Currently, Doi Chaang village is the biggest area producing coffee in Thailand. Throughout seed to cup the pulp must be removed from coffee cherry after harvesting and left as waste. Tannin is one of various composition in coffee pulp which is affected by soil nutrition and pH. In this study, we have characterized the amount of tanin in coffee pulp using UV-Visible spectroscopy and electronic structure calculation. The results showed that coffee pulp consist of 5.68% tannin . It was determined to condense tannin form. Moreover, the pH of soil after treated with modified coffee pulp with water, Ca(OH)2, Na2S2O5, 2% Ca(OH)2, and 2% Na2S2O5 is higher than that with non-modified case. Likewise, DFT calculations predicted the structure of tannin with smaller HOMO-LUMO gap in the condense tannin.

Pectin is a high value functional food ingredient widely used as a gelling agent and stabilizer. The chemical structure of pectin has been the subject of scientific investigations for decades. Coffee producers remove beans; the other source of pectin, from coffee cherries is thrown away. Our study showed that pectin extracted from coffee pulp has high degree of esterification and methoxyl content of 93.75% and 7.87 respectively, which indicated good gelation properties. Nevertheless, here we were interested in the primary structure of pectin which is a complex polysaccharides that contains 1, 4-linked a-D-galactosyluronic acid (GalpA) residue. A theoretical dimension, density functional theory (DFT) with Generalized Gradient Approximation (GGA)/ BLYP functions, was utilized to study methylester substitution in pectin model compounds. For further discussion, the use of a COSMO model in different solvent showed the significant results in the difference torsion angle and HOMO diagram.

Summary:The adhesion between dental materials could be improved by an increase of interfacial polarity. In this study, low temperature plasma was used to treat an epoxy-based post. The surface modifications after treatment were characterized by X-ray photoelectron spectroscopy (XPS) which showed the existence of N, O-containing groups in the epoxy-based post. Furthermore, functionalization positions were proposed by Quantum Mechanic (QM) calculation. It could confirm the position that such a functional group was formed at hydroxyl group and alpha-carbon with an energy level around 93-97 kcal/mol through hydrogen abstraction reaction. Both experiments and calculations show consistent results indicating polar group formation on the surface after plasma treatments.