Cereal grains form a major source of dietary nutrients for all people, particularly those in the developing countries. However, the nutritional quality of cereal grains and sensory properties of their products are inferior due to lower protein content, deficiency of certain essential amino acids, lower protein and starch availabilities, presence of certain antinutrients, and the coarse nature of the grains. The consumption of sprouted cereals is becoming popular in various parts of the world. Sprouting of grains for a limited period causes increased activities of hydrolytic enzymes, improvement in the contents of certain essential amino acids, total sugars, and B-group vitamins, and a decrease in dry matter, starch, and antinutrients. The digestibilities of storage proteins and starch are improved due to their partial hydrolysis during sprouting. The magnitude of the nutritional improvement is, however, influenced by the type of cereal, seed quality, sprouting conditions, and it is not large enough to account for in feeding experiments with higher animals. In this review, the available literature concerning the nutritional improvement of cereals by sprouting and utilization of sprouted cereals in traditional and processed foods has been compiled and is critically reviewed.

Nutritional improvement of cereals by sprouting

With an annual production of more than two billion tons cereals are amongst the most important commodities in the world. Thus, products made from cereals are staple foods that contribute considerably to the energy and nutrient intake of mankind. The major cereals are corn, wheat, rice, barley, sorghum, millet, oats, and rye. Their constituents affect the nutritional and technological properties of cereals. Carbohydrates are the main constituents with starch providing energy and texture. However, although nonstarch polysaccharides are minor constituents they represent dietary fiber and exhibit positive health effects, in particular for whole grain products. Cereal proteins are quantitatively less important than carbohydrates, but they are of major importance for the functional properties, in particular for the bread-making performance of wheat and rye or for the quality of tortillas made from corn. The protein composition of different cereals varies considerably, but they have in common that lysine and methionine contents are low. Thus, cereal proteins are of poor nutritional value. Lipids are a minor constituent of cereals, but particularly in wheat flour polar lipids positively affect dough properties and enable the production of bread with good texture and quality. Whole grain cereals are important sources of minerals and B-vitamins.

Chemistry of Cereal Grains

The practice of sprouting of cereal grains has become popular in the western world. Sprouted grains are thought of as having exceptional nutritive value. Sprouting is easy and can be done without sophisticated equipment. Untreated seeds of good quality and high germination percentage are placed in an environment of adequate water, a desirable temperature, and a certain composition of gases in the atmosphere for several days for sprouting. The sprouts can be kept for a few days to over a week under refrigeration. They can be used in many different foods including breakfast items, salads, soups, casseroles, pasta, and baked products. Sprouting of grains causes increased enzyme activity, a loss of total dry matter, an increase in total protein, a change in amino acid composition, a decrease in starch, increases in sugars, a slight increase in crude fat and crude fiber, and slightly higher amounts of certain vitamins and minerals. Most of the increases in nutrients are not true increases, however. They simply reflect the loss of dry matter, mainly in the form of carbohydrates, due to respiration during sprouting. As total carbohydrates decreases, the percentage of other nutrients increases. There are no nutritional evaluations of cereal sprouts in humans. Animal studies with cattle, pigs, chickens, and rats have failed to show a superior nutritive value of sprouted grains over ungerminated grains. Studies with humans are not likely to produce more encouraging results.

Cereal sprouts: composition, nutritive value, food applications

A brief review of literature on sorghum for human foods and on the relationship among some kernel characteristics and food quality is presented. The chief foods prepared with sorghum, such as tortilla, porridge, couscous and baked goods are described. Tortillas, prepared with 75% of whole sorghum and 25% of yellow maize, are better than those prepared with whole sorghum alone. A porridge formulation with a 30:40:30 mix of sorghum, maize and cassava respectively, has been shown to be the most acceptable combination. The cooked porridge Aceda has lower protein digestibility and higher biological value than the uncooked porridge Aceda. Sorghum is not considered breadmaking flour but the addition of 30% sorghum flour to wheat flour of 72% extraction rate produces a bread, evaluated as good to excellent.

Tsai Cy

Papers

Lysine and tryptophan increases during germination of cereal grains.