Effect of addition of thermally modified cowpea protein on sensory acceptability and textural properties of wheat bread and sponge cake. (1st March 2016)

• Record Type: Journal Article
• Authors: Campbell, Lydia; Euston, Stephen R.; Ahmed, Mohamed A.
• Is Part Of: Food chemistry. Volume 194(2016)
• Page Start: 1230
• Page End: 1237
• Publication Date: 2016-03-01
• Subjects: Cowpea protein isolate -- Protein denaturation -- Protein glycation -- Wheat bread -- Sponge cake; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2015.09.002
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Sensory acceptability in yeast bread and sponge cake of flour enriched with cow pea protein isolate is enhanced. Denaturation and glycation of cow pea protein lead to increased thermal stability and solubility. Inclusion in bread up to 4% glycated and denatured cow pea protein isolate is acceptable. Whole egg is replaced by 20% in sponge cake by 3.5% glycated and denatured cow pea protein isolate. Abstract: This paper investigates the sensory acceptability and textural properties of leavened wheat bread and sponge cake fortified with cow protein isolates that had been denatured and glycated by thermal treatment. Defatted cowpea flour was prepared from cow pea beans and the protein isolate was prepared (CPI) and thermally denatured (DCPI). To prepare glycated cowpea protein isolate (GCPI) the cowpea flour slurry was heat treated before isolation of the protein. CPI was more susceptible to thermal denaturation than GCPI as determined by turbidity and sulphydryl groups resulting in greater loss of solubility. This is attributed to the higher glycation degree and higher carbohydrate content of GCPI as demonstrated by glycoprotein staining of SDS PAGE gels. Water absorption of bread dough was significantly enhanced by DCPI and to a larger extent GCPI compared to the control, resulting in softer texture. CPI resulted in significantly increased crumb hardness in baked bread than the control whereas DCPI or GCPI resulted in significantly softer crumb. Bread fortified with 4% DCPI or GCPI was similar to control as regards sensory and textural properties whereas 4% CPI was significantly different, limiting its inclusion level to 2%. There was a trend for higher sensory acceptability scores for GCPI containing bread compared DCPI. Whole egg was replaced by 20% by GCPI (3.5%) in sponge cake without affecting the sensory acceptability, whereas CPI and DCPI supplemented cakes were significantly different than the control.