http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/1084 Innovative Food Science and Technology 2026-04-19T15:44:49Z http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/1102 Optimization of microwave-assisted extraction of bioactive compounds from different varieties of coffee pulp Mengistu Fiseha Mekonnen Nattaya Konsue Coffee, one of the most widely consumed beverages globally, generates large amounts of coffee pulp waste during processing. This Pulp, rich in bioactive compounds such as polyphenols, flavonoids, and sugars, presents an opportunity for valorization. This study aimed to optimize Microwave-Assisted Extraction (MAE) conditions for bioactive compounds from Geisha and Bourbon coffee pulp varieties using Response Surface Methodology (RSM). Microwave power (500–900 Watt), extraction time (45–80 min), and sample-to-solvent ratios (1:1 to 1:10 g/mL) were varied to evaluate their effects on extraction yield, total phenolic content (TPC), antioxidant activity (DPPH assay), and sugar content (fructose and galactose). The optimized conditions for microwave-assisted extraction (MAE) were 708.7 W for 72.3 min for the Geisha variety and 699.3 W for 71.05 min for the Bourbon variety, both utilizing a solvent-to-sample ratio of 10:1 (mL/g). Under these conditions, Geisha yielded 12.66%, with a total phenolic content (TPC) of 25.36 mg GAE/g, DPPH radical scavenging activity of 6.43 mg TE/g, fructose content of 6.65%, and galactose content of 1.46%. Bourbon yielded 10.74%, with a TPC of 23.57 mg GAE/g, DPPH activity of 6.18 mg TE/g, fructose content of 7.02%, and galactose content of 1.69%. These optimized MAE conditions for each variety were applied prior to comprehensive chemical characterization. Antioxidant activities, including ABTS and FRAP assays, as well as TPC and DPPH values, were subsequently evaluated and compared to results obtained using conventional hot water extraction methods. MAE significantly enhanced antioxidant compound recovery from coffee pulp compared to conventional extraction. TPC increased from 21.3 mg GAE/g to 25.36 mg GAE/g in Geisha and from 22.5 mg GAE/g to 24.50 mg GAE/g in Bourbon. DPPH rose from 3.16 mg TE/g to 7.51 mg TE/g in Geisha and from 3.61 mg TE/g to 7.56 mg TE/g in Bourbon. ABTS values improved from 21.25 mg TE/g to 33.78 mg TE/g in Geisha and from 20.89 mg TE/g to 32.43 mg TE/g in Bourbon. FRAP values increased from 2.44 mg TE/g to 4.56 mg TE/g in Geisha and from 2.32 mg TE/g to 4.12 mg TE/g in Bourbon. Mass spectrometry revealed a richer phenolic profile in MAE extracts, including flavonoids such as hibiscetin and alkaloids such as caffeine and trigonelline. Enzyme inhibition assays showed strong α-amylase (90%) and α-glucosidase (IC₅₀ = 2.8 mg/mL) inhibition in Geisha MAE extracts. Overall, MAE proved to be a rapid, eco-friendly method for extracting valuable bioactive from coffee pulp, with promising applications in functional foods, nutraceuticals, and sustainable waste utilization. Thesis (M.Sc.) -- Innovative Food Science and Technology, School of Agro-Industry. Mae Fah Luang University, 2025 2025-01-01T00:00:00Z http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/1093 Development of chitosan nanoencapsulated clove essential oil and Its antifungal efficacy against Aspergillus niger Ahmed Abdou Said Abdelmoaty Abdelwahed Suttiporn Pinijsuwan This study focused on the development and characterization of chitosan nanoencapsulated clove essential oil (CEO-CSNPs) and its antifungal efficacy against Aspergillus niger, a common spoilage fungus. A preliminary screening was conducted to evaluate the antifungal activity of three plant essential oils, clove, cinnamon, and lemongrass using the disc diffusion method. Clove essential oil exhibited the highest inhibition zone (50.20 ± 0.51 mm), and was therefore selected for nanoencapsulation using the ionic gelation method with sodium tripolyphosphate (TPP) as the cross-linking agent. The CEO-CSNPs were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), and Energy Dispersive X-ray Spectroscopy (EDS). These techniques confirmed the formation of spherical nanoparticles and the successful encapsulation of clove essential oil, as indicated by the presence of its characteristic functional groups within the chitosan matrix. Agar diffusion assays against Aspergillus niger demonstrated a concentration-dependent increase in antifungal activity of clove essential oil (CEO), with inhibition zones increasing by approximately 186% as the CEO concentration was raised from 5% to 100%. A similar trend was observed for nanoencapsulated CEO (CEO-CSNPs), where increasing the CEO-to-chitosan (CS) ratio from 1:1 to 1:2 resulted in an approximately 165% increase in the diameter of inhibition zones. These findings indicate that chitosan-based nanoencapsulation not only preserves but also enhances the antifungal efficacy of CEO. This encapsulation strategy offers a potential for the development of bio-based antifungal agents applicable in food preservation and shelf-life extension. supporting its potential application as a natural antifungal agent for food preservation and shelf-life extension. Thesis (M.Sc.) -- Innovative Food Science and Technology, School of Agro-Industry. Mae Fah Luang University, 2025 2025-01-01T00:00:00Z