In this study, the influence of ultrasound irradiation on the characterization and bioactivities of the polysaccharide from blackcurrant fruits (BCP, molecular weight: M_w=3.26 × 10⁴ kDa) was investigated. Two degraded polysaccharides (U-400, M_w=1.89 × 10⁴ kDa, and U-600, M_w=1.32 × 10⁴ kDa) were obtained by different ultrasound powers of 400 W and 600 W, respectively. Compared with BCP, U-400 and U-600 showed 63.52% and 68.85% reductions in the particle size (Z_avg), respectively; moreover, the dynamic viscosity of BCP was reduced by 27.88%, and 33.63%, separately. The reducing sugar content and thermal stability increased with the increase of ultrasound intensity. The degraded polysaccharides contained the same monosaccharide species as those of BCP but at different molar ratios. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic analysis confirmed that the degraded polysaccharides and BCP exhibited the similar structural features, which were mainly composed of six glycosidic bonds. A reduction in surface area of the flake-like structure was observed in the degraded polysaccharides compared to that of BCP, and they had no triple helix structure. Furthermore, the precise structural characteristics of U-600 were identified by 2D NMR analysis. The results of the bioactivity assays indicated that the ultrasound irradiation could evidently enhance the antioxidant (hydroxyl and superoxide radicals scavenging, lipid peroxidation inhibition, and DNA damage protection activities), α-amylase and α-glucosidase inhibition activities of BCP. These activities increased in the order of U-600> U-400>BCP. In particular, the DNA protection and α-amylase inhibition activities for U-600 were 52.19 ± 1.34% and 75.98 ± 0.77%, respectively, which were 2 times higher than those of BCP. U-600 prepared with the higher-intensity ultrasound exhibited the best physicochemical properties and bioactivities among the three polysaccharides. These results suggested that ultrasound irradiation was an efficient, green method to produce value-added polysaccharide for use in functional food or medicine.

在这项研究中，研究了超声辐照对黑加仑果多糖（BCP，分子量：M _w = 3.26×10 ⁴ kDa）的特性和生物活性的影响。通过400 W和600 W的不同超声功率分别获得了两种降解的多糖（U-400，M _w = 1.89×10 ⁴ kDa，U-600，M _w = 1.32×10 ⁴ kDa）。与BCP相比，U-400和U-600的粒径分别降低了63.52％和68.85％（Z _avg）， 分别; 此外，BCP的动态粘度分别降低了27.88％和33.63％。还原糖含量和热稳定性随着超声强度的增加而增加。降解的多糖含有与BCP相同的单糖种类，但摩尔比不同。傅立叶变换红外光谱和核磁共振光谱分析证实降解的多糖和BCP具有相似的结构特征，主要由六个糖苷键组成。与BCP相比，在降解的多糖中观察到片状结构的表面积减少，并且它们没有三螺旋结构。此外，通过2D NMR分析确定了U-600的精确结构特征。BCP的α-淀粉酶和α-葡萄糖苷酶抑制活性。这些活动按U-600> U-400> BCP的顺序增加。特别是，U-600的DNA保护和α-淀粉酶抑制活性分别为52.19±1.34％和75.98±0.77％，是BCP的2倍。用高强度超声制备的U-600在三种多糖中表现出最好的理化性质和生物活性。这些结果表明，超声辐射是生产用于功能性食品或药品的增值多糖的一种有效的绿色方法。