Padarat Ninjiaranai

Pineapple peels and cocoa husks are typically discarded as agricultural waste from food processing in many areas of Chiang Rai. Here, we aim to extract and characterize the pectin from the pineapple waste and cocoa husk collected in the Chiang Rai area. Pectin was initially extracted using organic solvents (hydrochloric acid and citric acid), followed by ethanol precipitation. The pectin extracted was then evaluated for its dry matter yield, equivalent weight, and degree of esterification (%DE). The results showed that the pineapple residue contained 1.50-2.97% pectin, whereas the cocoa husk contained 6.20-15.86% pectin. The gram equivalent weight of cocoa husk was approximately 800-900, while pineapple waste was 1,300. The extracted pectin displayed low methoxy content, with a low level of DE (11-22%). Finally, the functional groups of pectin extracted were confirmed by Fourier transform infrared spectroscopy, showing the existence of the –C=O and C–O stretching peaks at 1600-1700 and 1100-1200 cm-1, respectively. This preliminary study provides useful information for future studies on the gelling properties of the pectin from pineapple and cocoa husk waste.

A new naturally occurring diarylheptanoid, (1E,4Z,6E)-5-hydroxy-1,7-diphenylhepta-1,4,6-trien-3-one (3), was isolated from the rhizomes of K. elegans along with six known compounds, flavokawain B (1), 5,6-dehydrokawain (2), pinocembrin (4), cardamonin (5), alpinetin (6), and crotepoxide (7), among which compound 6 had not previously been isolated from this plant species. Two chalcones, flavokawain B (1) and cardamonin (5) were active against nitric oxide (NO) radicals released from LPS-induced RAW264.7 macrophages, resulting in 91.58% and 98.68% inhibition of NO production, respectively. Furthermore, compounds 1 and 5 showed superior cytotoxicity against MCF-7 (IC50 = 23.07 and 20.84 mM) and MDA-MB-231 (IC50 = 21.77 and 26.64 mM) cell lines, respectively. In silico molecular modeling studies of the most active compounds 1 and 5 against epidermal growth factor receptors (EGFR) suggested that π–π interactions with residues on the EGFR protein contributed to their anticancer properties. The results suggest that cardamonin (5) could be a promising candidate for further development of anti-inflammatory and anticancer agents.

Chitosan/modified cassava starch/curcumin (CS/S/Cur) films with a crosslinker were developed via the solvent casting technique for the application of food packaging. The effects of citric acid (CA) as a natural crosslinker were assessed at different concentrations (0–10.0%, w/w, on a dry base on CS and S content). To measure the most favorable film, chemical structure and physical, mechanical, and thermal properties were investigated. Successful crosslinking between CS and S was seen clearly in the Fourier Transform Infrared (FTIR) spectra. The properties of the water resistance of the CS/S/Cur films crosslinked with CA were enhanced when compared to those without CA. Furthermore, it was found that the addition of CA crosslinking would improve the mechanical properties of composite films to some extent. It had been reported that the CA crosslinking level of 7.5 wt% of CS/S/Cur film demonstrated high performance in terms of physical properties. The tensile strength of the crosslinked film increased from 8 ± 1 MPa to 12 ± 1 MPa with the increasing content of CA, while water vapor permeability (WVP), swelling degree (SD), and water solubility (WS) decreased. An effective antioxidant scavenging activity of the CS/S/Cur film decreased with an increase in CA concentrations. This study provides an effective pathway for the development of active films based on polysaccharide-based film for food packaging applications.