Processing of Maize SSA

8/6/2019 Processing of Maize SSA

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Harvest and Post-harvest

Processing of Hybrid Maize



Factors affect in producing hybrid maize

� Use of appropriate production technologies

� Environmental conditions during growing

period

� Time of sowing, harvesting, shelling and

cleaning

� Drying method

� Storage practice



insects

rodents

birds

GERMINATION

PLANTING

STORAGE

MARKETING SYSTEM PROCESSING

FOOD PREPARATIONFOOD CONSUMPTIONNUTRITIONAL UTILIZATION

EXPORT

HARVEST

MATURATION

agronomic

practices

insect

damagedisease

abiotic stress

birds / rodents / insectsmicroorganisms

climate

Physical losses

shelling

drying

handling

transport

transport

insects

rodents

microorganisms

viability losses

At what stages in the cycle do losses occur?



Post-harvest pipe line



Operations/ Steps Followed in Harvesting

and Post-harvest Processing of Maize

Time of Harvesting

Husking, Sorting and Harvesting method

Drying

Shelling

Cleaning

Weighing, Bagging and storing



Harvesting

- Plants show distinct sings of drying

- Plant leaves turns light yellow.

- Only few top leaves may be green.

- About 75% HK is almost completely dry and

turn to straw/brown colour.



Mature cobs in the field for harvesting



There are some hybrids

- Where cobs mature and dry earlier, butstalks remain green for a longer time.

- Some time force maturity also occurs.

For this consider

i) Degree of drying of HK

ii) MC of grain

iii) ³Black layer´ formation to determine

harvesting time.



Checking of ³black layer´ formation



Indications of seed reaching maturityIndications of seed reaching maturity

Milk layer Dry husks

Black layer



Germination

Dry weight

Size

Humidity

Physiological

maturity

Time after flowering

Seed development and maturation



Physiological maturityPhysiological maturity

This generally coincides with the maximum

accumulation of dry matter

At Physiological Maturity grains develop to

complete functional maturity and express

maximum quality potential

This generally coincides with the maximum

accumulation of dry matter

At Physiological Maturity grains develop to

complete functional maturity and express

maximum quality potential



As fodder



Harvest ² Timing - EarlyHarvest ² Timing - Early

¡ At physiological maturity (30±35% MC)

¡ Advantages

a) Prevents further damage from corn borer, ear worms,

ear rot fungi etc.

c) Market seed earlier

d) Land availability and timely sowing of subsequent crop

Disadvantages

a) MC remains too highb) Requires mechanical drying facilities

c) Drying cost often excessive harvesting at this stage

¡ At physiological maturity (30±35% MC)

¡ Advantages

a) Prevents further damage from corn borer, ear worms,

ear rot fungi etc.

c) Market seed earlier

d) Land availability and timely sowing of subsequent crop

Disadvantages

a) MC remains too highb) Requires mechanical drying facilities

c) Drying cost often excessive harvesting at this stage



Harvest ² Timing - LateHarvest ² Timing - Late

¡ At about 14±18% MC

¡Advantage-lower drying cost

¡Disadvantage ± Expose the crop toundesireable elements in the field such astemperature and moisture extremes, rainfall, losseslike shattering, diseases, insects, rodents, birds,theft , etc.

¡ At about 14±18% MC

¡Advantage-lower drying cost

¡Disadvantage ± Expose the crop toundesireable elements in the field such astemperature and moisture extremes, rainfall, losseslike shattering, diseases, insects, rodents, birds,theft , etc.



Harvesting at field maturity results

Improved appearance of grains.

Greater resistance to mechanical injury fromhandling in processing plants.

Reduce drying cost.



In dry and sunny days harvesting should

be done.

If it is possible, cobs can be harvested by

dehusking directly from the standing

plants.

Consider for harvest



Eff ec f yie on har e ing time

y Premature har e ting of maize re uce the yie

y De ay in har e ting e ose see s

rainfall, diseases and insects, birddamage, and theft.

y Fully mature grain will result in

maximum yield, improved appearance of grain and greater resistance to

mechanical injury.



Dehusking by bamboo stick



Harvest ² Methods - HandHarvest ² Methods - Hand

¡Advantages:

a) Less damage

b) Selective harvest

¡Advantages:

a) Less damage

b) Selective harvest

Disadvantages:

a) Labor availabilityb) Labor cost

c) Area - timing



Husking



Combine direct harvest

One pass maize harvest



Care after harvesting-drying After harvest, put the cobs on concrete/mats for

drying

Don¶t heap the un-husked cobs after harvesting

Drying- to bring down the MC prior to shelling

Dehusk the harvested cobs as early as possible -

because initial high moisture can quickly deteriorate

grain quality

After dehusking, immediately the ears spread for sun

drying prior to shelling



Spreading of harvested cobs Dehusking

Sun drying of dehusked ears



What to Sort out

1. Diseased ears

2. Pre-germinated

3. Moldy/insect damaged

Cob rot

Corn borer damage



Sorting/Selection



Methods of Drying

Conventional method

(1) Sun drying- It is not expensive

De-husked ears or shelled grain are dried by

spreading them evenly & thinly on concretefloor or mats, plastic or canvass.

Takes about 2 to 3 sunny days to dry, it

depends on initial MC and weather condition. MC of de-husked ears should be down to about

18-20% for shelling, while shelled grains about

12% for storage.



Precautions required in sun drying

No direct contract with soil, use

tarpauline, sheets, mats etc.

Frequent turning of cobs for uniform

drying.

(2) By natural ventilation

(3) Another method is suspending rows

of bundled cobs

Ear with husk open to expose the kernels

on bamboo poles.



DRYING



SHELLING

Shelling of ears can be done in various ways after drying

the ears down to about 18-20% MC, to minimize

mechanical damage.

Several types of manually operated corn sheller,

improved hand corn sheller can also be used.

Power driven BARI corn sheller - for commercial use.



Shelling



Drying the Seed CropDrying the Seed Crop

Sun drying

Labor is required to spread and turn

cobs (or grain) to evenly expose

them to sun

Sun drying

Labor is required to spread and turn

cobs (or grain) to evenly expose

them to sun



Important aspects while shelling to getgood quality grain

Shell at proper moisture (about 18-20% MC).

Check for mechanical damage if any, that makes

lower quality grain.



CLEANING AND DRYING OF SHELLED GRAINS

Shelled grains need proper drying prior to

market/store After shelling and drying, the grains should be

cleaned.

Before storing, the dried grains need for cooling

about 8-10 hrs.



Maize grain preservation



STORING

The aim of storing is to keep the grain in good

quality.

Before storing proper drying of grain (12% MC).

Grain should be stored in a dry, cool place.Quality will degrade in the storage if high MC

and mechanical damaged grains are stored.

High moisture will cause

Excessive mold growth and pest attack

Farmer level grain storage

jute bags, drum, polyethelene in jute bags



ReceptionDrying Grading

& Sizing

Temporary Storage Treatment andBagging

MarketingStorage

Cleaning

GENERAL FLOW IN SEED CONDITIONINGGENERAL FLOW IN SEED CONDITIONING



As human food

Processing of Maize SSA

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