Effect of primary processing of cereals and legumes on its nutritional quality: A comprehensive review

Abstract

Cereals and legumes are important part of dietaries and contribute substantially to nutrient intake of human beings. They are significant source of energy, protein, dietary fiber, vitamins, minerals, and phytochemicals. Primary processing of cereals and legumes is an essential component of their preparation before use. For some grains, dehusking is an essential step, whereas for others, it could be milling the grain into flour. Grains are subjected to certain processing treatments to impart special characteristics and improve organoleptic properties such as expanded cereals. All these treatments result in alteration of their nutritional quality which could either be reduction in nutrients, phytochemicals and antinutrients or an improvement in digestibility or availability of nutrients. It is important to understand these changes occurring in grain nutritional quality on account of pre-processing treatments to select appropriate techniques to obtain maximum nutritional and health benefits. This review attempts to throw light on nutritional alterations occurring in grains due to pre-processing treatments.

Keywords:

• milling
• sieving
• flaking
• nutritional composition
• phytochemicals
• nutrient digestibility

Public Interest Statement

Cereals and legumes are important part of human diets and a large variety are grown for edible purposes. They contribute significantly towards energy, protein, vitamins, minerals, dietary fiber, and phytochemical intakes. All grains undergo different types and levels of processing to make them edible and palatable. Pre-processing of grains is essential to prepare them for further processing and involves simple operations such as dehusking, milling, sieving, parboiling, germination, etc. Any kind of processing alters the nutritional quality of grains depending upon type and severity. Since the distribution of constituents in grain is not uniform, the milling processes can greatly influence the composition of resultant grain or flour. This review discusses the effects of pre-processing treatments on the nutrients, antinutrients, and phytochemical contents, and their digestibility and bioavailability in common cereals and legumes. This information will help us to understand the relative nutritional quality of pre-processed food grains.

Competing interests

The authors declare no competing interest for writing this review paper.

Additional information

Funding

The authors received no direct funding for this research.

Notes on contributors

Jamuna Prakash

The first author was a graduate student of the Institution, who worked for his PhD thesis on cereal grains and legumes. A very sincere and committed worker, he completed his thesis on a very comprehensive research topic related to food matrix and in vitro bioavailability of nutrients and bioactive components with reference to dietary fiber in selected foods. The work dealt with the effects of different processing treatments on nutritional quality of many cereal grains and legumes. The senior author was the research advisor and is an experienced faculty at the University. Her main research interests are nutritional composition of processed foods, functional properties of foods, product development, and sensory evaluation. In addition, she has also contributed significantly in the area of nutrient digestibility/bioaccessibility and antioxidant properties of foods. She is a prolific writer with many research and review papers to her credit.