| Summary: | 碩士 === 輔仁大學 === 食品科學系 === 101 === Deep-oil frying can provide foods with unique color, flavor and crispy texture. However, long-term of deep-frying at high temperatures may cause oil to produce toxic carbonyl compounds (CCs), which may be readily absorbed in the fried food products and are potentially carcinogenic to human. Thus, this study aimed to investigate the formation of CCs in the deep frying soybean oil and the reduction of toxic CCs in fried battered and breaded chicken breast (BBC) by adding chitosan derivatives (CDs). When soybean oil was continuously heated at 180℃ in presence of water, POV of frying oil rose to the highest values at 18 h of heating, all the TBARS, acid value and total polar compounds were increased with increases of heating time. After 24-h heating of oil, the acid value and total polar compounds of the frying oil were, respectively, 2.03 mg KOH/g oil and 28%, which had exceeded the level for replacing oil. After 12-h heating, the CCs formed in the frying oil include 2,4-decadienal, butanal, 2-butanone, haxanal, octanal, pentanal, pentanone, 2-heptenal, 2-nonenal, 4-hydroxy-2-hexenal, acrolein, propanal, acetaldehyde, 2-hexenal. All of the above 14 CCs in the soybean oil were significantly increased with increases of frying time. As Compared with 12-h heated oil, the percentage increase of CCs ranged 10.5-91.6 and 13.6-166.7% for frying oil with 18- and 24-h heating, respectively. Moreover, only the short-chain and highly water-soluble CCs, such as acetaldehyde, acrolein, propanal, butanal and pentanal were readily absorbed in the crust of fried BBC, whereas the other 9 CCs were not. The BBC with adding CDs could significantly reduce the amount of short-chain CCs in the crust, with the percentage reduction of 23.1-49.6, 10.4-56 and 23.9-66.1% for BBC fried at 180℃ in 12-, 18- and 24-h heated oil, respectively. The BBC without adding CDs could significantly reduce the hardness and adhesiveness of chicken meats after being fried in 12-h heated oil, i.e. the chicken meats had a softer texture and less adhesiveness between meat and teeth in chewing process. There were no significant difference in hardness, springiness and resilience between chicken meats of BBC with and without adding CDs. Increases of frying time and addition of CDs had no significantly effect on hardness and fracturability of crust of fried BBC. These results suggest that addition of chitosan derivatives in the batter of BBC can effectively lower the toxic carbonyl compounds absorbed in the crust of fried BBC without affecting in hardness, springiness, resilience of meat and hardness and fracturability of crust.
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