TNAU Agritech Portal :: Post Harvest Technology

Post Harvest Technology :: Agriculture :: MAIZE

MAIZE - POST HARVEST TECHNOLOGY

Nutrient composition of maize
The mature maize kernel is composed of four major parts: 1. Endosperm (82 %), 2. Germ (12 %), 3. Pericarp (5 %) and 4. Tip cap (1 %)

1.	Carbohydrate (%)	66.2
2.	Protein (%)	11.1
3.	Fat (%)	3.6
4.	Fibre (%)	2.7
5.	Minerals (%)	1.5

Starch is the predominant carbohydrate of maize.
Prolamine is the predominant protein known as zein
Maize germ is rich in glutelin.
Enhanced lysine and tryptophan available in QPM hybrids.
Major lipids of maize are triglycerides, have high proportion of oleic acid and linoleic acid.

Health Benefits of Maize

Rich in carotenoids which are known for their antioxidant activity.
Maize protein benefit for vegetarians who do not consume animal meat.
Gluten free food for people who have celiac disease and cannot consume wheat.

Processing of maize

Maize is milled by a dry or wet process. In both processes, the germ is separated from the grain in order to extract and recover germ oil. The germ oil is a valuable product, but if allowed to remain a constituent of maize meal would lead to the development of rancidity.

Dry Milling

Grains are dry milled and employs roller mills and the process is somewhat similar to wheat milling. In dry milling, the object is to recover the maximum amount of grits with the minimum amount of flour, with the least possible contamination of died germ.
In India, maize is ground for whole meal atta in power-driven or hand¬ operated chakkis. The meal is sifted to remove fibre. In large-scale milling, maida and suji are produced. Grits are used in the preparation of porridge, to make corn flakes, as a brewing adjunct and to manufacture glucose by hydrolysis.

Corn Wet Milling

Pure starch, pure germ and feed are the basic products of corn wet milling. A list of these by products with their uses is given. Sufficient amount of moisture is added to the corn during stepping in the wet milling process in order to prepare the corn for subsequent degerming, grinding and separation operations.

Corn wet milling products

Product	Feed / food uses	Industrial uses
Germ oil and meal foots	Livestock	Soap, glycerine, leather dressing, etc.
Refined oil	Salad and table oils, cooking oils, margarine	Pharmaceuticals
Steep water	Yeast – food	Phytic acid, inositol
Gluten and hulls	Livestock and Poultry feed
Starch	Corn starch, chewing gum, bakeries baking powder, brewing confectionary	Textiles, laundry, paper and paper boxes, explosives, cosmetics, adhesives
Syrup	Bakery products, canned fruits, ice cream, confectionery, soft drinks, chewing gums, mixed syrups and jellies	Textiles, leather tanning, pharmaceuticals, tobacco
Sugar	Bakery products, pharmaceuticals, jams and jellies, ice cream, canned foods, confectionary	Rayon, tanning, fermentation brewing, vinegar, caramel colour, fermentation products, tobacco.

Value Added Products

1.Corn flakes

Cereal flakes are popular breakfast products and at present they are mostly made from corn. Ready to eat corn flakes are very popular, being crisp and friable in texture.

2. Traditional maize incorporated products

Traditional foods are a rich heritage of India and offer wide diversity because of their origin in different regions and involvement of multidimensional culture. Our south Indian traditional foods like idli and dosa, rice was replaced with QPM maize upto 30% without altering the quality attributes at the same time the bioavailability of protein is enhanced.

3. Extruded maize products- Noodles

Extrusion cooking is one of the latest technologies used for the preparation of convenience food. Extruded products are mainly from wheat, as well as rice and from other sources. In order to meet the growing demand of population low cost maize flour was used in extruded products noodles by extrusion technology.

4.Expanded Snacks

Expanded snacks incorporating maize and other millets in the ratio of 80:20 could be processed by extruding through twin screw extruder. The maize extruded snacks provide good amount of protein, fibre and minerals with the shelf life of three months under flexible packaging material.

5.Pop corn

Of the different types of corn, popcorn (Zea mays everta) is the only one that pops. There are various types of popping corn, but only the yellow and white varieties are available commercially. Popping of corn is due to the water in the kernel. As the kernal is heated, the water in the kernel is superheated and at the time of popping converts into steam, which provides the driving force for expanding the endosperm after the kernel ruptures.

6. Papad

Papad is a popular snack food in south India. It is also known as ‘appalam’ which is a thin wafer like circular product normally consumed as roasted or fried product.

7. Maize based bakery products

Baked products are considered as an excellent vehicle for fortification, value addition and feeding at mass scale. The cookies and bread had a significant corn flavor which improved the organoleptic score value.

8.Maize based snack foods

Snacks contribute to an important part of many consumers’ daily nutrient and calorie intake. Consumers enjoy snack foods with good taste, flavour and pleasing textural mouth feel. Maize grits was used for processing of vada and pakoda at the level of 20% incorporation whereas for instant mixes like dosa mix 50% incorporated, adai mix (50%), pittu mix (75%). Hundred per cent of maize grits cereal be used for processing of kesari, uppuma and puliyotharai.

Updated on May 2023