% and of the latter from 20.1 to 19.3%; also it reduced the albumin plus globulin from 16.7 to 8.3% in sorghum and from 64.7 to 58.6% in 20% composite flour. The in vitro protein digestibility was reduced due to cooking from 49.3 to 42.1% in (SF) and from 60.1 to 56.4% in 20% composite flour. Fermented 20% composite flour was cooked and the effect of cooking after fermentation was detected; fermentation was found to reduce the negative effect of cooking on the nutritive value. The albumin plus globulin fraction was significantly (P<0.05) increased from 58.6% in cooked 20% composite flour to 60.2, 63.6, 65.1, 61.2 and 64.5% in 0, 8, 16, 24 and 32 hr fermented cooked. The prolamin decreased from12.0 in cooked 20% composite flour to 10.9% in 32 hr fermented cooked. The in vitro protein digestibility of 20% composite flour was decreased from 56.4% in cooked sample to 44.4, 70.2, 62.9, 67.3 and 65.2% in 0, 8, 16, 24 and 32 hr fermented cooked samples, respectively. The effect of supplementation and/or fermentation on the acceptability of sorghum flour was studied; the 25% composite flour was markedly accepTable than the 15% composite flour in terms of odor, taste and colour, however, the 20% composite flour was the most accepTable in odor, taste, colour and general acceptability than the 15 and 25% composite flour (25% was less accepTable in terms of colour). The 20% selected flour was fermented and tested for acceptability against the unfermented composite flour, fermentation leveled up the acceptability especially in case of taste and odor.
Description: 116 Pages
URI: http://khartoumspace.uofk.edu/handle/123456789/13103
Date: 2015-06-16


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