A beta-carotene rich maize line as a resource of bioactive compounds

Abstract

Maize is one of the major sources of provitamin A for humans. Thus, the improvement of provitamin A carotenoids in maize varieties through breeding or biofortification is a promising strategy to alleviate Vitamin A deficiency. Maize Research Institute Zemun Polje has a breeding program aimed to create beta-carotene rich (BCR) maize, using the integrated conventional and molecular breeding approach. One commercial standard maize (SM) inbred line was converted to its BCR counterpart with the aid of gene-specific molecular marker crtRB1-3ʹTE through marker assisted backcross breeding. The aim of this study was chemical evaluation of the improved line. Relevant bioactive compounds, such as carotenoids, tocopherols and free phenolic acids content were analysed, and quality index (tryptophan to protein ratio) was determined. Beta carotene content (BC) was significantly higher (p<0.05) in BCR line compared to the SM line. This increase of 49.11% has confirmed the success of the conversion process. Among tocopherols, alpha-tocopherol (α-T) content was significantly higher (p<0.05) in comparison with SM. Out of free phenolic acids, content of caffeic acid (CA) and ferulic acid (FA) were significantly higher (p<0.01), as well as gallic acid (GA) (p<0.05), while increase of p-coumaric acid (p-CoumA) content was not significant. Quality index (QI) was also elevated for 9.28% in BCR line, which implies improved nutritional quality of the protein. Furthermore, significant correlations (p<0.05) were identified between QI and GA, between BC and α-T, CA, p-CoumA, FA and protein content, as well as between α-T and CA and FA, indicating the possibility of simultaneous selection and improvement of these traits in our breeding material. Chemical evaluation has identified this BCR maize line as a good resource of bioactive compounds with beneficial effects on human health. Therefore, it will serve as an important breeding material for developing maize hybrids with improved nutritional value