Understanding the effects of pre-treatment and extraction methods on lipid fingerprint of cashew nut shell liquid (CNSL) by non-targeted lipidomics analysis

Cashew nut shell liquid (CNSL) is a brown liquid obtained from cashew nut waste, with several applications as a renewable feedstock for polymeric industries. To obtain it, cashew nuts must undergo thermal pre-treatment processes to soften cashew nut shell (CNS) and extraction operations to separate CNSL from CNS. Although it is well known that CNSL is mainly composed of phenolic lipids, the chemical identity of minor components has not been widely explored. Thus, this study analyzed the lipid profile of CNSL using untargeted lipidomics aimed to understand the effects of CNSL extraction and cashew nut pre-treatment methods. Here, based on multivariate analysis we elucidated the differences between CNSL extracted by Soxhlet or mechanical pressing from CNS pre-treated by roasting or steaming. It was found that CNS pre-treatment displays a significant effect on CNSL regardless of the method used most likely related to lipid thermal degradation in raw nut samples. Similarly, it was found that extraction methods cause variances on lipid profile due to solvent selectivity in soxhlet method. Thus, the study expands the knowledge related to chemical differences in terms of lipid profile associated with CNSL processing, demonstrating that performing pre-treatment on CNS affects CNSL indistinctively of the method implemented.