방사선 조사 주요 농산품의 휘발성 유기성분 변화와 식품포장재의 방사선 유도산물에 관한 연구

Abstract

This study was performed to find the effect of γ-irradiation on the volatile organic compounds in agricultural products and food packaging materials which have been consumed.

I. Analysis of volatile organic compounds in agricultural products

● The volatile organic compounds in agricultural products such as dried red pepper, carrot, Welsh onion and chinese pepper were extracted by simultaneous distillation and extraction (SDE) method and identified by GC and GC/MS analysis.

● Sixty one compounds were identified in dried red pepper, including 21 hydrocarbons (46.14%), 13 aldehydes (28.94%), 7 ketones (7.45%), 2 esters (4.65%), 4 N-containing compounds (3.65%), 6 alcohols (3.40%), 6 furans (3.05%) and 2 miscellaneous (2.72%). Major compounds were furfural, benzaldehyde, nerolidol, α-curcumene and 4-hydroxy-β-ionone.

● Forty seven compounds were identified in dried carrot and the major compounds were identified β-caryophyllene, α-patchoulene, α-selinene, α-humulene, caryophyllene oxide and eugenol. Terpenoids contributed on characteristic flavor of dried carrot.

● Twenty six compounds were identified and 17 S-containing compounds (87.93%) were detected as a major constituents of dried Welsh onion. The major compounds were dipropyl trisulfide and 1-propanethiol. (E)-Propenyl propyl disulfide, 3,5-diethyl-1,2,4-trithiolane, (Z)-propenyl propyl disulfide, propylene sulfide and methly propyl trisulfide were also identified.

● Sixty compounds were identified in dried Chinese pepper, including 4 acids (36.50%), 2 ether (35.69%), 13 aldehydes (10.74%), 13 alcohols (5.82%), 13 hydrocarbons (5.05%), 4 esters (3.13%), 6 ketones (2.45%) and 4 miscellaneous (0.62%). The major compounds were estragole, hexanoic acid, heptanoic acid, octanoic acid and nonanoic acid. Among them, estragole was found as the predominantly abundant component of dreid Chinese pepper.

II. Analysis of change of volatile organic compounds in agricultural products by γ- irradiation

● The volatile organic compounds from non- and irradiated agricultural products with doses of 3, 5, 10 and 20 kGy using 60Co were extracted by simultaneous steam distillation and extraction (SDE) method, and identified with GC/MS analysis.

● In dried red pepper, the types of volatile organic compounds in irradiated samples were similar to those of non- irradiated sample and the concentrations of these compounds differed between treatments. 1,3-Bis [1,1-dimethylethyl]-benzene was identified only in irradiated samples. The concentration of this compound increased with increase of irradiation dose level.

● In dried carrot, sesquiterpene hydrocarbons were detected as a major constituent of dried carrot. The types of volatile organic compounds in irradiated dried carrot were similar to those of non-irradiated sample, but the concentrations of these compounds differed between treatments. Interestingly, 1,3-bis [1,1-dimethylethyl]-benzene, a characteristic compound, was detected in only irradiated samples.

● In dried Welsh onion, the several S-containing compounds (methyl propyl disulfide, (Z)-propenyl methyl disulfide, (E)-propenyl methyl disulfide, dimethyl trisulfide, methyl propyl trisulfide and 2,4-dimethyl thiophene) were highly induced at 20 kGy of irradiation. This result suggests that application of γ-irradiation at 20 kGy did not bring any significant lose in total content of volatile organic compounds of dried Welsh onion.

● In dried chinese pepper, ether (estragole) constituted one of the main functional groups in the volatile organic compounds of sancho. Some of compounds were highly increased at low doses and started to decrease as irradiation doses increased, while some were highly increased at high irradiation doses. The response of compounds to irradiation was found to be variable.

● In this part, effects of γ-irradiation on the volatile organic compounds in agricultural products were determined by analyzing changes of volatile composition. The composition of volatile organic compounds were little changed, but few specific compounds induced by γ-irradiation were identified. Also, 1,3-bis[1,1-dimethylethyl]-benzene was identified only in irradiated samples (red pepper, carrot and Welsh onion). The variations of concentration in irradiated samples identified in this study could be due to the radiation sensitivity of compounds with the dose used.

III. Volatile organic compounds of irradiated food packaging materials ● Several research results about the effect of food irradiation have been reported, but any research about the irradiation of the food packaging materials has not been conducted in Korea. Therefore, we need to study about the volatile organic compounds from irradiated food packaging materials (Polyethylene, polyethylene terephthalate, polypropylene and polystyrene)

● In polyethylene and polypropylene, 1,3-bis[1,1-dimethylethyl]-benzene (1,3-DBB) was identifed only in irradiated samples. Levels of 1,3-DBB increased with increasing irradiation doses. Polymer stabilizers such as antioxidants used in polyethylene were found to be degraded by ionising radiation.

● In polyethylene terephthalate, 1,4-diphenyl-2-butene was increased after irradtiation. The variations of concentration in irradiated samples identified in this study may be related to the radiation sensitivity of compounds with irradiation doses.

● In polystyrene, most compounds identified were styrene monomer. The composition of volatile organic compounds were little changed.

● These results suggest may be useful in evaluation of γ-irradiation effects on food packaging materials.