Title: Cyanogenic glycoside levels and physicochemical characteristics of flour from various Manihot escule
1CLONAL VARIATIONS IN PASTING PROFILES AND
GRANULAR CHARACTERISTICS OF CASSAVA STARCH
Lorraine L. Niba1, Ph.D., Mpoko M. Bokanga2 ,
Ph.D. and Fatimah L. Jackson3,, Ph.D 1Virginia
Polytechnic Institute State University
Blacksburg, VA 24061 2International Institute of
Tropical Agriculture, Ibadan, Nigeria 3University
of Maryland, College Park, MD 20742
2Overview
- Introduction / background
- Rationale
- Sample selection
- Methods of analysis
- Results
- Conclusions and significance
3Introduction - Cassava (M. esculenta) botany and
ecology
- Tropical root crop, domesticated in the Amazon
- Family Euphorbiaceae
- Tuberous roots 3 - 36in plant 8ft high
- Ecological - sweet bitter
- Starchy parenchyma consumed
(Jackson et al., 1992 Onwueme Charles,
1994 FAO, 1998 Olsen Schaal, 1999)
4Rationale Determinants of Food Quality
- Plant Genotype
- ?Wild types
- Modified varieties
- Environment
- Growth conditions
- Handling and storage
X
- Primary Processing
- Traditional techniques
- Industrial processing
- Raw Material Quality
- Characteristics
- Functionality
X
- Secondary Processing
- Formulation
- Food ingredients
- Optimization
- Product sensory attributes
- Nutritional quality
X
End Product Quality
5Sample selection
- 12 month old plants
- Field plots on research farm (IITA crop
management program) - Agronomic fitness
- Eleven genotypes (Achinewhu et al., 1998
IITA Ann. Rep. 1998)
TMS 4(2)1425
TMS 82/00058
TME 1
TMS 50395
6Determination of cyanogenic potential (CNP)
7Production of cassava starch
8Determination of heating profiles by Rotary
Visco-analyzer (RVA)
- AACC method 61 - 02 (AACC, 1995 ICC, 1997)
- Sample slurry total weight 28 0.1g
- standard profile speed 960 - 160rpm
- temperature range 50 - 95oC
- Test period 13 minutes
9Assessment of starch granular structure by
Scanning electron microscopy
Starch particles (250?m) Adhesive backing tape
on stainless steel mount Starch on specimen
mount surface Surface coated with gold palladium
alloy (vacuum evaporator) Microscopic
examination (AMRAY-1820D ) Acceleration
potential 5.0KV tilt, 24o, working
distance35-50cm
10Cyanogenic potential of cassava root
11Representative Pasting Profiles of Cassava Starch
TME 1
TMS 91/02319
12Peak and Final Viscosities of Cassava Starch
13Setback Viscosity and Pasting Temperature
14Granular structure of cassava starch
representative micrographs
TMS 92/0326
TME 1
15Granular characteristics of cassava starch
16Granule size and characteristics of flour from
various M. esculenta genotypes
Starch granule size and peak viscosity
17Conclusions and Significance
- Differences are observed in starch granular
characteristics - Clonal differences observed in starch pasting
profiles - Implications in starch-based product development
and food processing - Relevance of assessment and analysis.
18Future Directions
- Characterization of cassava starch
- Food processing applications and parameters
- Impact on nutritional quality
- Recommendations for research directions.
19Special Thanks To
- Mentors / Advisors
- Committee on Africa and the Americas (UMD)
- IITA, Ibadan
- IITA Ibadan Biochemistry Unit technical staff
- Virginia Tech and CBN-V