Thermal inactivation of pectin methylesterase from different potato cultivars (Solanum tuberosum L.)

Effect of postharvest storage on potato (Solanum tuberosum L.) texture after pulsed electric field and thermal treatments

“…The starch content of the potato powders (Section 2.2.2) was measured using the Total Starch Kit (AA/AMG) of Megazyme Inc. (Bray, Ireland), following the instructions of the provider (Moens, De Laet, et al, 2021). Sugars were removed, starch was gelatinised and hydrolysed by α-amylase and amyloglucosidase, and the glucose content of the hydrolysate was determined spectrophotometrically (UV-1800, Shimadzu, Kyoto, Japan).…”

“…PME was extracted twice from each frozen potato sample using the method of Moens, De Laet, et al (2021). Therefore, the frozen potato cubes were homogenised (Grindomixer GM200, Retsch, Haan, Germany), and the puree was immediately mixed with 0.05% cold sodium bisulfite (0.6 L/kg puree) to prevent enzymatic browning.…”

“…The pH of the mixture was kept at 7 for 1000 s through addition of 0.01 M NaOH by an automatic pH stat titrator (718 STAT Titrino, Metrohm, Herisau, Switzerland) with cryostat (DC, Haake, Karlsruhe, Germany) at 22 °C. The rate of NaOH addition to maintain a pH of 7 was determined and one unit PME activity was defined as the amount of enzyme necessary to generate 1 µmol COOgroups per minute at 22 °C and pH 7 (Moens, De Laet, et al, 2021).…”

Effect of pulsed electric field, mild thermal pretreatment and calcium on texture changes of potato (Solanum tuberosum L.) during subsequent cooking

“…The larger amount and the longer pectic side chains of RG-I in potatoes may explain the smaller texture preserving effect of mild thermal pretreatments during subsequent thermal processing (Ranganathan et al, 2016). Moreover, PME extracts from potatoes show a lower activity than extracts from carrots (Moens et al, 2020;Moens, De Laet, et al, 2021). The activity of an extract, on the other hand, may not be representative for the activity in situ.…”

“…The activity of an extract, on the other hand, may not be representative for the activity in situ. Additionally, potatoes have a relatively high starch content (about 60-70% of dry matter) (Kolbe & Stephan-Beckmann, 1997;Moens, De Laet, et al, 2021), which may also affect the texture during thermal processing.…”