during baking and staling where the formation of gluten-lipid
network and starch retrogradation occurs which are difficult to
reverse using physical treatment [31].
3.2. Effect of pretreatment method on fermentation course of waste
bread with GSHE
The fermentation dynamics assessment shown that carbon
dioxide liberation from fermentation media was more advantageous
for enzymatically pretreated waste bread and for the SHF
process in comparison to other variants of experiment (data not
shown). The changes in reducing sugars concentration in microwaved,
sonificated and unpretreated samples was similar during
the fermentation process (Fig. 1a). Its concentration ranged ca.
53, 10 and 0.2 g L1 after 24, 48 and 72 h of fermentation respectively.
In enzymatically pretreated samples sugars concentration
after the first day increased by ca. 12 g L1 in comparison to initial
state. After subsequent days of fermentation the reducing
sugars content in this variant of experiment was below