• Food Science and Preservation
• /
• v.13 no.5
• /
• pp.563-568
• /
• 2006

The properties of mung bean were investigated depending on hydrolysis condition. The results showed that enzyme treatments (${\alpha}$-amylase and protease each at 0.1% (w/w)) by varying hydrolysis temperature showed better properties than non-pretense treatment (control group). The treatment with 0.08% ${\alpha}$-amylase was best for optimum hydrolysis of mung bean starch The treatment using a mixture of 0.08% (w/w) ${\alpha}$-amylase and 0.12% (w/w) protease was best for optimum hydrolysis of meg bean protein. The effects of Hydrolysis time of mung bean showed that the optimum time was 60 and 90 min and there fore the optimum time was set at 60 min. These result showed that the best hydrolysis conditions of mung bean were the treatment at $60^{\circ}C$ for 60 min using a mixture of 0.08%(w/w) ${\alpha}$-amylase and 0.12% (w/w) pretense, with the sugar level shown at $5.8^{\circ}Brix$, reducing sugar at 2,022.13 mg% and crude protein at 7,666.17 mg%.

• Food Science and Preservation
• /
• v.14 no.4
• /
• pp.364-368
• /
• 2007

The purpose of this study was to improve the stability and the processing property of vitamin C. Vitamin C was coated according to particle size(80-100 mesh, 100-140 mesh) and mixing ratio(1:1.6, 1:2.5, 1:3(w/w)) with coating solution(8% Zein-DP, 6% HPMC-FCC), and then the quality characteristics of fluidized bed micro coated vitamin C were investigated. The coating efficiency and the thickness of coating film were higher in $80{\sim}100$ mesh particle than in $100{\sim}140$ mesh particles, and coating efficiency was decreased as the coating material was increased. The distribution range of particle was more narrow in mixing ratio of 1:3(w/w) than in the other. DPPH radical scavenging activity was not affected by the particle size and the mixing ratio. There was no difference between the coating materials in terms of the quality characteristics. The optimum coating condition for fluidized bed micro-coating of vitamin C powder was selected as the particle size of $80{\sim}100$ mesh and the mixing ratio with coating solution of 1:3(w/w).

• Food Science and Preservation
• /
• v.14 no.4
• /
• pp.385-393
• /
• 2007

Much research is conducted on the biological activities of medicinal herbs, traditional plants, and agricultural products, cultivated in Korea. This study focused on optimization of hot-water extraction methods for such products, by analyzing and monitoring extraction characteristics using a response surface methodology. We found that the total phenolics contents, electron-donating abilities, and nitrite-scavenging abilities of extracts were significantly affected both by the solvent used for extraction, and by the nature of the particular herb or plant under study. The extraction efficiencies of valuable ingredients such as alliin, allicin, and total thiosulfinate, were greatly affected by extraction temperature, but not by extraction time or the solvent used. We elicited a regression formula for each variable. We first entered the optimal values of all extraction conditions giving active ingredients into the model. Next, we entered the optimal values of all extraction conditions favoring the retention of valuable antioxidant characteristics. Finally, we entered processing factors into the model. Overall, the optimal extraction was at $80^{\circ}C$ for 3.5 hr with 8.5 ml of solvent/g of sample. The predicted values of each variable were similar to the actual values.

• Food Science and Preservation
• /
• v.14 no.4
• /
• pp.345-350
• /
• 2007

Shelf-life and quality changes of four leaf lettuce cultivars packaged and stored at four different temperatures (0, 8, 16 and $24^{\circ}C$) were evaluated. Leaf lettuces were packaged in non-perforated polypropylene film (thickness 0.05 mm) bags. Weight loss, respiration rate, freshness degree, pigment content, and surface color were determined. At the storage temperature of $0^{\circ}C$, the weight loss, degree of freshness, pigment content, and change of surface color on packaged leaf lettuces showed no significant difference when compared with all other leaf lettuces. Meanwhile, an increase in storage temperature was observed with the quality changes of each flesh leaf lettuce. The leaf lettuces under storage conditions at $24^{\circ}C$ showed a difference in weight loss of the different types of leaf lettuces during a short storage period. However, there was no clear tendency in weight loss in different types of leaf lettuces as compared with each storage temperature. The rate of respiration and the contents of pigments in the four types of leaf lettuces also showed significant difference as the storage temperature increased.

• Food Science and Preservation
• /
• v.14 no.6
• /
• pp.722-726
• /
• 2007

Extracting and analytical conditions of curcumin, and removal of bitterness substance from Curcuma longa L. were investigated. Absorption maxima was shown to be 424 nm at methanol solvent. Optimal conditions for analysis of curcumin was Zorbax eclipse $C_{18}$ column ; mobile phase, 75% MeOH ; flow rate, 0.8 mL/min ; wave length, UV 424 nm. Curcumin component was analyzed to be the highest content in methanol extract. In all samples, extraction yield by heating was shown to be effective as compared to room temperature. Curcumin contents of methanol and ethanol extracts in extraction of room temperature were 14.4 and 14.2 times higher than that of water extract, respectively. Two hot solvent extracts has a high curcumin content being 150 mg% as compared to room temperature. Extracting time was an effective condition when it was extracted for 60 minutes for elevating the curcumin content of water and methanol extracts. Bitter substance (BS) was markedly decreased in water extract by heat treatment of above $80^{\circ}C$. BS was weak in $121^{\circ}C$ treatment than in room temperature and it was however strong in $100^{\circ}C$ treatment. RT and $70^{\circ}C$ heat treatment were not different in BS intensity.

• Food Science and Preservation
• /
• v.14 no.6
• /
• pp.598-604
• /
• 2007

Process development and standardization are necessary in maintaining high hygienicquality of side dishes. Seasoned perilla leaves are a typical side dish needing process development. In this study the optimum condition for preparing seasoned perilla leaves was investigated experimentally. The best sensory quality was established by response surface methodology. The rinsing and washing method of preparing fresh perilla leaves was optimized to decontaminate the raw material and preserve the product in chilled storage. Washing and rising with 3% salt water reduced the aerobic bacterial count of perilla leaves to 0.55 (log CFU/g), while rinsing reduced the load from 8.08 to 4.27 (log CFU/g). The effect of rinsing method was maintained during subsequent storage of the prepared seasoned leaves at $10^{\circ}C$. There was no significant quality change in the product during chilled storage at $10^{\circ}C$. Soaking in 3% salt water for 1 min, followed by rinsing with tap water, contributed positively to the microbial quality, and is proposed as the optimal preparation method.

• Food Science and Preservation
• /
• v.15 no.3
• /
• pp.377-384
• /
• 2008

The gamma irradiation process was performed to prolong a shelf-life of peaches and the effects of a gamma irradiation on the nutritional, physiochemical and sensory characteristics of peaches were evaluated during a post-irradiation storage at $4^{\circ}C$ and $25^{\circ}C$. Nutritional, physiochemical and sensory characteristics of peaches were stable at 1 kGy of an irradiation, a recommended dose for fruits and vegetables by CODEX, and the viable cell counts of contaminated microorganisms were reduced by 2 decimal reduction, at this dose. After a 1-week storage at ambient condition, the microbiological quality of the 1 kGy irradiated peach was stable, while all the non-irradiated peaches were deteriorated Furthermore, cold storage enhanced the shelf-life of the gamma irradiated peach and the nutritional and physiochemical characteristics of the peaches were comparatively stable up to 6 weeks. Right after gamma irradiation, the sensory evaluation results were not different in any of the samples, and the sensory quality of the irradiated peaches was adequate for a 4-week storage at $4^{\circ}C$. Our results suggested that gamma irradiation at 1 kGy can be used to enhance the shelf-life of peach without a significant loss in the quality attributes, especially upon cold storage after radiation treatment.

• Food Science and Preservation
• /
• v.23 no.5
• /
• pp.666-672
• /
• 2016

The objective of this study was to evaluate the effects of low temperature-adapted Saccharomyces cerevisiae Y297 and fermentation temperatures on the quality of Yakju brewed. Physicochemical properties of Yakju brewed were compared pH, total acidity, ethanol, free amino acid, organic acid contents, and volatile flavor compounds in S. cerevisiae Y297 with control treatment. Cooked non-glutinous rice and saccharogenic amylase in koji were mixed with ethanol-producing yeasts and then fermented at $15^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$ for 20 days. Yakju brewed using the Y297 treatment showed the highest ethanol yield (17.9%) at $20^{\circ}C$. Expression of heat shock protein (HSP) 104 was evaluated by immunoblotting as an indication of adaptation to low temperatures ($15^{\circ}C$); levels of the HSP104 protein were higher in the Y297 treatment than in the control. Organic acid analysis showed that the lactic acid content of Yakju brewed using the control was the highest at $25^{\circ}C$. Finally, free amino acid analysis showed that the Y297 treatment had a higher proportion of essential amino acids than the control. Overall, these results indicate that S. cerevisiae Y297 could be used as a suitable yeast for Yakju brewed under low temperature ($15^{\circ}C$) condition.

• Food Science and Preservation
• /
• v.13 no.1
• /
• pp.71-76
• /
• 2006

We monitored the characteristics of soybean hydrolysate prepared under various hydrolysis condition using response surface methodology. The yield was affected by protease content but 1be effect of hydrolysis time to yield gradually increased at over $0.4\%$ of protease, while the $R^2$ of polynomial equation was 0.978 (p<0.01). The soluble solid enlarged by increase of both variables and the $R^2$ of polynomial equation was 0.954 (p<0.01). The degree of hydrolysis was affected by protease content at low (under $0.4\%$) protease and maximized at $0.57\%$ protease and 5.49 hrs. The $R^2$ of polynomial equation for the degree of hydrolysis was 0.916 (P<0.05). The calcium intolerance capacity showed similar pattern like yield but the effect of hydrolysis time was rapidly increased at over $0.4\%$ protease. The $R^2$ of polynomial equation for calcium intolerance capacity was 0.932 (p<0.05). The total phenolic compounds increased in proportion to protease content and hydrolysis time, while the $R^2$ of polynomial equation was 0.920 (p<0.05). According to the results of this study, the optimal conditions for soybean hydrolysis were predicted to be $0.51\~0.66\%$ of protease and $6.5\~9.0\;hrs$, and the predicted values and actual values of each response variable were similar to each other when the hydrolysis was performed at a random point within the optimal range.

• Food Science and Preservation
• /
• v.10 no.3
• /
• pp.261-266
• /
• 2003

We investigated the efficacy of heat shock treatments to improve storage quality of green red pepper. Green red pepper were stored at 10$^{\circ}C$ for 4 weeks after no treatment (control) or hot water dips at 50-65$^{\circ}C$ for 10s. Treatments at 65$^{\circ}C$ generally caused high levels of heat injury on the surface of fruit. The hot water dips had no effect on firmness, Hunter ‘a’ and ‘b’ values and viable cell count by 3 weeks of storage. But color of fruit changed toward darker and redder direction and firmness was decreased by heat treatment at 4 weeks of storage. The contents of capsaicin and dihydrocapsaicin were not caused significant influence by different heat treatment, were decreased through the storage. The optimal hot water dip condition for maintaining fruit quality after prolonged storage was found to be 55$^{\circ}C$ for 10s, which can lead to reduced chilling sensitivity of green red pepper.