The conditions of blanching, freezing, and thawing for Shepherd’s purse (Capsella bursa-pastoris [L.]) were studied to improve its quality attributes during frozen storage. The washed samples were blanched with water at 100oC for 10, 20, 30, and 40 s. They were then soaked in cold water. The quality characteristics of the samples such as pH, texture, hardness, color value, and total viable cell were analyzed. The samples blanched for 30 s were frozen and thawed under several conditions and their physicochemical characteristics were analyzed. The pH value of raw samples was higher than that of the blanched sample. The values of brightness (L*), redness (a*), and yellowness (b*) decreased after blanching except the L* value of root at the condition of blanching for 40 s. Upon considering the bacterial cell counts, the proper condition was determined to be 30 s of blanching time. Blanching for 30 s was the optimal pre-treatment for minimizing the quality deterioration of the shepherd’s purse for freezing. Regarding its color change and microbial safety, faster freezing and thawing methods made less changes on the quality of frozen samples. Consequently, immersion freezing and radio-frequency thawing were the most effective in minimizing the quality change.

Background : Prepared Rehmanniae root (PRR) has been used as traditional medicine, and is one of the most important oriental herbal medicines. However, physical characteristics of PRR are not suitable for use in industry. This study was performed to suggest preparation method of PRR powder, and determine the physicochemical characteristics of PRR powder with different pre-freezing temperatures. Methods and Results : Moisture content, powder yield, particle size, bulk density, compressive stress, extraction yield, and 5-HMF content of PRR powders with different pre-freezing temperatures (-20℃, -40℃, -60℃, and -80℃) were analyzed, and correlation among these factors was determined. Powder yield increased and particle size decreased in a pre-freezing temperature-dependent manner from -20℃ to -60℃. Hausner ratio increased from 1.186 to 1.225 with decreasing temperature from -20℃ to -80℃, and compressive stress showed the opposite trend. Extraction yield and 5-HMF content were not significantly different between PRR and powder. Significant correlations were observed among pre-freezing temperature and physical characteristics (yield, particle size, hausner ratio, and compressive stress). Conclusion : These results suggest that pre-freezing temperature was important factors affecting physical characteristics of PRR powder, and the results of this study are industrially applicable to production of PRR powder.

Background: Rehmanniae radix preparata (RRP) has been used as a traditional medicine and is one of the most important oriental herbal medicines. However, the physical characteristics of RRP are not suitable for use in industry. The present study was undertaken to determined the preparation method of RRP powder and the physicochemical characteristics of RRP powder by milling under different pre-freezing temperatures. Methods and Results: Moisture content, powder yield, particle size, bulk density, compressive stress, extraction yield, and 5-HMF content of PRR powders by milling with pre-freezing temperatures (−20, −40, −60, and −80℃) were analyzed, and correlation among these factors was determined. Powder yield increased and particle size decreased in a pre-freezing temperature-dependent manner from −20 to −60℃. The Hausner ratio increased from 1.186 to 1.225 with decreasing temperature from −20 to −80℃, whereas compressive stress showed the opposite trend. Extraction yield and 5-HMF content were not significantly different between RRP powder. Significant correlations were observed among pre-freezing temperature and physical characteristics (e.g., yield, particle size, Hausner ratio, and compressive stress). Conclusions: These results suggest that the pre-freezing temperature is an important factor affecting the physical characteristics of PRR powder and applicable to the industrial production of RRP powder