• Food Science and Preservation
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• v.14 no.6
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• pp.605-610
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• 2007

The quality of guava (Psidium guajava L.) leaves processed using different methods, such as fermentation, steaming, and roasting were investigated. The total phenolics content was highest in the roasted guava leaves. While tyrosinase inhibition and electron donating abilities were highest in steamed guava leaves. The overall palatability showed higher scores in both fermented and steamed guava leaves compared to roasted ones. Upon blanching and steaming of guava leaves, the total phenolics content, tyrosinase inhibition ability, and electron donating ability decreased as the treatment time increased. The overall quality properties were significantly higher in steamed than the blanched samples. The sensory scores, however, were low mainly due to the astringent taste of guava leaves. Thus, it was found that the removal or masking of the astringent taste of guava leaves is of primary concern for their further use.

• Korean journal of food and cookery science
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• v.19 no.2
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• pp.174-180
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• 2003

The purpose of this study was to investigate the differences in vitamin C and mineral contents in perilla leaves as a result of different cooking methods. The results are summarized as follows. In cutting up the perilla leaves, the vitamin C content decreased by 40% with no significant difference made to the mineral content. Steaming was more effective in retaining vitamin C compared to blanching. With increasing treatment times. decreasing amounts of vitamin C remained. There was no significant change in mineral contents except for potassium. In the case of treating with vinegar or lemon juice, more vitamin C remained than when not treated, and there was little influence on the mineral contents. In the solubilization effect of calcium seasoned with acid, rice vinegar was most effective followed by lemon juice, apple juice, brown rice vinegar, then persimmon vinegar. There was a little or almost no vitamin C remaining in kkaennip kimchi. In terms of storing time, raw seasoned kkaennip kimchi had higher mineral contents than blanched or steamed kkaennip kimchis.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.372-376
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• 1998

Internal mass transfer during osmotic dehydration of gingers in sugar solution was examined as a function of concentration, temperature and immersion time of those solutions using moisture loss, sugar gain, molality and rate parameter. Influence of osmotic dehydration on browning reaction and texture properties of air dried rehydrated was also evaluated. Increasing the concentration and temperature of sugar solutions increased moisture loss, sugar gain, molality and rate parameter. Water loss and sugar gain were rapid in the first 3 min and then changed gentle slope. Moisture loss during osmotic dehydration using a sugar solution $(60\;Brix,\;80^{\circ}C)$ with 18 min immersion time was 40.05 g moisture/100 g wet ginger which was 52% reduction of initial moisture content in ginger (83.02%, wet basis). The changes of rate parameter were more affected by temperature than by concentration of sugar solution. Minimum browning degree (O.D.=0.027) was carried out by osmotic dehydration in sugar solution $(40\;or\;50\;Brix,\;80^{\circ}C)$ with 15 min immersion time compared to control (O.D.=0.132). Influence of osmotic dehydration on puncture forces of 3 min rehydrated ginger in boiling water were $22{\sim}34%$ of reduction, while blanching treatment had not affected compared to those of control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1688-1693
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• 2011

This study was evaluated mass production processes for flour noodles containing perilla leaf (FNPL) and to examine the antioxidant properties of FNPL. The processes for perilla leaf preparation before dough making were the main focus. The sensory evaluation was used as a tool to determine the optimal conditions for each step in the process. The appearance, taste, flavor, texture and overall acceptability were evaluated using a 9 point scale sensory evaluation. Eight minutes blanching of perilla leaf in boiling water (1:30, w/v) was found to be a suitable time to remove the unpleasant leaf flavor remaining in the final noodle product when fresh perilla leaf was used. The appearance, taste, texture and overall acceptability of FNPL were significantly different from FNPLs prepared with other blanching times. The appearance of FNPL containing 40% (w/v) perilla leaf homogenates was the best. In the dough making process, additional water was not required when 6 portions of 40% perilla leaf homogenate were added to 10 portions of flour, suggesting that the water adding step in the dough preparation process can be skipped. The antioxidant activity of FNPL was expressed as the radical scavenging activity. The DPPH ($IC_{50}$; 0.56 mg/mL), super oxide radical ($IC_{50}$; 9.53 mg/mL) and hydroxy radical scavenging activities ($IC_{50}$; 169.2 ${\mu}g$/mL) of FNPL were increased 19.6 (p<0.001), 1.4 (p<0.01) and 17.8 fold, respectively, compared to those for flour noodle (p<0.001). In conclusion, perilla leaf added to noodles at a final concentration of 19% (w/w) can increase the sensory and antioxidant properties of flour noodles.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.565-572
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• 2013

This study was performed to optimize the processing conditions and to select the optimum species for colored sweet potato chips (Shinjami, Juhwangmi and Hayanmi varieties) baked by far-infrared radiation. Sweet potato chips were prepared by different slicing thickness (1~3 mm), concentration of sucrose solution for soaking (15~30%), blanching time (15~60 sec), baking temperature ($110{\sim}140^{\circ}C$) and baking time (23~31 min) through sensory evaluation and failure stress measurement. Optimal processing condition of sweet potato chips using Shinjami was determined to 1 mm, 20%, 45 sec, $120^{\circ}C$ and 31 min, and those using Juhwangmi was determined as 1 mm, 25%, 45 sec, $130^{\circ}C$ and 29 min. Sweet potato chips using Hayanmi was determined as 1 mm, 20%, 45 sec, $120^{\circ}C$ and 31 min, respectively. Free sugar content of sweet potato chips was higher in chips than in raw materials. In the sensory evaluation, appearance, sweet taste, hardness, and overall acceptance were higher in Juhwangmi than in the Shinjami and Hayanmi varieties. Overall acceptance, sugar content, b-value and failure stress were highly correlated among factors affecting the sensory characteristics (p<0.01). From the results of this study, Juhwangmi variety was selected for production of sweet potato chips.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1881-1888
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• 2014

Pre-thermal treatment is important to minimize quality changes during main cooking or storage. In this study, to optimize pre-thermal treatment of carrots, three types of pre-thermal treatments were applied to carrots and quality changes such as physicochemical, nutritional, or sensory properties were observed. Washed and sliced carrots were thermally treated by hot-water immersion ($100^{\circ}C$, 1~10 min), steaming ($100^{\circ}C$, 1~10 min), and stir-frying with oil (10~80 sec). Carrot tissue was maintained until 2 min hot-water immersion or steaming, and they were damaged by just 30 sec of stir-frying. Color and hardness were significantly affected by treatment time and temperature. Color was completely changed after 5 min and 7 min by hot-water and steam treatments, respectively. Hardness decreased to 44% compared with fresh carrot (4,500 g) after 1 min, 3 min, and 20 sec of hot-water, steam, and stir-frying, respectively. For nutritional changes, ascorbic acid, organic acid, and peroxide activity were reduced by all treatments compared with fresh carrot. Especially, succinic acid was dramatically reduced by hot-water treatment. Otherwise, free sugar contents were increased with greater treatment time in all samples. In this study, pre-thermal treatment of carrot was optimal at 2 min steaming treatment.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.292-301
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• 1997

In drying process, to minimize the quality degradation by improved drying process and pretreatment methods, carrots, cabbages and radishes were dried and rehydrated. Physico-chemical properties of product were analyzed to determine the optimum pretreatment method and drying models were applied to explain drying mechanisms. Microwave, steam and water were used prior to drying as blanching method. In consideration of physical properties, optimum treatment time was decided that microwave was 1 min, steam and water were each 10 min. Control, steam, water, microwave and osmotic dehydration were treated prior to drying as pretreatment individually, osmotic dehydration was lower than the other treatmemt in drying efficiency, but carotene content was higher than the others. The effect continued after rehydration. Ten panelists tested dried and rehydrated carrots. After rehydration, the quality of air dried product with osmotic dehydration was superior to freeze dried without treatment. The fittness of drying models were conducted in order to explain the mechanism of drying each process. Quadratic model was most fittable to explain during drying. However, in rehydration process, no fittable model was found.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.5
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• pp.613-619
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• 2013

Konjac gel is known as a low calorie food, because the main component is water. Mugwort has been used for food and medicine for a long time due to itsfunctional property, which contains a lot of vitamins and minerals. Therefore, konjac noodle-added mugwort was prepared. The konjac gel was made by from a centrifuge after adding water, alkali and mugwort power in konjac flour. The centrifuge was used to remove air in the gel. After centrifuging by heating the gel in boiling water for one hour, konjac noodle was made by pressing using a flat heating press. The results are as follows. In the drying process of mugwort freeze drying after blanching in 1% $NaHCO_3$ solution is better than other drying methods. The physical properties (hardness, elasticity, cohesiveness, gumminess) of konjac gel were measured with a Rheometer. The optimum processing conditions were decided by these measured values. The optimum condition of making konjac gel is 9% concentration of konjac flour, a ph of 12.0, $Na_3PO_4$ coagulant and 1.5% concentration of mugwort power in konjac flour.

• Journal of Food Hygiene and Safety
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• v.4 no.2
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• pp.103-108
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• 1989

Three mushroom cannerries were selected by size which are representative vegetable processing firms in korea for monitoring microbial contamination of processing water, washing water, mushroom before and after washing through first and second washing tanks and, blanched and prolonged mushroom for certain time at room temperature. Total contamination degree was expressed as colony forming unit (CFU) of mesophilic aerobes. The contamination degree of processing water was $10^{2}\;CFU/100\;ml$ and washing water in first and second washing tank were 10 to 100 times higher than processing water. When 2.3 tons of washing water was used for washing 1 ton of mushroom, washing effect was showed by reduction of microbial load but cutting it to 1.8 tonsIl ton of mushroom, microbial load was higher than that of raw mushroom level. Blanching reduced microbial load to 50-500 CFU/g of blanched mushroom and it was not seen much increase of CFU in blanched mushroom left at room temperature for 3 hours in $16^{\circ}C$ processing water. Just after injection of $80^{\circ}C$ brine in container, CFU/ml of brine in container was $84{\times}10^{4}$ but it was increased rapidly to $20{\times}10^{7}$ after 2 hours at ambient temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1221-1226
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• 2016

This study investigated changes in the S-allyl-L-cysteine (SAC) content of garlic using different cooking methods. Methods for determining SAC were validated by determining specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using an high-performance liquid chromatography-fluorescence detection system. Results showed high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9999. The LOD and LOQ values for SAC were 0.15 and $0.47{\mu}g/mL$, respectively. The relative standard deviations for intra- and inter-day precision of SAC were less than 5%. The recovery rate of SAC was in the range from 97.35% to 97.47%. The SAC content of raw garlic was 2.77 mg/g, and there was no significant difference in SAC content according to blanching and microwave treatment. However, SAC content upon boiling and autoclaving at $110^{\circ}C$ and $121^{\circ}C$ increased from 3.50~9.16 mg/g, 6.52~16.21 mg/g, and 14.15~50.24 mg/g with increasing cooking temperature and time, respectively.