• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.987-997
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• 2015

Schisandra chinensis (Sc), a species of the family Schisandraceae used fruits as medicinal herbs. In the study, we performed to determine a comparison of antioxidant activity from Sc water extracts depending on stir-frying and stir-frying with liquids by 30% ethanol pretreatments. The contents of polyphenol and flavonoid, DPPH radical scavenging, ABTS radical scavenging and reducing power activity were measured to evaluate the antioxidant activity. Total polyphenol and flavonoid contents of Sc extracts were increased in stir-frying and 30% ethanol stir-frying pretreatments compared to a control. In particular, contents of stir-frying pretreatments Sc were highest increased at $220^{\circ}C$ treatments. The DPPH radical scavenging activity were highest increased in stir-frying pretreatments at $220^{\circ}C$. And result that measurement of the ABTS radical scavenging, it showed higher activity in 30% ethanol stir-frying pretreatments at $180^{\circ}C$ and $220^{\circ}C$. But Sc in the $140^{\circ}C$ showed higher activity in stir-frying pretreatments. In the reducing power activity, stir-frying pretreatments increased higher than 30% ethanol stir-frying pretreatments at $220^{\circ}C$. As in results, antioxidant activity of Sc water extracts in stir-frying and stir-frying with liquids process increased higher than a control, and it was most effectively in stir-frying pretreatments at $220^{\circ}C$.

• Preventive Nutrition and Food Science
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• v.17 no.4
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• pp.286-292
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• 2012

We investigated the effect of various cooking methods (boiling, steaming, stir-frying, and roasting) and three cooking times (5, 10, and 15 min) on the antioxidant properties of red pepper. Raw and cooked peppers were measured for proximate composition, ascorbic acid (AsA) content, total carotenoid content (TCC), total polyphenol content (TP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities. Results showed that the proximate composition, AsA content, TCC, TP, and antioxidant activities were significantly (p<0.05) affected by the cooking procedure; the loss rate varied among individual compounds. Boiling and steaming significantly reduced AsA content (24.3~66.5%), TP (13.9~54.9%), and antioxidant activity (21.7~60.5%) in red pepper, while stir-frying and roasting slightly reduced AsA content (2.7~25.9%), TP (1.8~4.9%), and antioxidant activity (4.9~17.9%). The highest loss was observed after boiling, followed by steaming, roasting, and stir-frying. Stir-frying and roasting better preserved AsA content, TCC, TP, and antioxidant activity. In conclusion, dry-heat cooking methods such as stir-frying and roasting may be preferred to retain the nutrient compositions and antioxidant properties of red pepper.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.209-219
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• 2005

In this study, we carried out the preparing standardization and regulation of processed Glycyrrhizae Radix (PGR) which have been widely used in oriental medicines. Glycyrrhizae Radix(GR) have been generally prepared by the stir-frying, or mix-frying with honey for the purpose of decreasing sweetness and augmenting vitality. Firstly, we tried to standardize PGR prepared by the stir-frying. We purchased 14 kinds of PGR and non-processed GR(NPGR) at oriental physician's offices and oriental pharmacies on a nation scale, respectively. The amounts of dry on loss, water extract, diluted ethanol extract, ether extract, total ash, acid insoluble ash, glycyrrhizin(GL), glycyrrhetic acid(GA) and liquiritin(LQ) of them were examined. The amounts of dry on loss, GL and LQ in commercial PGRs showed remarkable decrease, while GA showed increased as compared with NPGR. In order to standardize preparing method of PGR, the effect of heating time on physico-chemical parameters and biological activities were examined. Physico-chemical parameters such as dry on loss, extract amount, GL and LQ contents in PGRs showed decrease, however, GA was increased with heating time as compared with NPGR. Also, GA, obtained from heat-treated GR, was found as an artifact in PGRs. PGR was more effective than NPGA in vitro test of DPPH scavenging effect and TBA-Rs reducing effect. PGR and NPGR showed potent hepatoprotective effect on $CCl_4-intoxicated$ rats. Especially, PGR prepared by 80 min of heating was the most effective. Considering these results, the optimal condition for PGR preparation was $150^{\circ}C$ for 80 min.

• Korean journal of food and cookery science
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• v.12 no.1
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• pp.99-107
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• 1996

The cooking characteristics of Hicook with lecithin and GMS as emulsifier were examined for effect on the reduction of oil levels in fried foods. Hicook and soybean oil were used in stir-frying and pan-frying, and in case of Hicook the weight of oil absorbed and spattered during cooking were significantly lower than in case of soybean oil. Next this study attempt to standardize the recipe for preparation of selected Korean foods, especially in regards of the amount of oil used during cooking. The foods studied were all used frequently in Korea, they inculded stir-fried vegetables, stir-fried rice, and pan-fried fish and soybean curd. The results showed that Hicook, even in a half amount, made it possible cooking food with good properties, and calorie content of cooked foods could be lowered considerably. The trained panelists evaluated sensory characteristics of foods, flavor, appearance, and overall acceptability. Sensory qualities of food prepared with Hicook were highly acceptable, and rated better than controls in flavor and overall acceptability. But because stir-fried food was accepted greasy and oily in customarily, the appearance was rated lower than comtrol. In summary, application of hicook offers means of lowering fat levels while keeping sensory quality good. The emulsifier in Hicook is responsible for reduction of oil content and improvement of quality of fried foods.

• Toxicological Research
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• v.31 no.3
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• pp.307-312
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• 2015

Trans fat is a unsaturated fatty acid with trans configuration and separated double bonds. Analytical methods have been introduced to analyze trans fat content in foods including infrared (IR) spectroscopy, gas chromatography (GC), Fourier transform-infrared (FT-IR) spectroscopy, reverses-phase silver ion high performance liquid chromatography, and silver nitrate thin layer chromatography. Currently, FT-IR spectroscopy and GC are mostly used methods. Trans fat content in 6 vegetable oils were analyzed and processing effects including baking, stir-frying, pan-frying, and frying on the formation of trans fat in corn oil was evaluated by GC. Among tested vegetable oils, corn oil has 0.25 g trans fat/100 g, whereas other oils including rapeseed, soybean, olive, perilla, and sesame oils did not have detectable amount of trans fat content. Among cooking methods, stir-frying increased trans fat in corn oil whereas baking, pan-frying, and frying procedures did not make changes in trans fat content compared to untreated corn oils. However, the trans fat content was so low and food label can be declared as '0' trans based on the regulation of Ministry of Food ad Drug Safety (MFDS) (< 2 g/100 g edible oil).

• Journal of the Korean Society of Food Culture
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• v.37 no.1
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• pp.47-60
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• 2022

This study examines the effects of different cooking methods (stir-frying, steaming, superheated-steaming) on the contents and the true retention of moisture, water-soluble vitamins, and bioactive compounds of ten selected vegetables: broccoli, brussels sprout, cabbage, eggplant, green bean, onion, red cabbage, red onion, squash, and tomato. The total color difference (𝚫E) values were decreased after stir-frying the samples, except for eggplant, green bean, and tomato. The true retention of water-soluble vitamins (B₁, B₂, B₃, and C) was increased in most vegetables after superheated-steaming, as compared to steaming and stir-frying. Moreover, compared to the uncooked vegetables, a higher true retention of total polyphenol and flavonoid was obtained for most vegetables subsequent to superheated-steaming. Total anthocyanin content was detected only in eggplant, red cabbage, and red onion, and a smaller loss of anthocyanin was determined after subjecting red cabbage to superheated-steaming. Also, the free radical scavenging activities were higher in superheated-steaming vegetables, except in eggplant and squash. These results indicate that superheated-steaming induces a positive effect for retaining water-soluble vitamins and functional components of vegetables.

• Korean journal of food and cookery science
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• v.18 no.4
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• pp.461-469
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• 2002

In order to develop a better food preparation method in terms of vitamin retention in food service establishments, the retention rate of riboflavin in two kinds of Korean dish (stir-fried sausage with vegetables, stir-fried garlic young stems) were examined during various cooking stages, holding temperature and duration time. Riboflavin content of the sample was analyzed using by using a HPLC with a fluorescent detector at various holding durations and temperatures. Also the changes in the pH and water contents of the samples were measured during holding at various temperatures to find any relation among the pH, water contents and riboflavin content. In the results, there were significant differences in riboflavin contents at various cooking processes such as washing, slicing, blanching, soaking, etc. Also, the retention rates of riboflavin at various holding methods and temperature were significantly different from one another. Especially 50% reduction of riboflavin content occurred during blanching of young garlic stem and only 38% of riboflavin was left after slicing carrots for stir-frying of sausage.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.87-99
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• 2016

Phytosterol contents in nine vegetables such as paprika (red, yellow, and orange), kohlrabi, bamboo shoot, cherry tomato, cucumber, Chinese chive, and corn were analyzed by gas chromatography. Individual contents of ${\beta}$-sitosterol, campesterol, and stigmasterol in fresh and cooked vegetables (boiling, grilling, stir-frying, deep-frying, steaming, roasting, and microwaving) were determined and compared. Total phytosterol content of paprika, cucumber, Chinese chive and cherry tomato ranged from 23.19 to 46.51 mg/kg (0.002-0.005%) of fresh weight of raw vegetables. Total phytosterol content variation (%) was obtained as follows: [(the content of phytosterol after cooking) - (the content of phytosterol before cooking)] / (the content of phytosterol before cooking) ${\times}100$. Total phytosterol content was found to be high in raw kohlrabi at 138.99 mg/kg fw (0.01%), in corn at 302.86 mg/kg fw (0.03%), and in bamboo shoot at 443.15 mg/kg fw (0.04 %). Total phytosterol content variation (%) in orange paprika ranged from 27.5 to 267.3 while that in cherry tomato ranged from -11.0 to 337.5. Generally, high content variation of total phytosterol was found in stir-fried and deep-fried vegetables. Therefore, higher phytosterol levels were obtained from cooked vegetables than raw vegetables. We suggest that these data will be useful to investigate cooking methods for increased intake of phytosterols.

• Journal of the Korean Dietetic Association
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• v.9 no.1
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• pp.47-56
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• 2003

Currently, dietary life in Korea is rapidly changing. New food from other countries introduced to the diet with changing economic and social environment. The number of meals away from home is increasing. Also, number of students who served by the school food service are increasing. In this paper, the menu in the school food service are compared between 1995 and 2001. Analysis was done to see changes in the use of Korean traditional foods. Between July, 2001 and August, 2001, by mail 103 schools were surveyed to analyzed menu. Menu from 2001 survey are compared with menu from 1995 survey. The results are following; 1) New menus are introduced in 2001 compared with 1995. 2) The number of menu using animal foods are increasing in 2001. 3) Among cooking methods, stir frying, and deep frying, are used more in 2001 than that of 1995. 4) The number of Korean dish served are decreased in 2001. 5) Students favorite dish are changed. Students like dishes cooked with deep frying method and western foods. With these results, menu of school food services become more westernized and using more frying methods because of students' taste preference. These trend are not recommendable for the students health, because it is known that Korean traditional dishes are more healthful. There should be more research and effort to keep Korean tranditional foods in the menu of the school food service for students health.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.2
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• pp.234-241
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• 2015

This study investigated the effects of different cooking methods on contents of cholesterol, retinol, and tocopherol in poultry meats (chicken, Korean native chicken, and duck) using saponification extraction and HPLC analysis. The cooking methods were boiling, grilling, stir-frying, deep-frying, steaming, roasting, and microwaving. Generally, contents of cholesterol increased after cooking. Especially, after deep-frying, large amounts of cholesterol were detected from legs of chicken (94.25 mg/100 g) and wings of Korean native chicken (132.96 mg/100 g). High cholesterol content was detected in wings (233.77 mg/100 g) from duck after microwaving. However, contents of retinol decreased after cooking. The retinol contents of breast meat from Korean native chicken were low ($0.86{\sim}0.56{\mu}g/100g$) compared to other meats ($1.10{\sim}22.66{\mu}g/100g$ in chicken and $1.96{\sim}36.80{\mu}g/100g$ in duck), whereas raw materials from wings of all poultry showed the highest tocopherol contents. Of the various cooking methods, stir-frying and deep-frying resulted in increased ${\alpha}$-tocopherol contents in meats.