Changes in Total Phenolic and Protein Contents during Production of Protein Isolates from Carica papaya (Pawpaw) Seeds

The effect of different processing stages- defatting, solubilization, isoelectric precipitation, neutralisation and lyophilisation on the total phenolic content and protein content of Carica papaya (pawpaw) seeds (CPS) full-fat flour (CFF), defatted flour (CDF), protein concentrates (CPC) and protein isolates (CPI) was studied. The folin-ciocalteu procedure was used to assess the total phenolic concentrations of the Carica papaya products and results were expressed as gallic acid equivalent (GAE). Optimal protein content was estimated at pH 10 for all samples. Higher levels of polyphenols were extracted using water-methanol (20/80) mixture compared to 100% methanol. Total phenolic content (TPC) was demonstrated in a trend of CDF &62; CPC &62; CFF &62; CPI with CDF having the highest TPC. The finding suggested a more economical protein isolate production method. The study concludes that the processing of CPS into the various products (CFF, CDF, CPC & CPI) improves its protein and polyphenol content.