Innovative oat breads
Nordic Oat Days, 11.10.2011
Laura Flander
VTT Technical Research Centre of Finland
12/10/2011
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Why to study oats?
+ Oats is an important crop in Northern climate
+ Finland was the third largest producer of oats in year 2008 (FAO
2010)
+ The food use of oats has increased in Finland to 50-58 000 tn
during years 2007-2010 (it was 27-47 000 tn during 1995-2006)
+ Finland has valuable know-how in breeding and research of oats
as well as in research and development of functional foods -> good
basis for new innovations
+ Oats and oat products contain high amounts of
soluble fibre, -glucan -> lowers the cholesterol and
postprandial glucose levels in blood
nutritionally valuable proteins
vitamins and phenolics, as avenanthramides, which are
antioxidants and have anti-inflammatory properties (Meydani,
2009. Nutrition Reviews. 67:731-735)
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Advantages of oat breads
The light colour of oats is well suited for consumers who are
used to eat white breads
Oats keeps bread fresher for longer period of time
Oats is well suited for salty and sweet bakery products
Oat bread keeps hunger away but does not improve weight gain
Pure oats can be part of a gluten-free diet (EC, 2009. Official Journal
of the European Union 21.1.2009 L16/3)
Consumers appreciate the good taste and health promoting
properties of oats
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Dietary fibre
-glucan
Starch granule
Arabinoxylan and -glucan are the main dietary
fibre components of oats
-glucan content of whole grain oat is 2-8%,
endosperm wheat flour 0.2-0.3% of dry weight
Arabinoxylan content of whole grain oat is 2.04.5%, endosperm wheat flour 1.3-2.9% of dry
weight
Depending on the characteristics of oat material
28-100% of -glucan is soluble in water
Oats contain more soluble -glucan than
other cereals
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Structure of -glucan
1 4
2 1
3
3
•Makes the chain more flexible
1
Cellotriose
•3 glucose
•2x1 4 -linkage
•1x1 3 -linkage
•Improves the solubility
Cellotetraose
•4 glucose
•3x1 4 -linkage
•1x1 3 -linkage
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LDL- and HDL-cholesterol
•LDL-low density lipoprotein transfers cholesterol from
liver to other tissues of the body e.g. to build
membranes of the cells and formation of steroids
•Cell membrans have certain LDL-receptors, where
LDL bind and get to the cell
•Cells regulate the intake of cholesterol by the amount
of LDL-receptors
•If the cell has enough cholesterol, then new receptors
are not formed and excessive LDL-cholesterol stays
in blood stream (saturated+trans fatty acids decrease
the amount of LDL-receptors)
•Increased content of LDL-cholesterol increase the risk
of atherosclerosis, LDL-cholesterol may form plaques
in the walls of the blood vessels
•HDL high-density lipoprotein brings cholesterol from
tissues to the liver -> reduce the risk in plaque
formation
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Suggested mechanism for cholesterol lowering
effect of -glucan
Bile acid is formed in the liver from cholesterol, stored in galbladder
and excreted to small intestine to emulsify dietary fat to micelles
The body produces about 800 mg of cholesterol per day and about half of
that is used for bile acid synthesis. In total about 20-30 grams of bile acids
are secreted into the intestine daily. About 90% of excreted bile acids are
reabsorbed.
Viscous -glucan in the lumen increase excretion of bile acid and/or
slow absorption of bile acid back to the liver
Liver has to prepare more bile acid from cholesterol -> less LDLcholesterol in blood (Lia et al, 1995; Zhang et al, 1992; Andersson et al,
2002)
Concentration, solubility, structure and molecular weight determine
the viscous character and thus the cholesterol lowering property of oat glucan (Volever et al 2010, Åman et al 2004, Wood 2007)
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Case: whole grain oat baking
If the bread is intended to meet the requirements of the -glucan content (0.75
g/portion, 3 g/day) for cholesterol health claim:
At least 50% whole grain oat is needed (most of the commercially available oat
breads contain 20% oat flakes)
High fibre content of oats increase the water absorption of the dough
Lack of gluten weakens the viscoelastic nature of protein network
decrease the dough handling properties and the ability of dough to retain
gas during proofing
decrease the volume and softness of the bread
Enzymatic, chemical or mechanical reactions during baking process may reduce the
concentration, molecular weight or solubility of -glucan
the ability of -glucan to
lower cholesterol or attenuate to sugar levels of blood may be lost
Modification of the properties of dietary fibre components and -glucan
How to produce bread without gummy texture, but retain the viscous
properties of oat for health effects?
How to manage the distribution of water between different components in
dough from mixing to changes during bread storage?
Modification of the properties of proteins
How to improve the viscoelastic properties of proteins?
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Aims
To study the effects of bioprocessing, as sourdough and enzymes,
on the macropolymers of oat dough and structure formation of oat
bread in order to better exploit the health promoting properties of
oat in bread
Raw materials
Whole grain oat flour (100% oat or 51% oat and 49%
wheat flour)
Endosperm oat flour (80% oat and 20% potato starch)
Oat bread with sourdough (L. plantarum) or without
sourdough
Enzymes: laccase (Trametes hirsuta), tyrosinase
(Trichoderma reesei), xylanase (Pentopan mono BG,
Novozymes)
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Results of recipe and process optimization
The appearance of oat bread after preliminary screening test (A),
after optimization of the recipe (B) and after optimization of the
process (C).
A
B
Flander et al 2007, LWT 40: 860-870
C
Microstructure of oat bread. The
glucan in the cell walls has been
stained with Calcofluor and
appears blue.
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Results of sourdough process
Acidity of breads, and -glucan properties of flours and breads
Whole grain oat flour White wheat flour Sourdough oat bread Straight dough oat bread
5.5 0.05
5.8 0.01
pH
n.d.
n.d.
5.0 0.23
4.0 0.15
TTA (ml NaOH/10 g bread/sourdough)
6.0 0.04
0.26 0.01
2.7 0.18
2.4 0.06
ß-glucan content (g/100 g db)
ß-glucan content (g/100 g fresh weight)* 5.35
0.23
1.6
1.4
Mw of -glucan, x 105
> 10
n.d.
5.5
5.5
Mw distribution of ß-glucan, % of total
Mw > 1 000 000
60
30
30
Mw 200 000 - 1 000 000
30
30
30
Mw < 200 000
10
45
45
* Moisture contents: oat flour 10.6 g; white wheat flour 12.1 g; sourdough oat bread 39,4 g; straight dough oat bread 43,6 g/100 g
n.d., not determined
Weight average Mw analysed by HPSEC with
Calcofluor staining using RALLS for detection (Suortti,
1993)
Flander et al 2011, LWT 44: 656-664
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Results of enzymatic treatments
Water-soluble arabinoxylan content of oat-wheat doughs
2,70
2,40
2,10
% of f.w.
1,80
1,50
1,20
*
0,90
*
0,60
0,30
0,00
Dough 0
Dough lac
Dough xyl
Dough lac+xyl
Flander et al 2008, J. Agric. Food Chem. 56: 5732-5742
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Results of enzymatic treatments (cntnd)
Size-exclusion HPLC elution profiles of water-soluble non-starch
polysaccharides (WSNSP) of oat-wheat doughs with or without enzyme.
Oat-wheat
+
+dough+
+
+
+
+
40
36
32
28
MV
24
20
16
12
8
4
0
6
7
8
9
10
11
0
12
13
Minutes
lac
xyl
14
15
16
17
18
lac+xyl
The + signs refer to the molecular weights of the pullulan standards, + Mw of arabinoxylan
standard. Mw from left to right: 800 000, 400 000, 200 000, 100 000, 50 000, 20 000, and
10 000
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Results of enzymatic treatments (cntnd)
Specific volume and instrumental hardness of the oat-wheat breads
Oat/wheat bread
Spec. volume
Hardness, kg
ml/g
2 hr
72 hr
0
3,6 a
0,14 a
0,28 ab
laccase
3,7 b
0,12 ab
0,31 a
xylanase
3,7 b
0,11 b
0,24 c
laccase+xylanase
4,0 c
0,12 b
0,26 bc
0
lac
xyl
lac+xyl
15
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Results of enzymatic treatments (cntnd)
Effects of tyrosinase on oat dough proteins
1
2
3
4
5
6
7
8
kDa
113
92
52.9
35.4
29
0tyr
tyr10 nkat/g flour
tyr 30 nkat/g flour
21.5
Microscopy of oat dough proteins. Stained with Xylidine Ponceau,
0.2%, protein dyed red
Significantly higher count and area of protein
particles between 100-1000 m2 + formation of
higher molecular weight products with TYR
aggregated globulins formed by TYR-induced
crosslinking
Reduced SDS-PAGE profile
of LAC or TYR treated oat
globulins. Lanes: 1
molecular weight marker, 2
globulin, 3-4 lac+globulin, 56 tyr+globulin, 7 lac, 8 tyr
Flander et al 2011, J. Agric.
Food Chem. 59:8385-8390
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Results of enzymatic treatments (cntnd)
Effects of tyrosinase, laccase and xylanase on the baking quality of gluten
free oat bread
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Conclusions of oat baking studies
Oat bread with 51% whole grain oat of the flour weight was developed by
optimization of ingredients baking process
good textural and sensory properties
Application of sourdough technology to oat baking resulted in the same textural
characteristics than straight dough baking and improved the intensity of crumb
flavour without too extensive perceived sourness
Both straight dough and sourdough oat breads contained 1.4-1.6 g -glucan/100 g
fresh bread which corresponds to 0.75 g BFG/portion (2 slices)
The average molecular weight of -glucan was 5.5 x 105 in both types of bread,
while that of oat flour was 10 x 105
both straight dough and sourdough process
are suitable for production of healthy and tasty oat breads
Tyrosinase cross-linked oat proteins more efficiently than laccase, whereas laccase
was suggested to crosslink the soluble fiber, arabinoxylans, of the oat dough
Tyrosinase improved more oat bread volume than laccase
Combination of xylanase with laccase or tyrosinase was most effective in improving
the baking quality of oat bread (volume and softness )
Degradation of fibre by xylanase and crosslinking of protein by tyrosinase or
crosslinking of arabinoxylan by laccase were suggested to be the main
reasons for improved volume and softness
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Other oat bakery products
Developed at VTT together with companies (confidental projects)
Frozen buns
Savoury oat pastry
Par-baked oat bread
Par-baked frech loaf with oats
Oat bicuits
Sweet oat buns
Oat crisp bread
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Selection of commercial Finnish oat breads with high
oat/dietary fibre content
100% whole grain oat breads
Kaura100, Perheleipurit Oy,
fibre content 12.6%
100% Kaura, Vaasan group,
fibre content 10%
Oat-wheat breads
Pielisen kauraeväs,
Pielispakari Oy, oat flour,
wheat flour, oat flakes, oat
groat, 51% oat
Oat crisp bread
Fazer Bakeries, wheat flour,
oat bran 17%, rye bran, fibre
content 15%
Wheat-oat breads
Oululainen Pehmopalat
kaura, Fazer Bakeries, wheat
flour, oat flakes and fibre
19%, fibre content 7%
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Future and ongoing innovations?
Oat breads with high protein content for malnutrition
Oat breads with high protein and fibre content for weight
management and/or satiety promoting effect
Antioxidative properties of oat phenolics
Low GI oat bread
Tasty gluten-free oat bread with high fibre content
Frozen bake-off products of oats, par-baked oat bread
Crisp bread or pumpernickel from oat groats
Targeted modification of oat fibres or proteins for special
applications
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Health claims
Article 13 health claims (=functional claims):
claims that refer to the role of a nutrient or other
substance in growth, development and the functions of the
body
claims that refer to psychological and behavioural
functions
claims that describe slimming or weight control or a
reduction in the sense of hunger or an increase in the
sense of satiety or to the reduction of the available energy
from the diet.
Article 14 health claims:
claims that refer to the reduction of disease risk (=risk
factor)
claims that refer to children's development and health
EFSA has been estimated to issue its last opinions by the end
of 2011. The Commission takes a decision on each health
claim as soon as EFSA has issued its opinion. An up-to-date
list of the authorised and rejected health claims is provided on
the Commission's web site
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Health claims (cntnd)
EFSA panel on dietetic products, nutrition and allergies (NDA)
stated recently that foods providing 3 g oat -glucan per day can
bear a health claim “Oat -glucan has been shown to lower/reduce
blood cholesterol. Blood cholesterol lowering may reduce the risk
of heart disease” [EFSA, Panel on Dietetic Products, Nutrition and
Allergies (NDA) 2010] (Article 14.1)
The health claim needs to
be approved by the European Commission
Products with health promoting innovations are waiting the health
claim decisions of European Commission
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Succesfull bread innovations
Gain know-how which differentiates you
from your competitors
Choose the right marketing strategy for
your target group of consumers
Right balance between branding and price
of the product
Appearance and taste of the product
Must be tempting, but tuned after
your target group, e.g. traditional or
forerunners
Balance your costs and profit
12/10/2011
VTT creates business from
technology
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