Characterization and modeling of the effects of extraction parameters for tannin from the bark of the tropical wood Detarium microcarpum, utilizing the design of experiments method, aimed at exploring its potential application in formulating eco-friendly industrial resins

This work aims to optimize the conditions for extracting tannin from Detarium microcarpum (DM) using a rigorous, well-known methodological approach based on the Design of Experiments (DoE) method in order to maximize the yield and quality of the extracts. This study is the first to explore the potential of DM tannin for use in the formulation of biobased resins, thereby responding to the need for local valorization of underutilized resources. The DM tannin extraction process was optimized, taking into account liquid/solid ratios (6:1, 10:1, and 20:1), temperatures (70°C, 80°C, and 90°C), and extraction times (2 h, 3 h, and 4 h). The yield of each extraction (EY) was calculated, and the Stiasny number (SN) of the extracts was evaluated. The full experimental design method was used to model and optimize the EY and SN. FTIR, 13 C NMR, and MALDI-TOF analyses revealed that lower proportions of hydrolyzable tannin are mixed with condensed tannin in the DM tannin extract, which consists mainly of procyanidins, prodelphinidins, catechins, fisetinidins, and gallocatechins. The SN, varying between 65.25% and 123.75%, confirmed that the different extracts could be used to formulate adhesives, as they exceeded the required 65%. Analysis of variance (ANOVA) and the correlation coefficient showed that the established model is significant and can be used to predict EY values and SN. Optimization established the optimum parameters for an EY of 19.16% with an SN of 84.81% at a liquid/solid ratio of 19.69 at a temperature of 88.8°C and for a duration of 4 h.