Thermal Stability and Degradation Kinetics of Patulin in Highly Acidic Conditions: Impact of Cysteine

Abstract

The thermal stability and degradation kinetics of patulin (PAT, 10 μmol/L) in pH 3.5 of phosphoric-citric acid buffer solutions in the absence and presence of cysteine (CYS, 30 μmol/L) were investigated at temperatures ranging from 90 to 150 °C. The zero-, first-, and second-order models and the Weibull model were used to fit the degradation process of patulin. Both the first-order kinetic model and Weibull model better described the degradation of patulin in the presence of cysteine while it was complexed to simulate them in the absence of cysteine with various models at different temperatures based on the correlation coefficients (R2 > 0.90). At the same reaction time, cysteine and temperature significantly affected the degradation efficiency of patulin in highly acidic conditions (p < 0.01). The rate constants (kT) for patulin degradation with cysteine (0.0036–0.3200 μg/L·min) were far more than those of treatments without cysteine (0.0012–0.1614 μg/L·min), and the activation energy (Ea = 43.89 kJ/mol) was far less than that of treatment without cysteine (61.74 kJ/mol). Increasing temperature could obviously improve the degradation efficiency of patulin, regardless of the presence of cysteine. Thus, both cysteine and high temperature decreased the stability of patulin in highly acidic conditions and improved its degradation efficiency, which could be applied to guide the detoxification of patulin by cysteine in the juice processing industry.

Cysteine‐enhanced ultrasound degradation of patulin in acidic solution simulated pH of apple juice

“…There was a quick reduction in patulin concentration within the first 20 min in the presence of cysteine without ultrasound treatment ( p < .01), which was caused by the high concentration of cysteine. After 20 min, while no obvious difference was present in patulin degradation ( p > .05), which indicated that it was very difficult to further improve the degradation efficiency of patulin by cysteine without the help of ultrasound or heating processing under highly acidic conditions (Diao et al, 2021; Fliege & Metzler, 2000). A similar conclusion had been drawn that the sonolysis of azinphos‐methyl enhanced very quickly during the first 20 min and then it proceeded more slowly until 60 min (Agarwal et al, 2016).…”

“…For the physical strategy, thermal processing is often considered for the degradation of patulin (Collin et al, 2008;Diao et al, 2021;Kokkinidou et al, 2014). However, patulin has a high resistance to heat under acidic conditions (Lovett & Peeler, 1973).…”

“…According to the reported literatures, ultrasonic power plays an important role in degrading organic compounds including F I G U R E 1 Schematic of the ultrasound setup mycotoxins and pesticides (Cai et al, 2018;Pirsaheb & Moradi, 2020;Qin et al, 2014;Sun et al, 2016). Figure 3 heating processing under highly acidic conditions (Diao et al, 2021;Fliege & Metzler, 2000). A similar conclusion had been drawn that the sonolysis of azinphos-methyl enhanced very quickly during the first 20 min and then it proceeded more slowly until 60 min (Agarwal et al, 2016).…”

“…Three strategies have their own advantages and disadvantages in removing or degrading patulin in foods, which have been summarized by us (Diao et al, 2018). For the physical strategy, thermal processing is often considered for the degradation of patulin (Collin et al, 2008; Diao et al, 2021; Kokkinidou et al, 2014). However, patulin has a high resistance to heat under acidic conditions (Lovett & Peeler, 1973).…”

“…It was at 85°C for more than 50 h that patulin could be completely degraded in the pH 3.75 of apple juice model system (Kokkinidou et al, 2014). Recently, we also explored the thermal stability of patulin in the pH 3.5 of phosphoric‐citric acid (PCA) buffer solution, and found that heating treatment at 150°C for 180 min without adding cysteine (CYS) or at 150°C for 90 min with adding cysteine could completely remove it (Diao et al, 2021). Therefore, these results all indicate that effective removal of patulin in acidic foods needs a higher temperature and a longer time, which will seriously destroy the quality of treated foods.…”