Mycotoxins in apples and apple products

Jabolka zaradi svoje visoke vodne aktivnosti in vsebnosti sladkorjev omogočajo ugodne razmere za rast različnim plesnim. Najpogosteje se omenja plesni vrste Penicillium expansum, ki povzročajo modro plesen. Na jabolkih so te plesni sposobne sintetizirati sekundarne metabolite, med katerimi so tudi mikotoksini. V jabolkih in izdelkih iz jabolk je najbolj pogost patulin, ki je imunotoksičen in nevrotoksičen za ljudi, če se zaužije v visokih koncentracijah. Mejna vrednost za največjo dovoljeno vsebnost patulina v izdelkih iz jabolk je 50 µg/kg. Plesni najpogosteje vstopajo v notranjost sadja skozi poškodovano površino, kar se zgodi ob močnem dežju, napadu insektov ali neprevidnem rokovanju. Pogosto pride do okužb s plesnimi šele v skladiščnih prostorih. Najbolj priporočljivo je skladiščenje jabolk v hladilnicah in hladilnicah s kontrolirano atmosfero, kjer je nivo CO₂ in O₂ prilagojen tako, da je zorenje plodov čim bolj upočasnjeno. Kljub nizkim temperaturam in nizkim nivojem O₂ je rast plesni vrste P. expansum le upočasnjena in patulin še vedno lahko proizvajajo. Zato je patulin lahko prisoten v različnih izdelkih iz jabolk. Ker pa je patulin tudi termostabilen, je njegovo odstranjevanje zelo zahtevno. Učinkovito zniževanje vsebnosti patulina so pokazali nekateri procesi obdelave hrane, kot so čiščenje, pasterizacija in fermentacija. Poznamo pa tudi več fizikalnih, kemijskih in bioloških procesov odstranjevanja patulina iz izdelkov iz jabolk. Sem spadajo obdelava s toploto, svetloba UV, elektroporacija, uporaba visokih tlakov, ozona in mikroorganizmov. Nekateri postopki delujejo na principu adsorpcije patulina, drugi pa povzročajo njegovo degradacijo. Tudi s temi procesi obdelave odstranitev patulina iz končnih izdelkov ni možna v celoti, hkrati pa lahko pride tudi do nezaželenih sprememb v senzoričnih lastnostih in hranilni vrednosti živil.Apples provide favourable conditions for growth of various fungi, due to their high water activity and sugar content. Most commonly mentioned mould is Penicillium expansum, the cause of so called blue mould. On apples these fungi are able to synthesize secondary metabolites called mycotoxins. The most commonly present mycotoxin in apples and apple products is patulin, which is immunotoxic and neurotoxic to humans if ingested at high concentrations. The limit for maximum level of patulin in apple products is 50 µg/kg. Mould enters the fruit through the damaged surface, which occurs in case of heavy rain, insect attack or careless manipulation. However, mould infections often occur only in storage rooms. The most recommended way to storage apples is in refrigerated chambers and refrigerated chambers with controlled atmosphere, where the levels of CO₂ and O₂ are adjusted to slow down the ripening of the fruit. Despite low temperatures and low level of O₂ the growth of P. expansum is only slowed down and patulin can still be produced. Therefore, patulin can be present in various apple products. Since patulin is also thermostable, its removal is very difficult. Effective reduction of patulin has been demonstrated by certain food processing technologies, such as washing, pasteurization and fermentation. There are also several physical, chemical and biological processes of removing patulin from apple products. This includes heat treatment, light UV treatment, electroporation, use of high pressures, ozone and microorganisms. Some procedures function on patulin adsorption, while others provoke its degradation. Even with these processing technologies, the removal of patulin from apple products is not entirely possible, and there may also be negative changes in sensory quality and nutritional value of foods