*2.2.2 Unrefined grains*

These are grains that their germ and bran had not been removed through processing methods. They help to reduce the risk of type 2 diabetes, heart disease. Overall mortality is positively associated with high unrefined grain and nonfiber consumption. According to Willett et al. [49], preferred foods and shelf-life are the social and technological challenges faced when consuming whole grain. Most consumers of these products have adapted the fine texture and color of most refined flour, especially maize. However, there is a need for promotion and expansion in situations where unrefined maize has been consumed to increase its nutritional impact and meet consumer preferences [50]. These situations include roasted kernels, green maize, popcorn, wet-ground foods, and nixtamalization, along with short soaking time. The aleurone, germ, and pericarp of refined maize have been removed together with minerals and vitamin B. If this maize is not enriched after milling, the consumer's nutritional status will be negatively affected. There are little or no changes in the nutrient content of refined maize if it has been biofortified. Gannon et al. [51] compared the bioavailability of provitamin A from refined and whole maize grain with biofortified maize flours as there was no difference between their β-carotene bioefficiency. Furthermore, milling does not affect the bioavailability of zeaxanthin and β-cryptoxanthin in refined and whole-grain biofortified orange maize [52].

### *2.2.3 Fresh maize*

Any variety of maize harvested at the milky stage and prepared by boiling or roasting is referred to as fresh or green maize. Compared to conventional maize, QPM has higher glutelins, reduced zein protein, peak tryptophan, and lysine [25]. Alamu et al. [53] reported variations in the minerals and macronutrients retention of boiled and fresh maize in yellow, white, and high provitamin A carotenoid. The boiling of maize preserved lysine, zinc, and carotenoids at the milk stage.
