2. Materials and methods
2.1. Raw material
Waste wheat-rye bread (after shelf-life, returns from shops)
was obtained from local bakery. Whole loafs were manually cut
into dices of ca. 2–4 cm size. Obtained dices were dried in a forced
air oven at 40 C for 12 h and ground in a knife mill (Rotary Mill,
Brabender, Germany) with 1.5 mm internal mesh sieve. Raw material
was stored in an air tight jar at room temperature until used.
Starch content in waste bread was determined using Evers polarimetric
method [25] and it ranged 689.13 ± 4.52 g kg1 of raw
material dry matter. The amount of total sugars (as glucose) was
measured using the DNS method [26] after mild acid hydrolysis
(70 C, 10 min) with 80 g L1 HCl solution (1:7.5 m/v raw material
to HCl solution ratio) and it ranged 866.87 ± 2.85 g kg1 of raw
material dry matter. Raw material moisture content was measured
using WPS 50P weighing dryer (Radwag, Poland) and it ranged
41.43 ± 1.38 g kg1.
2.2. Enzymes and yeast
GSHE preparation STARGEN 002 was obtained from Genencor
International (USA). STARGEN 002 contains Aspergillus kawachii
a-amylase expressed in T. reesei and glucoamylase from T. reesei.
As declared by the manufacturer, the preparation activity is 610
glucoamylase units per gram and has an optimal temperature
range of 35–45 C. Neutrase 0.8 L (Novozymes, Denmark) is a bacterial
protease form Bacillus amyloliquefaciensis, its declared activity
was 0.8 proteolytic units per gram. Ceremix 6X MG
(Novozymes) is a preparation displaying multidirectional substrate
2. Materials and methods
2.1. Raw material
Waste wheat-rye bread (after shelf-life, returns from shops)
was obtained from local bakery. Whole loafs were manually cut
into dices of ca. 2–4 cm size. Obtained dices were dried in a forced
air oven at 40 C for 12 h and ground in a knife mill (Rotary Mill,
Brabender, Germany) with 1.5 mm internal mesh sieve. Raw material
was stored in an air tight jar at room temperature until used.
Starch content in waste bread was determined using Evers polarimetric
method [25] and it ranged 689.13 ± 4.52 g kg1 of raw
material dry matter. The amount of total sugars (as glucose) was
measured using the DNS method [26] after mild acid hydrolysis
(70 C, 10 min) with 80 g L1 HCl solution (1:7.5 m/v raw material
to HCl solution ratio) and it ranged 866.87 ± 2.85 g kg1 of raw
material dry matter. Raw material moisture content was measured
using WPS 50P weighing dryer (Radwag, Poland) and it ranged
41.43 ± 1.38 g kg1.
2.2. Enzymes and yeast
GSHE preparation STARGEN 002 was obtained from Genencor
International (USA). STARGEN 002 contains Aspergillus kawachii
a-amylase expressed in T. reesei and glucoamylase from T. reesei.
As declared by the manufacturer, the preparation activity is 610
glucoamylase units per gram and has an optimal temperature
range of 35–45 C. Neutrase 0.8 L (Novozymes, Denmark) is a bacterial
protease form Bacillus amyloliquefaciensis, its declared activity
was 0.8 proteolytic units per gram. Ceremix 6X MG
(Novozymes) is a preparation displaying multidirectional substrate
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