In the food industry, freezing storage has been an important process for maintaining the properties of food materials. In order to maintain the quality of blanched Colocasia esculenta (L.), Schott stem, packaging, freezing, and thawing methods were optimized by determinations of the physicochemical properties. For the comparison of packaging method, Colocasia esculenta (L.) Schott stem packed by air containment had the lowest significant differences of properties such as hardness and drip loss compared to the control samples. Overall, the drip loss of Colocasia esculenta (L.) Schott stem had lower value at fast freezing rate (immersion freezing). Considering the result of the drip loss, high frequency thawing was more effective than other thawing methods. Therefore, it was supposed that samples treated by air-containing packaging, immersion freezing, and high frequency thawing used the optimal method to maintain the original quality of Colocasia esculenta (L.) Schott stem.

Food freezing preservation is an important process due to its high quality and long shelf-life. In order to improve the quality of frozen sweet potato stem, the freezing rate, thawing, and packaging method was optimized by the determination of physical properties. There was no significant difference among the treatment of freezing rate. Further, the drip loss of sweet potato stem was higher at a relatively fast freezing rate (immersion freezing) than at slow freezing rate (natural convection freezing at -20 or -40oC). For the comparison of packaging methods, the aircontaining packaged sweet potato stem had the lowest significant differences from the result of color, pH, and hardness. From the result of the drip loss, the high frequency and microwave using thawing samples were more effective than room temperature and water thawing. Therefore, fast freezing and thawing rate with air-containing package were recommended to obtain the better quality of sweet potato stem.

The objective is to investigate effect of liposome coated hemicellulose on softening of carrot. To encapsulate hemicellulose in nanoliposome, 2% hemicellulase and 2% lecithin were processed by using high-speed homogenizer (10,000 rpm, 3 min) and ultrasonification (200 W, 54%). The carrot were cut into cylinder type (3×1 cm) and then immersed in distilled water (DW, control), hemicellulase (He) and nanoliposome coated hemicellulose (He/NL) for 48 h at 4oC. The final concentration of hemicellulose is 1% (w/v). The droplets properties of He, NL, He/NL analyzed using zeta-sizer. Moreover, the carrots treated different immersed solutions were characterized by measuring hardness, color, microstructural observation and enzyme activity (glucose contents). For the results, hardness of carrot immersed in He or He/NL solution decreased after 48 h by 47% or 31% (outline of carrot) and 35% or 31% (center of carrot) respectively compared to control (7,240 g). The total color difference value of all samples increased over immersion time. For microstructural observation, cell was destroyed after 24 h at He solution. For the enzyme activity, glucose contents of carrot in He solution increased than it in He/NL at 0 h sample however the enzyme activity was no significant difference with immersion time.