Development of technologies for the production of polyphenolic nutraceuticals from Muscadine grapes and Rabbiteye blueberries
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Muscadines grapes and Rabbiteye blueberries are a good source of polyphenolic compounds, which may reduce the occurrence of degenerative diseases caused by free radicals cancer, ageing, and Alzheimer’s. The overall objective of the research was to develop technologies to produce polyphenolic rich, shelf stable, non-sticky powders from these berries. Response surface methodology (RSM) was employed to optimize extraction and stability of total phenolics and anthocyanins. Aqueous extraction consisted of preheating slurries at 25, 45, and 60C for 0.5, 1, and 2 h respectively followed by pectinase incubation at the same temperatures for 1, 2, 3 h. The optimum region was ~60 C, and 1 h of incubation time. Pectinase treated slurries were extracted with aqueous ethanol (10 70% w/w) at an extraction temperature of 25, 45, and 60 C for 1, 2, and 3 H. The optimum regions were 30-40% ethanol for muscadines and 35-40% for blueberries at 60 C for 1 h. The fermentation parameters were 25 C, solid to solvent ratio 1:2, and ethanol concentration 11 % v/v. Total phenolics (g/K dry matter) extracted by aqueous, ethanolic, and fermentation approaches were 21.3, 20.6, and 25.0 for muscadines and 18.1, 28.4, and 17.0 for muscadines and blueberries, respectively. The stability of the total phenolics and anthocyanins in ethanolic extracts corresponded to removing ethanol under reduced pressure (T<65C). Purification and concentration of the extracts were conducted by adsorption/desorption onto neutral styrene-divinyl benzene resins (Sepabeads 700 and Sepabeads 70). Eighty to ninety percent of total phenolics and 100% of anthocyanins were recovered from the resin. Sepabeads 700 retained (mg/g wet resin) 54.5 total phenolics and 10.1 of anthocyanins compared to 13.4 of total phenolics and 2.26 of anthocyanins by Sepabeads 70. All the three extractions, followed by filtration, purification, and removal of ethanol from the extracts repeated at pilot scale with 20 G (76 L) of extracts. The concentrated extracts were spray dried to generate non-sticky powders. The total phenolics and the anthocyanins in the powders had a 22-52% recovery from original sources, which indicated the potential for commercial production of these materials.