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This paper, discussed the high-pressure homogenization (HPH) method for the preparation of large-leaf yellow tea polysaccharide conjugates (LYTP), and the effects of LYTP on physicochemical properties as well as antioxidant activity were investigated. The results show that HPH extraction time was less than 0.5 h, and extraction rate reached 15.4%, which was nearly 1.8 times faster than that of hot water extraction (HWE). Component analysis showed that the total polysaccharide content of LYTP was higher, while the contents of polyphenols and free protein were lower than those of HWE. It is noteworthy that the 9.1% free protein content at 40 MPa was lower than that of the Sevag method (11.2%), indicating that HPH can eliminate the cumbersome protein removal process and is more environmentally. The small-molecule polysaccharide content extracted by HPH increased, but the monosaccharide composition did not change. Meanwhile, HPH decreased the particle size of the polysaccharides, and the changes in the surface topography of LYTP upon homogenization were confirmed with scanning electron microscopy. As a consequence, HPH extraction can improve the antioxidant capacity of LYTP. HPH extraction is an efficient, rapid and environmentally method for the preparation of polysaccharides, which could be widely used in the food industry. [Display omitted] • High-pressure homogenization extraction of polysaccharide from large-leaf yellow tea. • This non-heating method is efficient, and can greatly shorten the extraction time. • The physicochemical properties of the tea polysaccharides were determined and compared. • The polysaccharides exhibited stronger antioxidant activities in vitro. [ABSTRACT FROM AUTHOR]

Our previous studies have revealed that the Tricholoma lobayense polysaccharide TLH-3, which has an IC50 value for scavenging superoxide radicals comparable to that of Vitamin C (VC), could be prepared by hot water extraction and column chromatography. However, this method is tedious and inefficient. In this study, high-pressure homogenization (HPH) was used to extract polysaccharides from T. lobayense Heim. The yield of 17.3% using HPH was higher than the 12.3% yielded by traditional extraction. Moreover, the operation combined quaternary ammonium salt precipitation with ultrafiltration (QASP-UF) to purify the crude polysaccharides successfully, which provided a higher TLH-3′ yield, a larger separation volume, and a shorter purification time than that of column chromatography. The whole process for TLH-3′ preparation presented here exhibited significant advantages of quicker processing, low consumption, high efficiency, and flexible compatibility with follow-up studies. Based on a characterization of molecular weight, Fourier Transform Infrared Spectroscopy (FT-IR) analysis, and monosaccharide composition analysis, it can be concluded that TLH-3 and TLH-3′ are the same polysaccharide. Antioxidant activity was tested to prove that the TLH-3′ prepared in this study could scavenge DPPH and superoxide radicals, with IC50 values of 111.7 μg/mL and 160.0 μg/mL, respectively. Its outstanding antioxidant ability was comparable to that of ascorbic acid. [ABSTRACT FROM AUTHOR]