Date of Graduation

5-2019

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Food Science

Advisor/Mentor

Howard, Luke

Committee Member/Reader

Wang, Ya-Jane

Committee Member/Second Reader

Wickramasinghe, Ranil

Abstract

Anthocyanins are well known for their health-promoting benefits. The goal of this study was to evaluate a distillation-based membrane technology to concentrate aqueous anthocyanins extracted from muscadine grape pomace using polypropylene (PP) or ethylene chlorotrifluoroethylene (ECTFE) membranes. A hot water extraction method was utilized to extract the anthocyanins from the pomace. A pre-experimental run using DI water as feed was conducted to optimize the NaCl brine concentration for osmotic distillation and it was determined that 4M was the optimal concentration. The aqueous anthocyanins extraction was filtrated through a series of filter of different pore sizes before the distillation process. Membrane distillation (MD), osmotic distillation (OD), and membrane osmotic distillation (OMD) were all carried out over a 6-hour period to determine the optimal distillation process. Among the three processes, OMD demonstrated the highest permeate flux value, therefore, it was utilized to conduct the concentration using either PP or ECTFE membranes. The anthocyanins contents before and after the concentration process were measured by High Performance Liquid Chromatography machine. The result shows that OMD paired with ECTFE membrane concentrated the aqueous anthocyanins up to 196% but OMD with PP membrane exhibited a better performance. Concentrating the aqueous anthocyanin extract 280% over a 12-hour period. In addition, the quality of the concentrate was also investigated in terms of NaCl transferring across the membrane to the feed solution. only 0.02% - 0.03% of NaCl was transferred across the membrane to the feed side, indicating it is feasible to obtain concentrated anthocyanin extracts with low salt concentration

Keywords

anthocyanin concentration, hot water extraction, muscadine grape pomace, membrane osmotic distillation, membrane technology, anthocyanin

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