Qin Xiaopeng, Li Linbo, Yu Xiao, Deng Qianchun, Xiang Qisen, Zhu Yingying
College of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China.
Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
Foods. 2022 Jun 21;11(13):1820. doi: 10.3390/foods11131820.
This study aimed to comparatively elucidate the composition structure and techno-functionality of flaxseed protein isolate (FPI), globulin (FG), and albumin (FA) fractions. The results showed that FA possessed smaller particle dimensions and superior protein solubility compared to that of FG (p < 0.05) due to the lower molecular weight and hydrophobicity. FA and FG manifested lamellar structure and nearly spherical morphology, respectively, whereas FPI exhibited small lamellar strip structure packed by the blurring spheres. The Far-UV CD, FTIR spectrum, and intrinsic fluorescence confirmed more flexible conformation of FA than that of FG, followed by FPI. The preferential retention of free phenolic acids was observed for FA, leading to excellent antioxidant activities compared with that of FG in FPI (p < 0.05). FA contributed to the foaming properties of FPI, relying on the earlier interfacial adsorption and higher viscoelastic properties. FA displayed favorable emulsifying capacity but inferior stability due to the limited interfacial adsorption and deformation, as well as loose/porous interface. By comparison, an interlayer anchoring but no direct interface coating was observed for lipid droplets constructed by FG, thereby leading to preferable emulsion stability. However, FPI produced lipid droplets with dense interface owing to the effective migration of FA and FG from bulk phase, concomitant with the easy flocculation and coalescence. Thus, the techno-functionality of flaxseed protein could be tailed by modulating the retention of albumin fraction and specific phenolic acids.
本研究旨在比较阐明亚麻籽分离蛋白（FPI）、球蛋白（FG）和白蛋白（FA）组分的组成结构和技术功能性。结果表明，由于分子量和疏水性较低，FA与FG相比具有更小的颗粒尺寸和更高的蛋白质溶解度（p<0.05）。FA和FG分别表现出层状结构和近球形形态，而FPI呈现出由模糊球体堆积而成的小层状条带结构。远紫外圆二色光谱、傅里叶变换红外光谱和内源荧光证实，FA的构象比FG更灵活，其次是FPI。观察到FA对游离酚酸有优先保留作用，与FPI中的FG相比，其抗氧化活性优异（p<0.05）。FA有助于FPI的起泡性能，这依赖于其更早的界面吸附和更高的粘弹性。由于有限的界面吸附和变形以及松散/多孔的界面，FA表现出良好的乳化能力但稳定性较差。相比之下，观察到由FG构建的脂滴存在层间锚定但没有直接的界面包覆，从而导致较好的乳液稳定性。然而，由于FA和FG从本体相的有效迁移，FPI产生的脂滴具有致密的界面，同时容易絮凝和聚结。因此，通过调节白蛋白组分和特定酚酸的保留量，可以调控亚麻籽蛋白的技术功能性。
