Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Photon Science, Deutsches-Elektronen Synchrotron DESY, Hamburg, Germany.
Food Chem. 2018 Oct 30;264:367-376. doi: 10.1016/j.foodchem.2018.04.125. Epub 2018 Apr 30.
Chelation of iron and zinc in wheat as phytates lowers their bio-accessibility. Steeping and germination (15 °C, 120 h) lowered phytate content from 0.96% to only 0.81% of initial dry matter. A multifactorial experiment in which (steeped/germinated) wheat was subjected to different time (2-24 h), temperature (20-80 °C) and pH (2.0-8.0) conditions showed that hydrothermal processing of germinated (15 °C, 120 h) wheat at 50 °C and pH 3.8 for 24 h reduced phytate content by 95%. X-ray absorption near-edge structure imaging showed that it indeed abolished chelation of iron to phytate. It also proved that iron was oxidized during steeping, germination and hydrothermal processing. It was further shown that zinc and iron bio-accessibility were respectively 3 and 5% in wheat and 27 and 37% in hydrothermally processed wheat. Thus, hydrothermal processing of (germinated) wheat paves the way for increasing elemental bio-accessibility in whole grain-based products.
小麦中植酸结合的铁和锌会降低其生物可利用性。浸泡和发芽（15°C，120 小时）将植酸盐含量从最初干物质的 0.96%降低至仅 0.81%。在一项多因素实验中，对经过浸泡/发芽的小麦进行不同时间（2-24 小时）、温度（20-80°C）和 pH（2.0-8.0）条件处理，结果表明，在 50°C 和 pH 值为 3.8 下对发芽（15°C，120 小时）小麦进行 24 小时的湿热处理，可使植酸盐含量降低 95%。X 射线吸收近边结构成像表明，它确实破坏了植酸与铁的螯合。这也证明了铁在浸泡、发芽和湿热处理过程中被氧化。进一步表明，小麦中锌和铁的生物可利用性分别为 3%和 5%，而湿热处理的小麦中则分别为 27%和 37%。因此，湿热处理发芽的小麦为提高全谷物产品中元素的生物可利用性铺平了道路。
