Occurrence of 6-methoxymellein in fresh and processed carrots and relevant effect of storage and processing

The occurrence of 6-methoxymellein (6-MM) in fresh and conventionally processed carrot products (for a total of 176 samples) marketed in European locations and the effect of Alternaria spp. infection and storage conditions on 6-MM accumulation were investigated. 6-MM was found in 78% of tested samples with levels ranging from 0.02 to 76.00 microg/g, with only 1 of 79 fresh carrots exceeding the "just noticeable difference" level for 6-MM. Storage of carrots at 1 degree C was suitable to maintain low levels of 6-MM for a period of at least 17 weeks. No effect of Alternaria spp. infection was observed on 6-MM occurrence. The fate of 6-MM during carrot juice processing was also investigated by using different enzyme formulations for maceration and blanching procedures. Levels of 6-MM in blanched carrots obtained by boiling water or steam treatment were reduced by 69 or 33%, respectively, as compared to fresh carrots. No decrease in 6-MM levels was observed after maceration with pectinolytic enzyme preparations (Rapidase Carrot Juice and Ultrazym AFP-L). A reduction of 6-MM by 85 or 94% was obtained after the entire cycle of carrot juice processing, depending on the blanching procedure used.