• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.201-206
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• 1998

The antibrowning effcts of cysteine, citric acid and ascorbic acid on the browning reaction of enzymatic garlic hydrolyzate were investigated at 37$^{\circ}C$ for 12 days. Cysteine was the most effective antibrowning agent followed by citric acid. The antibrowning effects of cysteine and citric acid were greater as concentrations increased, and the optimal concentration of both cysteine and citric acid as antibrowning agents was 0.3%. Ascorbic acid itself contributed to the browning reaction and showed an accelerating effect as the concentration increased. The addition of 0.1% ascorbic acid as synergist either to 0.3% cysteine or 0.3% citric acid did not enhance significantly the antibrowning effect of cysteine or citric acid. When stored at 3$0^{\circ}C$, 4$0^{\circ}C$ and 5$0^{\circ}C$, the browning reaction was accelerated as the temperature increased, especially at 5$0^{\circ}C$. Even though the effects of citric acid and cysteine as inhibitors on the browning reaction decreased as temperature increased, cysteine was more effective in decreasing browning reaction than citric acid.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.454-458
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• 2002

The effect of antibrowning agents such as PVPP (polyvinylpolypyrrolidone), bentonite, gelatin, celite 545, tannic acid and sodium sulfite in apple concentrate was investigated for the control of enzymatic browning by comparing physicochemical properties (pH, color, turbidity), polyphenoloxidase activity and contents of polyphenol compounds. In color value, apple concentrate containing PVPP showed higher L value (lightness) than control and other antibrowning agents. The turbidity (absorbance at 660 nm) of apple concentrate added PVPP, gelatin celite 545, tannic acid and sodim sulfite were 0.003, 0.038, 0.018 and 0.022, respectively. PVPP was regarded to remove suspended solids effectively. Polyphenoloxidase activity and polyphenolics(catechol, catechin, chlorogenic acid, epicatechin) content of apple concentrate used PVPP significantly reduced. Therefore PVPP was proved to be effective for enzymatic antibrowning agent considering to color, turbidity, polyphenoloxidase activity and polyphenol compounds in apple concentrate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.529-534
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• 1996

Using cystine, ascorbic acid and citric acid, retarding and synergistic effect on the browning reaction of onion juice concentrate was evaluated. Cysteine retarded the browning reaction most effectively followed by citric acid ; on the contrary, ascorbic acid accelerated rather than retarded the reaction at the concentration of 0.1%. The retarding effect of cysteine increased abruptly up to concentration of 0.3% and remained unchanged. Citric acid acted more effectively than ascorbic acid in terms of synergism. The browning reaction of onion juice concentrate exhibited activation energies of 62J/mol with cysteine and citric acid as compared to 73J/mol for control. $Q_{10}$ was determined to be 2.52 and 2.38 for control, 2.2 and 2.09 for treatment in the temperature range of 30~4$0^{\circ}C$ and 40~5$0^{\circ}C$, respectively.

• Food Science and Preservation
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• v.18 no.4
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• pp.584-589
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• 2011

This study was conducted to investigate the effects of Taraxacum platycarpum and Chrysanthemum indicum extracts on the browning of apple slices. The inhibition of the PPO activities, total phenolic contents, and DPPH free-radical-scavenging activities was measured from water and from the 80% EtOH extracts of Taraxacum platycarpum and Chrysanthemum indicum as natural antibrowning agents. Apples were cut into 15-mm-thick slices, and each slice was dipped for 1 min in different treatment solutions (1% Taraxacum platycarpum and Chrysanthemum indicum extracts, 1% citric acid) and was stored at room temperature. The inhibition of the PPO activity in the Chrysanthemumin indicum extract was better than that in the Taraxacum platycarpum extract. The highest DPPH free-radical-scavenging activity (76.10%) was found in the 80% EtOH extract of Chrysanthemum indicum. After 24 h, the ${\Delta}E$ value of the apple slices that were treated in the 80% EtOH extract of Chrysanthemum indicum was at the lowest level (2.22). The total phenolic content was 94.07 mg/g, and the total flavonoid content was 102.60 mg/g, in the 80% EtOH extract of Chrysanthemum indicum. The antibrowning effect of Chrysanthemum indicum was higher than that of Taraxacum platycarpum in the apple slices.

• Food Science and Preservation
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• v.17 no.1
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• pp.160-164
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• 2010

Chemical methods using browning inhibitors have been used to control the browning of chopped garlic. However, consumer demand for natural products is increasing, and we therefore investigated the antibrowning effect of natural licorice root extract on chopped garlic. We used a combination of licorice extract and citric acid. Chopped garlic was exposed to citric acid and licorice extract at various levels and L values were measured during storage at $10^{\circ}C$. Licorice extract was effective as an initial antibrowning, and a mixture of licorice extract and citric acid was effective in inhibition of browning during storage. The effective mixing ratio of licorice extract and citric acid was 5:5 and 2:8. This indicates that licorice extract and citric acid synergistically act to inhibit browning of chopped garlic. Licorice extracts with higher levels of glycyrrhizin were more effective as antibrowning agents for chopped garlic.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.20-24
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• 2007

The effects of phenolic acids on inhibition of browning by the Maillard reaction were investigated with a glucose-glutamic acid model for doenjang with citric acid as the antibrowning agent and phenolic acid as its synergist. Five phenolic acids, cinnamic, coumaric, caffeic, hydroxybenzoic, and protocatechuic acids, were used. In order to investigate the antibrowning capacity, 0.1M glucose, 0.1M glutamic acid, 50mM citric acid, and 1mM phenolic acid were dissolved in 1M phosphate buffer (pH 7.0), heated at $50^{\circ}C$ for 24hr in the presence of 0.2mM $FeCl_{2}$, and stored at $4^{\circ}C$ or $30^{\circ}C$ for four weeks. Phenolic acid addition more efficiently inhibited browning during storage at $30^{\circ}C$ than at $4^{\circ}C$, without changes in pH. Hydroxybenzoic acid was the most efficient and increased the antibrowning capacity by 13% compared to sample without phenolic acids. Although caffeic and protocatechuic acids inhibited most the formation of 3-deoxyglucosone or fluorescence, they increased browning by forming colored complexes between two hydroxy groups of phenolic acids and iron ions. Hydroxybenzoic acid will be able to be a useful synergist of citric acid, an antibrowning agent in doenjang, since it is permitted for doenjang.

• Food Science and Preservation
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• v.8 no.4
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• pp.385-392
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• 2001

This study was to investigate the inhibiting effect of electrolyzed oxidizing (EO) water with/without freezing point depressing agents on polyphenol oxidase (PPO) activity of peeled chestnut. 0.85% sodium chloride, 0.5% citron and 0.5% lemon juice were used to freezing point depressing agents. The content of total phenolics was 13.36 mg% at the earlier stage of storage, and then suddenly increased at around 8∼1ldays. At the 11th day, PPO activity of untreated chestnut was 1,152 units, that was higher than any ethers. EO water adding lemon and citron juice showed synergistic effects on the enzyme inhibition, and their PPD activities were 143.3 and 180.22 units after 4 weeks, respectively. Sensory analysis showed that acceptance of peeled chestnuts was dependent on color and taste, which was related to PPO activity and sweetness. The peeled chestnut treated with EO water added citron or lemon juice tended to show the highest score fur acceptance.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1417-1422
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• 2009

This study was conducted to investigate the effect of ultrasound with ascorbic acid on the quality of fresh-cut apples. Prepared apple cubes were dipped in distilled water (US) or in 1% ascorbic acid solution (AS), both were treated with ultrasound at 40 kHz, while the other sample was just dipped in 1% ascorbic acid solution for 1 min (AA). All samples were stored at $4^{\circ}C$ for 12 days. AS treatment had an effect on apple cube color as indicated by its significantly higher L values and lower ${\Delta}E$ value whereas AA- and US-treated samples showed a considerable browning. Higher inhibition rate on browning and polyphenol oxidase (PPO) activity of 46 and 98%, respectively, were observed after AS treatment. The highest total phenolic content of AS-treated samples was shown during whole storage periods. This investigation revealed that the use of ultrasound in combination with ascorbic acid had a positive effect on quality maintaining of fresh-cut apples.

• Food Science and Preservation
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• v.4 no.2
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• pp.147-153
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• 1997

Oriental melon has been increased in production amount, but its processed food was not made in spite of the fact that shelf-life of the fresh fruit is short. This study was carried out to develop a dried product with no use sulfur treatment. Fresh melons were peeled, cut into 6 pieces, and soaked to the following pretreatments soaking in sugar syrup(SS), sodium chloride(SC), ascorbic acid(AA) and sodium polyphosphate(SP). After preatreatments the melon pieces were dried by hot air drying at 5$0^{\circ}C$ for 9 and 12 hours, and the dried melons were air blown at $25^{\circ}C$ for 1 day. The dried samples were evaluated for moisture content, texture, rotor, and sensory quality. The moisture content of dried melons soaked in SS and SC were lower than those that were soaked in AA and SP after hot air drying. The melons dried for 12 hours were high in hardness, gumminess, chewness and adhesiveness and excellent in sensory evaluation compared to 9 hours. The "L" value of SS was higher and the "a" value was lower in Hunter color. And SS treatment inhibited browning of the dried melon and improved sensory characteristics in color, flavor, texture and taste. Sucrose concentration had no significant effect on color, hardness and sensory score in banal product. The combination of SS with SP represented a highly effective antibrowning treatment for the dried melon and the product was kept in good color for 3 months at room temperature.at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1419-1425
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• 2004

This study was performed to examine in vitro antioxidative activities such as DPPH radical scavenging activity, reducing power and tyrosinase inhibitory effect of various solvent fractions from Chionanthus retusa leaves. Ethyl acetate fraction showed potent antioxidative activity and tyrosinase inhibitory effect. The active compound was isolated from the butanol fraction by silica gel column chromatography and MPLC. The isolated compound was luteolin-4'-O-glucoside determined by $^1H$, $^{13}C$-NMR and 2D NMR. Compared with several antioxidant compounds, luteolin-4'-O-glucoside exhibited effective DPPH radical scavenging activity and reducing power in a concentration dependent manner. Bioassay with pure luteolin-4'-O-glucoside showed a dose-independent inhibitory effect on L-DOPA oxidation by mushroom tyrosinase and its $IC_{50}$ values were established as 23.2 ${\mu}g/mL$. Therefore, we may suggest that luteolin-4'-O-glucoside can be used as a food additive possessing the potent antioxidative activity and skin-whitening cosmetic material.