To prepare the dried Cirsium setidens Nakai appropriate to the gondre-namul, this study investigated the effects of steaming and blanching on its color characteristic, degree of browning, peroxidase activity, rehydration, and preference test. Cirsium setidens Nakai (gondre) was steamed for 5-15 min and blanched in different blanching solutions for 1-5 min, followed by drying at 50oC. The blanching solutions used in this study were water, and 0.5% (w/v) solutions of NaCl, CaCl2, and sodium polyphosphate (SPP). The control was dried without pre-treatment. Relative to the control, the lightness of dried Korean thistle decreased, except for that blanched with NaCl solution, whereas its redness decreased except for that steamed. All treatments exhibited lower yellowness than the control. Also, all treatments revealed a lower degree of browning and peroxidase activity than the control. Rehydration was reduced by pre-treatments of Korean thistle relative to the control. Korean thistle blanched for 1 min with CaCl2 solution exhibited higher points for color, flavor, taste, and overall acceptability than those of the control. Overall, blanching with CaCl2 solution would be an appropriate way of preparing the gondre-namul using dried Korean thistle, accompanying the common way by blanching with NaCl solution.

The objective of this study was to develop a microcapsule by the entrapment of Ainsliaeaacerifolia extract (AAE) in native starch and citrate starch matrices through spray-drying and dry heating reaction. AAE microcapsules were assessed based on recovery, encapsulation capacity, FT-IR, FE-SEM, swelling power, solubility, releasing pattern of AAE from microcapsules, and antioxidant activity. Upon increasing the addition levels of AAE and adding citric acid in the pre-emulsion mixtures, the spray-drying recovery and encapsulation capacity of AAE microcapsules increased. AAE microcapsules exhibited irregular shapes due to excessive shrinkage of their spheres. FT-IR spectra implied the formation of ester groups between starch molecules and either citric acid or phenolic compounds in AAE. Swelling powers and solubility of AAE microcapsules were significantly higher for citrate starch matrix (relative to native starch). The effects of temperature and enzyme hydrolysis on AAE releasing patterns were similar over AAE microcapsules prepared in this study. AAE microcapsules facilitated the free radical scavenging in an aqueous (relative to alcoholic) reaction system. Overall, the entrapment of AAE into the matrices from native starch and citrate starch would be one of the possible ways to expand the utilization of raw materials, by-product, and extract from Ainsliaeaacerifolia in food industries.

The effect of drying temperature and steaming time on the browning and antioxidant activity of dried Platycodon grandiflorum was investigated. Thirteen treatment conditions were constructed using central composite face-centered design containing 5 center points. Drying temperature and steaming time (as factors) were 45-75oC and 15-45 min. According to treatment conditions, dried Platycodon grandiflorum was assessed for color characteristic, degree of browning, total polyphenol content, and DPPH and ABTS free radical scavenging (as responses). When increasing drying temperature within a given steaming time, dried Platycodon grandiflorum exhibited decreased lightness, increased redness, degree of browning, and total polyphenol contents, and enhanced antioxidant activities. Except for total polyphenol contents and antioxidant activities, steaming time within a given drying temperature exhibited similar effects to those observed in drying temperature. However, steaming time did not likely influence total polyphenol contents and revealed the opposite trends observed for the effect of drying temperature on their antioxidant activities. The overall results suggested that drying temperature was the main factor for changes in the browning and antioxidant activity of dried Platycodon grandiflorum.