Title: SHELFLIFE STABILITY OF OAT GROATS PROCESSED WITH SUPERHEATED STEAM
1SHELF-LIFE STABILITY OF OAT GROATS PROCESSED WITH
SUPERHEATED STEAM
- D. Head1, S. Cenkowski1, S. Arntfield2 K.
Henderson3 - 1Biosystems Engineering, UofM,
Winnipeg, MB - 2Food Science, UofM, Winnipeg,
MB - 3Can-Oat Milling, Portage la
Prairie, MB
Presentated at the CSBE/SCGAB 2008 Annual
Conference Vancouver, BC, July 13 - 16, 2008
2Oats are heat processed
- to enhance stability (high lipid content, 5-7)
- to develop characteristic flavour
- Routine industrial process includes
- Roasting, steaming and drying to
- inactivate the fat splitting enzymes
- Roasting at 88-115?C for 90-104 min (up to 80
inactivation) - then steaming at 100-104?C for 8-10 min
- Grain is dried andprocessed to
- Commercial products (flour, bran, rolled oats)
3(No Transcript)
4Limiting factors for storage and handling
- Degradation of lipids via enzymatic hydrolysis
followed by oxidation leading to rancidity and
off-flavours development - Prevention
- Hydro-thermal inactivation of the lipolytic
enzymes - The kiln drying operation is difficult to
control, lengthy and not energy efficient - Risk of grain cross-contamination with
microorganisms present in the air used for
cooling of the grain after kiln drying - Superheated steam drying and processing is an
attractive technology offering variety of
advantages over the kiln drying
5Objective
- to determine the shelf-life stability of oat
groats processed with the optimum superheated
steam parameters and stored at 21?C - Optimum SS processing conditions were
established in previous studies - steam temperature of 110?C
- steam velocity of 1 m/s
- processing time of 10 and 14 min
6Materials and methods
- Groats standard kilned at a commercial plant A
and B - SS processed groats at 110?C at 1m/s for 10 and
14 min (SS10 and SS14) - Storage at 21?C for 6 months and measured
- Moisture content
- Pasting viscosity at 64?C (Rapid Visco Analyzer)
- Hexanal and free fatty acids content
- Sensory evaluation (flavour oaty, toasted, raw,
bitter, rancid) - Color determination (L, a, b values)
7Results
Storage at 21?C
Commercial plants
110?C, 10min and 14 min
Plant A
Plant B
Fig. 1 Storage time effect on the final viscosity
(at 64?C (commercial plant A B) or
processed with superheated steam (SS)
8Storage at 21?C
Commercial plants
110?C, 10min and 14 min
Fig. 2 Moisture content of oat groats processed
commercially (Plant A and B) or with SS
at 110?C and 1 m/s for 10 and 14 min.
9Storage at 21?C
Commercial plants
110?C, 10min and 14 min
Fig. 3 The effect of storage time on free fatty
acids content of oat groats processed
commercially or with superheated steam
(SS) at 110?C
10Commercial plants
110?C, 10min and 14 min
Storage at 21?C
Fig. 4 The effect of storage time on level of
hexanal released from oat groats
processed commercially (Plant A and B)
or with superheated steam (SS) at 110?C
11Storage at 21?C
Commercial plants
110?C, 10min and 14 min
Fig. 5 The effect of storage time on intensity of
oaty flavour of oat groats processed
commercially or with superheated steam
(SS) at 110?C
12Commercial plants
110?C, 10min and 14 min
Storage at 21?C
Fig. 6 The effect of storage time on intensity of
toasted flavour of oat groats processed
commercially or with superheated steam
(SS) at 110?C
13Commercial plants
110?C, 10min and 14 min
Storage at 21?C
Fig. 9 The effect of storage time on intensity of
rancid flavour of oat groats
processed commercially or with superheated
steam (SS) at 110?C
14Commercial plants
110?C, 10min and 14 min
Storage at 21?C
Fig.10 The effect of storage time on L value
(lightness) of oat groats processed
commercially or with superheated steam
(SS) at 110?C
15Summary
- The shelf-life stability of oat groats processed
with superheated steam at 110?C for 10 and 14
min, and stored at 21?C was acceptable and
exceeded the intended storage time period of 6
months