Epsilon Archive for Student Projects

Abstract

Growing world population and changing environmental conditions have made the search of new potential foods, specifically protein sources, even more emergent. An alternative that has been the subject of studies recently is the use of processed green leafy biomass. One material obtained from the biomass is green juice which contains proteins alongside polyphenols and other compounds. Although polyphenols can sometimes be beneficial for the body, in food products they can cause bitterness and astringency that necessitates their removal. The removal of polyphenols can be done in different ways, with the focus of this thesis being the use of polymeric resins. Here, the polymeric resin SAX002 was used for polyphenol removal from green juice, and the subsequent recovery of the proteins was investigated. Lucerne and sugar beet leaves were the source of the green juice used. First the protocol was established. It was revealed by the BCA assay that the detectable protein concentrations decreased by up to 40% upon the resin treatment, therefore upon polyphenol removal . Through SDS-PAGE analysis following centrifugation, it was concluded that the proteins were forming insoluble aggregates. Then, different conditions for resin treatment were tested. The reasons for low protein solubility upon polyphenol removal was investigated and ways to solve the low solubility were explored. Upon the conditions tested, the most effective was the addition of PBS, followed by addition of urea or NaCl. This suggested that hydrophobic interactions and ion and hydrogen bonds were at play. Also, an LT-QToF analysis was conducted to confirm the removal of polyphenols and gain further insight alongside the Folin-C assay. An 80% reduction in the polyphenol content was observed. Overall, it was seen that the SAX002 was successful in the removal of polyphenols but the exact process that makes the proteins insoluble and how to combat it directly was not finalized. Further studies are required to establish a more efficient process.