From Table 3 it can be also observed that 5-HMF is formed during
extraction at the studied extraction conditions. It seems that
formation of 5-HMF occurs at TeP100 C, whereas at 60 C no
5-HMF is formed. Interestingly, the highest amounts of 5-HMF are
obtained at 100 C, whereas at higher temperatures lower amounts
are obtained. Also, at 130 C and 160 C a decrease of 5-HMF with
te can be observed. At 130 C the decrease of 5-HMF is visible after
30 min of extraction for all M/S ratios and at 160 C the decrease
can already be observed after 5 min of extraction. This decrease
in concentration could indicate the previously mentioned further
hydrothermal degradation of 5-HMF to other products, such as
organic acids (levulinic acid and formic acid).