In addition to valuable proteins, sunflower oil press cakes also contain polyphenols, which can influence colour, taste and technological properties. The aim of Benita Meßmer’s thesis was to further optimise processes for obtaining sunflower proteins from organic oil press cake and to investigate ways of reducing these accompanying substances.
The study evaluated various cold extractions for polyphenol reduction, different drying methods and processes for producing and purifying protein isolates. The results show that a simple washing step alone reduced the polyphenol content of the press cake by around 70%, while protein loss at low extraction temperatures was limited to around 13%. Freeze-drying proved particularly suitable for drying, as no undesirable colour changes or off-flavours occurred. Analytical approaches for faster assessment of polyphenol-containing samples were also investigated. By combining adapted extraction, precipitation and purification steps, an almost white, sensorially neutral protein isolate of almost 100% purity was produced. The protein yield was around 40%, while the residual polyphenol content was reduced to around 0.2%.
The thesis shows that both polyphenol-reduced sunflower press cakes and high-purity protein isolates can be produced, and provides important insights for further optimising the corresponding processing methods.
Source: Benita Meßmer, bachelor’s thesis ‘Optimierung der Isolierung von Sonnenblumenproteinen aus Bio-Ölpresskuchen’ (‘Optimising the isolation of sunflower proteins from organic oil press cake’), 2016.
