Kerdpiboon, Soraya
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Preferred name
Kerdpiboon, Soraya
Alternative Name
Kerdpiboon, S.
Main Affiliation
Email
soraya.ke@kmitl.ac.th
3 results
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Item type:Publication, Recovering bioactive compounds and antioxidant capacity of medium roasted spent coffee grounds through varied hydrothermal brewing cycles(2025-04-01) ;Maiyah, Nur; ; ;Kerr, William L.Spent coffee grounds (SCGs) are the residual product from brewing coffee and contain valuable bioactive compounds. This study investigated the effects of hydrothermal brewing cycles on the bioactive compounds and antioxidant capacity of medium roasted Arabica (A) and Robusta (R) SCGs. SCGs from A and R were prepared using 3 levels of brewing cycles at 92–95 °C/900 kPa. The SCGs were collected and air dried at 60 °C to achieve a moisture content of less than 4 % wb. Field emission scanning electron microscopy (FE-SEM) imaging showed that brewing increased SCGs porosity, allowing more moisture retention and enhanced extraction of compounds on subsequent cycles. SCGs also became less pigmented after additional brewing. Fourier-transform infrared (FTIR) spectra confirmed the retention of chemical components after each cycle, indicating a level of stability in the functional groups. Ethanol extraction yielded higher total phenolic content (TPC), while water extraction resulted in greater total flavonoid content (TFC); however, both decreased with additional hydrothermal brewing cycles. Caffeine and chlorogenic acid were more abundant in ethanol extracts, whereas water extracts exhibited stronger antioxidant activity (measured by ABTS and FRAP), particularly in Robusta SCGs. The bioactive compounds and antioxidant capacity were reduced with additional SCGs brewing. Significant correlations between TPC, TFC, caffeine, and antioxidant measures underscore the potential for the sustainable reuse of SCGs as a bioactive resource. Overall, hydrothermal brewing cycles enhanced the extraction and utilization of bioactive compounds from SCGs, contributing to the development of value-added products that promote health and sustainability. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Process optimization, antioxidant activity and sensory characteristics of green tea made from young fragrant rice leaves cultivar Damgatondam(2019-01-01) ;Uthai, N. ;Thamakorn, P.; Nokkoul, R.Green tea was made from one-month old leaves of the Thai upland black waxy rice cultivar Damgatondam (DGTD), which has a pleasant smell of jasmine. The objective was to determine the optimum process required to produce green tea that is acceptableto consumers and has health benefits. The processing conditions were steaming at 98 ± 2°C for 30, 45, 60 75, 90 or 105 sec then pan roasting at 70 ± 2°C for 5, 10, 15, 20, 25 or 30 min and finally tray drying by using electrical cabinet tray dryer at 60 ± 2°C for 30, 45, 60 or 90 min. Brewed samples were compared to brewed samples of seven commercially available Camellia sinensis tea products by descriptive analysis with 10 trained panelists. The highest quality of DGTD tea was: steaming at 98 ± 2°C for 60 sec, which completely inactivated peroxidase enzymes and preserved the green color, followed by pan roasting at 70 ± 2°C for 30 min and tray drying at 60 ± 2°C for 90 min in order to achieve a moisture content of less than 5%. The proximate analysis showed the DGTD tea prepared by the above method had: 3.77% moisture content, 7.94% ash, 22.59% crude fiber, 2.58% fat and 17.73% protein. Moreover, Ca, Mg, K, Fe, Mn and Na were 3400, 3200, 20400, 66.4, 139.1 and 113.8 mg/kg, respectively. It was found that protein, fat, crude fiber, ash, Mg, K and Na contents in DGTD tea, were higher than levels in tea from Camellia sinensis. Total phenolic content of DGTD tea was 9.53 mg GAE/g and antioxidant activity was 357.52 mM TE/g by Ferric reducing antioxidant power ( FRAP) , l34.08 mM TE/g by 2,2 diphenyl-1-picrylhydrazyl assay (DPPH) and 108.89 mM TE/g by 2,2'-azino-bis ( 3-ethylbenzothiazo line-6-sulphonic acid) ( ABTS) . The descriptive analysis of trained panels identified 11 particular attributes of DGTD tea, consisting of yellowness, clearness, tea odor, hay odor, green odor, seaweed odor, jasmine rice odor, tea flavor, seaweed flavor, bitter taste and astringent taste. The descriptive analysis showed that the DGTD tea was less bitter and astringent than the Camellia sinensis tea and its jasmine odor was positively accepted. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact of roasting levels and brewing cycles on bioactive compounds in spent coffee grounds(2026-02-01) ;Maiyah, Nur; ;Kerr, William L. ;Klaypradit, WanwimolSmithisukul, ChayadaSpent coffee grounds (SCGs) represent a potential source of residual bioactive compounds for sustainable reuse. Effects of roasting levels and sequential brewing cycles on recovery of total phenolic content (TPC), total flavonoid content (TFC), caffeine, and chlorogenic acid (CGA) from Arabica and Robusta SCGs were investigated. Coffee beans were roasted (light, medium, dark), brewed through three hydrothermal cycles, and the resulting SCGs extracted with 70% ethanol. The first brewing cycle removed most water-soluble bioactive compounds, while subsequent brews induced smaller compositional changes, indicating the persistence of functional compounds. Roasting influenced the initial bioactive profile, but its impact diminished after brewing. Robusta SCGs retained higher TPC and antioxidant activity while caffeine diminished with brewing cycle, they were relatively stable to roasting while CGA was more heat-sensitive. Principal component analysis confirmed brewing history as the main factor governing SCG chemical profiles. These findings support brewing-informed SCG valorization for sustainable functional food applications.
