Production of platform molecules from cocoa pod husk by green methods

Abstract

Approximately 48 million tons of cocoa crop residues are produced annually, which can be used to obtain platform molecules (PM) as a base to produce value added products. This work aimed to obtain and elucidate PM by microwave assisted hydrothermal pretreatment (MA-HTP) and combining statistical and spectroscopic tools as an alternative to cocoa pod husks (CPH). Lignocellulosic components, antioxidant capacity, and mineral profile of CPH were determined. MA-HTPs were evaluated by targeted and non-targeted metabolomics MIR-NIR and NMR, and PM was determined by one- and two-dimensional NMR. MA-HTP was optimized by Box Behnken Response Surface Analysis (RSA-BBD), and PM obtained in CPH extracts was elucidated and quantified by 1H-RMN. As a result, cellulose, hemicellulose, and lignin contents of 30.5%, 19%, and 23.9% were obtained, respectively, and 7.7% ash with a profile of 13 minerals were obtained; Fe, Ba, and Zn with 164.4 µg/g, 63.5 µg/g, and 63.4 µg/g were the most abundant. Phenolic content: 24.5 mg EAG/g, antioxidant capacity ABTS: 304.8 µmol ET/g and FRAP: 145.8 µmol ET/g. MIR-NIR NMR and OPLS-DA metabolomics showed that the 200°C MA-HPT clustered with the mono - and disaccharide standards. NMR elucidation identified Allose, Cellobiose, D-fructose, D-galactose, Fructose 6-phosphate, N-acetylmanosamine, Gluconolactone, Gluconic acid, Glycerol, Glycerol 3-phosphate, Cytidine, D-maltose, D-xylose, and Trehalose. RSA-BBD was used to predict the optimum temperature, power, and time for the extraction of glucose: 135.4°C-180.6 W and 5.8 min; sucrose: 154.3°C-256.3 W and 20. 2 min and fructose from CPH: 129.5°C-173.8 W and 5.27 min. For glucose: 142.2°C-204.4 W and 10.5 min; for sucrose, 148.8°C-215.6 W and 14.3 min and fructose from HMC-CPH: 151.6°C-231.6 W and 13 min.