11.1 Role of physical biological in deterioration of grains.pdf

Storagedeteriorationisanyformoflossinquantityandqualityofbio-materials.
Themajorcausesofdeteriorationinstorage
•Physical
•Biological
•Mechanical
•Chemical
Storageonlypreservesquality.Itneverimprovesquality.
Itisadvisabletostartstoragewithqualityfoodproduct.Productwithinitialpoorqualityquicklydepreciates

1. Role of physical, biological,
mechanical, and chemical factors in
deterioration of grains
By
Dr. U. Pirithiraj, P.hD.
Assistant Professor (Entomology)
JSACAT
Affiliated to Tamil Nadu Agricultural University

2. Storagedeteriorationisanyformoflossinquantity
andqualityofbio-materials.
Themajorcausesofdeteriorationinstorage
•Physical
•Biological
•Mechanical
•Chemical
Storageonlypreservesquality.Itneverimproves
quality.
Itisadvisabletostartstoragewithqualityfood
product.Productwithinitialpoorqualityquickly
depreciates.
Introduction

3. Causes
Heat from external source (sun) due to
unsuitable storage structures
•False location, Insufficient shade,
Poor ventilation facility
Physical factors
Temperature
Effects
Losses in weight and losses in quality (nutritional value, germination power)
Development of fungi and formation of mycotoxins. Improved conditions for the
development of pests. Loss in germination and vigor
Causes
• Insufficient drying before storage and high relative
humidity (high grain moisture)
• Constructional faults (unsuitable materials, unsealed
floor, walls and roof, holes, gaps, etc.)
• Produce stored on the floor or next to the walls
Moisture

4. Biological factors
Causes of infestation
• Cross infestation from neighboring lots
• Hiding places in stores (cracks, fissures)
• Use of infested bags
• Introduction of infested lots
Effects
• Losses in weight and quality (impurities
such as droppings, cocoons and parts of
insects, reduction of nutrition value)
• Increase of temperature and moisture
Insect pest

5. Causes of infection
• High moisture content of stored produce
• High relative humidity in store
• Condensation
• Humidity and moisture produced by insects
Microorganisms
Effects
• Loss of weight (mould) and loss of quality (smell, taste, color, reduction in nutritional value and
germination %)
• Formation of mycotoxins
• Further condensation

6. Causes of infestation
• Badly closing doors, windows, ventilation
openings and holes
• Lack of barriers and lack of hygiene in store and
surrounding area (possible breeding and hiding
places)
Effects
• Loss of weight
• High loss in quality due to contamination of
produce with faecesand urine
• Contamination of produce with pathogenic agents
(typhoid, rabies, hepatitis, plague, etc.)
• Damage of material (bags, doors, electric cables)
Rodents

7. Causes of infestation
• Open or broken doors, windows, ventilation
openings and roofs
Effects
• Losses in weight and damage to bags
• Contamination of stored produce with
droppings and pathogenic agents
Birds

8. Causes
• Incorrect harvesting methods
• Poor handling, threshing, shelling,
cleaning, sorting, drying
o No temperature insulation
o No moisture proofing
o No rat and bird proofing
o Not disinfected
Effects
• Losses in quantity and quality
• Increased vulnerability to infestation
from pests, fungi and rodents
Mechanical factors
Curtain wall made of concrete
Hardware clothRat proofing

9. Causes
• Chemical changes accelerated by
•Mycotoxins
•Pesticides
•Insecticides-prophylactic treatment
•Fumigants-curative treatment
Effects
• Degradation of nutrients
• Losses in weight and quality (germination %, nutritional value)
Chemical factors

10. The interaction is more important than the factors alone.
The interaction of all these factors decide the fate of grain during
storage