Optimization of Spontaneous Fermentation Conditions of Kohlrabi by Response Surface Methodology
Citation
Karaoglan HA, Aktas AB. Optimization of Spontaneous Fermentation Conditions of Kohlrabi by Response Surface Methodology. Fermentation. 2023; 9(6):550. https://doi.org/10.3390/fermentation9060550Abstract
Kohlrabi is a valuable crop due to its substantial amount of macro- and micronutrients. It
is mostly consumed in fresh form, as jam or fermented product. This current work aimed to optimize
the spontaneous fermentation conditions of kohlrabi in order to improve its product functionality
and diversity. For this purpose, a Box Behnken design was employed to evaluate the effects of boiling
time (0–8 min.), vinegar ratio (0–50%), and salt content (2–8%) on chemical and microbiological
properties of fermented kohlrabi. Some chemical and microbiological analyses, including total
phenolic content, total antioxidant capacity, total acidity, pH, salt content, total counts of yeast and
molds, and mesophilic and lactic acid bacteria, were determined. The total antioxidant capacity of
samples changed between 11.91 and 75.75 µmol Trolox/100 g, respectively. Both ANOVA results
(p < 0.05) and PCA model (R2 = 0.99; Q2 = 0.72) confirmed that boiling time is the important
factor affecting the fermentation process. The optimal fermentation parameters for kohlrabi were
determined to be 44.12% vinegar and 2.07% salt concentrations without the boiling step by response
surface methodology