• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1149-1156
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• 2017

We investigated the quality characteristics and the antioxidant efficacy of roasted maize tea according to different moisture contents (9% to 14%) using the puffing system (PS) and the roasting system (RS). Compared with the RS, the PS caused higher turbidity (0.017 vs. 0.003 in PS-14% vs. RS-14%), brown color intensity (0.170 vs. 0.059 in PS-14% vs. RS-14%), a-values (0.20 vs. -0.44 in PS-14% vs. RS-14%), b-values (7.90 vs. 5.57 in PS-14% vs. RS-14%), and a lower L-value (19.67 vs. 21.03 in PS-14% vs. RS-14%). Total polyphenol and flavonoid contents of roasted maize tea were increased along with the moisture content and they were higher with the PS (polyphenol; 5.95 mg GAE/g, flavonoids; 1.27 CE/g in PS-14%) than with the RS (polyphenol; 5.39 mg GAE/g, flavonoids; 1.12 mg CE/g in RS-14%). The DPPH and ABTS radical scavenging effects of roasted maize tea were also increased along with the moisture content, and the scavenging efficacy was significantly higher with the PS (DPPH; 160 mg TE/100g, ABTS; 507 mg TE/100g in PS-14%) compared with the RS (DPPH; 120 mg TE/100g, ABTS; 362 mg TE/100g in RS-14%). The polyphenol levels were significantly correlated with turbidity, brown color intensity, and L, a, and b-values of the roasted maize tea. In addition, an increase of the total polyphenol content in roasted maize tea induced antioxidant activities. As a result, an increase in polyphenols during the roasting process induced antioxidant activities which could prevent damage from free radicals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1316-1326
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• 2017

We evaluated the proximate compositions of raw materials, total polyphenols, total flavonoids, and radical scavenging activities of roasted maize tea according to cultivation period and variety. Proximate compositions of raw materials were significantly different according to cultivation period and variety, and quality characteristics of roasted maize tea extracts were significantly different according to cultivation period. Total polyphenols, total flavonoids, and radical scavenging activities of roasted maize tea were significantly different before and after roasting. The total polyphenol content of Pyeonggangok cultivar sown on April 5th was elevated about 3.60-fold before and after roasting by $3.42{\pm}0.16$ and $12.22{\pm}0.67mg$ gallic acid equivalents/g, respectively. Overall, total polyphenol content was higher in roasted maize tea produced using maize sown on April 5th. 1,1-Diphenyl-2-picrylhydrazyl radical scavenging activity of Gangdaok cultivar sown on April 5th was elevated about 31.6-fold before and after roasting by $7.61{\pm}1.93$ and $240.37{\pm}8.82mg$ Trolox equivalents (TE)/g, respectively. 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity of Pyeonggangok cultivar sown on April 5th was elevated about 5.5-fold before and after roasting by $153.84{\pm}1.32$ and $843.54{\pm}3.64mg$ TE/g, respectively. The correlation between proximate compositions of raw materials and quality as well as antioxidant characteristics of roasted maize tea showed overall significance.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.10a
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• pp.184-184
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• 2017