In this study, Hericium erinaceus polysaccharide (HEPS, with a purity of more than 92%) was modified using a redox system consisting of Na₂SeO₃ and ascorbic acid (VC) to obtain selenized HEPS (HEPS-Se). The structural and physiochemical properties of HEPS-Se were investigated by atomic absorption spectrometry (AAS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), and nano-zetasizer analysis. The anti-proliferation activity of HEPS-Se on A549 human lung cancer cells and DU145 human prostate cancer cells was evaluated. Results showed that HEPS-Se had a regular spherical shape and four elements C, O, Se and Pt at a ratio of 32.92:24.74:30.46:11.87 were determined in HEPS-Se. Its selenium content was 481.79 μg/g. FTIR analysis showed that HEPS could bind to selenium nanoparticles mainly through –OH and –C=O groups. Compared with HEPS, the particle size of HEPS-Se decreased significantly and the absolute potential increased by 69.12%. Meanwhile, HEPS-Se exhibited significantly anti-proliferative effects on DU145 cells and A549 cells in a dose-dependent manner. This study provides a theoretical basis for the development of organic selenium supplements.

In this study, we monitored changes in fruit hardness, cell wall-modifying enzyme activities such as polygalacturonase (PG), pectin methylesterase (PME), pectin lyases (PL) and β-galactosidase (β-Gal), and physiochemical properties of three cell wall polysaccharides including water soluble polysaccharide (WSP), trans-1,2-cyclohexanediaminetetraacetic acid (CDTA)-soluble polysaccharide (CSP) and Na₂CO₃-soluble polysaccharide (NSP) in ‘Yate’ kiwifruits during postharvest cold storage. Results showed that postharvest kiwifruits went through a ‘fast-slow’ softening process. PG activity showed a maximum value of 670.76 U/mg after 10 days of storage. PL and PME activities showed a maximum increase over the first five days of storage, reaching up to 3.41 and 9.17 U/mg, respectively. Particularly, β-Gal activity continuously increased during storage and showed a negative correlation with fruit hardness (r = −0.888). The pectin contents of WSP, CSP and NSP increased significantly with storage time. Moreover, the results of high performance gel permeation chromatography (GPC) showed that the weight average molecular mass of WSP increased, that of CSP initially decreased and then increased, and that of NSP gradually decreased during storage. Furthermore, a decrease in the area and an increase in the lamellarity of WSP were observed by scanning electron microscopy (SEM), whereas CSP was found to be soft and muslin-like after 15 days of storage, and the cluster-like accumulation of NSP was gradually dispersed with more debris being observed. These results may provide a solid theoretical basis for elucidating the exact mechanism of kiwifruit softening.