Whole Grains and Phenolic Acids: A Review on Bioactivity, Functionality, Health Benefits and Bioavailability

Abstract

Cereal grains represent one of the major sources of human food and nowadays, their production has increased to fulfill the needs of the world's population. Among whole grains, wheat is the most popular and contributes significantly to the human diet. Whole grains possess great nutritional and bioactive properties due to their fractions, bran and germ, that comprise unique health-promoting bioactive components. The evidence of health benefits in human intervention studies, as well as a World Health Organization report for 2012⁻2016, supports the dietary consumption of whole grains and whole-grain foods. The inverse correlation between whole grain consumption and the reduced risk of chronic diseases and metabolic syndromes was underlined by several epidemiological studies. This article focuses on the bioactive components of whole grains and their fractions, namely phenolic acids, starting from their chemical structure, bioactivity and bioavailability. According to the conclusive evaluation of the human intervention studies conducted using cereal bran and whole grains intake, the assumption that the bioactive compounds determine health outcomes is illustrated. In the last part of the work, the functional potential and the health claims related to whole grains and bran intake are discussed, as well as new technologies and strategies to enhance their health potential by an increased bioavailability.

Keywords: bran; phenolic acids; whole grains.

Figure 1

Whole-wheat grain main sections (adapted from Reference [37]).

Figure 2

From macro to molecular levels, the most nutritionally interesting technological fractions of wheat bran and aleurone layer, as well as arabinoxylan and ferulic acid components (adapted from Reference [43]).

Figure 3

Schematic representation of wheat grain fractions (adapted from Reference [43]).