苹果汁中棒曲霉素臭氧脱毒设备的设计与应用

Design and application of ozone detoxification equipment for patulin in contaminated apple juice

为了高效降解苹果汁中棒曲霉素,研制了一套利用臭氧技术降解棒曲霉素的设备。该设备利用臭氧的强氧化性,使其与苹果汁充分接触,从而使苹果汁中的棒曲霉素发生氧化分解。以人工污染的苹果汁为试验材料,研究了该设备的脱毒效果及对果汁主要品质指标的影响。研究结果表明:该臭氧脱毒设备能够有效降解苹果汁中的棒曲霉素,且臭氧浓度和臭氧处理时间均显著影响棒曲霉素的降解效果(P<0.05)。在果汁棒曲霉素起始浓度约为201.60μg/L,pH值3.5和可溶性固形物质量分数为15%时,用12 mg/L的臭氧在3 L/min流速下处理15 min,可将棒曲霉素减少到约49.24μg/L,降解率达75.58%,达到世界卫生组织(WHO)和英国软饮料协会(British soft drinks association,BSDA)设定的最大允许限量50μg/L的要求。臭氧处理对果汁可溶性固形物含量、pH值和总酸度无显著影响(P<0.05),但对果汁透光率、色值、苹果酸和总酚含量影响较大(P<0.05)。该设备具有投资小、脱毒效率高、脱毒成本低、环保无污染、结构简单、易操作、适合各种规模的果汁企业等优势,具有良好的经济效益和社会效益。

Apple juice can be contaminated by patulin inevitably due to the improper production, processing and storage,which seriously threats the health of consumers. In order to effectively degrade patulin in apple juice, an equipment fordetoxifying patulin using ozone technology is designed. The ozone detoxification equipment is made of stainless steel, and itincludes 6 systems： ozone preparation system, gas delivery system, ozone concentration adjusting and detecting system, juicedelivery system, detoxification system, and ozone decomposition system with heating. Patulin in apple juice is degraded basedon the strong oxidation role of ozone by full contacting between juice and ozone. The degradation efficiency of patulin inartificially contaminated apple juice by ozone and its effects on main quality of juice were studied using the designedequipment. The experiments were carried out at 0-12 mg/L ozone concentration and 3 L/min ozone flow rate, and the exposuretime of ozone was set from 0 to 30 min with an interval of 5 min based on the preliminary studies. The results showed thatpatulin in apple juice could be degraded effectively by ozone, and ozone concentration and exposure time could obviouslyaffect the degradation efficiency of patulin （P〈0.05）. Patulin was significantly reduced with the increase of ozoneconcentration （P〈0.05）. When the initial concentration of patulin in apple juice was 247.13 μg/L, patulin was decreased to87.03 μg/L after detoxification at 7 mg/L ozone concentration for 10 min of ozone exposure, with a reduction of 64.78%. Whenthe ozone concentration increased to 12 mg/L, patulin in apple juice was decreased to 45.30 μg/L, and it was reduced by81.67% under the other same conditions. The residual patulin in apple juice was well fitted using a power regression curvewith a determination coefficient （R2） of 0.954 3. The exposure time of ozone is also a very important factor influencing thedegradation of patulin. The residual patulin was significantly reduced with the increase of ozone exposure time （P〈0.05）.When the patulin initial concentration, pH value and soluble solid content of apple juice were 201.60 μg/L, 3.5 and 15.0%,respectively, patulin was decreased to 49.24 μg/L at the ozone concentration of 12 mg/L and ozone flow rate of 3 L/min for 15min of exposure, which was reduced by 75.58%. It is lower than the limit level in apple juice （50 μg/L） set by WHO （WorldHealth Organization） and BSDA （British Soft Drinks Association）. The relation between the residual patulin and ozoneexposure time followed a first-order kinetic model with a determination coefficient （R2） of 0.974 9. Ozone treatment has nosignificant effects on the soluble solids, pH values, and total acids of apple juice （P〈0.05）, while adverse effects on itstransmittance rate, color, malic acid, and total phenol contents （P〈0.05）. The phenolic compounds and organic acids areresponsible for the flavor and taste of apple juice, so the effects of ozone detoxification on the critical nutritional properties ofapple juice should be considered by processors prior to its adoption as a detoxification technique. The results are helpful in thedevelopment and commercial application of the ozone detoxification equipment in fruit juice processing.