Types of spoilage, Causes of Bread Staling, How to Prevent Spoilage and Bread Staling

1. Submitted by :
HABIB-UR-REHMAN
PFTF18M006
Institute of Food Science and Nutrition
University of Sargodha, Sargodha

2. Contents
• Bread Spoilage
• Types of Bread Spoilage
• Moldiness
• Ropiness
• Chalky Bread
Bread Spoilage Bread Staling
Types of Bread Spoilage Introduction
1. Moldiness Characterized By
Causes of Moldiness Theories explaining bread staling
How to prevent Moldiness? Starch Retrogradation
2. Ropiness water migration & Water redistribution
Causes of Ropiness Decrease in crumb moisture is caused by
How to prevent Ropiness? Protein-starch interaction
3. Chalky Bread Prevention of staling

3. Bread Spoilage
• Spoilage of bread can be caused by bacteria,
yeast and molds.
• Generally, breads have a relatively high
moisture content and water activity between
0.94 and 0.97 at a pH of about 6 with sliced,
pre-packed and wrapped breads belong to the
most susceptible bakery products for
mold spoilage.

4. Types of bread Spoilage
• Spoilage of bread is usually of two types
 Moldiness (the quality of smelling or tasting old or
stale or mouldy due to mold growth mustiness,
must. staleness - having lost purity and freshness as a
consequence of aging.)
 Ropiness (Ropiness in bread is usually due to
bacterial growth and is considered more prevalent in
home made breads.)
 Chalky Bread (Another type of spoilage of bread is
chalky bread which is caused by growth of yeast.)

5. Causes of Moldiness
• The molds which are prevalent are Rhizopuss
tolonifer(referred as bread mold),Penicillium
expansum, Aspergillus niger.
• Factors Involved in Moldiness
Moisture(The moisture trapped in the bag is absorbed by
the fungus and it grows at a faster rate.)
Temperature(Most moulds grow best between room
temperature and 30-37 degrees Celsius. However, it does
depend a bit on the type of mould.)

6. How to Prevent bread Mold?
• Moisture contributes to the faster growth of mold.
Hence, do not allow your bread to turn moist. It is
always better to preserve the bread that is brought
from the store, in its original packaging bag.
• If you are making bread at home, use ingredients
that contain oils, like butter, eggs, milk, etc. This will
allow the bread to stay fresh for longer period.
• Never store the bread at room temperature or in the
refrigerator for extended period. Freezing will be
helpful if prolonged storage is required.

7. Causes of Ropiness
 The chief causative organism is Bacillus
subtilis or B. licheniformis.
 In ropiness, the hydrolysis of bread flour protein
(gluten) takes place by proteinases. Starch is also
hydrolysed by amylases, which encourage
ropiness.
 The manifestation of ropiness is development
of yellow to brown color and soft and sticky
surface. It is also accompanied by odor.

8. How to prevent Ropiness?
• The bread crumb should have a pH of below
5.2.
• After baking, the breads should be allowed to
cool down as quickly as possible. The storage
temperature should not exceed 30°C.
• If ropiness has been determined in bread, the
sourdough proportion in production should be
increased for safety reasons.

9. Causes of Chalky Bread
• Chalky Bread is caused by growth of yeast like
fungi Endomycosisfibuligera and Trichosporon
variable.
• This spoilage is characterized by development
of white chalk like spots.

10. Bread Staling
• Bread staling is a complicated process that
involves loss of aroma, changes in mouth feel,
loss of crumb softness and development of
crumbliness.
• It is a term which indicates decreasing
consumer acceptance of bakery products
caused by changes in crumb other than those
resulting from spoilage organisms.

11. Introduction
• Bread staling is a complex phenomenon that
originates from multiple physico-chemical
events (amylopectin retrogradation, water loss
and redistribution and gluten-starch
interactions and gluten transformations) that
are not yet completely elucidated. (Curti, et al,
2011).

12. Characterized by :
• It is usually characterized by
loss of aroma.
changes in mouth feel.
development of crumbliness.
toughening of the crust.
firming of the crumb.
loss of moisture and flavor.
loss in product freshness.

13. Theories explaining bread staling
• The main causes of bread staling are thought
to be:
• Starch retrogradation
• water migration and redistribution
• Protein-starch interaction
• Gluten transformations

14. Starch Retrogradation
• Retrogradation is a reaction that takes place in
gelatinized starch when the amylose and
amylopectin chains realign themselves causing
the dissolved starch difficult to re-dissolve.
• Starch undergoes swelling or gelatinization
when heated in the presence of water – Starch
gelatinization.

15. water migration
• Water migration and Redistribution The
migration of water in cellular solid foods
during storage has been found to cause loss of
crispness.
• Migration of water occurs within bread and
from bread to the environment causing bread
to firm.

16. Water redistribution
• Water migration and Redistribution When
bread is stored with crust.
• Water migrates from crumb to the crust The
crumb firms.
• Loss of crispiness
• The crumb moisture content and water
activity decreased.
• Decrease in freezable water

17. Decrease in crumb moisture is caused
by:
• Incorporation of water into the starch
crystalline structure
• Loss of water to the surrounding environment
• Moisture migration from crumb to crust
reduces the level of plasticizing water of the
biopolymer networks and contributes to
crumb firmness at longer storage times

18. Protein-starch interaction
• Bread firmness is thought to result from glucan
chains of partially leached amylose and
amylopectin attached to swollen starch granules
forming hydrogen bonds with other starch
granules and, to a smaller extent, with gluten
fibrils.
• The distribution of water is shifted from gluten to
starch, thereby changing the nature of the gluten
network during starch retro gradation. (Gray &
Bemiller, 2003)

19. Gluten transformations
• Gluten is the composite of a gliadin and a
glutenin, which is conjoined with starch in the
endosperm of various grass-related grains.
• There is considerable uncertainty about the
role of protein in bread staling.
• One of the main problems with gluten-free
breads is their texture and their rapid staling

20. Gluten transformations
• High protein breads shows lower extent of retro
gradation and hence staling.
• Waxy wheat flour blends have been also found
with the ability to retard staling of breads.
• Protein is thought to retarded bread staling by
diluting starch and hence reducing starch
retrogradation.
• Addition of bacterial protease to sourdough has
been found to increase bread firmness and
staling indicating that proteins actually are
important in retarding bread staling

21. Prevention of staling
• Enzymes – Heat stable Alpha Amylases
• Shortenings
• Emulsifiers- Surface active agents
• Reheating - Temperature 70-80 Degrees C
• Packaging
• Soy addition
• Malting and Fermentation
• Incorporation of high fiber flour