Quality dynamics of biscuit semi-finished products during storage

Abstract

Background. Longer storage of biscuit semi-finished products is based on the use of ingredients whose chemical composition slows staling of product that helps reduce shrinkage. Staling of biscuit semi-finished products is associated with changes in the state of starch and gluten flour.
The aim of the study is to determine the shelf life of fresh baked biscuit semi-finished products "Chernivetskyi" and "Zorianyi" with the addition of flour from sprouted wheat and carob powder by the parameters of deformation and fragility of crumb that  characterize staling process, and key indicators of safety – microbiological.
Material and methods. The study of the storage period of biscuit semi-finished products lasted seven days. Biscuit semi-finished products were stored in boxes from a cardboard at a temperature of 18–20 °C according to standard documentation and relative humidity of air of 75 %. Weight reduction of the biscuit, and therefore shrinkage rate, was determined by weighing freshly baked cake and re-weighing it every 48 h. The fragility of the crumb of semi-finished biscuit was determined by the method of [7], and its deformation by the automated penetrometer Labor every 48 h [8].
The Total Quantity of Mesophilic Aerobic and Facultative Anaerobic Micro­organisms (QMAFAnM), the presence of the bacteria Escherichia coli, pathogens and molds in the finished product was determined in accordance with GOST 26670 and DSTU Standards 4803: 2007 [6].
Results. The proposed technology of biscuit semi-finished product  "Chernvetskyi" and "Zorianyi" is different from the traditional to the fact that the recipe uses sprouted wheat flour (SWF) [9] and carob powder [10; 11]. Given the changes in the rheological and nutritional properties, it is useful to explore how long the new varieties of biscuit semi-finished products stay fresh.
It was determined that in 48, 96, 144 and 168 h of storage slightly more shrinkage of biscuit "Chernivetsyi" compared with control was recorded – by 0.4, 0.56, 0.84 and 2.3 %, respectively. Insignificant loss of moisture of a biscuit semi-finished product "Chernivetskyi" in the first 144 h increases and in 12 h is 2.9 %.
In a biscuit semi-finished product "Zoryany" in 48 h of storage loss of moisture of a biscuit increased by 1.6 %, in 96 h – by 2.5 %, 144 h – by 3.4 %, 168 h – by 4.3 % in comparison with control sample "Praha".
Biscuit shrinkage during storage also reduces the rate of deformation of its crumb. This figure for biscuit "Chernivetskyi" after 48 h of storage is higher than the control by 42.1 %, after 96 h – by 28 %, after 144 h – by 19.9 %, after 192 h – by 4.14 % respectively. A similar decline in the deformation was observed in semi-finished biscuit "Zorianyi" with the addition of SWF and carob powder. So, after 48 h it was higher than the control by 6.6 %, after 96 h – 10.6, 144 h – 14.7 to 192 h – by 11.7 %.
The fragility of the control and biscuit semi-finished product "Chernivetskyi" during storage increases. So, after 48 h fragility of biscuit semi-finished product "Chernivetskyi" was 1.7 times lower than the control, after 96 h it decreased 1.4 times, after 144 h – 1.2 times, and after 168 h – 1.1 times compared to the control sample. During the study was found that the shrinkage of biscuit semi-finished product "Chernivetskyi" was faster than the control sample.
Compared with the control fragility of the biscuit semi-finished product "Zorianyi" has increased (see Fig. 3). After 48 h of storage, it increased 1.1 times, after 96 and 144 h – 1.09 times, and after 168 h – 1.08 times compared to the control sample.
Microbiological indicators of biscuit semi-finished products "Chernvetskyi" and "Zorianyi" does not exceed the standard.
Conclusion. Having added 30 % to FSW to the biscuit semi-finished product "Chernivetskyi" it stales slower than the biscuit semi-finished product "Zorianyi". Adding carob powder facilitates rapid staling within 48 h.
The results showed that the fresh baked biscuit semi-finished product "Cherni­vetskyi" and "Zorianyi" can be stored without significant changes in the structure for 48 h.