Structural and mechanical properties of egg sponge dough with flour "Zdorovia"

Abstract

Background. Having analysed the modern references it was established that improvement of the existing technologies of biscuit semi-finished products is directed mainly to using various nonconventional raw materials to regulation the nutritional value and increase stability of egg sponge during production and baking [1–17].
Technological process for the purpose of receiving a biscuit semi-finished product with the set properties allows to conduct its regulations given measurements of viscosity and ways purposefully.
The aim of the work is todefine the influence of concentration of flour from germinated seed of wheat (FGSW) and the powder of kerob in compoundings on structural and mechanical properties of egg sponge.
Material and methods. Research object isdough for the basic biscuit and with replacement 10, 20, 30, 40, 50 % of high-grade flour for FGSW; egg sponge for an butter biscuit "Pragа"and with replacement of 100 % of powder of cocoa with the powder of kerob.
The research is conducted on the rotational Reotest-2 viscometer on the system of S, S₃ cylinders at a temperature of 20 ^оC [20].
Shift tension τ_r is determined by a formula:

τ_r =z·a,

   where z isa constant of the cylinder, dynes/cm²;
   a – value of division of a scale of the device. 
   The viscosity η was determined by a formula: 

η= τ_r: D_r·100,

   where η is effective viscosity,
   Pa ·с, τ_r – tension of shift, dynes/cm²,
D_r – shift speed, c^-1.
Results. By results of a research the general tendency of insignificant increase in viscosity of dough for a basic biscuit when replacing wheat flour by FGSW ranging from 10 up to 50 % concerning control was established. At the fixed speed of shift
24.3 s^-1(figure 2) two sites –within 0–30 and 30–50 % of replacement of wheat flour for FGSW at which various intensity of increase in effective viscosity is observed were identified. So, in the first interval increase in viscosity is by 40.8 % (from 1.42 up to 2.00 Pas·c), and in the second by 50 % (from 2.00 up to 3.00 Pas·с).
The specifics of dough for a biscuit "Pragа" explain low values of its effective viscosity (see figure 4, poses. 1) in the range of speeds of shift from 0.167 to 24.3 s^-1 that lies within 44.6–1.2 Pas·c.
While researching the effective viscosity of egg sponge containing 30 % of FGSW and the powder of kerob insignificant decrease in viscosity within 43.21–1.20 Pas·s was established with (see figure 4, poses. 4) concerning control.
Conclusion. Due to the developed technology an opportunity and expediency of using FGSW and the powder of kerob in compoundings of egg sponge was proved. Replacement of 30 % of wheat flour by FGSW in the test for a biscuit of the basic increases its effective viscosity and allows to receive foamy system, steadier to shift tension. Replacement in the test for a biscuit "Pragа" of 30 % of wheat flour for FGSW and cocoa powder on the powder of kerob allows to receive dough with the rheological indicators which aren't conceding control.