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VTT TECHNICAL RESEARCH CENTRE OF FINLAND LTD
ARE WE SOLID WITH THE INFORMATION
ON OATS AND GUT HEALTH?
Natalia Rosa-Sibakov
Anna-Marja Aura
Noora Mäkelä
Tuula Sontag-Strohm
Emilia Nordlund
2VTT 2018
Oats have an excellent nutritional composition and
are traditionally trusted as promoters for gut wellbeing
Foods rich in oat beta-glucan have EU-authorised
health claims approved by EFSA
Lowering blood cholesterol, maintenance of
blood sugar levels and increase bowel function
Health claims and gut wellbeing linked to oats
3VTT 2018
β-glucan content is essential for the positive health impacts, but
also…
…processing of oat foods is expected to modify the physiological
functionality of oats, especially via changes in β-glucan molecular weight
Impact of β-glucan molecular weight
Then again, challenges to utilize native
(unmodified) β-glucan in certain food
products slimy texture avoided only
by decreasing the molecular weight
4VTT 2018
OAT your GUT - Oat-derived Wellbeing by Clinical and Perceived Assessment
Funding: Business Finland, Finnish research and company partners Partners: University of Turku (coord.), University of Helsinki, VTT Ltd + 11 Finnish food companies Project duration: 01.04.2017 – 30.9.2019
Aims of the project• Generation of scientific evidence for
understanding on the oat-consumption factors affecting gut wellbeing
• Use digital mobile device for monitoring gut discomfort symptoms during consumption of oat-based products in clinical trials
• Study molecular level changes in beta-glucanin distinct food matrixes and during storage in relation to physiological behaviour and sensed characteristics
5
Objective of the study
Oat bran1. Viscosity of intestine digesta
Absorption of nutrients
2. Bile acid binding
Cholesterol lowering
3. Colonic gas production
Fibre fermentability
To evaluate the role of beta-glucan molecular weight (Mw) and the presence
of other oat bran carbohydrates on the gut health
Approach: in vitro digestion of modified oat ingredients
Bioprocessing
Modified oat bran
ingredients
In vitro methods:
Enzyme-aided treatment was used to modify the β-glucanmolecular weight
Process for oat bran modification
• Oat material used: Oat bran concentrate
(OBC) – 20% β-glucan
• Enzymes (0, 1, 5 and 50 nkat/g)
Mix beta-glucanase, xylanase,
cellulase)
Pure (purified β-glucanase)
• Treatment conditions: 10% dm, 50°C, 2h
Purified β-glucanase did not impact AX
Enzyme mix clearly solubilized AX
Blanc 1 5 50 1 5 50
Pure
Mix
nkat/g nkat/g
Water-soluble AX content
7VTT 2018
Molecular weight of β-glucan was reduced by both enzymetreatments (Enzyme Mix and Pure β-glucanase)
B
D1
D5
D50
dw
t/d
(lo
gM
)
0,00
0,50
1,00
1,50
2,00
0,00
0,50
1,00
1,50
2,00
Slice Log MW
3,00 3,50 4,00 4,50 5,00 5,50 6,00 6,50
Blanc
1 nkat/g
5 nkat/g
50 nkat/g
Mix 950
450220
90
BG20
P1 b
P5
P50
dw
t/d
(lo
gM
)
0,00
0,50
1,00
1,50
2,00
0,00
0,50
1,00
1,50
2,00
Slice Log MW
3,00 3,50 4,00 4,50 5,00 5,50 6,00 6,50
Blanc
1 nkat/g
5 nkat/g
50 nkat/g
Pure 950
435320
Intensive treatment with Pure (50 nkat/g) did not
reduce the Mw as the enzyme mixture
350*
OBC treated
samples
Viscosity of the small intestine digesta with theenzyme-treated oat bran samples
Findings
• OBC Blanc (highest Mw) had the highest viscosity
• Viscosity decreased significantly due to enzyme hydrolysis
• Pure vs Mix: samples treated with Mix had higher viscosity
contribution of other small oligosaccharides to the intestinal
viscosity
Amylase + pepsin
+ pancreatin, bile Centrifugation
PrecipitateSupernatant
Analysis of
β-glucan content & viscosity
MethodMix
Pure
Bile acid binding of the enzyme-treated oat bransamples
MW 950
MW 450MW 220
MW 90
Oral phase +
Gastric phase +
Intestinal phase
SupernatantBile acids
Volume, density
Swelling
Findings
• OBC Blanc was the most efficient to reduce bile acids
• Bile acid binding was decreased with enzyme hydrolysis.
• OBC treated with Mix enzyme inverse correlation between β-
glucan Mw and bile acid binding capacity (r =-0.9**)
Method
Colonic gas production of the enzyme-treated oat bransamples
+ Human faecal
inoculum
Faecalsuspension
On-line gasmeasurement
MethodOBC treated
samples
Production of gases increased by enzyme hydrolysis
Initial rate of gas formation (1-3h)
Inverse correlation
between β-glucan Mw and
initial rate of gas formation
(r =-0.9**)
Findings
FOS
FOS
M1 M5 M50
11VTT 2018
Reduction of the β-glucan and other non-starch carbohydrates of oat bran
concentrate affected the parameters measured in vitro
However, it seems that oat ingredients with “medium Mw” (300-500 kDa) may still
have similar benefits to the higher Mw samples
Viscosity still detectable
Binding of bile acids notable
Gas formation clearly lower than with FOS
Next, human studies to study the correlation of in vitro
studies to gas pressure formation and intestinal comfort
(performed by University of Turku, Kaisa Linderborg’s group)
Conclusions
