Now showing 1 - 4 of 4
  • Some of the metrics are blocked by your 
    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 your 
    Item type:Publication,
    Sous-vide meat properties as a function of physical and surface changes during processing
    (2022-01-01) ;
    Kerr, William L.
    ;
    Klaypradit, Wanwimol
    ;
    Sous-vide is a method of cooking of vacuum-packed samples at relatively low temperature for longer periods than practiced with conventional cooking. Sous-vide is applicable to a wide variety of foods, and optimized sous-vide processing of meat can result in more tender products with less cooking loss. In this study, chicken breast and Thai local beef round were compared under sous-vide (vacuum-packaged and cooked at 60 to 80 °C for 1 to 7.5 h) and traditional cooking temperatures. The physical properties and surface texture of meat during sous-vide cooking were determined. It was found that the L<sup>*</sup> (lightness) and a<sup>*</sup> (redness) of cooked chicken breast were not affected by cooking temperatures or times (p >0.05), while the color of cooked beef depended on both temperature and time (p ≤0.05). It was found that cooking at higher temperature and for longer time resulted in meat with lower cooking yield and higher sous-vide loss, but with less re-heating loss (p ≤0.05). These results were supplemented with surface texture images which showed that larger spaces developed between the fibers after cooking at higher temperatures for longer time than those for samples cooked by sous-vide. Sous-vide chicken breast cooked at 60 °C for 2 h and 80 °C for 0.5 h, as well as beef cooked at 60 °C for 2.5 h and 80 °C for 2 h, were the most tender as measured by the lowest shear force values.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Novel sous-vide pressure technique affecting properties of local beef muscle
    (2023-02-01) ;
    Kerr, William L.
    ;
    Klaypradit, Wanwimol
    ;
    The low-temperature, long-time method of cooking known as sous-vide was used with increased pressure to enhance the tenderness and cook yield of local Thai beef round. The cooking was done in specialized equipment at 60 °C and 101, 200 or 300 kPa for 0–4 h. Beef treated with pressure was slightly lighter in color, and samples cooked for 2 h at 200 kPa had greater red saturation. Cooking at 200 kPa improved cook yield while reducing cook loss, with values of 78% after 4 h at 200–300 kPa versus 67% at 101 kPa. Cooking at 200–300 kPa resulted in more tender beef than at 101 kPa after 2 h. Sensory evaluation showed sous-vide pressure beef had higher ranking scores for tenderness and juiciness compared to control. SEM showed connective tissue of sous-vide pressure-cooked beef was diffuse and with looser muscle fibers than boiled or raw beef. Electrophoretic profiles showed that thick and thin filament bands decreased with cooking time. However, myosin heavy chain was sensitive to both heat and pressure. Reducing conditions showed pressure and heat induced disulfide bonding. Studies by FTIR showed cooking at 200 kPa caused the greatest decrease in α-helix content and increase in β-structures than non-treated and boiled beef.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Physical and Functional Properties of Spent Coffee Ground after Various Drying Techniques
    (2025-01-01)
    Maiyah, Nur
    ;
    Auenchitr, Yatima
    ;
    ;
    Sirijariyawat, Arpassorn
    ;
    Spent coffee ground (SCG) consists of impact compositions and functional ingredients that could be applied to food products. Drying techniques and conditions had an impact on the qualities of SCG. The aim of this research was to investigate the chemical compositions of roasted coffee ground (CG) and SCG from Arabica (A) and Robusta (R) coffee, as well as the physical and functional properties of SCG before and after different drying using hot air tray dryer and freeze dryer. It was found that SCG had moisture and carbohydrate content of 64.79–65.87% wb and 16.55 18.57%. Arabica spent coffee ground (ASCG) had more lipid and less protein, caffeine and phenolic content than that of Robusta spent coffee ground (RSCG). The dried SCG had moisture content lower than 5% for all drying conditions. Moreover, the dried SCG had Aw, solubility, and rehydration in a range of 0.25-0.55, 6.02-6.92%, and 140.67-180.37%, respectively. Freeze-dried SCG retained more functional ingredients than tray-dried SCG across all drying conditions.