• Journal of the Korean Dietetic Association
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• v.23 no.1
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• pp.14-26
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• 2017

The purpose of this study was to determine the optimal recipe of rice cookies with two different amounts of Stevia rebaudiana leaf and grape seed oil, using a central composite design (CCD). In addition, mixing conditions of rice cookies were optimized by sensory evaluation and mechanical and physicochemical analysis using response surface methodology (RSM). RSM was used to obtain 10 experimental points (including two replicates of Stevia rebaudiana leaf and Grape seed oil), and the formulation of Stevia rebaudiana leaf added rice cookies was optimized using rheology. The results of mechanical and physicochemical analysis showed significant values for lightness, redness, yellowness, hardness, spread factor, loss rate, leavening rate, sweetness, moisture, pH, and density (P<0.001), results of the sensory evaluation showed significant values for color, flavor, taste, texture, appearance, and overall quality (P<0.05). As a results, optimal sensory ratio was found to be 1.98 g of Stevia rebaudiana leaf and 37.94 g of Grape seed oil.

• Journal of the Korean Dietetic Association
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• v.20 no.2
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• pp.77-86
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• 2014

This study was carried out to evaluate the effects of stevia (Stevia rebaudiana Bertoni) leaf powder on soybean milk quality. Soybean milk was prepared with the addition of 0.1 g (SP1), 0.2 g (SP2), 0.3 g (SP3), 0.4 g (SP4) of stevia leaf powder. The pH of soybean milk added with stevia leaf powders ranged from 7.90 to 7.98, whereas that of control was 7.88. The viscosity of soybean milk added with stevia leaf powder was 11.13~12.71 cp while that of control was 11.09 cp. Soymilk added with stevia leaf powder yielded values of Hunter L (59.40~64.94), a (-7.63~-6.45), and b (18.71~19.63), whereas that of control were 67.45, -4.74 and 20.13, respectively. There was decrease upon addition of stevia leaf powder. During storage, the pH, viscosity, L, and b values were decreased continuously. According to sensory evaluation, taste, and flavor of SP3 were better than the other groups. Quality characteristics between control and SP3 showed no significant differences. Therefore, this study showed the possibility of substituting 0.3 g of stevia leaf powder instead of sugar for creating a standard quality soybean milk with low calories. Upon the results of this study, it may be assumed that there are consequences positive responses to health-oriented consumers when using stevia leaf powder.

• Korean journal of food and cookery science
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• v.30 no.4
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• pp.419-427
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• 2014

This study was carried out to evaluate the effects of stevia leaf powder on bread quality. Different breads were prepared by the addition of 0%, 0.5%, 1.0%, 1.5% and 2.0% stevia leaf powder to wheat flour. The weight of the breads containing stevia leaf powder ranged from 525.0~543.5 g, while that of the control was 548.8 g. The volume of the breads prepared by adding stevia leaf powder was 2225.0~2278.8 mL, while that of the control was 2307.5 mL. The height and specific volume of the breads decreased with the addition of stevia leaf powder. The Hunter L values of the breads also decreased, whereas a and b values increased with the addition of stevia leaf powder. The L and b values of the bread decreased continuously during storage. The hardness, springiness, cohesiveness and chewiness all increased with the addition of stevia leaf powder. Overall the acceptability and taste determined by sensory evaluation of the bread with 1.5% stevia leaf powder were better than that of the control.

• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.151-154
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• 2003

This study was conducted to determine the optimal concentrations of plant hormones (2,4-D, picloram, dicamba, NAA, kinetin) and the suitable explants among seeds, hypocotyl, and cotyledons on calls formation and plant regeneration of stevia(Stevia rebaudiana Bertoni). The frequency of cellus formation was higher in the young leaf-explants then the older ones, and in the seeds then the hypocotyls and cotyledons on MS medium with 1mg/L 2,4-D. After transfer of seed-derived stevia callus producing embryogenic callus on plant-regeneration medium, the frequency of plant regeneration from callus was 23.8% in MS medium with 1mg/L NAA and 3mg/L kinetin.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.201-209
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• 2021

Agarwood (Aquilaria spp) has high economic value. However, essential oil production from agarwood is a time-consuming process. Additionally, agarwood leaves have not been utilized even though they contain various bioactive ingredients. In this study, agarwood leaves were fermented using Lactobacillus plantarum ATCC 8014 with or without Stevia (4, 8, and 12%; v/v). The fermented fluid was mixed with maltodextrin (15%; w/v) and subjected to spray drying (inlet temperature, 120℃; outlet temperature, 65-70℃). The contents of polyphenols, polysaccharides, saponins, and flavonoids and the viability of L. plantarum were determined. Fermentation enhanced the levels of bioactive compounds. The contents of polyphenol (69.19 ± 4.05 mg GAE/g of sample), polysaccharide (20.75 ± 0.98 mg GE/g of sample), saponin (305.23 ± 4.21 mg OAE/g of sample), and flavonoid (7.86 ± 0.72 mg QE/g of sample), and the viability of L. plantarum (8.72 ± 0.17 log CFU/ml) were markedly upregulated in the samples containing Stevia (12%; v/v). This indicated that the supplementation of Stevia during fermentation decreases the fermentation time (9 h), upregulates bioactive compound production in agarwood leaves, enhances microencapsulation during spray drying, and increases the viability of L. plantarum under simulated gastric digestion conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.6 no.1
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• pp.55-59
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• 1977

The consumption of sugar in our diet increased so great that much U. S. dollars are spended to import sugar source from foreign contries. To replace a part of it we adopted mother plant and seeds of the well-known Stevia (Stevia rebaudiana Bertoni M.) originated from south America, from the Agricultural Experimental Station of Hokkaido, Japan, in 1974. In order to determine the growth condition of Stevia in our climate and soil condition, the results of survey and determination were as follows: 1. Germination rate of Stevia was averaged 33.6% at 35 th day after seedling and the maximum germination period was between 5 and 20 days after seedling. 2. The seedling rate of Stevia was about 8%. 3. Establishment of roots of Stevia propagated by cutting method was above 90% but only S-1 strain showed lower rate., 75%. 4. S-2 strain showed the best growth rate that was about 160cm by plant height and it was decreased by the following order : S-4, S-3, S-1, S-6 and S-5 strains. 5. S-4 strain resulted in 45 branches that was the highest number among strains tested and S-2 strain was the next. 6. The content of sweetening compound of Stevia, stevioside, was 5.3% in S-1, S-2, S-5 and S-4 strains but S-3 and $S^*$-6 strains were relatively low content, 4.9%. From the above results we obtained Stevia could be propagated by cutting method and the growth conditions including plant height, number of branches and content of stevioside were relatively better in S-2 and S-4 strains that were differentiated by the shape of leaf.

• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.156-163
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• 2014

In order to develop tea by using the leaves of stevia, which is a herbal plant, and to solve the disadvantages of stevia dried leaf tea, we have manufactured the steamed tea, stir-fried tea and fermented tea by changing the manufacturing processes. As a result of the sensory tests, the steamed tea, stir-fried tea and fermented tea received higher evaluations than the dried leaf tea. In terms of efficiency, it is desired that the total number of steaming and stir-frying is only once, but the fermentation is found to be the most desirable for 2 days. There are no trends for changes in the general ingredients, mineral and free amino acid contents of stevia leaf teas by different manufacturing processes. As a result for the measurement of antioxidant activities, the steamed tea and dried leaf tea did not show significant differences, but the stir-fried tea and the fermented tea show significantly low antioxidant activities as compared to the steamed tea. The contents of stevioside in both the stir-fried tea and the fermented tea were less than that in the dried leaf tea, but in the steamed tea, there was no significant difference in the content of stevioside. Base on the present observations, this study supports high potentials of steaming process in order to produce new stevia leaf tea.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.189-197
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• 2012

This study was carried out to develop the improved useful mutants for yield or composition of stevia plants using the gamma ray or chemical mutagens treatments. The seeds of stevia 'Suwon No. 11' were irradiated up to 400 Gy of gamma ray. Chemical mutagens were treated on the seeds of the 'Suwon No. 11' using 0.07% colchicine, 10 mM sodium azide, or 10 mM NMU for various durations. The germination rate, and shoot and root growth of seedling were estimated at 30 days after gamma ray irradiation or chemical mutagen treatment, and the plant height, the number of branches, and leaf length and width were examined at 3 months after mutagenesis treatments. In the case of gamma ray treatments, the germination rate and early-stage growth were decreased as the increase of radiation dose, and the 50% lethal dose was found to be 200 Gy. the plant height was decreased as the increase of radiation dose, while the number of branches per plant and leaf length were increased. Leaf shape was modified to the relatively longer one compared to the control, which was identified more apparently at the treatments of higher than 150 Gy. In the treatment of chemical mutagens, the rate of germination and survival were decreased as the increase of incubation time. The 50% lethal dose for germination rate were identified as the conditions of the 15 hours incubation in 0.07% colchicine, the 4 hrs in 10 mM sodium azide, and the 2 hrs in 10 mM NMU, in the three chemical mutagens treatments. Chemical mutagens had no influence on shoot growth, while root growth was increased, especially as the incubation time was extended. The highest root growth occurred in the NMU treatment at 6 hrs incubation time. The plant height was decreased as the increase of incubation time in the chemical mutagens treatments. Among the chemical mutagens, NMU was the most effective to induce the mutants with long-shaped or the least lobed leaves.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.69-89
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• 1981

Stevia (Stevia rebaudiana Bertoni) is a perennial herb widely distributed in the mountainous area of Paraguay. It belongs to the family Compositae and contains 6 to 12 percent stevioside in the leaves. Stevioside is a glucoside having similar sweetening character to surgar and the degree of sweetness is approximately 300 times of sugar. Since Korea does not produce any sugar crops, and the synthetic sweetenings are potentially hazardous for health, it is rather urgent to develop an economical new sweetener. Consequently, the current experiments are conducted to establish cultural practices of stevia, a new sweetening herbs, introduced into Korea in 1973 and the results are summarized as followings: 1. Days from transplanting of cuttings to the flower bud formation of 6 stevia lines were similar among daylengths of 8, 10 and 12 hours, but it was much greater at daylengths of 14 or 24 hour and varietal differences were noticable. All lines were photosensitive, but a line, 77013, was the most sensitive and 77067 and Suweon 2 were less sensitive to daylength. 2. Critical daylength of all lines seemed to be approximately 12 hours. Growth of plants was severely retarded at daylengths less than 12 hours. 3. Cutting were responded to short daylength before rooting. Number of days from transplanting to flower bud formation of 40-day old cuttings in the nursery bed was 20 days and it was delayed as duration of nursery were shorter. 4. Number of days from emergence to flower bud formation was shortest at short day treatment from 20 days after emergence. It was became longer as initiation of short day treatment was earlier or later than 20 days. 5. Plant height, number of branches, and top dry weight of stevia were reduced as cutting date was delayed from March 20 to May 20. The highest yield of dry leaf was obtained at nursery duration of 40-50 days in march 20 cutting, 30-40 days in April 20 cutting, and 30 days in May 20 cutting. 6. An asymptotic relationship was observed between plant population and leaf dry weight. Yield of dry leaf increased rapidly as plant population increased from 5,000 to 10,000 plants/10a with a reduced increasing rate from 10,000 to 20,000 plants/l0a, and levelled off at the plant population higher than 20,000 plants/l0a. 7. Stevia was adaptable in Suweon, Chengju, Mokpo and Jeju and drought was one of the main factors reducing yield of dry leaf. Yield of dry leaf was reduced significantly (approximately 30%) at June 20 transplanting compared to optimum transplanting. 8. Yield of dry leaf was higher in a vinyl house compared to unprotected control at long daylength or natural daylength except at short day treatment at March 20. Higher temperature ill a vinyl house does not have benefital effects at April 20 transplanting. 9. The highest content of stevioside was noted at the upper leaves of the plant but the lowest was measured at the plant parts of 20cm above ground. Leaf dry weight and stevioside yield was mainly contributed by the plant parts of 60 to 120cm above ground but the varietal differences were also significant. 10. Delayed harvest by the time of flower bud formation increased leaf dry weight remarkably. However, there were insignificant changes of yield as harvests were made at any time after flower bud formation. Content of stevioside was highest at the time of flower bud formation and earlier or later harvest than this time was low in its content. The optimum harvesting time determined by leaf dry weight and stevioside content was the periods from flower bud formation to right before flowering that would be the period from September 10 to September 15 in Suweon area. 11. Stevioside and rebaudioside content in the leaves of Stevia varieties were ranged from 5.4% to 14.3% and 1.5% to 8.3% respectively. However, no definit relationships between stevioside and rebaudioside were observed in these particular experiments.

• Food Science and Preservation
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• v.14 no.5
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• pp.497-503
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• 2007

In order to develop a new rice bran danmooji, changes in physicochemical characteristics and texture of danmooji treated with rice bran, Stevia rebaudiana Bertoni leaf powder, succinic acid, or yeast extract were investigated during salting for 90 days. The PH of rice bran danmooji decreased from PH6.41 initially to pH 4.09 (control group), pH 4.10 (S. rebaudiana treatment S1), pH 3.84 (S. rebaudiana + succinic acid treatment S2), and pH 3.90 (S. rebaudiana+succinic acid+yeast extract treatment S3) after 90 days of salting. At this time, the salinities of rice bran danmooji of the S1, S52, and S3 groups were 2.32%, 1.94% and 2.15% respectively. The hardness of all groups decreased rapidly in the first 30 days of salting, and thereafter showed no changes. After 90 days of salting, the hardness of all groups was $1,186-1,368\;g/cm^2$ with no significant differences between groups. Redness, the a value, of the S2 and S3 groups treated with succinic acid, was lower than that of S3, whereas yellowness, the b value, of S3 treated with succinic acid and yeast extract was the highest of the three groups. Sensory evaluation of rice bran danmooji after 90 days of salting resulted in S3 attaining the highest scores for flavor, taste, texture, and overall acceptability. These results indicate nut high-quality rice bran danmooji may be prepared by addition of S. rebaudiana leaf powder, succinic acid and yeast extract to rice bran.