In this study, the determination of total proteins present in WSE
was performed using the Bradford colorimetric method. In the past
it has been proven that the interference of carbohydrates present
in the sample matrix significantly deviates the actual absorbance
of the proteins, resulting in less accurate results if not primarily
removed (Banik, Pal, Ghorai, Chowdhury, & Khowala, 2009). Since
the primary aim of these preliminary studies was to observe the
hydrothermal degradation of proteins in SubCW and not quantify
the exact amount of proteins in extract, carbohydrates present in
WSE were not primarily precipitated and were analysed directly
using the above mentioned method.
In contrast to the minimally hydrolysed triglycerides, total proteins
(Fig. 2a) and carbohydrates (Fig. 2b) present in WSE show a
much more different course.
From Fig. 2a it can be observed that after 5 min of extraction
again the lower temperature kinetic curves (60 C and 100 C) show
no dependence on extraction time. The highest amounts of water
soluble proteins are obtained at 60 C equaling to approximately
30 wt.%. At temperatures higher than 100 C overall protein yield
in WSE decreases significantly with increasing Te and at 160 C
the concentration of proteins (wBSA) even starts to decrease with
te. The decrease of overall wBSA with increasing Te is probably a consequence
of lower solubility of protein at higher temperatures,