Pectins from cashew apple fruit (Anacardium occidentale): Extraction and chemical characterization

The cashew tree (Anacardium occidentale) is a tropical evergreen tree largely cultivated in Brazil, which produces the cashew apple, a peduncle rich in carbohydrates and considered an industrial waste of the nut production. Until now, there were no data available about the chemical structure of cell wall polysaccharides found in cashew apple. In this work, its pectic polysaccharides have been characterized through monosaccharide composition, HPSEC, methylation and ¹³C and ¹H/¹³C HSQC-DEPT-NMR analyses. Highly methyl esterified homogalacturonan with a DE of 76% mixed with arabinogalactan were found. This latter was purified and presented a highly branched type II arabinogalactan (AG II) and small amounts of a type I rhamnogalacturonan in which the AG II could be anchored. These findings about the chemical structure of cashew apple pectins could contribute to develop future nutritional, biotechnological and pharmacological uses for this industrial waste from the cashew nut production.