Ding Ziwen, Jiang Fan, Liu Kun, Gong Fangshuo, Liu Yuanfa, Zheng Zhaojun, Xu Yong-Jiang
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Research Center for Functional Food, National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
Foods. 2023 Mar 27;12(7):1416. doi: 10.3390/foods12071416.
Hemp protein, with its important nutritional and industrial value, has trickled into the aisles of protein demand; however, its poor functional properties have largely limited its implementation in food. Herein, we aimed to modify hemp protein isolate (HPI) via glycosylation coupling with pullulan polysaccharide, and we subsequently characterized its structural and functional properties. The conjugation variables were HPI to pullulan ratio (i.e., 3:1, 2:1, 1:1, 1:2, and 1:3 /), incubation temperature (i.e., 50, 60, 70, 80, and 90 °C), and incubation time (i.e., 3, 6, 12, 24, and 48 h). Native HPI was used as a control for comparison purposes. We found that DG tended to decrease when the pullulan to HPI ratio was greater than 1:1 and when the temperature exceeded 80 °C. SDS-PAGE analysis shows that when the DG is increased, wider and heavier molecular weight bands emerge near the top of the running gel, while such observations were absent in the control. Further, glycosylation could loosen the HPI's secondary and tertiary structures, as well as increase surface hydrophobicity. The solubility of HPI after glycosylation significantly increased ( < 0.05) at pH 7.0 compared to HPI without glycosylation. Emulsifying activity improved significantly ( < 0.05), with glycosylation with HPI-pullulan at a ratio of 1:3 showing maximum emulsifying activity of 118.78 ± 4.48 m/g (HPI alone: 32.38 ± 3.65 m/g). Moreover, the HPI-pullulan glycosylation time of 24 h showed maximum foaming activity (23.04 ± 0.95%) compared to HPI alone (14.20 ± 1.23%). The foaming stability of HPI (79.61 ± 3.33%) increased to 97.78 ± 3.85% when HPI-pullulan was conjugated using a glycosylation temperature of 80 °C. Compared with the un-glycated HPI, HPI-pullulan also increased WHC (4.41 ± 0.73 versus 9.59 ± 0.36 g/g) and OHC (8.48 ± 0.51 versus 13.73 ± 0.59 g/g). Intriguingly, correlation analysis showed that protein functional characteristics were significantly and positively correlated with DG. Overall, our findings support the notion that pullulan conjugation provides further functional attributes to the HPI, thereby broadening its potential implementation in complicated food systems.
大麻蛋白具有重要的营养和工业价值，已逐渐进入蛋白质需求的市场；然而，其较差的功能特性在很大程度上限制了它在食品中的应用。在此，我们旨在通过与普鲁兰多糖进行糖基化偶联来修饰分离大麻蛋白（HPI），随后对其结构和功能特性进行表征。偶联变量包括HPI与普鲁兰的比例（即3:1、2:1、1:1、1:2和1:3）、孵育温度（即50、60、70、80和90°C）以及孵育时间（即3、6、12、24和48小时）。天然HPI用作对照以进行比较。我们发现，当普鲁兰与HPI的比例大于1:1以及温度超过80°C时，取代度（DG）趋于降低。SDS-PAGE分析表明，当DG增加时，在电泳凝胶顶部附近会出现更宽且分子量更大的条带，而对照中未观察到此类现象。此外，糖基化可使HPI的二级和三级结构松弛，并增加表面疏水性。与未糖基化的HPI相比，糖基化后的HPI在pH 7.0时的溶解度显著增加（P<0.05）。乳化活性显著提高（P<0.05），HPI与普鲁兰以1:3的比例进行糖基化时显示出最大乳化活性，为118.78±4.48 m/g（单独的HPI为：32.38±3.65 m/g）。此外，与单独的HPI（14.20±1.23%）相比，HPI-普鲁兰糖基化24小时显示出最大发泡活性（23.04±0.95%）。当使用80°C的糖基化温度使HPI与普鲁兰偶联时，HPI的泡沫稳定性从79.61±3.33%提高到97.78±3.85%。与未糖基化的HPI相比，HPI-普鲁兰还提高了保水性（WHC）（4.41±0.73对9.59±0.36 g/g）和持油性（OHC）（8.48±0.51对13.73±0.59 g/g）。有趣的是，相关性分析表明蛋白质功能特性与DG呈显著正相关。总体而言，我们的研究结果支持以下观点，即普鲁兰偶联为HPI提供了进一步的功能属性，从而拓宽了其在复杂食品体系中的潜在应用范围。
