The influence of ionizing radiation on the patulin content of apple juice concentrate was investigated. The results indicated that patulin, at an initial concentration of about 2 mg/kg, disappeared after irradiation of the concentrate with doses as low as 2.5 kGy. For lower doses, the extent of patulin degradation was proportional to the absorbed dose. Irradiation of the concentrate with doses sufficient for patulin disappearance did not change the titratable acidity, the content of reducing sugars and carbonyl compounds or the amino acid composition. The content of ascorbic acid slightly decreased and the colour of the concentrate brightened. The intensity of the patulin absorption spectra after irradiation of mycotoxin in aqueous solutions decreased.

The effect of irradiation on the patulin content and on the chemical composition of apple juice concentrate during storage at 4 degrees C over a period of several weeks was investigated. The radiation-induced disappearance of the mycotoxin in relation to the absorbed dose followed an exponential relationship. The radiation dose (D50), i.e., the dose which reduced the patulin content to 50% of its initial value was equal to 0.35 kGy. Storage of the irradiated concentrate had no effect on the patulin content; however, storage did lead to a slight increase in the titratable acidity and a decrease in the amounts of the carbonyl compounds and the ascorbic acid concentration. The development of non-enzymatic browning during storage of the irradiated samples followed the same kinetics as that of the non-irradiated samples.

The effects of ?-irradiation on the browning reaction in the model system of fructose-phenylalanine solution were investigated. The optical absorption recorded for irradiated and heated solutions of fructose-phenylalanine was different from those of only irradiated or only heated solutions.T o explain the role of carbonyl compounds formed during radiolysis of fructose and phenylalanine investigations of their N-methyl-benzothiazolone hydrazone hydrochloride derivatives were undertaken. It has been found that as a result of irradiation of the model system mainly aliphatic aldehydes are formed, besides a small amount of cyclic aldehydes. However during heating the contribution of aliphatic and cyclic products is similar.

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