• Analytical Science and Technology
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• v.30 no.5
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• pp.295-302
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• 2017

This study presents a method validation for extraction and quantitative analysis of levulinic acid in soy sacues using high performance liquid chromatograph-photodiode array detector (HPLC-PDA). The levulinic acid in samples were extracted with distilled water, and then purified with C18 Sep-Pak cartridge. The calibration curves showed good linearity (R > 0.999) in a relatively wide concentration range ($2.5-400{\mu}g/mL$). Mean recoveries and relative standard deviation (RSD) of levulinic acid spiked in soy sauce samples at different spiking levels ($2.5-400{\mu}g/mL$; 6 point). Recoveries were 87.58-97.26 % with RSD less than 15 %, and limit of detection (LOD) and limit of quantification (LOQ) were 0.64 and $1.64{\mu}g/mL$, respectively. According to monitoring result with the established method, levulinic acid was found in 43 of 59 domestic commercial soy sauces, soy sauce based sauces and seasoned meats. The contamination levels were 0.44-1.23 mg/mL for soy sauces, 0.03-0.83 mg/mL for soy sauce based sauces and 8.43-38.94 mg/mL for seasoned meats. The results indicated to be rapidly and accurately qualifying levulinic acid and can be used as a suitable quality control method for soy sauce and soy sauce related commodities.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.317-322
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• 2003

Changes of physicochemical properties during the preparation of persimmon pickles were investigated. The salinity in persimmon pickles increased during storage time $(0{\sim}50\;days)$ with soy sauce and soy paste. When the fermented soy sauce and soy paste was added to the soaking solution with $80{\sim}100%$, the salinity increased more rapidly. The hardness of persimmon pickles with soy sauce and soy paste was slightly increased up to the 20 or 30th day of storage and then decreased. L value of persimmon pickles was gradually decreased, but a and b value were slightly increased. The concentration of soluble tannin in persimmon pickles was slightly decreased down to the 20th day of storage and then decreased rapidly. The activities of polygalacturonase and pectinesterase as softening enzyme in persimmon pickles with soy sauce and soy paste increased during storage time $(0{\sim}50\;days)$ and enzyme activity was inhibited by high concentration of soaking solution.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.660-666
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• 2008

This study was designed to compare the thermal oxidative stability of lard, soy bean oil, and hot pepper seed oil for 0-3 d at $100^{\circ}C$, and to evaluate the effect of capsaicin on thermal oxidative stability in lard and soy bean oil. As result, thermal oxidation stability was shown in the order hot pepper seed oil>soy bean oil>lard for 0-3 d at $100^{\circ}C$. In blended oils, hot pepper seed oil effectively inhibited lipid oxidation when mixed with lard than soy bean oil by showing the ratio of 30% pepper seed oil plus 70% lard and 60% pepper seed oil plus 40% soy bean oil inhibited lipid oxidation during storage periods. And to investigate the antioxidative effect of antioxidants such as capsaicin and alpha-tocopherol in hot pepper seed oil, 1,200 and 2,400 ppm capsaicin, or 0.3% alpha-tocopherol were added in soy bean oil and lard and stroed for 0-3 d at $100^{\circ}C$. Capsaicin inhibited lipid oxidation in lard but not in soy bean oil, however alpha-tocopherol exhibited a prooxidaton effect in soybean oil. Therefore, it suggests that the application of hot pepper seed oil or capsaicin in lard may be better for thermal oxidative stability.

• The Korean Journal of Food And Nutrition
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• v.19 no.3
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• pp.318-326
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• 2006

Soy sauce was prepared with the addition of Gorosoe and Kojesu saps instead of tap water to make ordinary soy sauce, respectively. The changes of free sugar, organic acid, mineral, amino acid and nucleotides and other compounds during the fermentation of soy sauce were assessed. The free sugar were found to be fructose, glucose, galactose and sucrose in soy sauce of saps but sucrose was not detected in ordinary soy sauce. Galactose contents were dominant free sugar in all samples. The contents of butyric acid were dominant among 7 kinds of organic acid while fumaric acid was trace amount during the fermentation of soy sauce. The contents of potassium and phosphorus among 13 kinds of minerals were dominant during the fermentation of soy sauce. In the amino acid composition of soy sauce, dominant amino acid was glutamic acid(185.6${\pm}$1.0 mg/100 ml above), but proline and arginine were not detected. AMP detected above 7.5${\pm}$O.2 ${\mu}$mol/100 ml was dominant while inosine was not detected during the fermentation of soy sauce. The results of sensory evaluation in the fermented soy sauce of Gorosoe was 'liked more' than that of soy sauce of Kojesu and control.

• Journal of Food Hygiene and Safety
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• v.25 no.3
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• pp.278-280
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• 2010

This study was aimed to develop a novel qualitative multiplex polymerase chain reaction (PCR) for simultaneous detection of genetically modified (GM) soy and maize within a single reaction. The specific primers designed to detect four respective GM events (A2704-12, MON88017, Bt11, and MON863) were included in the tetraplex PCR system. Each of PCR products for four GM events could be distinguished by agarose gel based on their different lengths. The specificity and reproducibility of this multiplex PCR were evaluated. This multiplex PCR consistently amplified only a fragment corresponding to a specific inserted gene in each of the four GM events and also amplified all four of the PCR products in the simulated GM mixture. These results indicate that this multiplex PCR method could be an effective qualitative detection method for screening GM soy and maize in a single reaction.

• Korean Journal of Community Nutrition
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• v.9 no.5
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• pp.606-614
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• 2004

This study was conducted to investigate the attitude to various soy foods and to estimate dietary isoflavone intake among Korean adolescents. The survey was carried out by self-administered questionnaire with 800 middle and high school students residing in urban and rural areas and 714 questionnaires were collected: resulting in 89% response rate. The dietary isoflavone intake was estimated by food frequency questionnaire developed for rapid assessment of isoflavone intake. Soybean paste, soybean curd, soy milk, bean sprouts and dambuk were recognized as nutritious and healthy food in order. Dambuk got the lowest score in taste and flavor. Bean sprouts, soybean curd and soybean paste were recognized as familiar food in order. Stuffed rice in fried soybean curd got the highest score and Miso soup got the lowest in preference. More than 50% of the subjects consumed soybean paste stew/soup and soybean curd over twice per week and 12.3% of the subjects consumed soybean over once a day. The estimated daily intake of isoflavones ranged from 0 to 227 mg, and the mean daily isoflavone intake of the subjects was 28.1 mg (16.3 mg genistein and 12.0 mg daidzein) whereas the median value of isoflavone intake was 19.7 mg. There was statistically significant relationship among Kyung Gi Do, Chung cheung Do and Seoul residents in their intake of isoflavone. The highest monthly income group consumed isoflavone more than the other groups. These results suggest that Korean adolescent perceived the soybean dishes as high quality foods but they didn't take much because of difficulty to cook or less chance to eat. Nutrition education program is needed to enhance consuming soy foods for prevention of chronic diseases related to dietary isoflavone intake. More detailed information on easy cook method of soy food is also needed.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.290-293
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• 2005

Soy isoflavones have drawn much attention due to their potential to prevent breast and prostate cancers, osteoporosis, heart disease, and other postmenopausal symptoms. Soy germ is one of the richest sources of isoflavones, and thus has good potential to be used as the ingredient of health foods. This study examined the extraction rate of isoflavones from soy germ at various conditions. After the effect of extraction temperature and duration on isoflavones extraction from soy germ was examined, the optimum concentration of ethanol as extraction solvent was determined. When ethanol concentration was fixed at $60\%\;(v/v)$, the maximum isoflavone extraction was achieved at 2 hrs and $30^{\circ}C$. Among various concentrations of ethanol tested, $80\%\;(v/v)$ ethanol showed the highest extraction efficiency. In conclusion, the maximum extraction of isoflavones was obtained using $80\%\;(v/v)$ ethanol as a solvent, at $30^{\circ}C$ of temperature, and 2 hrs of extraction time.

• Preventive Nutrition and Food Science
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• v.12 no.1
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• pp.11-15
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• 2007

This study was conducted to evaluate the influence of diets containing genistein and soy extract on the growth of MDA-MB-231 cells implanted into female Balb/c mice. Four-week-old female athymic nude mice (Balb/c) were acclimated to an AIN-93G control diet for 1 week and then injected MDA-MB-231 cells ($1{\times}10^6$/site) and were continued on the on AIN-93G control diet. Five weeks after injecting the MDA-MB-231 cells ($1{\times}10^6$/site), two experimental groups were assigned to diets containing genistein (750 ${\mu}g/g$ AIN-93G diet) or 0.6% soy extract (containing genistein at 750 ${\mu}g/g$ AIN-93G diet) until they were sacrificed. Tumor growth was significantly reduced in the groups treated with genistein and soy extract compared to the control group. The results of the proliferating cell nuclear antigen (PCNA) assay also revealed that genistein and soy extract treatment reduced the proliferation of MDA-MB-231 cells in vivo. In the present study, dietary isoflavone was provided just before solid tumor formation, and thus the timing of dietary isoflavone administration may be critical to the suppression of tumor growth.

• Korean journal of food and cookery science
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• v.11 no.5
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• pp.521-526
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• 1995

The survey on consumption pattern of consumer for Korean traditional soy sauce and sensory evaluation of seaweed soups cooked with soy sauce were summarized as follows:1) 83.5％ of the subjects used Korean traditional soy sauce to cook at home and the old subjects used it more than the young. 60.5％ of soy sauce users made it at home and the old users showed the trend making it at home more than the young. 19.1% of the users were given it by relatives and 18.4％ of the users bought it at the market and purchasing rate is higher in the young. 88.0% of the users consumed Korean traditional soysauce for the reason of umami taste and flavor. 27.5％ and 27.5％ of the users purchased it for the reasons of convenience and confidence respectively. 2) The most important characteristics of the Korean traditional soy sauce were responded to umami taste and flavor. The food having highest frequency to use Korean traditional soy sauce was seaweed soup (84.5%). 3) According to consumer sensory evaluation test of the seaweed soups cooked with soy sauce, preference was somewhat different with the age. It seemed that the old consumers prefered the seaweed soup cooked with Korean traditional soy sauce more than the young.

• The Korean Journal of Community Living Science
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• v.15 no.3
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• pp.113-120
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• 2004

This study is to investigate the effect of dietary L-carnitine supplementation on lipid metabolism in rats fed with isolated soy protein and casein for their source of protein. Four experimental groups were organized and each group had eight Sprague-Dawley male rats with the initial weight of around 180g. The four groups were CO (casein only supplemented group); CC (casein and 3% L-carnitine supplemented group); ISO (isolated soy protein only supplemented group); ISC (isolated soy protein and 3% L-carnitine supplemented group). All groups were supplemented with the experimental diet for four weeks and carnitine comprised 3% of. their diet. The results were as follows; 1. There was no significant difference in food intake among the groups. 2. Final weight gain was significantly lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (P<0.05). The groups with supplemented casein and carnitine showed the effect of weight reduction (p<0.05). 3. Food efficiency ratio was lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (p<0.01). The groups supplemented with casein and carnitine showed low food efficiency ratio. 4. The serum total lipid was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein (p<0.05). 5. Serum total cholesterol was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein. 6. There was no significant difference in triglyceride, HDL-cholesterol, and LDL-cholesterol in serum among the groups. 7. Out of the groups supplemented with isolated soy protein the total cholesterol level in liver was low in the groups to which carnitine was supplemented (p< 0.05). However, there was no significant difference of liver total lipid and triglyceride among the groups. 8. There was no difference in TBARS levels and GSH-Px activities in liver among the groups.