• Korean Journal of Food Science and Technology
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• v.5 no.2
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• pp.84-88
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• 1973

The antioxidant activity of some extracts from various stages of a Mailard type browning reaction mixture, a 0.2 M glucose + 0.2 M glycine solution heated at $100^{\circ}C$, was determined, using edible soybean oil as a substrate. The activity was compared with the length of reaction times, and also with the intensity of color of the reaction mixture at various stages. The absorbance, at $490\;m{\mu}$, of the reaction mixture appeared to increase almost in proportion to the length of the reaction times. All the extracts from the reaction mixture exhibited considerable antioxidant activity. However, unlike the Absorbance of the reaction mixture, the antioxidant activity of the extracts from the reaction mixture did not appear to increase in proportion to the length of the reaction times. The activity of the extract from the reaction mixture heated for 30 hours was indeed greater than that of the extract from the reaction mixture heated for 2 hours, but the difference of the activity was not so great as one might expect. The results appear to indicate that most of effective antioxidative compounds formed during the Mailard type browning reaction could not be brown-colored pigments formed during the reaction.

• Korean Journal of Food Science and Technology
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• v.10 no.3
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• pp.350-355
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• 1978

An attempt was made to compare the antioxidant activity of ethanol extracts of a glucose-ammonia (0.2 M+0.2 M) browning mixture with that of the corresponding glucose-glycine mixture, in soybean oil substrates, on the basis of peroxide value (POV), thiobarbituric acid value (TBA-value) and acid value (AV) development. Absorbances, at 470 nm, of the former mixture after 2 and 5 hour browning were 1.88 and 3.42 while those of the latter mixture were 0.02 and 0.07. The POVs of the supstrates containing the extracts taken after 2, 15, and 40 hrs from the former mixture were 15.8, 14.2, and 12.6 after 30 day storage at $42.3{\pm}2.6^{\circ}C$. Those of the latter mixture were 17.4, 16.1, and that of the control was 82.1. TBA and acid value developnent followed similar trends. These results indicated that the antioxidant activity of the extracts of the glucose-ammonia mixture was slightly stronger than that of the glucose-glycine mixture. They also suggested that effective antioxidants had already been formed in the earlier stages of the glucose-anmonia mixture, and that brown-pigments formed did not contribute significantly to the activity of the mixture.

• Korean Journal of Food Science and Technology
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• v.18 no.5
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• pp.376-381
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• 1986

A hypothesis that Korean home-made fermented soybean products are brown-pigmented in large part by contaminated bacteria is proposed. Twenty six strains of bacteria forming brown pigments in the presence of L-tyrosine were isolated from home-made soybean paste. They were characterized and all were identified as strains of Bacillus subtilis. The isolates produced dark brown to brownish black pigmentation on yeast extract-peptone-glucose agar (YPGA) supplemented with 0.1% L-tyrosine in 72 hours but not on YPGA. They also caused different depress of lighter pigmentation on potato dextrose agar and nutrient agar. When an arbitrarily chosen pigmenting isolate was cultivated in a liquid medium supplemented with L-tyrosine, it began to produce pigments only after cell growth stopped. The tyrosinase enzyme was extracted and the enzyme activity was measured by using L-tyrosine and 3-hydroxytyrosine (L-dopa) as substrates. The crude enzyme preparation porduced pigments at rates of $2.1\;{\times}\;10^{-3}\;and\;5.0\;{\times}\;10^{-3}$ optical density units/min measured at 490㎚ for tyrosine and dopa, respectively. Possible content of L-tyrosine in a soybean paste formula was calculated.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.457-463
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• 2018

Various health benefits of turmeric have been reported. Therefore, an innovative application of turmeric as a functional food was explored. In the current study, effects of an extrusion process on the chemical properties and antioxidant activities of turmeric were investigated. Extrusion of turmeric was performed at $150^{\circ}C$ using screw revolution speeds of 500, 1,000, 1,300, and 1,600 rpm. A significant reduction in turmeric pigments and the formation of browning compounds occurred due to the extrusion. The degradation of pigments was proportional to the increase in screw speed. Infusion yields were significantly increased after the extrusion. The content of proteins and polyphenols, as well as the content of flavonoids in infusions and EtOH extracts were significantly reduced by the extrusion. Scavenging activities of turmeric against DPPH and ABTS radicals were also significantly reduced following the extrusion. These results indicate that the extrusion process caused a significant loss of pigments and decreased the antioxidant activities of turmeric. Therefore, further study related to the development of a proper extrusion process is to be needed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.109-116
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• 1984

In order to assess the protein nutritional quality of salted and dried yellow corvenia, which was prepared using the different salting methods like dry and brine salting, the changes of trypsin indigestible substrate(TI) and in vitro apparent protein digestibility were studied during storage at room temperature($24{\pm}1^{\circ}C$). It was also examined the retention of available lysine and formation of nonenzymatic brown pigments under the same conditions of preparing and storage mentioned above and confirmed the relationship between in vitro digestibility and the antinutritional factors, such as nonenzymatic browning, unavailability of lysine and TI content, TI content was gradually increased during the storage and in showed $1.5{\sim}2$ times more after 57 days storage than at the initial stage which ranged from 0.11 to 0.17mg/g solid. Of all the products, $25\%$ brine salting product contained the least TI content in 0.21 mg/g solid, while $10\%$ dry salting products was the most abundant in 0.30 mg/g solid using Hamerstrand method(1981). In vitro protein digestibility of all dried products was decreased significantly up to 30 days as the contents of TI increased, except $25\%$ brine salted products. After storing for 57 days, the in vitro digestibility was only $4\%$ drip showed in $25\%$ brine salted products. The nonenzymatic brown pigments were also developed on the level of available lysine reduced as in vitro protein digestibility was decreased throughout storage. Of all the various salted and dried products of yellow corvenia, $25\%$ salting product showed the lowest rate of browning development and loss of available lysine. Therefore, it was revealed that unavailability of lysine and development of nonenzymatic brown pigments were major factors influencing the protein quality in salted and dried yellow corvenia.

• Korean Journal of Food Science and Technology
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• v.7 no.1
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• pp.37-42
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• 1975

The color intensity (Absorbance at 490nm) and the antioxidant effects of absolute and 90% ethanol extracts obtained from a Maillard-type browning reaction mixture (0. 5M glucose and 0. 5M glycine mixture, heated at $100^{\circ}C$) were determined. The color intensity of the absolute and 90% ethanol extracts were compared with the length of reaction time and the antioxidant effects of the extracts of both types were compared one another. The results obtained are as follows. 1. The color intensity of the absolute ethanol extracts remained almost unchanged as the browning reaction proceeded. The color intensity of the 90% ethanol extracts appeared to increase nearly in proportion to the length of reaction time. 2. The absolute and the 90% ethanol extracts seemed to possess significant antioxidant activity on the autoxidation of an edible soybean oil. which was kept at $45{\pm}0.5^{\circ}C$ for 21 days. It was noteworthy that the absolute ethanol extracts showed stronger antioxidant effects than those of the 90% ethanol extracts, which contained a far greater amount of brown-colored pigments. Since the PVs of the controls in both groups, after the end of the storage period, did not differ much from one another, the possibility of residual water playing some prooxidant role in the substrates containing the 90% ethanol extracts should be ruled out. Extracts of both types obtained at earlier stages of the brownig reaction demonstrated less but comparable antioxidant activity to that of extracts taken at later stages of the reaction. 3. The results of the present study appeared to suggest that the effective antioxidant compounds, produced in the Maillard-type browning reaction, were probably intermediate products such as reductones formed at fairly earlier stages of the browning reaction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.10-16
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• 1997

To confirm the possibility of seaweed extracts for functional food, water or ethyl alcohol solubles were extracted from laver, Porphyra yezoensis and evaluated those food components such as proteins, carbohydrates, nucleic acids, taurine, pigments and browning extent. The amount of proteins, polysaccharides and nucleic acids extracted decreased with increasing ethyl alcohol concentration, which was maximal when water was used as extraction solvent. The extractability of proteins, polysaccharides and nucleic acids was different between the dried and the roasted laver. Taurine was extracted about 1% from the dried and the roasted laver in the range of o~7o% ethyl alcohol concentration. The amount of carotenoids extracted by 95% ethyl alcohol from the dried and the roasted laver were 146.6 and 138.4mg%, respectively, which was 66 ~ 80% of yield extracted by methanol/acetone(1/1) solvent. The browning value of 50 ~6o% ethyl alcohol extraction group from roasted laver was highest among water/ethyl alcohol extraction group. The extraction yield was maximum when laver was extracted with water, and the value was 26.3% for the dried laver and 27.5% for the roasted layer. Organoleptic characteristics from four kinds of extraction groups containing hot water extraction showed that extracts from the roasted laver were evaluated most eminent and thought to be applicable to various preparation of food.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.179-185
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• 2009

Soybean grits, fortified with various bioactive components, were produced by solid-state fermentation using Bacillus subtilis HA. ${\alpha}$-Amylase activity gradually increased during fermentation over 5 days. Fibrinolytic and protease activities were highest in the soybean grits fermented for 7 days. The grits fermented for 5 days also showed the highest tyrosine content, indicating a higher peptide content. Peptides of low molecular weight (below 3,000 daltons) and browning pigments increased with increasing fermentation time. The fermented soybean grits showed higher contents of total phenolic compounds, to approximately 18 mg/g. DPPH free radical scavenging effects were higher in the soybean grits fermented for 3 days. Also, ABTS radical scavenging effects were greater in the fermented grits compared to the unfermented grits. Overall, the soybean grits fermented by solid-state fermentation for 5 days showed enhanced production of bioactive compounds and greater antioxidant properties.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.808-811
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• 2001

Performance of pilot plant scale extraction and concentration of purple-fleshed sweet potato anthocyanin pigment was tested and the characteristics of pigment extracts and concentrates were investigated. Fifty kilograms of purple-fleshed sweet potato was extracted with 500 L of 1% citric acid in 20% ethanol. As a whole, extraction pattern of the large scale extraction was similar to that of the laboratory scale extraction. The extracted pigment solution was filtered twice with a bag filter and a winding type microfilter and the filtrate was concentrated by a large scale vacuum evaporator at $40^{\circ}C$ and 600 mmHg vac. The mean values of total optical density (TOD) of the extract and the concentrate were 6.53 and 120.45, respectively. Browning index (BI) and Degradation index (DI) of extract were 5.86 and 1.55 and those of concentrate were 5.89 and 1.56, respectively, which indicated that the pigments were not changed or degraded through the extraction and concentration process.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1149-1157
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• 2000

To confirm the factors concerning color changes of traditional kochujang, heating, U.V. and $N_2$ gas substitution treatment were conducted on duk(rice cake) kochujang and shikhae(malt digested syrup) kochujang. The value of L, a and b value by Hunter of each kochujang were gradually decreased during fermentation and ${\delta}E$ increased. The ${\delta}E$ value of duk kochujang treated by U.V. was higher than those of the other treatments and non heated shikhae kochujang showed higher ${\delta}E$ value. The main cause of color change by factor analysis on various factors of duk kochujang and shikhae kochujang were light, and light and heat respectively. The acetone and water extracted pigments had maximum absorbance at 450-470 nm and 200-205 nm respectively.