Optimized pulsed electric field-assisted extraction of biosurfactants from Chubak (Acanthophyllum squarrosum) root...

In this study, a face-centered central composite design was applied to optimize pulsed electric field parameters (voltage: 1, 4, 7 kV cm^-1 ; pulse number: 10, 65, 120) for the extraction of natural saponins from Chubak root. Data analysis showed that increasing the voltage from 1 to 4 kV cm^-1 and pulse number from 10 to 65 increased foaming ability (FA) and emulsion stability, and decreased foam density (FD), foam stability (FS) and lightness, due to the improved extraction of saponins.

Whereas, an opposite trend was observed for FA, FD and FS on increasing the voltage from 4 to 7 kV cm^-1 as a result of more impurities being extracted. Furthermore, the Chubak root extract (CRE) (0, 1.5, 3.0 and 4.5 g kg^-1 ) obtained under the optimized conditions (voltage of 6.4 kV cm^-1 and pulse number of 80) was used in ice cream formulation because of its ability to reduce surface tension. Based on the results, the samples containing higher amounts of CRE showed higher viscosity, consistency coefficient, overrun, melting resistance and creaminess, as well as lower values of flow behavior index, hardness, adhesiveness, coarseness and coldness. This could be related to the increased water retention, improved whipping ability, greater fat destabilization and smaller ice crystals. Although more bitterness was perceived as a result of an increase in the level of CRE, it had no negative effect on the overall acceptance assessed by trained sensory panelists.

The results of this study briefly support the conclusion that CRE has a very high potential for use as a foaming, emulsifying and stabilizing agent to improve the quality of ice cream. © 2020 Society of Chemical Industry.