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Patulin (PAT) contaminant in apple juice has attracted extensive attention. As a biosorbent, $\beta$-1,3-D-glucan shows great advantages in removing toxic contaminants. The aim of this study was to reveal the adsorption mechanisms of PAT by $\beta$-1,3-D-glucan. Four $\beta$-1,3-D-glucans with different number of side chains: curdlan, a hypothetical glucan, schizophyllan (SPG) and lentinan were simulated. Performance of molecular docking was observed to predict the binding mode and affinity. The most potential compounds were performed molecular dynamics (MD) simulation. The results show that the interaction between $\beta$-1,3-D-glucan and PAT is driven by steric complementarity, intermolecular H-bond and Pi–Sigma interaction. SPG has a large internal helical space to facilitate the insertion of PAT into the helix, and has relatively strong interaction with PAT. The side and main chains form a cavity to wrap PAT inside the helix. Furthermore, the binding free energy calculation was carried out using Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) approach. SPG showed high negative $\mathrm{\Delta }{G}_{\mathrm{\text{bind}}}$ value. Structural and energetic analyses demonstrated the adsorption characteristics of the four $\beta$-1,3-D-glucans. SPG is the most promising adsorbent for PAT. The side chain plays a major role in the adsorption process of the $\beta$-1,3-D-glucans. It provides a basis for the development of $\beta$-1,3-D-glucan as PAT adsorbent.

Three methods for determination of patulin in apple juice have been studied comparatively. The selected procedure for liquid samples implies liquid-liquid extraction with ethyl acetate/hexane (96:4, v/v). The collected patulin was then analyzed by liquid chromatography with UV-Visible detection. The obtained recovery was 82.9±3.2 % and the limit of detection was 2.0 µg/kg of juice, which are according to the valid guidelines established by the European Union. The developed analytical method has been used for the determination of patulin in various Spanish apple juices, where this mycotoxin has not been detected.

The capacity of bee pollen as a substrate for production of patulin (PAT) by strains of Penicillium expansum was studied. Eleven solid media were assayed: yeast extract sucrose medium (YES), YES supplemented with 0.5, 1 and 3% bee pollen, Wickerham medium, aflatoxin production medium, potato-glucose medium, bee pollen-glucose agar (BDA) containing different concentrations of bee pollen (0.5, 1 and 3 %). Cultures were kept at 25 °C for 2 weeks and analyzed for PAT by liquid chromatography with ultraviolet detection on days 3, 7, and 14. PAT accumulation in BDA was significantly higher than in other media. On the basis of the preliminary results obtained in this study it can be hypothesized that bee pollen consumption may constitute an important risk factor concerning the presence of PAT in the diet of consumers of that nutritious food.

The influence of the fungicide imazalil and factors such as water activity (a_w), temperature and time on the growth and production of patulin (PAT) by P. expansum was studied. The experiments were carried out in potato-glucose-agar (PDA) and the ranges for the experimental factors were the following: 0-70 μg/kg for imazalil sulfate, 0.93-0.99 for a_w and 4-24 °C for incubation temperature. Imazalil concentration and temperature had significant effects on lag phase duration. The highest lag-times were observed at 4 °C at high imazalil doses. Temperature and covariate lag phase had significant effects on the growth rate of P. expansum, which increased with increasing temperature. PAT accumulation was studied as a function of the three previously considered factors and time. All factors, except temperature, significantly affected PAT accumulation in the medium. It can be concluded that in PDA low doses of imazalil sulfate increase the lag phase duration of P. expansum, do not substantially decrease fungal growth rate once growth is apparent and do not increase PAT accumulation.