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    Production of Coffee oil and Bioactive Peptides from Spent Coffee Grounds via Supercritical Carbon Dioxide Extraction and Enzymatic Hydrolysis
    (2024-04-01)
    Hunsub, Panusorn
    ;
    Ponmana, Kanokporn
    ;
    Ngamprasertsith, Somkiat
    ;
    Sakdasri, Winatta
    ;
    Karnchanatat, Aphichart
    Supercritical carbon dioxide (SCCO<inf>2</inf>) extraction was applied for recovering non-polar compounds in spent coffee grounds (SCGs) before enzymatic hydrolysis was performed. The SCCO<inf>2</inf> extracted oil yield of 11.93 wt% was observed at 30 MPa and 50 °C. The detectable volatile compounds in SCGs oil were aldehydes and flavor compounds classified as furans. Although the degree of hydrolysis of SCGs and defatted SCGs (DFSCGs) were not significantly different, the soluble protein of DFSCGs was higher than that of SCGs. Electrophoretic profiles of SCGs and DFSCGs comprise polypeptide bands at < 20 and ~ 24 kDa, which are mainly derived from 11S globulin subunits. After hydrolysis, the molecular masses of 4–20 and 24 kDa were virtually eliminated, thus releasing polypeptides with molecular masses < 4 kDa. Furthermore, the DFSCGs hydrolysate had higher total phenolic content and antioxidant capacity than that of SCGs hydrolysate. Pretreatment of SCGs with SCCO<inf>2</inf> enhances enzymatic accessibility, improves the quality of protein hydrolysate, and procures SCGs oil as a by-product. Graphical Abstract: (Figure presented.)
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    The Effects of Foaming Conditions on Plasticized Polyvinyl Chloride Foam Morphology by using Supercritical Carbon Dioxide
    (2018-01-01)
    Chuaponpat, Natthapong
    ;
    Areerat, Surat
    This research studies the effects of foaming conditions by using supercritical (scCO<inf>2</inf>) as a physical blowing agent on plasticized polyvinyl chloride (PVC) foam morphology. Foaming conditions were foaming temperature of 40, 60, and 80 <sup>o</sup>C, foaming pressure of 120, 150, and 170 bar at constant soaking time of 30 min. Depressurization was employed to activate nucleation and samples were cooled at room temperature about 30 <sup>o</sup>C for stabilization, which cause shrinkage behavior. PVC foam samples were calculated percentage of shrinkage (Sh) by using density at before and after aging process at 30 <sup>o</sup>C for 12 h to make sure for completely permeation of air into foam structure. PVC foam by using scCO<inf>2</inf> as a physical blowing agent reveal uniform closed bubble and regular foam structure with thin bubble wall (less than 5 μm). At high solubility of scCO<inf>2</inf>, PVC foam samples contain bubble diameter with less than 20 μm and high bubble density within the range of 10<sup>8</sup> - 10<sup>11</sup> bubbles/cm<sup>3</sup>. PVC foam samples at low solubility foaming conditions display a large bubble diameter (more than 140 μm) and lower bubble density (10<sup>6</sup> bubbles/cm<sup>3</sup>). These foam samples are be able to reduce the density about 75% when compared with unfoamed sample but it structure highly shrink with Sh more than 50%.
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