• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.589-594
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• 2007

The effect of synergists having chelating ability on inhibiting browning were studied with a giucose-glutamic acid model for doenjang containing citric acid as the anti-browning agent and iron ion. The model solutions were prepared by dissolving 0.1 M glucose, 0.1 M glutamic acid, 50 mM citric acid, 0.2 mM $FeCl_2$ and synergist in 1 M phosphate buffer (pH 7.0), heating at $50^{\circ}C$ for 24 hr and storing at $30^{\circ}C\;or\;40^{\circ}C$ for four weeks. Synergists were chitosan, gallic acid, methyl benzoate, pyrophosphate and tannic acid; they were used at the following concentrations: gallic acid, pyrophosphate and tannic acid at 0.015% and 0.15%; chitosan and methyl benzoate at 0.0075% and 0.015%. Anti-browning capacities had a tendency to decrease greatly after three weeks in the case of storage at $30^{\circ}C$, whereas they decreased with storage time during storage at $40^{\circ}C$. However, anti-browning capacities of samples containing 0.015% tannic acid and 0.15% pyrophosphate were higher than that of sample without synergist by 32% after storage at $30^{\circ}C$ for four weeks. Gallic acid, tannic acid and pyrophsphate also inhibited the formation of Maillard reaction intermediates such as fluorescent compound and 3-deoxyglucosone due to the high chelating ability with iron ion after four weeks of storage at $30^{\circ}C$. The effect of these compounds on the inhibition of formation of Maillard reaction intermediates was higher at 0.15% than at 0.015%. Moreover, gallic acid increased the browning by forming colored complexes, and tannic acid generated black precipitates. Therefore, pyrophosphate of food additives was found to be the most useful synergist of citric acid, the anti-browning agent for doenjang.

• Food Science and Preservation
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• v.7 no.4
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• pp.409-413
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• 2000

Previously, the methanolic extracts of thirty Korean medicinal plant seeds were screened for tyrosinase inhibitors using a rapid and simple TLC method, which was superior to a conventional spectrophotometrical in vitro assay. As a result, the methanolic extracts of Thuja orientalis seeds was found to have strong tyrosinase inhibitory activity. To isolate active tyrosinase inhibitors, the seeds were defatted with n-hexane under reflux, and then extracted twice with methanol under reflux at 90$^{\circ}C$. The methanolic extract was evaporated to a small volumn in vacuo, and then successively fractionated with ether, ethyl acetate and n-butanol. The ether extract showing significant tyrosinase inhibitory activity was solubilized with 5% NaHCO$_3$and then acidified with 6N HCI. The ether souble acidic fraction was successively ohromatographed on silica gel, Sephadex LH-20 and preparative TLC. Among four compounds isolated, two of them showed stronger tyrosinase inhibitory activity, comparable to that of L-ascorbic acid (IC$\sub$50/=28$\mu\textrm{g}$/$m\ell$). These results suggest that Thuja orientalis seeds may be useful as potential sources of antibrowning agents in fruits and vegetables, and anti-melanoma agents in cosmetics and phamaceuticals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.792-799
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• 2013

This study was designed to develop natural browning inhibitors. The anti-browning effects of distilled water (SBD) and 80% ethanol extracts (SBE) of Scutellaria baicalensis Georgi in apple slices were investigated by L and ${\Delta}E$ values. Both SBD and SBE were effective in reducing the browning of apple slices and were successively fractionated into chloroform ($CHCl_3$), ethyl acetate (EtOAc), and water ($H_2O$) fractions. These extracts were measured for total phenolic content, flavonoid content, anti-oxidative activity (through free radical scavenging activity and the FRAP assay), ferrous ion chelation, and the inhibition of PPO (polyphenol oxidase) activity. Overall, fractions of SBE were better than fractions of SBD in all measurements. The highest total phenolic and flavonoid content were measured in the EtOAc and $CHCl_3$ fractions of SBE. EtOAc and $CHCl_3$ fractions also exhibited the highest anti-oxidative activities (in DPPH and ABTS free radical scavenging and the FRAP assay). Unusually, the highest ferrous ion chelating capacity was found in the $H_2O$ fraction of SBD, but the other fractions showed more than triple the ascorbic acid already in use. Also, $CHCl_3$ fractions showed a stronger inhibition of PPO activity than ascorbic acid. All of these results suggest that EtOAc and $CHCl_3$ fractions from Scutellaria baicalensis can be used as natural anti-browning agents.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.291-297
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• 2000

Oleoresin was extracted from fresh garlic by microwave-assisted extraction (MAE) and its functionality and antibrowning effect were investigated at various extraction conditions. The yield and polyphenol contents of the garlic oleoresin were inversely related to extraction time. The highest yield was l2.9% and maximum polyphenol contents was 574.3 mg% when the oleoresin was extracted for 5 min with ethanol. Apparently, the electron donating abilities of garlic oleoresin increased with extraction time, but there were no significant differences among extraction time intervals. The highest nitrite scavenging effect was found at pH 1.2 and decreased as pH increased. Tyrosinase inhibitory effect was less than 30% for most garlic oleoresin but the 15 minute extraction with ethanol resulted in higher inhibitory effect. Angiotensin I-converting enzyme (ACE) inhibitory effect was highest (89.2%) when oleoresin extracted with ethanol for 20 min. The addition of cysteine, ascorbic acid and citric acid to oleoresin extracts retarded browning action of garlic oleoresin during 10 day storage. 0.1 % cysteine retarded browning reaction and some synergistic effect was found in the combination of citric acid and ascorbic acid.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.43-50
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• 2002

To develop commercial semi-solid apple baby food, the physicochemical characteristics of apple puree in relation to different preparing methods and the effect of the addition methods of ascorbic acid on browning reaction were investigated. The preparing methods were classified into 3 groups by initial heating treatment: no heating (A), steaming at $120^{\circ}C$ (B), and blancing at $100^{\circ}C$ (C). The viscosity of tested apple puree was $2,600{\sim}5,856\;cp$, and contents of anhydrogalaturonic acid (AGA) and neutral sugar ranged $4.15{\sim}11.92\;mg%$ and $6.18{\sim}10.65\;mg%$, respectively. Among free sugars tested, level of fructose was the highest $(5.43{\sim}8.87%)$, followed by glucose $(2.11{\sim}4.23%)$, sucrose $(1.64{\sim}2.94%)$, in that order. Since small amounts of ascorbic acid were detected $(1.54{\sim}1.83\;mg%)$, it seemed to be lost by heating process in preparing of apple puree. For apple puree A, its lightness was lower and redness was higher than those of apple puree B and C. Its degree of browning of apple puree was so high that sodium ascorbic acid was added as a antibrowning agent. Puree had low sensory score and nutrient quality. The adding methods of ascorbic acid were classified into 4 groups by adding time: dipping, blending (2), heating (3), and blending + heating (4). Considering color and preference evaluation, preparing method B and adding method 2 showed the highest inhibitory activity on apple puree browning and desirable color for retort baby food. After retort sterilization, the viscosity of apple baby food was decreased from 3,477 cp to 2,294 cp, thiamin was destroyed completely, and the contents of riboflavin and ascorbic acid were decreased 41% and 21%, respectively. However, contents of free sugar and free amino acid and sensory parameter were not influenced by retort sterilization. In overall, the preparing method B-adding method 2 was a good processing condition for the retort apple baby food.

• Korean journal of food and cookery science
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• v.21 no.1 s.85
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• pp.24-32
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• 2005

Changes in apple slices during cold storage were investigated by evaluating the physical properties such as degree of browning and compression force. Chemical properties such as PPO activity and total phenol contents were also determined and sensory evaluation was carried out. The correlation analysis between browning parameters was conducted. Degree of browning was increased in the order of fresh apple slice, water-dipped apple slice, $0.5\%$ ascorbic acid solution-dipped apple slice and CP(caramelization product) from sucrose-dipped apple slice. PPO activity was increased in the order of fresh apple slice, water-dipped apple slice, $0.5\%$ ascorbic acid solution-dipped apple slice and CP(caramelization product) from sucrose-dipped apple slice. Amongst several treatments, CP from sucrose-dipped apple slice showed the lowest degree of browning and PPO activity. Total phenol contents were decreased from 60 to 56.2 mg and from 59.6 to 56.0 mg in fresh apple slice and water-dipped apple slice, respectively, but CP from sucrose-dipped apple slice and $0.5\%$ ascorbic acid solution-dipped apple slice were increased from 51.9 to 52.8 mg and from 54.1 to 54.4 mg, respectively, showing the smallest changes when compared with fresh apple slice and water-dipped apple slice. Compression forces of apple slices during cold storage were decreased in the order of fresh apple slice, water-dipped apple slice, $0.5\%$ ascorbic acid solution-dipped apple slice and CP from sucrose-dipped apple slice. In sensory evaluation of apple slices during cold storage, CP from sucrose-dipped apple slice had higher score than the other treatments. In addition, a significant correlation was observed among degree of browning, PPO activity and phenol content. Therefore, CP from sucrose-dipped apple slice seems to be effective in controlling of enzymatic browning during cold storage. In addition, CP from sucrose-dipped apple slice seems to be effective on other several factors. These results suggest that CP from sucrose should be a potential source for controlling enzymatic browning during storage of vegetables and fruits.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.834-844
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• 2014

Postharvest browning of mushroom (Agaricus bisporus) reduces the shelf life of harvested mushrooms. Here, mushrooms were dipped in various solutions (distilled water; DW, 0.25% rice bran extract; RB, 0.1% ascorbic acid; AA, RB + AA) for 3 min. After air-drying at room temperature, the dipped mushrooms were packaged in a polypropylene (PP) films and stored at 4 or $15^{\circ}C$. The quality changes of mushrooms were measured in terms of color, gas composition, firmness, and sensory evaluation during storage. Rice bran extract was measured for total polyphenol content, total flavonoid content, DPPH, ABTS radical scavenging, chelating activity and PPO inhibition activity. No difference in firmness were found in the mushroom samples regardless of dipping solution or storage temperature. At both 4 and $15^{\circ}C$ storage temperatures, RB + AA solution-dipped samples showed the highest L value and lowest delta E value. During the storage period, sensory evaluation showed that overall acceptability of mushrooms treated with RB and RB + AA solution was higher than that of the untreated mushrooms. Total polyphenol and flavonoid contents of 0.25% rice bran extract were $36.42mg\;GAE{\cdot}g^{-1}$ and $4.85mg\;QE{\cdot}g^{-1}$, respectively. The DPPH and ABTS radical scavenging activity of 0.1% ascorbic acid was higher than that of 0.25% rice bran extract. The highest copper ($Cu^{2+}$) chelating activity was found in the 0.25% rice bran extract. The PPO inhibition activity of 0.1% ascorbic acid was higher than that of 0.25% rice bran extract. Our results suggest that 0.25% rice bran extract with 0.1% ascorbic acid is effective anti-browning agent for maintaining quality of Agaricus bisporus during storage.