Cohen Yifat, Levi Moran, Lesmes Uri, Margier Marielle, Reboul Emmanuelle, Livney Yoav D
Department of Biotechnology & Food Engineering, Technion - Israel Institute of Technology, Haifa, 3200000 Israel.
Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, Haifa, Israel.
Food Funct. 2017 Jun 1;8(6):2133-2141. doi: 10.1039/c7fo00323d. Epub 2017 May 17.
The pandemic of vitamin D (VD) deficiency, and the global rise in obesity stimulate a need for staple low-fat foods and beverages enriched with VD. In light of consumer demand for a clean label, the use of natural endogenous food ingredients as delivery vehicles is of great interest. To this end, re-assembled casein micelles (rCM) have been shown to help retain VD during processing and shelf life and provide high bioavailability in low-fat milk and non-fat yoghurt. This follow-up study focused on the performance of VD-loaded rCM after drying and reconstitution, considering VD retention during simulated digestion, and the subsequent in vitro bioavailability of the vitamin. rCM conferred great protection to VD during simulated digestion with a significant increase in vitamin retention for 1 h under gastric conditions. This observation is believed to arise from the vitamin-casein binding and the system's natural gelation (curd formation) near the casein isoelectric point that seclude the vitamin from environmental stressors and couple its release with digestive proteolysis of the rCM matrix. Vitamin absorption by Caco-2 cells from digested rCM was not significantly different from the absorption of the digested free VD. However, thanks to the highly protective effect of the rCM, against VD gastric degradation, the overall effect of the rCM was a 4-fold higher bioavailability, compared to the free VD.
维生素D（VD）缺乏症的流行以及全球肥胖率的上升，促使人们需要富含VD的低脂主食食品和饮料。鉴于消费者对清洁标签的需求，使用天然内源食品成分作为递送载体备受关注。为此，重组酪蛋白胶束（rCM）已被证明有助于在加工和保质期内保留VD，并在低脂牛奶和脱脂酸奶中提供高生物利用度。这项后续研究聚焦于干燥和复溶后负载VD的rCM的性能，考虑了模拟消化过程中的VD保留情况以及该维生素随后的体外生物利用度。在模拟消化过程中，rCM对VD具有很强的保护作用，在胃部条件下1小时内维生素保留率显著增加。据信，这一现象源于维生素与酪蛋白的结合以及酪蛋白等电点附近系统的自然凝胶化（凝乳形成），从而使维生素免受环境应激因素的影响，并使其释放与rCM基质的消化蛋白水解相耦合。Caco-2细胞对消化后的rCM中维生素的吸收与消化后的游离VD的吸收没有显著差异。然而，由于rCM对VD胃部降解具有高度保护作用，与游离VD相比，rCM的总体效果是生物利用度提高了4倍。
