Department of Health Science and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
Laboratory of Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland.
Carbohydr Polym. 2022 Oct 1;293:119724. doi: 10.1016/j.carbpol.2022.119724. Epub 2022 Jun 14.
Use of spin labels to study structures of polymers has been widely spread in polymer science. However, for the studies of neutral water-soluble dietary fibers (DFs), labelling efficiencies in past studies have only been sufficient for application of continuous wave electron paramagnetic resonance spectroscopy (CW-EPR), but still insufficient for some advanced methods such as pulse EPR. Thus, in this paper, two spin labelling strategies, namely, site-selective mono-spin-labelling and stochastic multi-spin-labelling, were examined on linear cereal β-glucan, as well as linearly branched arabinoxylan and galactomannan. The effects of both methods in DF properties were evaluated. For the mono-labelling pathway, labelling efficiency could reach up to 46 %. In the stochastic labelling strategy, a degree of substitution (DS) up to 150 % could be reached, whereas optimized conditions for this strategy were achieved at DS = 3 % to obtain DFs whose bioactivity properties were still preserved while spin labelling efficiency was still sufficient for CW and pulse EPR experiments.
利用自旋标记研究聚合物结构在聚合物科学中得到了广泛的应用。然而，对于中性水溶性膳食纤维（DFs）的研究，过去的研究中的标记效率仅足以应用连续波电子顺磁共振波谱学（CW-EPR），但对于一些先进的方法如脉冲 EPR 仍然不够。因此，在本文中，我们考察了两种自旋标记策略，即位点选择性单自旋标记和随机多自旋标记，用于线性谷物β-葡聚糖以及线性支链阿拉伯木聚糖和半乳甘露聚糖。评估了这两种方法对 DF 性质的影响。对于单标记途径，标记效率可达 46%。在随机标记策略中，可以达到高达 150%的取代度（DS），而该策略的优化条件是在 DS=3%时达到，以获得生物活性性质仍得以保留，而自旋标记效率仍足以进行 CW 和脉冲 EPR 实验的 DFs。
