Tropical Tuber Crops

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What were the principal results obtained and their scientific technological significance ?

During the period under report, I have been involved in four major projects in the institute, one ad-hoc project on physicochemical and structural characterization of minor root crop starches and advanced training in starch chemistry in the UK and sabbatical at the Sweden. Three students also carried out their work under my supervision for their PhD degree. The work over the period covered a wide area which includes studies on the cooking quality of cassava , extraction process for starch from minor tuber crops, basic studies on the starches of tropical tuber crops, production and properties of starch derivatives for application in food and industry and interaction with industry and entrepreneurs for extension of technologies. The salient findings and results are outlined below under the different headings.

1. Cooking quality of cassava
   1. Physical changes during cooking
   2. Factors responsible for cooking quality
      1. Starch content
      2. Starch properties.
         1. Granule size
         2. Crystallinity
         3. Molecular weight
         4. Amylose content
         5. Swelling power and solubility
         6. DSC patterns
         7. Gelatinization temperature
         8. Pasting temperatures
         9. Viscosity
      3. Effect of other ingredients
         1. Distribution of starch and sugars in different parts of the tubers
         2. Effect of other ingredients on starch swelling
2. Extraction of starch
3. Basic studies on the tuber starches.
   1. Other components in starch
   2. Color and appearance
   3. Granule size and shape
   4. Spectral features
   5. X-ray diffraction pattern
   6. Molecular weight
   7. Amylose content
   8. GPC Patterns
   9. DSC characteristics.
      1. MDSC in starch gelatinization
      2. Starch-surfactant complexation in determination of amylose content in various starches
      3. Influence of chain length on the starch gelatinization
      4. Effect of native lipids on the gelatinization of different starches
   10. Gelatinization and Pasting temperatures
   11. Viscosity
   12. Theological studies on tuber starches.
       1. Viscosity
       2. Storage modulus
       3. Phase angle
       4. Strain sweep tests
   13. Swelling power and solubility
   14. Clarity and Sol stability
   15. Digestibility
4. Modification of starches.
   1. Physical modifications.
      1. Steam pressure treatment
      2. Blending of starches
   2. Chemical modifications.
      1. Incorporation of surfactants and lipids
      2. Starch derivatives
         1. Starch esters
            1. Direct reaction with acid
            2. Reaction of acid/anhydride in presence of bases
            3. Catalytic esterification
            4. Reaction with acylating agents
         2. Cross linking
         3. Oxidative reactions
         4. Pregelatinised Starch
         5. Modification by fermentation
5. Value added products from starch
   1. Starch adhesives
   2. Carboxymethyl starch
   3. Starch phosphate
   4. Fructose syrup