Fresh Guizhou was purchased from an organic farmer in Prachinburi, Thailand. The edible leaves of Guizhou were washed with tap water for 2 minutes. Guizhou leaves were pretreated by three methods, including soaking in acid, blanching and steaming.
Acid pretreatment involves soaking the samples in acetic acid solution at 0.5% v/v (glacial acetic acid, J.T. Baker, Phillipsburgh, USA). The Guizhou leaves to acid solution ratio was 1:10 (w/v). The mixture was shaken in a rotary shaker at 120 rpm for 5 minutes and at 30°C.
The blanching conditions were predetermined to inhibit peroxidase. For hot water blanching pretreatment, the sample to boiling water ratio was 1:10. The samples were blanched in boiling water for 4 minutes during which the enzyme peroxidase activity was not detected. Steam blanching pretreatment was followed by a water bath (Memmert,
Model WNB22, Germany). A single layer of the Guizhou leaves sample was steamed by placing it on a perforated tray suspended over hot water at 97 °C for 2 minutes. After blanching the samples were immediately cooled in a water bath at 4-5°C. Fresh Guizhou leaves were used as control.
Phungamngoen C., Detchewa P., Tanongkankit Y., & Moongngarm A. (2021). PHYSICOCHEMICAL PROPERTIES OF DRIED GUIZHOU AS AFFECTED BY PRETREATMENTS, DRYING TECHNIQUES AND STORAGE PERIOD. Journal of Sustainability Science and Management, 16(5), 1-21.
