• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.313-323
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• 1980

The objective of this experiment was to improve the quality and shortening the aging time of Kochujang by adding mixed starter cultures of yeast strains. Kochujangs were mashed during the summer season with mixed starter cultures of Saccharomyces rouxii, Torulopsis versatilis and Torulopsis etchellsii. Enzyme activities and chemical composition of the Kochujang were determined during the period of aging and their organoleptic values were tested. The maximum activities of liquefying amylase and saccharogenic amylase in the Kochujang were obtained during 20 to 60 days and 20 to 30 days after mashing respectively. The acidic protease activity was reached maximum during 20 to 40 days. All enzyme activities were decreased markedly during the final stage of aging period. Among mixed starter cultures tested, mixed culture of T. versatilis and T. etchellsii shows the highest liquefying and saccharogenic amylase activities. Ethyl alcohol contents in 10 days after mashing were highest in the Kochujang with S. rouxii and T. versatilis, followed in order of S. rouxii and T. etchellsii mixture, T. versatilis and T. etchellsii mixture and control without addition of yeast. But the contents in all sample became similar after 20 days with the level of 2.3 to 2.8% and then decreased gradually. The level of reducing sugar contents was markedly increased during the first 10 days, especially in the batches of T. versatilis and T. etchellsii mixture and control. However, the concentration became similar in all samples after 40 days. The contents of amino nitrogen were increased markedly during the first 10 days then slowly up to 90 days. The rate was high in the Kochujang with T. versatilis and T. etchellsii when compared with others. The organoleptic values of all Kochujang made with addition of yeast starter cultures were superior to control, especially in flavor, taste and color. The Kochujang with T. versatilis and T. etchellsii marked the highest value. The data obtained from this experiment suggests that the quality of Kochujang could be improved by using starter culture of suitable yeast strains according to product characteristics and aging time.

• The Korean Journal of Mycology
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• v.10 no.2
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• pp.75-83
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• 1982

As a primary study for cell growth and alcohol production of a cider yeast, Saccharomyces sp. R-11, cultural and nutritional characteristics of the strain were investigated. The results obtained were as follows: The optimum culture medium for this strain was a synthetic medium, Henneberg B, and sucrose was the best carbon source for yeast growth and alcohol production. Optimum sugar concentrations for yeast growth and alcohol production were 15% and 25%, respectively. Optimum pH and temperature of the basal medium for growth of this strain were 4.5 and $30^{\circ}C$ respectively. The yeast growth was enhanced by the addition of 100 ppm of $Mg^{2+}$, but significantly inhibited by the addition of 100 ppm of $Co^{2+}$. Lower temperature and maintenance of optimum pH for yeast growth increased the final alcohol concentration. Under optimum condition for cell growth at stationary culture, generation time and specific growth rate of the strain were 7.5 hr and 0.092 $hr^{-1}$, respectively. At 8% initial alcohol concentration, yeast growth was inhibited about 50% and this strain could not be grown at more than 12% initial alcohol. The strain could be grown at less than 125ppm $SO_2$without alcohol addition, and at less than 75 ppm $SO_2$ with 8% initial alcohol. The higher sulfur dioxide concentration of a medium, the longer lag phase in yeast growth was observed. This strain could induced alcoholic fermentation at less than 10% initial alcohol concentration with 0 and 25 ppm $SO_2$, at less than 8% initial alcohol with 50 and 75 ppm $SO_2$, and at less than 6% initial alcohol with 100 and 125 ppm $SO_2$.

• Food Science and Preservation
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• v.18 no.4
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• pp.559-566
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• 2011

In this study, the good brewing conditions for the 24 $^{\circ}Brix$ freeze-concentrated apple wine were investigated. The four selected Saccharomyces cerevisiae strains MM10, SS89, SS812, and WW108, could ferment quickly when brewed with high sugar levels. During the fermentation, the reducing sugar contents slowly declined while the total acid in all the yeasts increased and the final alcohol content was 12-13%, a typical wine's alcohol content. The viable counts were shown to be 6-6.8 log cfu/ml. During the fermentation, the organic acid content was shown to be within the range of 2.36-3.11%, and the free sugar content, except for the SS89 and WW108 strains, was shown to consist only of sorbitol, although fructose was somewhat detected in the SS89 and WW108 strains. Methanol was not detected, or only a trace of it was detected, and the aldehyde content was 107.68-114.27 ppm. As for the fusel oil contents, a trace of propanol was detected. Isobutanol and butanol were present in 40.16-54.65 and 25.47-27.73 ppm, respectively. The isoamy1 alcohol content was shown to be the highest (108.88-217.26 ppm). The final total phenolic compounds were shown to be 0.1-0.16%. The final Hue values were shown to be 1.3-3.6, and the final intensity was 0.1-0.45. The lightness (L) was within the range of 91.78-98.51, the redness (a) was at a neutral position at red and green, and the yellowness (b) was within the range of 2.38-7.7. In the sensory evaluation, the SS812 strain was found to be the best in terms of color, the SS89 strain in terms of odor, and the WW108 strain in terms of taste. Overall, SS812 was found to be the best apple wine.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.368-373
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• 1996

Korean general medicinal herbs-sasam, gilkyung, jakyak, danggwi, hwangki, and chunkung-were added In the normal brewing procedure as a raw material or in the distilling procedure as a packing material. The distillates from the former procedure and those from the latter procedure were compared in quality and distillation properties. As distillation proceeded, pH of the medicinal herb wine distillate and the control(not added herbs) distillates were decreased, whereas that of the herb packing distillate was increased slowely of $0.05{\sim}0.97$ during $1{\sim}4$ fractions and decreased remarkably of $0.92{\sim}0.98$ afterward. Average pH was the highest of 5.70 in jakyak and lowest of 4.37 In gilkyung. Absorbances of the herb Packing distillate were decreased rapidly of $0.60{\sim}1.59$ in the $1{\sim}4$ fractions but slowely of $0.19{\sim}0.54$ in the next fractions. During distillation both fractional alcohol concentration of the distillates and distillation rate were decreased. Their values were decreased more slowly than the control. Distillation rates of medicinal herb wine distillate were varied by medicinal herb varieties and alcohol concentration of fermented wine. Danggwi and control showed the highest average distillation rate as $0.12\;m{\ell}/sec$ and gilkyung the lowest value as $0.073\;m{\ell}/sec$. Maximum concentration of index component, paeoniflorin of jakyak was observed as 293 mg% in the 5th fraction of herb packing distillate and decrusin of danggwi as 3514 mg% In the 1st fraction of herb packing distillate. The extraction rate was 41.3% for paeoniflorin and 20.5% for decrusin. From sensory evaluation, the highest overall Qualify was observed in the medicinal herb wine distillate of hwangki added wine, the next in those of danggwi and jakyak added wine.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.15-32
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• 2002

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s-1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great progress and success was obtained in development of high-quality japonica cultivars and quality evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice cultivars and special rices adaptable for food processing such as large kernel, chalky endosperm, aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer, Recently, new special rices such as extremely low-amylose dull or opaque non-glutinous endosperm mutants were developed. Also, a high-lysine rice variety was developed for higher nutritional utility. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and texture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak, hot paste and consistency viscosities of viscosities with year difference. The high-quality rice variety "IIpumbyeo" showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic microscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high probability of determination. The $\alpha$-amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were IIpumbyeo, Chucheongyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tonsil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogradation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice breed. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large grain rices showed better suitability far fermentation and brewing. The glutinous rice were classified into nine different varietal groups based on various physicochemical and structural characteristics of endosperm. There was some close associations among these grain properties and large varietal difference in suitability to various traditional food processing. Our breeding efforts on improvement of rice quality for high palatability and processing utility or value-adding products in the future should focus on not only continuous enhancement of marketing and eating qualities but also the diversification in morphological, physicochemical and nutritional characteristics of rice grain suitable for processing various value-added rice foods.ice foods.