Purification, Characterization, and Immobilization of a Novel Protease-Resistant α-Galactosidase from Oudemansiella radicata and Its Application in Degradation of Raffinose Family Oligosaccharides from Soymilk

Xueran Geng; Jiayu Lei; Tergun Bau; Dongdong Guo; Mingchang Chang; Cuiping Feng; Lijing Xu; Yanfen Cheng; Ningke Zuo; Junlong Meng

doi:10.3390/foods11193091

Purification, Characterization, and Immobilization of a Novel Protease-Resistant α-Galactosidase from Oudemansiella radicata and Its Application in Degradation of Raffinose Family Oligosaccharides from Soymilk

Foods. 2022 Oct 5;11(19):3091. doi: 10.3390/foods11193091.

Authors

Xueran Geng^{1

2}, Jiayu Lei^{1

3}, Tergun Bau⁴, Dongdong Guo^{1

3}, Mingchang Chang^{1

3}, Cuiping Feng^{1

3}, Lijing Xu^{1

2}, Yanfen Cheng^{1

2}, Ningke Zuo^{1

3}, Junlong Meng^{1

3}

Affiliations

¹ College of Food Science and Engineering, Shanxi Agricultural University, Taigu 030800, China.
² Shanxi Key Laboratory of Edible Fungi for Loess Plateau, Taigu 030800, China.
³ Shanxi Engineering Research Center of Edible Fungi, Taigu 030800, China.
⁴ Inner Mongolia Agriculture, Animal Husbandry, Fishery and Biology Experiment Research Centre, Inner Mongolia Agricultural University, Hohhot 010019, China.

Abstract

α-galactosidase (EC 3.2.1.22) are glycosidases that catalyze the hydrolysis of α-1,6-linked D-galactosyl residues of different substrates, which has been widely applied in the food industry. Oudemansiella radicata is a kind of precious edible medicinal mushroom, which is a healthy, green, and safe food-derived enzyme source. In this study, a novel acidic α-galactosidase was purified from the dry fruiting bodies of O. radicata by ion-exchange chromatography and gel filtration, and designated as ORG (O. radicata α-galactosidase). ORG was further immobilized to obtain iORG by the sodium alginate-chitosan co-immobilization method. Then, the characterization of free and immobilized enzymes and their potential application in the removal of the RFOs from soymilk were investigated. The results showed that ORG might be a 74 kDa heterodimer, and it exhibited maximum activity at 50 °C and pH 3.0, whereas iORG showed maximum activity at 50 °C and pH 5.5. In addition, iORG exhibited higher thermal stability, pH stability, storage stability, and a better degradation effect on raffinose family oligosaccharides (RFOs) in soymilk than ORG, and iORG completely hydrolyzed RFOs in soymilk at 50 °C within 3 h. Therefore, iORG might be a promising candidate in the food industry due to its excellent stability, high removal efficiency of RFOs from soymilk, and great reusability.

Keywords: Oudemansiella radicata; purification; raffinose family oligosaccharides; α-galactosidase.

Grants and funding

This study was financially supported by the Doctoral Science Foundation of Shanxi Agricultural University (2017YJ33), Key Project of Coal-based Science and Technology of Shanxi Province (FT2014-03-01), and Key Team of Scientific and Technological Innovation of Edible Fungi of Shanxi Province (201805D131009).