• Journal of Food Hygiene and Safety
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• v.19 no.1
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• pp.25-30
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• 2004

This study was conducted to investigate effect of mungbean sprout and soybean sprout against the growth of spoilage microorganism (Bacillus subtilis, Bacillus cereus, Pseudomonas fluorescens, and Listeria monocytogenes). After blanching at different conditions, the viable cells of the spoilage microorganisms were increased with storage time, but the viable cells were almost same after treating with either mungbean sprout or soybean sprout. The viable cell population in minimal broth treated with filtrate of mungbean sprout was higher than that of soybean sprout after 24 hr. However, the growth of spoilage microorganism in filtrate of mungbean sprout and soybean sprout was depending upon strain type. During incubation for 72 hr at $25^{\circ}C$, the color change of mungbean sprout was appeared moderately, but in soybean sprout it was appeared clearly at 24 hr. These results indicate that the effect of mungbean sprout and soybean sprout against growth of spoilage microorganism was not different.

• Food Science and Preservation
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• v.22 no.1
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• pp.44-50
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• 2015

This study was performed to optimize the preparation of frozen lotus roots. Prior to freezing, an optimal blanching condition at $100^{\circ}C$ for 5 min was established, based on the microbial growth, texture, total phenolic content (TPC), and sensory evaluation results. The blanched samples were then frozen under various freezing conditions ($-20^{\circ}C$ in a freezer for 2 hr, $-70^{\circ}C$ in a gas nitrogen convection chamber for 7 min, and $-196^{\circ}C$ in liquid nitrogen for 20 sec), and their qualities after thawing were determined. The scanning electron microscopic analysis indicated that the microstructure of the sample frozen at $-70^{\circ}C$ was similar to that of the control sample, compared with the other freezing conditions (-20 and $-196^{\circ}C$). The antioxidant activities of the frozen samples decreased compared to those of the control, but there was no significant (p<0.05) difference among the treatments. In terms of TPC, the samples frozen at -70 and $-196^{\circ}C$ had significantly (p<0.05) higher values than the sample frozen at $-20^{\circ}C$. In addition, the drip loss of the sample frozen at $-20^{\circ}C$ was higher than those of the other frozen samples. These results suggest that freezing at $-70^{\circ}C$ in a gas nitrogen convection chamber can be an optimal freezing method of producing high-quality frozen lotus roots.

• Food Science and Preservation
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• v.19 no.4
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• pp.470-476
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• 2012

Enzymatic action and microbial growth degrade the quality of fresh-cut lettuce. Browning, a bad smell, and softening during storage are the major forms of quality deterioration. Health-oriented consumers tend to avoid foods treated with chemicals to maintain their freshness. This study was conducted to evaluate the change in the quality of fresh-cut lettuce with combined low-temperature blanching (LB) and ultrasonication (US). The optimum condition was selected using the response surface methodology (RSM), through a regression analysis with the following independent variables; the ultrasonication time (X1), blanching temperature (X2), blanching time (X3), and dependent variable; ${\Delta}E$ value (y). It was found that the condition with the lowest ${\Delta}E$ value occurred with combined 90s US and $45^{\circ}C$ 90s LB (US+LB). The combined treatment group (US+LB) was stored at $10^{\circ}C$ for 9 days with the control group and each single-treatment group, with low-temperature blanching and ultrasonication. Overall, the US+LB group had a significantly high $L^*$ value, which indicates significantly low $a^*$, $b^*$, ${\Delta}E$, browning index, PPO, and POD activity values, and a low total bacteria count (p < 0.05). The US+LB group also had the highest sensory score (except for aroma and texture; p > 0.05).

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.371-376
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• 2018

Consumption of wild edible greens (WEG) has risen in Korea recently, and processing of WEG at greenhouses is increasing. In this study, we investigated chamchwi (Aster scaber Thunb), a major WEG, to assess the effect of growth conditions on nutritional quality and blanching process. Field-grown chamchwi had 1.5-2-fold more total phenolic compounds and anti-oxidative capacity than the house-grown one. Among functional compounds, quercetin was significantly higher (about 5-fold) in the field samples (approximately $430{\mu}g/g$ fresh weight) than in the house samples. Soluble sugars in field-grown chamchwi were 2-fold higher than in the house samples. For both the samples, blanching process decreased chamchwi quality significantly, but the degree of loss for each component was different. Consequently, field-grown chamchwi exhibited superior nutritional quality than greenhouse-grown one, and blanching process resulted in a similar decrease of nutritional quality in both the samples.

• Korean journal of food and cookery science
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• v.28 no.6
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• pp.857-863
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• 2012

This study prepares dried sweet pumpkins to optimize pretreatment conditions of blanching, steaming and microwave heating and to investigate the quality characteristic of each method. The sweet pumpkin blanching treatment of moisture content decreased gradually with increasing temperature, and soluble solids, and weight loss was increased. Color temperature is lower, and a higher value of L value and b value increased. As for the sweet pumpkin steaming treatment of moisture content, it was observed that the longer the steaming time was decreased, sugar content was increased. Change of color in the L value, the longer the steaming time a and b values. Also, as for the microwave treatment of the sweet pumpkin, the longer the time the moisture content decreased, it slightly increased soluble solids and weight loss. Blanching showed the lowest hardness of texture, followed by steaming, and microwaves, in order. Penetration per 20 hours per type was determined by sensory evaluation of sugar, and sugar:fructose(1:2)ratio were higher in the composition.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1948-1953
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• 2014

This study examined changes in antioxidant activity as well as contents of rosmarinic acid, homoplantaginin, and luteolin, which is the main substance of Salvia plebeia R. Br. (SPR) known to have anti-inflammatory efficacy, according to drying, blanching, and fermentation conditions. Rosmarinic acid content was 16.42 mg/g upon hot-air drying and 10.19 mg/g upon hot-air drying after blanching, and there was no significant difference in the case of leaf and root freezing or cold-air drying. Rosmarinic acid content was 8.69 and 8.15 mg/g in the case of air-drying in the shade and freeze-drying, respectively, and decreased to 0.05 mg/g or undetected after fermentation. SPR processed by freeze-drying, cold-air drying in the shade, and hot-air drying showed ABTS radical scavenging ability over 98.5% at a concentration over $500{\mu}g/mL$ as well as excellent radical scavenging ability of 87.3% in the case of hot-air drying after blanching. Root showed lower ABTS radical scavenging ability than leaves. SOD-like activity was measured to be 6.1~27.8% at a concentration of $1,000{\mu}g/mL$, which was significantly difference from ABTS radical scavenging ability. As rosmarinic acid and homoplantagine, an anti-inflammatory material contained in SPR, are almost undetectable after oxidation fermentation during processing, hot-air drying after blanching or drying seems to be suitable to develop SPR as a functional substance.

• Food Science and Preservation
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• v.19 no.1
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• pp.74-80
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• 2012

To enhance the application of lotus roots and to provide basic data for processed foods with lotus roots, lotus root powder was processed under four different conditions, and their physicochemical properties were analyzed as follows. In the Hunter's color value results, the salted sample had the highest L value, and the vinegared sample had the highest a and b values. The water-holding capacities of the salted, vinegared, and blanched samples were higher than that of the control sample. The amylase contents were in the 19.57-20.43% range but were not significant. The swelling power and solubility of the processed samples increased as the temperature rose. The blanched sample had the highest swelling power and solubility (65 and $60^{\circ}C$, respectively). The crystallinity of the processed samples, as determined via X-ray diffraction, reached their peak at $16.9^{\circ}$, and the other peaks at 14.6, 22.2, and $23.8^{\circ}$ were typical of the B type. In addition, the relative crystallinity, gelatinization temperature, and enthalpy, as determined via DSC thermogram, were highest in the vinegared sample and lowest in the blanched sample. In the amylogram results, the vinegared sample had the highest maximum viscosity and breakdown. The retrogradation of the vinegared sample was the slowest as its setback value was the lowest.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.497-502
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• 1990

The effect of sugar concentration, immersion time and temperature on water loss, solid gain or loss, and sugar molality of potatoes during osmotic concentration was analyzed by a response surface methodology (RSM), and those values were predicted by using a second degree polynomial regression model. Effect of osmotic concentration and blanching on vitamin C retention of air dried potatoes (6% MC: wet basis) was also evaluated. The most significant factor was sugar concentration for water loss, solid gain or loss, sugar molality, rate parameter and retention of vitamin C. Second and third factors were immersion time and temperature respectively. Water loss and solid gain were rapid in the first 10 min and then levelled off. A 44.6% of water loss was observed during osmotic concentration using a sugar solution $(60\;Brix,\;80^{\circ}C$) with 20 min of immersion time. Dried potatoes after osmotic concentration had higher vitamin C content than dried potatoes after blanching. Optimum regions for osmotic concentration process of potatoes were $60-70^{\circ}C$ of immersion temperature, 60 Brix of sugar solution and 16-20 min of immersion time based on above 30% of water loss and 50% of vitamin C retention.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.399-405
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• 2010

After Gomchui tea was prepared from leaves of Ligularia fischeri (Ledeb.) Turcz by blanching method, the antioxidant activity of major compounds in Gomchui tea was assessed. On-line HPLC-ABTS analysis revealed that caffeoylquinic acids (chlorogenic acids), such as 5-O-caffeoylquinic acid (5-CQA), 3,4-di-O-caffeoylquinic acid (3,4-DCQA), 3,5-di-O-caffeoylquinic acid (3,5-DCQA) and 4,5-di-O-caffeoylquinic acid (4,5-DCQA), were the major antioxidant compounds in Gomchui tea. The extraction efficiency of these compounds were examined in the various conditions such as extraction temperature, time and solvent. The results demonstrated that the extraction amount with water increased in proportion to extraction time (1~10 min) and temperature ($8{\sim}80^{\circ}C$). These active compounds were also extracted with water even at $8^{\circ}C$ (60% of $80^{\circ}C$), indicating that water is very good extraction solvent for extraction of these antioxidant constituents. However, the extraction efficiency of these compounds decreased when ethanol percentage in water increased. The extraction efficiency between Gomchui powder (no blanching) and tea was significantly different, and 60% of total antioxidant compounds in tea was removed from fresh leaves into water in blanching process, especially 3,5-DCQA (over 90%). Meanwhile, the sonication method didn't affect the extraction of these compounds in all solvents. These results suggest that Gomchui tea can be a good candidate for the tea beneficial to human health.

• Journal of the Korean Society of Food Culture
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• v.33 no.1
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• pp.78-85
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• 2018

This study examined the changes in antioxidant activity and contents of phenolic compounds inblanched, steamed, and autoclaved burdock root (BR). The total polyphenolic and flavonoids contents of raw and cooked BR were determined spectrophotometrically. The antioxidant activity of BR was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and oxygen radical absorbance capacity (ORAC) assays. The main phenolic compounds in BR were quantified by HPLC (high performance liquid chromatography). Both blanching and steaming treatments significantly increased the antioxidant activities of BR in all groups (5 min, 15 min, and 30 min), whereas in autoclaving treatment, the 30 min treatment only showed an increase in the antioxidant activities of BR. The 30 min blanched BR exhibited the strongest DPPH and ABTS radical scavenging activities and possessed the highest total polyphenol and flavonoid phenolic contents. The 15 min-steamed BR showed the highest ORAC value. The main phenolic compound of the 15 min-steamed BR was CGA (chlorogenic acid). These results suggest that heat cooking methods, such as blanching and steaming, improve the antioxidant activity of BR by increasing the concentration of phenolic compounds.