Abstract
The baking properties of prefermented frozen doughs were
examined with frozen storage times up to 14 days at
-20°C. Different types of flour, prefermentation times,
water contents, and hydrocolloids were investigated. The
factors used to explain the observed improvements were
yeasted dough rheology, pore structure, and water state.
The deterioration in loaf properties was observed to fall
into two categories: those due to freezing and subsequent
thawing (freeze-thaw stability), and those occurring over
longer frozen storages (frozen storage stability).
Shorter prefermentation time (25 vs. 40 min) improved the
freeze-thaw stability of frozen doughs and increased the
loaf volumes on average by 20%. In the same way the
baking properties became more independent of flour
quality, and extra-strong flours were not needed to
achieve loaf volumes similar to those of fresh baking. In
the pore structure studies, shorter prefermentation time
was observed to change the structure for more even.
Smaller air bubbles with thicker cell walls were not so
sensitive to ice crystal damage.
Shorter prefermentation time did not significantly
improve the frozen storage stability of prefermented
frozen doughs. The major decrease in loaf volumes during
frozen storage occurred during the first week, after
which there was little change. For the achievement of
fresh-like loaf properties after 14 days frozen storage,
lower water contents were needed (2 per-centage units
reduction from the fresh baking optimum). The role of
water became clear in the analyses of water state in
frozen doughs. The self-diffusion coefficient and the
amount of liquid phase increased during frozen storage
because of ice crystal growth, but the increase could be
minimized by reducing the water content and adding
hydrocolloids. Thus, the major deteriorations in
prefermented frozen doughs are caused by ice crystals.
When shorter prefermentation time was combined with
reduced water content, yeasted dough rheology after
frozen storage was similar to that of fresh dough.
Original language | English |
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Qualification | Doctor Degree |
Awarding Institution |
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Supervisors/Advisors |
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Award date | 17 Jun 1998 |
Place of Publication | Espoo |
Publisher | |
Print ISBNs | 951-38-5241-5 |
Electronic ISBNs | 951-38-5242-3 |
Publication status | Published - 1998 |
MoE publication type | G5 Doctoral dissertation (article) |
Keywords
- food industry
- bakery products
- doughs
- frozen food
- frozen storage
- prefermentation
- water content
- hydrocolloids
- rheological properties