Enzymatic hydrolysis of stilbene glucosides in spruce bark extract

Spruce inner bark houses a variety of valuable compounds such as stilbenes. Despite this opportunity, this raw material is often incinerated to generate energy or simply landfilled. Stilbenes are polyphenols existing in plants as an extractive with antioxidant and radical scavenging properties that are reported widely in the literature. They are mostly found bonded to a glucose unit which in turn, makes them less bioavailable. In this work, some improvements on the extraction process using spruce bark were investigated and a commercial cellulase enzyme was employed to deglycosylate the stilbene glucosides present in spruce bark extract. The enzyme activity was explored using a Box-Behnken design and optimized via response surface methodology. The possibility of using high performance anion exchange chromatography and gas chromatography methods was investigated for quantification of the results and high performance liquid chromatography was employed for producing the results used in the model. Mass spectroscopy was utilized for the identification of the peaks. In optimized conditions at pH of 5 and 6.28 h, 92.3% of the stilbene species inside the extract solutions were in aglycone form showing great success in the biotransformation. Additionally, 21.4 mg of stilbenes per g of dry wood was extracted as a result of the modifications made in the extraction stage