On Potential Use of Carob, Malt and Soybean Flours in Bread Production

Procedure

The moisture content was determined by measuring the mass of the sample before and after water is removed by evaporation in an oven at 130В°C for 1.5 h (until constant mass was achieved). Total nitrogen and proteins content were determined by the Kjeldahl method, using a conversion factor of 5.7 for converting nitrogen into proteins (AOAC, 2007).

Fat content was determined by SOXHLET method and starch content by the method as described by Mathew et al. (2006). Suitable quantity of flour samples (5g) were mixed with 100 ml cold water and left for 1 hour. After the removal of the soluble ingredients, the residues were subjected to acid hydrolysis with 37% HCl acid for 2.5 hours. Subsequently, the samples were cooled, neutralized with 5N NaOH and centrifuged.

The determination of the formed sugars was performed using a 3.5 dinitrosalicylic acid spectrophotometric method at 540 nm, using glucose as standard. The sugars to starch conversion factor used was 0.9. The ash content was determined according to the official methods by incineration five gram of sample at 900В°C during 2 h (AACC, 2000). Standardized methods were used to determine falling number (ICC 107/1), wet and dry gluten content (ICC 137/1) and Zeleny sedimentation index (ICC 116/1).

Dough formulation

The baking tests were conducted to obtain the intensive dough kneading of wheat flour, yeast, water, and salt with the incorporation of different improvers added to each sample. The basic dough formula consisted of appropriate weight of wheat flour sample (or composite flours) 1kg (14% moisture basis) was placed in the mixer, 600 ml of cold water (60% flour basis) at 27В°C, 20g of sodium chloride (2% flour basis) and 20 g of dried yeast (2% flour basis) were added to the sample.

After mixing for 15 min, the control and composite dough were rounded and bulk fermented at 27В°C for 40 minutes. After proofing, dough was divided into 100 and 200 g dough pieces, baked at 250В°C for 30 min and then evaluated after one hour of cooling. The breads obtained are subjected to different sensory tests and examined in terms of the external and internal presentation.

Alveogram characteristics

The alveograph (Chopin NG France) was used to determine characteristics that provided insight in the fermentation tolerance of the dough as may be exhibited during proofing stage of bread making (AACC, 2010). Characteristics of interest that were measured included the overpressure (P in mm), extensibility indicated by length (L in mm) of the avleogram curve (abscissa at rupture), energy input (10-4 Joules) required to the mechanical deformation of the dough (W), inflation required for maximum development (G), and (P/L) ratio were measured with the Chopin alveograph on 250 g samples.

Sensory evaluation

The sensory evaluation was performed to determine the degree of the acceptance of the bread by consumer using a 5-point hedonic scale with 1: less good, 3: acceptable, 5: very good. The panelists were selected after an oral interview conducted on the basis of a criteria checklist that included: Good health, nonsmoker, nonallergic to wheat, malt, carob and soy bean, willingness to participate, and passion/likeness for the consumption of bread. Ten selected trained participated in the evaluation and they were asked to fill in a questionnaire which included the following questions for the external aspects (section shape, color, odor and crust delicacy) and internal characteristics (texture of crumb, color and odor). Each sample was evaluated with Quantitative Descriptive Profile Analysis (QDA).

Statistical analysis

All experiments and analyses were conducted in triplicates and data are presented as mean values. The statistical analysis of the data was performed by analysis of variance (ANOVA) to determine significant differences among samples and statistical test with statistical error did not exceed 5% (with a 95% confidence level) using SPSS, version 9.1 (StatSoft, Inc., USA).