Reduction of patulin during apple juice clarification

Patulin is a mycotoxin produced by a number of molds involved in fruit spoilage. This compound is carcinogenic and teratogenic. Various methods are currently used to reduce the levels of patulin in apple juice, namely, charcoal treatment, chemical preservation (sulfur dioxide), gamma irradiation, fermentation, and trimming of fungus-infected apples. Many of these processes are expensive and time-consuming. Therefore, there is a need to find a convenient and economical process to control patulin levels. This study was undertaken to evaluate the effectiveness of several clarification processes for the reduction of patulin. Clarification was carried out on a laboratory scale. Apple pulp was spiked with patulin, pressed, and clarified using four different processes, namely, fining with bentonite, enzyme (pectinase) treatment, paper filtration, and centrifugation. Patulin was recovered from the clarified juice by liquid-liquid extraction, and solid-phase chromatography was used for sample clean-up prior to analysis by high-performance liquid chromatography (HPLC). The minimum detectable limit using HPLC was 20 microg/liter. Pressing followed by centrifugation resulted in an average toxin reduction of 89%. Total toxin reduction using filtration, enzyme treatment, and fining were 70, 73, and 77%, respectively. Patulin reduction was due to the binding of the toxin to solid substrates that was verified by analyzing the clarified juice as well as the filter cake, pellet, and sediment. The combined concentrations correlated to the spiked concentration. These results reveal that clarification was successful in the reduction of patulin levels in apple juice. However, clarification resulted in high levels of patulin in the pressed pulp after filtration and centrifugation, and this could be harmful if they are used as animal feeds.