Recently, semi-dried sweet potato is popular as a natural snake for children’s dessert. The drying condition was optimized to obtain high quality of sweet potato by oven drying process. The mashed yellow and chestnut sweet potato was dried using the oven drier at different temperature (50, 60, 70, and 80°C) then evaluated for the moisture content, appearance observation, texture properties, and sugar contents and sensory test in every 2, 6 and 12 hours. During the dehydration and drying process, the ending point of moisture content divided in three zone from 0-2 hour, 4-6 hour and 8-12 hour. The moisture content was dramatically decreased from 0 hour - 8 hour, but after 8 hour there is no significant decrease. Yellow sweet potato dried at 80°C for 6 hours was investigated as good product base on the sensory test, hardness value, and color appearances as compared to chestnut potato.

In this study, we investigated the effects of different pre-treatment conditions such as blanching and drying process to improve its quality. Bracken samples were treated by drying (70°C for 40 min), blanching (100°C for 2 min) or mixed (blanched and dried [BD]), respectively. These treated samples were analyzed for their physicochemical properties such as pH, color and microbial growth. The pH of bracken increased from 6.6 to above 6.9 through all treatment. From color observation, the L* and b* values increased after drying process, whereas, the a* values decreased. Water contents of bracken decreased by about 80% from 93% through drying process. After samples treated by pre-treatments, hardness increased, especially after drying process. For the microbial study, raw bracken had 5.6 log CFU/g of aerobic bacteria and 2.8 log CFU/g of total coliform. Blanched and BD samples had about 2 log CFU/g of aerobic bacteria and 1.8 log CFU/g of total coliform, acceptable for food. From our results, it is concluded that the properties of blanched samples had similar to raw samples to guarantee for microbial safety. From the obtained results, the blanching process without drying process is necessary to apply freezing process as pretreatments.

The freezing process of the freeze-drying procedure is important to optimize the physic-chemical properties of agricultural product. Therefore, our study was carried out to study the effect of freezing methods on the properties of freeze-dried apples. The sliced apples was frozen at -18°C as a general refrigerator (GR), -30°C with a individual quick freezing machine (IQF), and -80°C with deep freezer (DF), and subsequently, each sample was sublimated under 0.1 mbar for 24 hours. The samples were characterized by determination of color, texture properties, sugar contents, and morphology observation. The quality of color (L*, a* and b*) did not show significant discoloration. The hardness and sugar contents of IQF samples showed the greater value than GR and DF one. The morphology of IQF samples displayed the uniform and relatively small pore size as compared to GR and DF samples. From the sensory test, the IQF samples obtained the high score for overall acceptability, and consumer preference. From our results, the IQF treated apples are best results to produce good quality of freeze-dried apples.

The reduction of the content of sodium chloride in noodle was studied to prevent the problems related to excessive sodium intake, such as high blood pressure and cardiovascular diseases. This study investigated the effect of hydrolyzed anchovy products (HAP) on the salty taste of cooked noodle. The experiment was set up to determine the general properties of dough in dried and cooked noodles, with a sensory test used while increasing the concentration of HAP at same salt contents. There was no significant difference in water binding capacity, solubility, swelling power, lightness, and cooking properties. The redness, yellowness, and hardness were increased upon increasing the contents of HAP. From the sensory evaluation, cooked noodle with added HAP had a high score in appearance, color, texture, and flavor. Moreover, 50% and 75% HAP showed higher values than the control item in saltiness, preference of saltiness, and overall acceptance. Consequently, the HAP could have an effect on dried noodles or cooked noodles as a salty taste enhancer without changing the noodle’s properties.

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.

This study was carried out to investigate the effect of liposome-coated salt (LCS) on the salty taste intensity of noodle. Dough, dried noodle, and boiled noodle with LCS were evaluated physico-chemically for water content, water binding capacity, solubility, swelling power, color, texture, cooking properties, and sensory test. There were no significant differences in water content, water binding capacity, lightness, yellowness, and texture of noodle between the noodles with liposome-coated salt and non-coated salt. For the sensory analysis, the panel did detect more salty taste at 1.0% and 2.0% of LCS compared to the control. From these results, this study demonstrates that liposome coated salt can enhance salty taste, maintaining the same salt concentration without the physical property changes of noodle.

There are a lot of types of wild vegetables such as Colocasia esculenta (L.) Schott stem in Korea. However, the consumption of these wild vegetables is restricted because their storage decreased dramatically after harvest. To maintain original quality of vegetables, pre-treatments such as blanching and drying are important. But conditions for these treatments were still not optimized for many vegetables including Colocasia esculenta (L.) Schott stem. Thus, the objective of this study was to set up an optimal pre-treatment method for freezing storage. Colocasia esculenta (L.) Schott stems were peeled and cut equally (10 cm) for sample preparation. Dried samples (D) were dried at 90℃ for 3 h. Blanched samples (B) were blanched in hot water at 100℃ for 2 min. Blanched and dried samples (BD) were blanched and dried as same protocol. Physicochemical properties were analyzed to evaluate the quality including texture, moisture content, total color difference and viable cell count. Raw sample had 6.85 kg/cm 3 of hardness and 78.75 of chewiness whereas B was 6.83 kg/cm 3 of hardness and 7.8 of chewiness. B had the similar value compared to raw samples. Moisture content of raw sample was 94.4% and that of B was 94.1%, though there were not any significant differences between them. ΔE value of B showed lower value than those of the others. Viable cell counts and total coliforms were not detected after treatment, while raw sample had 5.39 log CFU/g of viable cell count without total coliform. Therefore, pre-treatments are essential for microbial safety of samples. All results considered, it is supposed that blanching is the optimal pre-treatment to sustain its original quality of Colocasia esculenta (L.) Schott stems before freezing.

The overconsumption of dietary salt is recognized to play a negative effect on human health such as increasing blood pressure. The purpose of this study is to investigate the effect of hydrolyzed anchovy products (HAP) on the salty taste of dried noodle. The physicochemical properties and sensory test of dried noodle were determined at different concentrations of HAP. The lightness of the noodle samples was decreased with increasing levels of HAP whereas their redness and yellowness were increased. There were no significant changes in hardness and texture properties by HAP concentration, compared to those of the control. From the sensory evaluation, the 25% and 50% HAP samples showed a high score on saltiness, preferredness, and overall taste acceptability. Consequently, the HAP could be utilized in dried noodles or cooked noodles as a salt enhancer without significantly altering the charateristics of noodles.