• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.677-681
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• 2014

The effects of toasting, simulated gimgui (dried and toasted laver) manufacturing, on lipid oxidation and antioxidant and pigment contents of dried laver (Porphyra spp.) were evaluated by peroxide value (POV) and conjugated dienoic acid (CDA) value measurement, HPLC, and spectrophotometry. Dried laver was toasted for 40 or 300 s at $120^{\circ}C$, or for 2 or 5 s at $250^{\circ}C$. The POV and CDA contents were significantly higher in the toasted samples (0.60-0.69 mmol/kg and 2.17-4.20%, respectively) except in samples toasted at $120^{\circ}C$ for 40 s, compared to those in the non-toasted samples (0.43 mmol/kg and 1.21%, respectively). Chlorophyll was the most stable pigment during toasting (>90% retention), followed by carotenoids (50-77% retention) and phycocyanins and phycoerythrins (13-73% retention). Porphyran was the most stable antioxidant (>95% retention), and polyphenols, the most unstable antioxidant (24-75% retention). Despite the degradation of pigments and antioxidants during toasting, the dried laver still contained health-benefiting components after toasting.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.711-718
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• 2011

Effects of heating conditions and seed roasting on the lipid oxidation and antioxidants of perilla seeds were studied. Perilla seeds, that were unroasted or roasted at $180^{\circ}C$ for 20 min, were ground and heated over steam at $100^{\circ}C/1$ atm or at $135^{\circ}C/2$ atm. Lipid oxidation was evaluated by peroxide value, conjugated dienoic acids contents, and fatty acid composition. Tocopherols and polyphenols were also determined. Lipid oxidation of perilla seeds was higher during heating at $135^{\circ}C/2$ atm than at $100^{\circ}C/1$ atm, and the oxidation rate was lower in unroasted seeds than in roasted seeds. Degradation of tocopherols and polyphenols in perilla seeds during heating was faster under high pressure and temperature, and was decreased by seed roasting. Contribution of polyphenols to the oxidative stability of perilla seeds during heating was higher than that of tocopherols, suggesting polyphenols and seed roasting as important factors in lipid oxidation of perilla seeds.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.680-685
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• 2012

The effects of chlorophyll (0.33 mg/kg) and ${\beta}$-carotene (3.3, 9.9, 19.8 mg/kg) addition to a mixture of roasted perilla seeds, rice, and water (30:45:225, w/w/w) on the lipid oxidation and tocopherol contents were studied during heating at $100^{\circ}C$ for 120 min to simulate cooking of perilla and rice porridge. Lipid oxidation was evaluated with peroxide values (POV) and conjugated dienoic acid (CDA) values, and chlorophyll, ${\beta}$-carotene, and tocopherols were determined by HPLC, POV, and CDA values were increased during heating, indicating the occurrence of lipid oxidation in the perilla and rice porridge. ${\beta}$-Carotene decreased the POV and CDA values of the samples in a concentration-dependent manner, while the addition of chlorophyll did not affect them. Chlorophyll and ${\beta}$-carotene which were added, and tocopherols naturally present in samples were degraded, following the first order kinetics during heating, and ${\beta}$-carotene protected tocopherols from degradation.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.399-403
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• 2006

The effect of flour storage conditions on the lipid oxidation of fried products during storage was studied. Wheat flour was stored at $60^{\circ}C$ in the dark and at water activity (Aw) of 0.3, 0.5, or 0.8 for 21 days. The square-shaped dough ($2{\times}2{\times}0.1\;cm$) made with the stored flour and water was fried in soybean oil at $160^{\circ}C$ for 1 min. The fried products were stored at $60^{\circ}C$ for 15 days in the dark. The degree of lipid oxidation of the fried products was evaluated by conjugated dienoic acid (CDA) content and p-anisidine value (PAV). Both CDA content and PAV of the fried products increased with lengthening storage time of the fried products, suggesting that longer storage of the fried products raised the lipid oxidation. Furthermore, the lipid oxidation of the fried products made with flour that had been stored for a longer time tended to be higher than that of those made with unstored or short-term-stored flour. However, Aw at which the flour was stored did not significantly affect the lipid oxidation of either flour or the fried products during storage. The storage time of flour clearly exerted a greater effect than Aw on the lipid oxidation of the fried products during storage at $60^{\circ}C$ in the dark. This suggests that for the storage stability of fried products, the flour storage time is a more important factor than Aw at which the flour is stored.

• Food Science and Preservation
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• v.30 no.2
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• pp.334-346
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• 2023

The antioxidant ability of 80% ethanolic extract of nutmeg seed (NM80) was evaluated using in vitro assays and bulk oil and oil-in-water (O/W) emulsion matrices. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging, and oxygen radical antioxidant capacity (ORAC) in vitro assays were used to evaluate the antioxidant ability of the extract. The DPPH radical scavenging activities of 25, 50, 100, and 200 ㎍/mL NM80 were 12.5, 20.9, 35.1, and 62.8%, respectively, while the ABTS cation radical scavenging activities were 2.7, 6.5, 30.5, and 29.8%, respectively, demonstrating a dose-dependent effect. The ORAC value was significantly higher at an NM80 concentration of 25 ㎍/mL than the positive control (p<0.05). The conjugated dienoic acid (CDA), ρ-anisidine, and tertiary butyl alcohol values in 90-min-heated corn oil containing 200 ppm of NM80 were significantly reduced by 3.26, 16.94, and 17.34%, respectively, compared to those for the sample without NM80 (p<0.05). However, the headspace oxygen content and CDA value in the O/W emulsion containing 200 ppm of NM80 at 60℃ had 6.29 and 82.85% lower values, respectively, than those for the sample without NM80 (p<0.05). The major volatile compounds of NM80 were allyl phenoxyacetate, eugenol acetate, and eugenol. NM80 could be an effective natural antioxidant in lipid-rich foods in bulk oil or O/W emulsion matrix.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.409-414
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• 1995

Antioxidative characteristics of dihydroxyphenylalalnine(DOPA), melanin and enzymatic oxidation products of tyrosine(EOPTs) were studied in a model system. EOPTs were prepared by the tyrosine-tyrosinase reaction at pH 6.5 and $25^{\circ}C$ at various time intervals(0~120min). All EOPTs were brown in varied intensities with increased absorption at 200~210, 280, 310~320nm, and 450~490nm. EOPTs obtaiend at the early stage of the reaction(1~3min especially) showed a higher antioxidative activity than those from the later stage on the inhibition of peroxide, conjugated dienoic acid and malonaldehyde formations in linoleic acid autoxidation. Additionally among the substances of tyrosine, DOPA and melanin, DOPA showed the highest antioxidative activity while that of tyrosine was the lowest during the linoleic acid autooxidation. It was observed that DOPA and melanin had the ability of free radical scavenging, which may party contribute to their antioxidative activity.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1213-1220
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• 2000

The mutagenicity of the thermally oxidized soybean oils was investigated. Each oil sample was taken after 0, 8, 16, 24, 32, 40, and 48 hours of heating at a temperature of $180{\pm}3^{\circ}C$, and was used to study the changes of peroxide value(POV), acid value(AV), iodine value(IV), conjugated dienoic acid content(CDA content, %), and fatty acid composition. Another set of samples was fractionated into non-oxidized and oxidized fractions by column chromatography using silica gel. The mutagenicity of the samples taken from the thermally oxidized oils as well as the non-oxidized and oxidized fractions was investigated with the Ames test. Bacterial tester strains used in the present study were the histidine auxotrophic strains of S. typhimurium TA100, TA1535 and TA 102 for the detection of base pair, and TA98 and TA1537 for frame shift mutations. Each set of samples was dissolved in tetrahydrofuran and tested at doses ranging from 0.05 to 5 mg/plate. The oxidized fractions increased significantly the number of $His^+$ revertant colonies of TA100, TA1537 and TA102, thereby showed mutagenic activity on these strains. However none of the oil samples taken within the 48 hours oxidation period showed any mutagenic activity with and without metabolic activation.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.995-1000
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• 2004

Nutritional composition and antioxidative capacity of mulberry fruit (Ficus-4x) were investigated for evaluation as new red-colored fruit. Contents of moisture, crude fat, crude protein, and vitamin C were similar, whereas that of crude ash was higher, to those of other berry fruits. Contents of minerals (Ca, 14.33 mg/100 g; P, 39.98 mg/100 g; Fe, 6.01 mg/100 g; Zn, 4.04 mg/100 g; Mn, 2.26 mg/100 g), particularly Fe, were higher than those of other berry fruits. Hardness, springness, cohesiveness, gumminess, and chewiness of mulberry fruit were higher, and color values (L, 36.03; a, 1.80; b, 1.54) were lower than those of strawberry. Relative scavenging activities of mulberry fruit methanol extract and its cyanidine 3-glucoside on 1, 1-diphenyl-2-picrylhydrazy radical (DPPH) were 35.7 and 78.2%, respectively, using butylated hydroxyanisole (BHA) as standard. Antioxidant activities in corn oil (peroxide values and conjugated dienoic acid) were tertiary butylhydroquinone (TBHQ) > mulberry fruit ethanol extract > mulberry fruit water extract > butylated hydroxytoluene (BHT) > tocopherol. Results show mulberry fruit can be very useful red-colored fruit for development of functional foods with beneficial effects on radical scavenging and antioxidative capacities.