Enzymatic preparation of fructooligosaccharides-rich burdock syrup with enhanced antioxidative properties

Background: Burdock (Arctium lappa L.) is a fructan-rich plant with prebiotic potential. The aim of this study was to develop an efficient enzymatic route to prepare fructooligosaccharides (FOS)-rich and highly antioxidative syrup using burdock root as a raw material. Results: Endo-inulinase significantly improved the yield of FOS 2.4-fold while tannase pretreatment further increased the yield of FOS 2.8-fold. Other enzymes, including endo-polygalacturonase, endo-glucanase and endo-xylanase, were able to increase the yield of total soluble sugar by 11.1% (w/w). By this process, a new enzymatic process for burdock syrup was developed and the yield of burdock syrup increased by 25% (w/w), whereas with FOS, total soluble sugars, total soluble protein and total soluble polyphenols were enhanced to 28.8%, 53.3%, 8.9% and 3.3% (w/w), respectively. Additionally, the scavenging abilities of DPPH and hydroxyl radicals, and total antioxidant capacity of the syrup were increased by 23.7%, 51.8% and 35.4%, respectively. Conclusions: Our results could be applied to the development of efficient extraction of valuable products from agricultural materials using enzyme-mediated methods.

Easy approach to DNA shuffling: its potential implication in health sciences.

Directed evolution experiments rely on the cyclical application of mutagenesis, screening and amplifications in a test tube. During the laboratory evolution of biological molecules, recombination has been used to generate novel sequences in a process known as DNA shuffling. DNA shuffling is a recently developed technique that allows accelerated and directed protein evolution for desired properties in vitro, which recombines and evolves genes to rapidly obtain molecules with improved biological activity and fitness. DNA shuffling is generally achieved by DNaseI treatment and by PCR. This has led to the creation of novel proteins for a wide range of applications. The use of improved enzymes for medical, industrial and environmental purposes is prevalent today, and will be expanding. New applications in vaccine development and disease diagnosis are among the key features of DNA shuffling. However, directed evolution currently requires an uncertain, typically large number of labor-intensive and expensive experimental cycles before proteins with improved function are identified. A simplified and low-cost DNA shuffling protocol for random recombination of homologous genes in vitro is described here.