This document summarizes the steps for extracting starch from potatoes. It details the cleaning, rashing, and separation processes to remove the potato juice. The extracted starch milk then undergoes refining, dewatering, and drying. Potato juice is a waste product but contains proteins, minerals, and vitamins. Most starch is used in food processing and modified for non-food uses like adhesives, drilling fluids, plastics, and textiles.

1. DR AQEELA ASHRAF
Biology Department, LGU, Lahore

2. Lahore Garrison University
In previous lecture we studied starch, Characteristics
of potato starch and over view of starch extraction
from procedure

3. Lahore Garrison University
•
•
•
At the end of this lecture the students are expected to
understand and explain:
Detailed steps of starch extraction from potato
Waste products of the process
Applications of starch in food and no-food industry

4. Lahore Garrison University

5. Lahore Garrison University
•
•
•
•
•
•
CLEANING:
Scrubbers
Straw and stone separators
Water used is purified and recycled
RASPING OF TUBERS:
Rotatory grater
Disruption of cell walls occur
Removal of cellular juice

6. Lahore Garrison University
•
•
•
•
•
•
•
•
•
POTATO JUICE SEPARATION:
Recovery of full-value proteins.
STARCH EXTRACTION:
Starch washing unit
Steam oriented washers
Starch milk contamination
STARCH MILK RAFFINATION:
Refining process includes:
Removal of small fibres
Removal of juice water
Starch milk condensation
Chemical refining using sulphurous acid

7. Lahore Garrison University
•
•
•
•
DEWATERING of refined starch milk and Starch drying:
Leave 20% of moisture
Prevent starch gelatinization
Dewatering using rotatory vacuum
Pneumatic dryer to dry moist starch

8. Lahore Garrison University
•
•
Potato juice is a liquid waste product
separated from the potatoes pulp
after the rasping, using centrifuges or
decanters.
It contains about 5% of dry substance,
including about 2% valuable protein
of the potato of high nutritional value,
minerals, vitamins and other.

9. Lahore Garrison University
•
•
•
•
The usage of raw starch is relatively small. Starch is mainly used
as material both in the manufacture of food and non food
products.
In food processing a lot of starch is converted to starch
hydrolysates.
Also it is used to receive puddings, jellies, desserts, caramel and
other food products.
In addition, starch is processed to modified starch in order to
change material properties. The modified starches have a wide

10. Lahore Garrison University
•
•
•
•
•
Production of dextrin and adhesives,
Drilling fluids
Biodegradable plastics, gypsum binders and many other.
In addition modified starches are used as fillers, emulsion,
stabilizers, consistency modifiers etc.
Other important fields of starch application are textiles,
cosmetics, pharmaceuticals and

11. Lahore Garrison University
• https://www.youtube.com/watch?v=aMmXm3p48BE

12. Lahore Garrison University
Where do we use most of starch in food products or
no-food products?

13. Lahore Garrison University

14. Lahore Garrison University
Lahore Garrison University

15. Lahore Garrison University
Please go through video and slides given and notes
provided

16. Lahore Garrison University
•
•
Starch extraction from wheat through Martin method
Advantages and disadvantages of method

17. Lahore Garrison University