• Korean Journal of Food Science and Technology
• /
• v.30 no.2
• /
• pp.333-340
• /
• 1998

The research was investigated to determine the effect of irradiation or blanching either alone or in combination on the shelf-life of juices of Spuriopinella bracycarpar during storages. The juices was made from fresh or blanced Spuriopinella bracycarpar and gamma irradiated at the doses (0.5 kGy to 5 kGy). Microbial growth, color change, vitamin C, and sensory evaluation were evaluated during storage at 4 and $25^{\circ}C$. Blanched juices had little effect on the inhibition of microbial growth compared to that of fresh juices. However, significant reduction of microbial counts was observed in the 0.5 kGy irradiation of both juices and inhibition efficiency was greatly increased when irradiated juices was stored at $4^{\circ}C$ rather than at room temperature. Fresh juices without irradiation were little different from the irradiated fresh juices until 20d storage on color change because the juices was rapidly browned immediately after getting the juices from extractor, but blanched juices showed more bright and clear color than that of fresh juices. However, irradiated blanched juices showed greatly reduced the L, a, and b value compared to the non-irradiated blanched juices during storage. The loss of vitamin C from non-irradiated fresh juices was increased during storage and the irradiated fresh juices had little effect on the vitamin C change compared to the non-irradiated fresh juices. However, blanched juices showed less reduction of vitamin C than fresh juices and the irradiated blanched juices had little difference on the vitamin C change compared to the non-irradiated blanched juices, and both treatment showed less vitamin C loss at $4^{\circ}C$ storage. Fresh juces showed more strong grass flavor and biterness than blanched juices and irradiated fresh juices showed little difference on brightness, grass flavor, bitterness, freshness and acceptability, but irradiated blanched juices had better sensory evaluation on grass flavor, bitterness, freshness, and acceptability than non-irradiated branched juices.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.6
• /
• pp.885-891
• /
• 2011

We conducted this study to determine the optimum dose of gamma irradiation needed for the sterilization of milk porridge for patients. Milk porridge, known as Tarakjuk, was irradiated with gamma ray at doses of 0, 1, 3, 5, 7, or 10 kGy. The microbial contamination, $D_{10}$ values of isolated microbe spores, color, and viscosity were measured during storage at $35^{\circ}C$. The initial count of total aerobic bacteria was 2.60 log CFU/g in the non-irradiated milk porridge, but coliforms, spore-forming bacteria, yeast, and molds were not detected. The total counts of aerobic and spore-forming bacteria in the non-irradiated and 1 kGy irradiated milk porridge increased with storage period. These microbes were not detected in the milk porridge irradiated with 10 kGy. The $D_{10}$ values of isolated spores from milk porridge were 2.71 kGy (in milk porridge) and 2.21 kGy (in saline solution). All CIE color increased with gamma irradiation, but the sensory value of color did not significantly change. The viscosity of the milk porridge decreased with gamma irradiation and storage period, and the decrease in viscosity with storage period became smaller as the radiation doses increased. Sensory evaluation scores of the milk porridge were above normal (4.0) when irradiated with less than 5 kGy. These results indicate that gamma irradiation could be beneficial for preparing food with higher nutrient density and lower viscosity, especially for gastric tube-fed patients.

• Applied Biological Chemistry
• /
• v.13 no.1
• /
• pp.1-27
• /
• 1970

The process of the forced aging of flue-cured tobacco leaves were studied extensively from various scientific points of view. The Flue-cured tobacco leaves were inoculated and fermented with nicotine resistant Hansenula yeast, or the leaves were subjected under simple forced aging. The above two processes of forced aging were studied from the summarized points of microbiology, physics, chemistry, and biochemistry, and the resulted products ware compared in their physical, chemical and biochemical quality determining factors with that of raw material tobacco leaves (dried-tobacco leaves) and 2 years aged high quality tobacco leaves. The summary results were as follows. 1) The Korean flue-cured tobacco leaves, were forcedly aged under the basic optimum aging condition, temperature $40^{\circ}C$, moisture contents 18%, relative humidity 74%. It was found that this aging condition was the best in bringing the quality of forcedly aged tobacco leaves to the utmost state. 2) Under this optimum temperature and moisture condition of forced aging in about 20 days the forcedly aged tobacco leaves both with yeast inoculation and without yeast inoculation showed the equivalent tobacco qualities comparable with that of more than 2 years aged tobacco leaves. 3) The forcedly aged tobacco leaves both with and without yeast inoculation under $40^{\circ}C$ temperature and $74^{\circ}C$ relative humidity achieved the necessary quality determining physical and chemical changes in about 20 days. 4) The microbial changes during the forced aging were as follows. The population of yeasts and bacteria increased until to 15 days of aging, then decreased thereafter. Whereas the molds grew continously until the end of fermentation. 5) The tobacco quality determing physico-chemico-properties of yeast inoculated aged and simple forcedly aged tobacco leaves, progressed as the follows in time. As the forced aging progresses, swelling and combustibility properties were improved. The pH, total reducing materials, total sugars, alkaloids contents decreased. The contents of organic and ether extractable materials increased. The total nitrogen, protein, crude fiber, ash contents showed no changes. The color properties, excitation purity, luminance, main wave length, showed equivalent changes comparable with that of 2 years aged tobacco leaves. 6) The changes in chemical components in yeast treated and simple forcedly aged tobacco leaves during $15{\sim}20{\;}days$ of forced aging were as follows. The following chemical components decreased as the aging. Sugars-sucrose. rhamnose, glucose. Pigments-chlorophyll, carotenes, xanthophyll and violax anthine. Polyphenols-rutin, chlorogenic and, coffeic acid. Organic acids-iso-butylic, crotonic, caprylic, galacturonic, tartaric, succinic, citric acid. Alkaloids-nicotine, nornicotine. The following components increased as the forced aging progressed. Sugars-frutose, maltose, raffinose. Amino acids-proline, cystine. Organic acids-formic, acetic, propionic, n-butyric, iso-valeric, n-valeric, malic, oxalic, malonic, ${\alpha}-ketoglutaric$, fumaric, glutaric acid. 7) During the forced aging of tobacco Leaves the oxygen-uptake decreased gradually. The enzyme activities of polyphenol oxidase, ${\beta}-amylase$ ${\alpha}-amylase$ decreased gradually. The activities of the enzymes, catalase, and invertase increased once then decreased at the later stage.

• Korean journal of food and cookery science
• /
• v.21 no.6 s.90
• /
• pp.895-907
• /
• 2005

In an attempt to improve the taste and storage characteristics of Sulgidduk, a Korean traditional rice cake product, baekbokryung(White Poria cocos Wolf) powder was supplemented as one of the ingredients and Product Quality waw assessed. The baekbokryung Powder was added in rations of 0, 5, 7, 10, and $15\%$(w/w) per rice powder during the raw material preparations. The sensory, objective quality, and microbiological characteristics of the products were examined at 4-hr intervals during storage for 36 hours at $20^{\circ}C$ The sensory evaluation was conducted based on the acceptability and intensity characteristics of the product. In the acceptability test, a $5\%$ treatment wae renerally ranked with the highest score, among all the treatments while the preference differed according to ages of the panels ; namely, those in their 20's to 30's liked a $5\%$ supplementation while those in their 40's to 60's Preferred a $7\%$ one. The addition of baekbokryung Powder proportionally decreased the moisture content of the products. The colorimetric redness(a) and yellowness(b) of the Products increased with increasing added baekbokryung Powder. The redness values began to decrease slowly from the beginning while the rates were accelerated after 8 to 12 hours of the storage. In the textural characteristics, hardness, gumminess and adhesiveness values increased with increasing added baekbokryung powder. The rapid increase in adhesiveness during the initial 4 hour of storage and the following stabilization was noted. Cohesiveness and springiness values tended to decrease gradually with increasing added baekbokryung Powder. Except for the control sample, no significant differences in the total microbial counts among the treatments were noted. After 20 hours of storage, the control sample exhibited a rapid increase in total microbial count, while the Proliferations of microorganisms were rather suppressed in baekbokryung Powder treatments according to the added amounts The results of the study support the benefits of baekbokryung powder supplementation in Sulgidduk in the aspects of taste and functionality. The degree of further increase of baekbokryung Powder in Sulgidduk without causing the adverse qualify effects remains for future study.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.1
• /
• pp.58-64
• /
• 2007

Antioxidative activity and functional properties of the powder obtained from ground Opuntia ficus-indica var. saboten fruit were studied. Cupcakes containing 1,3, and 5% (w/w) of O. ficus-indica vu. saboten powders were prepared and evaluated for their sensory property, textural quality, and shelf-life. The antioxidative activity, measured by DPPH radical scavenging activity of O. ficus-indica var. saboten powder, increased as the concentrations of O. ficus-indica var. saboten powder increased. No coliform bacteria, yeasts, and molds were detected in either the O. ficus-indica var. saboten powder or in the cupcakes. However, total aerobic bacteria counts were 4.41 log CFU/g in the O. ficus-indica var. saboten powder and were a negligible level (<$10^2$ CFU/g) in the cupcakes. Moisture content of the cupcakes was not significantly different in all samples. Lightness (L) and yellowness (b) of cupcake color decreased as the concentration of O. ficus-indicar var. saboten powder increased, whereas the redness (a) increased. Increasing the concentration of O. ficus-indica var. saboten powder, the mechanical characteristics of the cupcakes, such as hardness, gumminess, and chewiness, while decreasing cohesiveness and springiness. The sensory properties, such as color, flavor, taste, texture, and overall acceptability, of the cupcakes containing the 1% 0. ficus-indica var. saboten powder were superior to the control sample. The results exhibited that the adding the O. ficus-indica var. saboten powder into the cupcakes increased antioxidant activity and showed no effect on shelf-life of the cupcakes. The highest quality improvement was obtained by incorporating the 1% (w/w) of 0. ficus-indica var. saboten powder into the cupcake formula.

• Journal of Animal Science and Technology
• /
• v.47 no.5
• /
• pp.867-876
• /
• 2005

The microbial contamination of ice cream product commercially available in Korea was determined using ice bar, ice cream, ice milk and non-milk fat ice cream. Irradiation effect on enhancement of microbiological safety was also investigated at doses of 1, 3, and 5 kGy. In all products, yeast and molds were not detected, however, total aerobic and coliform bacteria were detected at 1-2 and 1-1.5 Log CFU/g level, respectively. According to the different flavor used in ice cream, total aerobic bacteria were detected as 2.30, 2.90, and 3.32 Log CFU/g level in vanilla, chocolate, and strawberry ice cream, respectively. Yeast and mold was not detected in vanilla ice cream but 2.30 and 2.70 Log CFU/g in chocolate and strawberry ice cream, respectively. Coliforms were also detected 1-2 Log CFU/g in the ice cream with different flavors. Listeria inocua and Escherichia coli were detected from 3 commercial samples but Salmonella spp. was not detected using API kit. Gamma irradiation significantly reduced the level of the contaminated total aerobic bacteria, yeast and molds and coliform population in the ice creams. These results indicated that irradiation(5kGy or less) is effective to ensure safety of ice cream.

• Korean Journal of Food Science and Technology
• /
• v.34 no.6
• /
• pp.962-968
• /
• 2002

Effects of gamma-irradiation of 1 to 10 kGy on the microbial growth, contents of amino acids, fatty acids, and free sugars, and changes in acid values in soybean powder were studied. Irradiation doses at $3{\sim}5\;kGy$ inhibited the mold growth completely in two kinds of imported soybean powders. Contents of sulfur-containing amino acids, such as cysteine, in both soybean powders decreased with irradiation, whereas no significant changes in free amino acid and fatty acid contents of both soybean powders were observed. Free sugar contents of stachyose and sucrose in Chinese soybean powder decreased with increasing irradiation dose level, whereas, those of other sugars remained unchanged. Results of this study confirm that $3{\sim}5\;kGy$ irradiation can be safely applied to apply to soybean powder without causing significant quality deteriorations microbiologically and chemically.

• Journal of Life Science
• /
• v.34 no.5
• /
• pp.304-312
• /
• 2024

This study was conducted to characterize strain Y10, isolated from discarded chicken feathers. Strain Y10 was identified as Bacillus amyloliquefaciens through phenotypic and 16S rRNA gene analysis. B. amyloliquefaciens Y10 exhibited plant growth-promoting activities, including the production of fungal cell-degrading enzymes (cellulase, lipase, protease, and pectinase), siderophores, ammonia, and indoleacetic acid. Furthermore, strain Y10 was able to inhibit the mycelial growth of several phytopathogenic fungi. When 0.1% sucrose as a carbon source and 0.05% casein as a nitrogen source were added to the basal medium, adjusted to pH 10, and cultured at 35℃, the degradation rate of chicken feathers by strain Y10 was about two times higher than that of the basal medium, with the feathers almost completely degraded in four days. Strain Y10 also degraded various keratin substrates, including duck feathers, wool, and human nails. It was confirmed that the feather hydrolyzates prepared using strain Y10 exhibited antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (EC₅₀ = 0.38 mg/ml) and superoxide dismutase-like activity (EC₅₀ = 183.7 mg/ml). These results suggest that B. amyloliquefaciens Y10 is a potential candidate for the development of bioinoculants and feed additives applicable to the agricultural and livestock industries, as well as the microbiological treatment of keratin waste.

• Journal of the East Asian Society of Dietary Life
• /
• v.13 no.6
• /
• pp.608-614
• /
• 2003

This study was conducted to investigate the quality characteristic of bread added with 0, 2, 4 and 8% liquid calcium acetate(LCA-breads) to the dough prepared with brown rice, vinegar and ash of black snail replacing wheat flour. The pH of the dough was 5.38 in control and 5.39∼5.42 in the LCA-broads, which showed that the higher the content of LCA, the higher the pH. There was no big difference of the baking loss between control (10.73%) and LCA-breads(10.11∼10.81%). The loaf volume index was 7.12 in the control, 7.18 in the 2% LCA-bread, while the index was 6.22 in the 4% LCA-bread, 5.80 in the 8% LCA-bread. Calcium content was 16 mg% in the control, 30, 60 and 120 mg% in 2, 4 and 8% LCA-bread, respectively. The hardness, gumminess and brittleness of LCA-breads were higher, while springiness and cohesiveness were lower than that of the control. In the LCA-breads, $L^{*}$ values were lower and $b^{*}$ value was higher than those of the control, while there were no significant difference in af values. Increasing the LCA, air cells were bigger and irregular, and starch matrix was unstable. There were no significant difference in sour and bitter taste. The scores of stickiness of the 2∼4% LCA-breads were similar to that of the control and higher in the 8% LCA-bread. The scores of the flavor and overall taste in the LCA-breads were similar to the control, while the values were lower in the 4∼8% LCA-breads. The shelf-life evaluated by the number of moldy spots was not different between the control and 2% LCA-bread, while it was extended two times in 4% and three times in the 8% LCA-bread.ead.

• KSBB Journal
• /
• v.24 no.6
• /
• pp.508-514
• /
• 2009

This study investigated the production of catalase from Bul-kyo soil bacteria through fermentation process. Isolation and selection of bacteria was performed through chemical and physiological analysis. Catalases were produced from bacteria which belong to 3 different species (Bacillaceae bacterium BKBChE-1, Bacillus sp. BKBChE-2, Bacillus flexus BKBChE-3) confirmed by using 16S rDNA sequence method. The catalases were found to be stable in the temperature range of $30^{\circ}C-60^{\circ}C$ for BKBChE-1, BKBChE-2 and BKBChE-3 and also in the pH range of 9.0-12.0 for BKBChE-1 and BKBChE-3. Long-term stability of the catalases was about 20 days at $4^{\circ}C$. However, BKBChE-2 has kept its activity over 30 days at $4^{\circ}C$.