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Research design Sampling Cassava Varieties
Starch extraction
Determination of Resistant Starch (RS)
Hydrothermal modification of RS (Synthesis of RS)
Application of RS in Yogurt processing
Lab and Sensory evaluation
CHAPTER THREE: MATERIALS AND
METHODS
University of Nairobi ISO 9001:2008 1 Certified http://www.uonbi.ac.ke
Raw material acquisitionCassava roots samples from three different cassava varieties (NASE14, THE I92/0057 and GARUKUNSUBIRE) of 12 months in the field will be collected from RAB field research stations of Rubona and Rilima
Starch extracting
Measurement of RS
Objective 1: Determination of
the levels of RS in three Rwandese
cassava varieties
University of Nairobi ISO 9001:2008 2 Certified http://www.uonbi.ac.ke
Starch Extraction Starch will be extracted using the wet method as described
by Benesi et al. (2004).Starch properties • Moisture content and dry matter content determination
(ISO 1660 -1996),• Water absorption and Solubility Index will be carried out
as per Anderson (1982), •Texture analysis: Texture Analyser will be used (Kaszab et al., 2002),• Pasting profile of starch (AACC Approved Method 61.02.).
Determination of the levels of RS in three
Rwandese cassava varieties con’t
University of Nairobi ISO 9001:2008 3 Certified http://www.uonbi.ac.ke
Resistant starch determinationRS will be determined as per AOAC Method (2002.02).Triplicate samples will be analyzed and ANOVA will be carried out to determine significant differences at 5% level of significance.
Determination of the levels of RS in three
Rwandese cassava varieties con’t
University of Nairobi ISO 9001:2008 4 Certified http://www.uonbi.ac.ke
Heat-moisture treatment (HMT) The moisture levels of the starch samples will
be increased to 18%, 24% and 30%, The samples will be sealed in glass jars and
heated in an air oven at 80°C for 16 hours, The starch samples will be air dried and
subjected to RS measurement.
Objective 2: Hydrothermal
modification of RS
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Annealing Starch (100g) will be heated in excess water
at a temperature of 45°C and 55°C for 24 hours,
Samples will be centrifuged, air-dried and will be subjected to RS determination.
Hydrothermal modification of RS
cont’
University of Nairobi ISO 9001:2008 6 Certified http://www.uonbi.ac.ke
Starch profiling•Moisture content and dry matter content determination (ISO 1660 -1996),•Water absorption and Solubility Index will be carried out as per Anderson (1982), • Texture analysis: Texture Analyser will be used
(Kaszab et al., 2002),•Pasting profile of starch (AACC Approved Method 61.02.).
Hydrothermal modification of RS
cont’
University of Nairobi ISO 9001:2008 7 Certified http://www.uonbi.ac.ke
Pasting profile of starch (AACC Approved Method 61.02.)Flour (40 g) and water (420 ml) will be heated from 30°C to 93°C and held for 15 min, The temperature will be decreased at a constant rate of 1.5°C/ min until 30°C and held there for 15 min.The resistance to stirring as a viscosity curve will be recorded,
The pasting temperature, peak viscosity, hot paste viscosity and cold paste viscosity will be determined from the pasting curve.
Hydrothermal modification of RS
cont’
University of Nairobi ISO 9001:2008 8 Certified http://www.uonbi.ac.ke
Data analysis A 3x5 factorial design will be usedEach experiment will be done in triplicateTotally, 45 treatments will be analysed in GenStat application
N45 : Annealing at 45°C AN55 : Annealing at 55°CHMT-18: 18% M.C HMT-24: 24% M.C HMT-30: 30%M.C
Hydrothermal modification of RS cont
University of Nairobi ISO 9001:2008 9 Certified http://www.uonbi.ac.ke
Treatments HMT-18
HMT-24
HMT-30
AN-45 AN-55Varieties
NASE14THE I92/0057 GARUKUNSUBIRE
yoghurt will be treated with 0.1%, 0.5% and 1% of cassava starch with high RS levels as thickener,
Yoghurt with no thickener will be used as a control
Objective 3: Application of resistant
starch in yoghurt
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Application of resistant starch in
yoghurt con’t
University of Nairobi ISO 9001:2008 11 Certified http://www.uonbi.ac.ke
Preliminary treatment of milk (standardization)
Homogenization
Starch Heat treatment (950C for 15 Min)
Cooling (430C) Starter culture
Inoculation with starter culture
Stirred yogurt
Packaging (250C)
Cooling and storage (50C)
Sensory Evaluation
Analysis of yoghurt Texture analysisTexture Analyser will be used to objectively evaluate the
texture of modified yoghurt as per Kaszab et al. (2002). Viscosity analysisViscosity will be measured by Viscometer as per
Djurdjević et al., 2001. Syneresis By centrifugation Method pH and Acidity (Titration) Total solids : ISO 13580: 2005 Levels of RS
Application of resistant starch in
yoghurt con’t
University of Nairobi ISO 9001:2008 12 Certified http://www.uonbi.ac.ke
Sensory evaluation A panel of 20 people will be tasked to evaluate the quality characteristics (taste, colour, flavour, aftertaste, texture and overall acceptability),
A 7 point hedonic scale will be used: where 7= like very much, 6= like moderately, 5= like slightly, 4= dislike slightly, 3= dislike moderately, 2= dislike very much and 1= dislike extremely.
Application of resistant starch in
yoghurt con’t
University of Nairobi ISO 9001:2008 13 Certified http://www.uonbi.ac.ke
Scoresheet
Data analysis Sensory evaluation data will be analysed in a complete randomised design
Application of resistant starch in
yoghurt con’t
University of Nairobi ISO 9001:2008 14 Certified http://www.uonbi.ac.ke
parameter
Colour
Taste Flavour
Aftertaste
Texture
Overall acceptanceSamples
Untreated0.1%0.5%1%
WORK PLAN
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Proposed Budget
University of Nairobi ISO 9001:2008 16 Certified http://www.uonbi.ac.ke
THANK YOU
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