Abstract
BACKGROUND: Cashew nutshell liquid (CNSL) is an agro-industrial residue from cashew production that has gained relevancedue to its possibilities to generate valuable by-products. Although lab-scale CNSL extraction has been studied in terms of yieldand energy efficiency, the effect of industrial-scale extraction and nut pre-treatment methods on the physicochemical proper-ties of the extract remains underexplored. Thus, this work focuses on using a multiscale approach to study the relationshipbetween the most common extraction (Soxhlet and mechanical pressing) and pre-treatment processes (roasting and steaming)with CNSL chemical composition and its physicochemical properties.
RESULTS: The study revealed minimal variations (<0.5% w/w) on phenolic lipids mass fraction of different CNSL samples. How-ever, Soxhlet extracted samples revealed an increase of 2.9%–6.7% (w/w) of cardanol content, as well as 50% lower viscosityand 34% lower saponification value than pressed CNSL samples. Additionally, the study demonstrated that pre-treatment oper-ation influences CNSL composition since CNSL from raw nuts exhibits 35% less amount of phenolic lipids than pre-treated sam-ples. Samples from raw nuts also exhibited vibration of ester groups on their FTIR spectra, which may indicate the presence ofdiacylglycerols.
CONCLUSION: The findings demonstrate that while extraction methods have limited effect on CNSL physicochemical proper-ties, nut pre-treatment markedly alters its chemical nature. By clarifying how pre-treatment impacts CNSL quality, this workreduces technological barriers for cashew producers and processors, enabling informed selection of efficient methods for trans-forming CNSL into valuable by-products, and enhancing the economic and sustainable utilization of this bioresource.