Maize Based Products Compiled and Edited by Dr Shruti Sethi, Principal Scientist & Dr. S. K. Jha, Principal Scientist & Professor Division of Food Science and Postharvest Technology ICAR-Indian Agricultural Research Institute, Pusa New Delhi 110012 Maize is also known as Corn or Makka in Hindi. It is one of the most versatile crops having adaptability under varied agro-climatic conditions. Globally, it is known as queen of cereals due to its highest genetic yield potential among the cereals. In India, Maize is grown throughout the year. It is predominantly a kharif crop with 85 per cent of the area under cultivation in the season. The United States of America (USA) is the largest producer of maize contributing about 36% of the total production. Production of maize ranks third in the country after rice and wheat. About 26 million tonnes corn was produced in 2016-17 from 9.6 Mha area. The country exported 3,70,066.11 MT of maize to the world for the worth of Rs. 1,019.29 crores/ 142.76 USD Millions in 2019-20. Major export destinations included Nepal, Bangladesh Pr, Myanmar, Pakistan Ir, Bhutan The corn kernel has highest energy density (365 kcal/100 g) among the cereals and also contains vitamins namely, vitamin B1 (thiamine), B2 (niacin), B3 (riboflavin), B5 (pantothenic acid) and B6. Although maize kernels contain many macro and micronutrients necessary for human metabolic needs, normal corn is inherently deficient in two essential amino acids, viz lysine and tryptophan. Maize is staple food for human being and quality feed for animals. It has diverse uses. It can be transformed into varied products. Maize serves as a basic raw material as an ingredient to thousands of industrial products including starch, oil, protein, alcoholic beverages, food sweeteners, pharmaceutical, cosmetic, film, textile, gum, package and paper industries etc The starch obtained from maize can further be transformed into a number of valuable food and pharma ingredients. The waste or residue generated during all these processes can be further used for fuel production or used as livestock feed. Corn classification It may be classified as flint corn, flour corn, dent corn, pop corn, sweet corn, baby corn, QPM, waxy corn. The quantity and quality of endosperm varies among different types of corn. Flint corn has hard and glossy endosperm with smooth and hard pericarp. Flour corn consists of endosperm made of soft starch and thin pericarp. Dent corn has partly soft endosperm and partly hard endosperm and thus falls between flint and flour corn. Dent corn has dent when it gets dried. Pop corns have small kernels with hard endosperm. Sweet corn possesses sugary gene which slows down the conversion of sugar to starch in the grain. Waxy corn has starch made of 100% amylopectin. This deficiency of essential amino acid in maize has been genetically overcome by development of Quality Protein Maize (QPM) which contains twice the amount of lysine and tryptophan, thus making it rich source of quality protein. It has been found that QPM yields 10% more grain than the traditional varieties of maize. Also, QPM contains 70-100% more of lysine and tryptophan than the most modern varieties of tropical maize. These two amino acids allow the body to manufacture complete proteins, thereby eliminating wet malnutrition. In addition, tryptophan can be converted in the body to niacin, which theoretically reduces the incidence of Pellagra. It has also been reported that QPM grits have lower glycemic response as compared to milled rice and rice-corn grits making it suitable for diabetic people. Introduction of this QPM in the regular diet as diversified product can definitely help in solving the problem of malnutrition to certain extent. Lot of research in targeted towards development of specialty maize such as quality protein maize (QPM), sweet corn, pop corn, baby corn, high oil corn etc. Some of the varieties released I India regarding these are mentioned in Table below. Type of corn Varieties developed and released in India Quality Protein Maize Shakti-1, Shaktiman-1, Shaktiman-2 Sweet corn Maduri, Priya Sweet Corn Pop corn Amber pop corn, VL pop corn Baby corn Co1, Him123, Early composite, VL64, PEHM-1, PEHM-2 High starch Ganga111, Hi-starch, Deccan 103, Deccan 105, Trishulata, Sheetal, Paras High oil Source populations HOP-1, HOP-2 Source: Technologies for processing specialty maize in India (2003) Directorate of Maize Research, ICAR, New Delhi and Angricultural Research Station, Amberpet, ANGRAU, Hyderabad Indian Institute of Maize Research (IIMR), Ludhiana under the aegis of Indian Council of Agricultural Research has documented the cultivars of maize developed by All India Coordinated Research Project on Maize (AICRPM) and released for cultivation in India (https://iimr.icar.gov.in/cultivars-2/) some of which are as given below: Speciality maize Maize cultivars developed under AICRPM QPM • Pusa HM-8 Improved (AQH-8), ICAR-IARI, New Delhi • Pusa HM-9 Improved (AQH-9), ICAR-IARI, New Delhi • Pusa HM-4 Improved (AQH-4), ICAR-IARI, New Delhi • Pusa Vivek QPM-9 Improved (APQH-9), ICAR-IARI, New Delhi • Shalimar QPMH-1 (KDQH-49) SKUAST, Kashmir • Shaktiman-5 (MHQPM 09-08) Rajendra Prasad Central Agriculture University Sweet corn • Shalimar Sweet Corn-1 (KDM-1263SC) SKUAST, Kashmir • VL Sweet Corn Hybrid-2 (FSCH-75)VPKAS , Almora • Central Maize VL Sweet Corn 1 (FSCH18)VPKAS, Almora, Uttarakhand Pop corn • DMRHP 1402, IIMR, Ludhiana • Shalimar Pop Corn-1 (KDPC-2) SKUAST, Kashmir • BPCH-6 Acharya N. G. Ranga Agricultural University, Hyderabad Baby corn • Vivek Hybrid 27 (Central Maize VL Baby Corn 2) VPKAS , Almora High oil lines • IC0584601, ICAR-Indian Institute of Maize Research (IIMR), Pusa Campus, New Delhi (6% oil) • IC0584602, CCS Haryana Agricultural University (CCSHAU), Regional Research Station (RRS), Uchani, Karnal, Haryana (6.31% oil) • IC0589137, ICAR-Indian Institute of Maize Research (IIMR), Pusa Campus, New Delhi (6.34% oil ) Milling of Corn In corn, two types of milling are generally used. The milling practices are known as dry and wet milling. While the main objective of dry milling is to get grits (flaking grits/brewery grits), wet milling is intended to obtain starch. Dry milling of corn Dry milling of corn consists of unit operations like cleaning, tempering or conditioning, degerming and milling. Cleaning is usually done by dry cleaning methods. Air screen cleaner, specific gravity separator, magnetic separator are employed to clean corn prior to conditioning. Tempering or conditioning of clean grain is done by addition of moisture and allowing the grain to stand for pre-fixed time. The amount of moisture and time for tempering depends upon the intended end product quality and the method of degermination and milling to be used. If the degerming is through roller mill, grain moisture need to be raised up to 15-5 to 16.5% for 2-6 hour but major end product is grit for household consumption. Degermination through Beall or similar equipment may require the grain moisture to be raised to 20-24% with tempering time 2-6 hour; flaking and brewery grits are the major products to be obtained. If brewery grits are the requirement, decorticator and roller mills could be used which may need the grain to be moistened up to 17-18% for 2-6 hour. Roller mill used for degerming and/or milling is similar to the roller mill used for modern wheat milling. There are break passages, sizing passage and the purification passage. Germ and hull are obtained as major by-products of the dry milling of corn. Germ can be used for edible oil extraction or in breakfast cereal. Hull can be used as animal feed. Wet milling of Corn It consists of unit operations like steeping, germ separation, fibre separation, starch and protein separation, and starch refinement. In steeping corn is dipped into water for softening of the grain. Temperature of water and dipping time is carefully controlled during the process. The water at the end of the process gets enriched with water-soluble constituents, which is used as animal feed. Steeped corn is sent to disk mill for release of germ which is separated from the mixture using hydroclone. Milling and separation of germ is carried out in multiple pass. The slurry obtained after germ separation is passed through fine screen for separation of fibre. The fibres are retained on the screen whereas the starch- protein passes through. Protin is insoluble in water and is lower in density compared to starch, so washing followed by filtration allows the starch to pass through the filter and thus separation between protein and the starch. Starch is further refined several times through washing to ensure to get pure starch. Starch is a major ingredient for several industries. Germ obtained can be used for oil extraction or in breakfast cereal. Hull and protein obtained are used as animal feed. Value added products from normal corn Maize can be processed into variety of value added products such as corn flour, dalia, corn flakes, tortilla chips, corn nut, pop corn, puffed products etc. Corn Flour Corn flour is a flour prepared by grinding dried whole corn kernels. It contains all components of the grain ie hull, germ, and endosperm of the corn and is thus a whole grain flour. The texture of the flour is fine and smooth. It differs from cornmeal, which is coarser in terms of texture. Corn flour can be incorporated into various recipes like breads, muffins, pancakes, battered and fried foods etc. Mills of various sizes from domestic level to commercial level are available in the market for making corn flour. It is important that before grinding, thorough cleaning of the grain is done removing all unwanted materials from the grain lot.