Separation of beta-D-glucans and polyphenol oxidase inhibitor from hot-water extracts of golden needle mushroom, Flammulina velutipes
Date Issued
2007
Date
2007
Author(s)
Wu, Cheng-Wei
DOI
zh-TW
Abstract
Flammulina velutipes, a popular edible mushroom contain many biological active substances including immuno-modulating β-D-glucans, fungal immuno-modulating proteins (FIP) and polyphenol oxidase (PPO) inhibitor. The molecular-weight distribution of the glucans, FIP and the PPO inhibitor are following the order from large to small. In this study we successfully used hollow-fiber ultra-filtration technique to enrich these three substances into fractions in succession. The sequence of molecular-weight cut-off (MWCO) values of ultra-filtration membrane was 100, 10 and 3kDa following the separation order. The results indicated that retentate of 100kDa MWCO was mainly β-D-glucans, proteins were dispersed in 10-100kDa MWCO range and the polyphenol oxidase inhibitor was in fraction of molecular weight smaller than 3kDa. To understand the efficiency of each separation steps, we used ethanol precipitate fractionation to collect (1, 3)-β-D-glucans as control. The hot-water extracts containing 6.8% of (1, 3)- β-D- glucans was used in this study. The results indicated that (1, 3)-β-D-glucans recovery of using 40% ethanol precipitation and 76% ethanol precipitation were 85.0% and 95.1%, respectively. The ultra-filtration separation using 10kDa MWCO could recover 28.7% of solid and 95.1% (1, 3)-β-D-glucans in hot-water extracts, respectively. A method combining freeze-thaw cycle has been developed to recover (1, 3)-β-D-glucans which is large in molecular weight and having highly tendency to aggregate. The combination method could recover 3.8% of solid and 17.0% of (1, 3)-β-D-glucans in hot-water extracts, respectively. The content of (1, 3)-β-D- glucans was enriched 4.5 folds. The polyphenol oxidase inhibitors were concentrated in the fraction which permeated the MWCO of 3kDa membrane. The fraction could significant inhibited enzymatic browning of apple puree. The effective concentration was 12.5 mg/mL comparing to the effective concentration 18.75mg/mL for hot-water extract.
Subjects
金針菇
(1,3)-β-D-葡萄聚醣
超過濾
多酚氧化抑制劑
褐變
Flammulina velutipes
(1,3)-β-D-glucans
ultra-filtration
polyphenol oxidase inhibitor
browning
Type
thesis
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