• Journal of Nutrition and Health
• /
• v.14 no.4
• /
• pp.175-181
• /
• 1981

This study was carried out to investigate the feasibility of production of soy yogurt, which is inexpensive and high protein product with an acceptable flavor, from soy milk using lactic acid bacteria. Utilization of various carbohydrates by Lactobacillus acidophilus, Streptococcus thermophilus and Lactobacillus bulgaricus was stuied. Sucrose, the major carbohydrate in soymilk, was fermented by L. acidophilus and S. thermophilus. None of the testing microorganisms was able to ferment melibiose and raffinose. Growth of lactic acid bacteria in soymilk was examined every 4 hour. L. acidophilus exhibited the highest growth rate during the early stage. After 16 hours of incubation, however, all the cultures with the exception of L. bulgaricus grew at nearly equal rates. Microscopic examination of mixed cultures showed that the presence of S. thermophilus was much more pronounced than that of L. bulgaricus. All the cultures with the exception of L. bulgaricus formed acid rapidly during 16 hours of incubation, bringing the titratable acidity to 0.6% and pH to 4.3, which was sufficient to cause coagulation of soymilk. L. bulgaricus produced acid to a much lesser extent and caused coagulation of soymitk after 30 hours at earliest. Three kinds of yogurts were prepared from 100% soymilk, 100% milk and 50% soy-50% milk combination by S. thermophilus and were evaluated by taste panel. Soy yogurt received a significantly lower mean odor score than milk yogurt. Soy yogurt had custardlike texture, while milk yogurt was syrupy. However the scores for texture as well as those for color and flavor did not differ significantly among the treatment. The mean total scores for yogurts were not significantly different and were equivalent to ratings between good and high fair.

• Korean Journal of Medicinal Crop Science
• /
• v.8 no.3
• /
• pp.194-200
• /
• 2000

The main objective of this study was to characterize physico-chemical properties, sensory property and oxidative stability of safflower seed obtained by various roasting temperature and time. The contents of water soluble solids decreased in the higher roasting temperature and time. Sensory evaluation of safflower seed roasted in various conditions showed significant differences in taste, color, flavor and palatability. The safflower seed roasted at $190^{\circ}C$ for 20min had the best palatability. At the change of Hunter's values, L values were decreased, and a, b and ${\Delta}E$ values were increased in the higher roasting temperature and time. The content of free sugars such as sucrose and raffinose were reduced significantly in higher roasting time of $190^{\circ}C$ and $210^{\circ}C$. During the storage period after roasting treatment, peroxide values (POV) were highly increased after eight months at the all treatment except for $150^{\circ}C$. Therefore, it is inadequate over eight months after roasting treatment.

• Korean Journal of Food Science and Technology
• /
• v.32 no.4
• /
• pp.881-888
• /
• 2000

Lactic acid bacteria(LAB) fermented food was prepared with milk or egg white powder(EWP) and added with freeze drying protectant(FDP). 0.2% of Tween 80 or 1% of ascorbate was added to milk sample and 3% of raffinose or 1% of ascorbate was added to EWP sample. Effects of FDP on sensory property, volatile aroma compounds and physical property of LAB fermented food were investigated. In case of non-freeze dried samples, sensory properties of milk sample with ascorbate were slightly better than those of reference sample(milk), while sensory properties of EWP sample or EWP sample with FDP were slightly inferior to reference sample. Sensory properties of all of the freeze dried/reconstituted samples were not different. Sensory properties of milk sample with ascorbate were reduced by freeze drying/reconstitution, while those of sample with ascorbate were not changed. Although all of the volatile aroma compounds were reduced by freeze drying, the residual ratio was slightly different between milk samples and EWP samples. Difference in volatile aroma compounds between milk samples and EWP samples before freeze drying was relatively large, while difference between two sample groups after freeze drying/reconstitution was relatively small. Rheological properties of milk samples were markedly changed by freeze drying/reconstitution, while those of EWP samples were changed slightly.

• Journal of Life Science
• /
• v.27 no.3
• /
• pp.339-345
• /
• 2017

Carotenoids are natural lipid-soluble pigments, which are produced primarily by bacteria, algae, and plants. Many studies have focused on the identification, production, and utilization of natural sources of astaxanthin from algae, yeast, and crustacean byproducts as an alternative to the synthetic pigment, which is mostly used today. The aim of the present study was to identify a mutant of Paracoccus haeundaensis by exposure to UV and ethyl methanesulfonate (EMS). The mutant was then exposed to nutrient stress conditions to isolate an astaxanthin-hyperproducing strain, followed by characterization of the mutant. The survival rate decreased in accordance with an increase in the UV exposure time and an increase in the EMS concentration. A mutant of the original P. haeundaensis strain was identified that showed hyperproduction of astaxanthin following exposure to UV irradiation (20 min) and EMS treatment (0.4 M concentration). The optimal culture conditions for the PUE mutant were $25^{\circ}C$, pH 7-8, and 3% NaCl. The effects of various carbon and nitrogen sources on the growth and astaxanthin production of PUE were examined. The addition of 1% raffinose and 3% potassium nitrate influenced cell growth and astaxanthin production. The selected mutant exhibited an increase of 1.58 folds in astaxanthin content compared to initial wild type strain. A genetically stable mutant strain obtained using mutagen (UV irradiation and EMS treatment) may be a suitable candidate for further industrial scale production of astaxanthin.

• Korean Journal of Food Science and Technology
• /
• v.26 no.3
• /
• pp.336-342
• /
• 1994

Changes in physicochemical characteristics were investigated for immature barley kernels roasted at $160{\sim}220^{\circ}C$ for $1{\sim}12$ min. Only small differences in chemical constituents including starch, protein, fat, ash, total dietary fiber, and ${\beta}-glucan were observed between immature and mature barley kernels. The amounts of 75% ethanol-soluble sugars and amino acids present in immature barley kernels were considerably higher than those in mature kernels, and gradually decreased in the process of roasting. Of free sugars, sucrose, raffinose, glucodifructose($GF_{2}$) and maltose were reduced by roasting. Glucose and fructose, simple reducing sugars, decreased at the early stage of roasting, followed by a slight increase at the later stage. Starch and nitrogen contents decreased slowly, while TDF(total dietary fiber) had a tendency to increase slightly. Stacking volume of immature barley kernels increased markedly, especially at the higher temperatures. L value of immature barley decreased throughout roasting, and a, b values increased at the early stage of roasting but b value decreased with continued roasting. The degree of roasting was strongly affected by the roasting temperature. Darkness of immature barley kernel, depending on the degree of roasting, was highly associated with concentrations of brown pigments extracted from roasted immature barley kernels.

• Applied Biological Chemistry
• /
• v.14 no.1
• /
• pp.43-50
• /
• 1971

Measuring the changes of free amino acids, organic acids, free sugars, for after-ripening of the peel of hot pepper, the writer has obtained the following results; 1. Glutamine, asparagine, and glutamic acid as free amino acid of hot pepper are rich, while the total amount of free amino acids is greatly decreased through after-ripening. 2. The major organic acids of hot pepper is malic acid and citric acid, and their total amount comes to 80% of the total acid through the whole after-ripening period. Malic acid, however, is greatly decreased while citric acid is increased through after-ripening. And in the course of after-ripening the total amount of acid is decreasing, particularly with a sharp decrease in the post-cli. stage. 3. As free sugar in hot pepper, glucose is the major one, fructose, galactose and sucrose are identified, and existence of raffinose is presumed. Through after-ripening the total amount of free sugar is decreased about 25% in the post-cli. stage, and reducing sugars and non-reducing sugars also are decreased.

• Korean Journal of Food Science and Technology
• /
• v.39 no.6
• /
• pp.676-680
• /
• 2007

This research was conducted to investigate the changes in quality characteristics of cheonggukjang made with 24-hr germinated soybeans during fermentation. Our study confirmed that the pH of the 24-hr germinated soybeans was 6.7, and the value increased as fermentation progressed. The amount of viscous substances in the cheonggukjang produced with the 24-hr germinated soybeans constantly increased to 5.89% at 36 hr of fermentation, and then remained unchanged. Free sugars (raffinose, sucrose, glucose, and fructose) rapidly decreased with the fermentation process. The levels of free amino acids in the 24-hr germinated agakong and the 48-hr fermented cheonggukjang were 391.0 and 10,994.8 mg%, respectively. Glutamic acid content was highest, followed by aspartic acid, lysine, leucine, and proline. The ratio of glutamic acid to total free amino acids at 48-hr of fermentation was 18.0%. Finally, it was confirmed that the sensory evaluation score of the 24-36 hr fermented cheonggukjang, made with the 24-hr germinated soybeans, was superior to that of the 24 and 48-hr fermented cheonggukjang.

• Korean Journal of Food Science and Technology
• /
• v.19 no.6
• /
• pp.520-527
• /
• 1987

This study was attempted to identify microorganisms in fermenting soybean curd residues (SCR). The changes in contents of free amino acids, nucleosides, reducing sugars, and oligosaccharides were also studied. The fermentation of SCR which was by change inoculation was carried out at $55^{\circ}C$ for 48 hrs. pH increased gradually during fermentation and isolated microorganisms were identified as Bacillus subtilis and Bacillus licheniformis. Moisture content decreased from 80.8% to 58.4% at 48 hrs of fermentation and other proximate composition did not show any changes during fermentation. The content of total free amino acids increased rapidly and the number and quantities of each amino acid analyzed also increased during the course of fermentation. Glutamic acid, phenylalaine, lysine and aspartic acid were rapidly liberated during fermentation. As to the changes of nucleotides, 5'-AMP little changed during the first 36 hrs but subsequently decreased to approximately 1/6 after 48 hrs of fermentation. On the other hand, 5'-IMP plus 5'-GMP did not show almost any change during the first 36 hrs but increased about 3.5 times at 48 hrs of fermentation. However, 5'-XMP was not detected. The reducing sugar level showed rapid and steady increase throughout the fermentation and that of stachyose plus raffinose decreased slightly. From these results, a possible way of utilization of fermented SCR was proposed as a substitute for soybean in meju preparation.

• Korean Journal of Food Science and Technology
• /
• v.22 no.3
• /
• pp.241-247
• /
• 1990

In order to develop a type of instant tea cassia tora seed, changes of constiuent amounts before and after roasting $(3{\pm}0.5min\;at\;170{\pm}5^{\circ}C)$ effective extracting solvent and it's optimum concentration, dehydration method and sensory scores were investigated. Moisture, lipid, reducing sugar, emodin and rhein were decreased by roasting, whereas protein, and total sugar of cassia tora increased. Color intensity and extracting efficacy were also increased. Of three kinds of solvent (water, methanol and ethanol), ethanol was highest in redness and yellowness of exeracts, and filtrate yield. Effective extracting concentration of ethanol for cassia tora was 50%(V/V). Freeze dry product(FDP) and spary dry product(SDP) showed coffee and aloe-like smell, coffee like brown color, rapid soluble in cold and hot water, and fast caking in air during storage. Free sugar contents were high in order of raffinose>fructose >glucose>maltose>sucrose Metallic contents were high in order of sodium>calcium>potassium>magnesium>iron. In sensory score for color, taste and aroma, FDP and SDP were both above 8.0 point, however, of them FDP more or less higher than SDP In addion, score in developing value as an instant tea was above 8.0 point (valuable).

• Korean Journal of Food Science and Technology
• /
• v.19 no.6
• /
• pp.492-498
• /
• 1987

Dried soybeans (varieties: Saeal, Kwanggyo, Tanyob) took up water rapidly for first 3hr followed by a slower rate of uptake. The beans took up an equal weight of water (100% hydration)after approximately 3.5hr at $50^{\circ}C$, 5hr at $30^{\circ}C$ and 7.5hr at $20^{\circ}C$ respectively. pH of the soaking solutions decreased during the soaking period. This was undoubtedly caused by the ionization of the cellular components resulting in increased levels of hydrogen ions in the liquor. Soluble solids were leached out of the beans at fairly steady rate throughout the hydration and the amount was greater with higher temperature. This amounted to 0.4-0.7g at $20^{\circ}C$ and 10.2-15.0g at $50^{\circ}C$ per 100g soybeans. Temperature was the most important factor in determining the rate of water absorption and of solid losses. Of the total solids lost, 12-25% was protein. The proportion of protein loss increased as the soaking time and temperature increase. Amount of protein loss was 80-200mg at $20^{\circ}C$ and 440-480mg at $50^{\circ}C$ after 24hr soaking per 100g soybeans. About 5% of soluble sugars, including fructose, sucrose, raffinose, and stachyose, was removed from the beans after 24hr soaking at $20^{\circ}C$.