Bioaccessibility and total content of ultra-trace elements in Brassica rapa lines cultivatedin southern Spain

Abstract

Introduction: Nowadays, the adaptation of vegetable varieties to new climatic conditions is one of the main challenges facing agriculture. Vegetable species belonging to Brassiceae genus (among them Brassica rapa) are considered as one of the first cultivated and domesticated plant groups. Brassica vegetables can be a proper source for some nutritional relevant ultra-trace elements with a high bioaccessibility due to its low content of chelanting agents such as oxalic acid and phytic acid. Material and methods: Four Brassica rapa lines selected with respect to their production capacity of turnip tops production and the different length of their productive cycle have been cultivated in the edaphoclimatic conditions of the South of Spain. Cr, Ni and Co contents in Brassica rapa were analyzed by ET - AAS. Ultra-trace element bioaccessibility was determined by a process based on mimicking the physiological conditions of the gastrointestinal tract. Results and discussion: Cr content ranged between 561 – 1555 μg/Kg. Regarding Ni, concentrations of this trace element ranged between 245 – 1232 μg/Kg. Statistically significant differences were found between the four varieties for both trace elements studied. Finally, Co contents ranged between 46 – 120 μg/Kg. Cr bioaccessible concentrations ranged between 73 – 131 μg/Kg with a higher uniformity among analyzed samples. Cr bioaccessibility in Brassica rapa varieties showed medium percentages around 12%. It was also observed a high bioaccessibility of Ni present in Brassica rapa with percentages close to 100% for the four lines. Co bioaccessible concentrations were negligible. A simulation software (@Risk) was used to determine the contributions of Brassica rapa lines to Dietary References Intakes (DRI) for these elements. It was found that intake between 15 – 20 g of these dehydrated vegetables provided for 50th percentile, 22.2 μg of Cr (widely covering the DRI of this micronutrient) 11.1 μg of Ni or 1.47 μg of Co (covering DRI of vitamin B12).