Recycling lipases as a promising strategy in sponge cake development

Lipases were used in this study with rapeseed oil in order to generate insitu mono- and di-glycerides of fatty acids (MDGs) and free fatty acids (FFAs). Those compounds are interesting to preserve softness in sponge cakes and largely, this strategy can be used as a clean-label approach to replace some added synthetic additives. Modifying rapeseed oil with such enzymes can only be made through an emulsification. With this biphasic system, the modified oil can be easily removed and used for food application whereas the aqueous phase (containing lipase) can be re-emulsified with fresh oil. In this study, we investigated the possibility of recycling the lipase and followed the overall activity up to 25 cycles thanks to Acid Value and ¹³C NMR as main indicators for molecular determination in the oil phase as well as ¹H NMR for glycerol accumulation in the aqueous phase. A decrease of triglycerides conversion (-56 %) as well as a change in the selectivity (+50 % of FFAs with a slight change in MDGs production) was obtained and may be explained by an accumulation of glycerol at the interface. Nevertheless, when modified oils were used as ingredient in sponge cake fabrication and compared to rapeseed oil, the softness was preserved during a storage period of 3 months, regardless of the number of cycles (+104 % in hardness for the control product and a range of +26-45 % when oils are preferably used). Thus, recycling lipases can be considered as an economically valuable strategy.