浓缩苹果汁加工链中棒曲霉素的动态分析研究

研究了浓缩苹果汁加工过程中各工序对棒曲霉素含量的影响。结果表明,喷淋、拣选、清洗是去除棒曲霉素的关键步骤,去除率为60.18％;吸附树脂对棒曲霉素去除效果显著。此外,研究了加工季节中棒曲霉素的变化规律,为果汁加工厂家建立科学完善的HACCP管理体系提供了理论依据。     

酿酒酵母发酵混合果汁的功能性研究

采用酿酒酵母Saccharomyces cerevisiae KD对苹果、猕猴桃、梨混合果汁进行发酵,研究了该混合果汁发酵过程中酿酒酵母对真菌毒素棒曲霉素的去除作用及其降解产物对大肠杆菌的毒性,并对其发酵过程中的抗氧化能力及对α-淀粉酶、脂肪酶的抑制效果进行分析。结果发现,混合果汁发酵过程中棒曲霉素的含量持续下降直至完全降解,且棒曲霉素的降解产物对大肠杆菌无毒害;对抗氧化能力指标进行检测,发现发酵果汁的DPPH·、ABTS+·清除率和还原力相比新鲜果汁分别提高了15.0%、45.9%和9.6%,抗氧化能力显著增强(P<0.05)。此外,混合发酵果汁可以有效地抑制与肥胖相关的α-淀粉酶、脂肪酶的活力,抑制率分别为52.4%和45.2%。本文的研究结果可为开发功能性发酵果汁提供科学依据和技术支持。     

欧盟抬高果汁标准 国内企业难招架

由欧盟委员会通过的自2004年4月生效的果汁准入新标准已在欧盟各成员国施行,无须再转化为成员国的本国规定。果汁,特别是苹果汁及含苹果汁的酒精饮料中,棒曲霉素最大限量为50μg/kg,固体苹果产品中,棒曲霉素最大限量为25μg/kg,儿童用苹果汁和婴儿食品中,棒曲霉素最大限量为10μg/kg。欧盟新的标准对中国苹果汁出口质量提出了更高的要求。中国大约有40家苹果汁加工企业,95%以上的果汁出口。根据欧盟新的标准,目前,国内果汁企业100%达到欧盟要求还比较困难,预计两年之后,国内绝大多数企业可以达到欧盟新的标准。但专家担心这是欧盟对中国果汁…     

应对欧盟新法规要求--如何预防和减少苹果汁中棒曲霉素污染

欧盟委员会于2003年8月发布了(EC)NO1425/2003规则--关于棒曲霉素(EC)NO466/2001的修订规则以及<关于预防和减少苹果汁和含苹果汁成分饮料中棒曲霉素污染的建议>等有关生产规范.欧盟委员会(EC)NO466/2001规则最新被修订为(EC)NO563/2002规则,对在果汁、浓缩果汁、水果蜜饯、酒精饮料、苹果酒和其它来源于苹果或含有苹果汁的发酵饮料中的棒曲霉素的最高限量进行修订,要求各成员国采取适当措施,力争到2005年6月30日将棒曲霉素的最高限量从50 μg/Kg降低到 25μg/Kg.     

南丰蜜桔残次果富集培养果酒酵母的研究

以南丰蜜桔残次果为原料,添加磷酸二氢钾、氯化铵富集培养果酒酵母,对果汁培养基配方和发酵条件进行优化实验,结果表明,果汁培养基最佳配方为:糖含量9%、磷酸二氢钾添加量0.08%、氯化铵添加量0.04%;最适果酒酵母发酵条件为:pH4.5,接种量6%,装液量100mL/250mL,发酵时间16h.     

短乳杆菌发酵苹果汁工艺优化及有机酸变化

该研究利用短乳杆菌发酵苹果汁,生产能够调节人体肠道功能的乳酸菌苹果汁。通过单因素实验确定最适碳源、氮源以及缓冲因子;并以总酸、还原糖的变化为依据,进行响应面优化,确定最适发酵工艺条件,采用高效液相色谱法测定苹果汁发酵过程中有机酸组成及含量变化。结果表明,优化后发酵苹果汁的最佳培养基条件为:葡萄糖质量浓度50 g/L,蛋白胨质量浓度9 g/L,K₂HPO₄质量浓度4 g/L;菌种接种量为8%,发酵温度为36℃,发酵时间为6 d。在该条件下测得苹果汁的总酸为2. 61 g/100 g、还原糖为5. 027 g/100 g;经短乳杆菌发酵后苹果汁的品质明显优于发酵前。发酵后乳酸、富马酸、乙酸、奎宁酸含量显著增多;苹果酸、琥珀酸含量均持续减少,酒石酸含量无明显变化。     

苹果酒主发酵工艺研究

通过进行正交试验分析,研究接种量、温度、SO2添加量、起始糖度四个因素对苹果酒主发酵的影响。试验结果表明:最适反应温度为50℃,酶解时间3~4h。通过响正交试验优化的最适发酵条件为:苹果汁接种量2.0g/L、发酵温度28℃、SO2添加量100mg/L、起始糖度24%。     

苹果醋饮料生产工艺的研究

以新鲜苹果汁为原料,通过正交试验研究了发酵温度、接种量、起始糖度、时间对酒精发酵的影响以及初始酒精度、接种量、装液量对醋酸发酵的影响。结果表明:酒精发酵的最佳条件为:发酵温度27℃、糖度20%、接种量8%。醋酸发酵过程中,以酒精转酸率和酒精转化率为考查指标时的最佳发酵条件为:初始酒精度15%(体积分数)、接种量20%、装液量65 mL/100 mL三角瓶、发酵温度30℃。     

硅藻土吸附梨果汁中棒曲霉素的动力学模型研究

目的寻找一种有效去除梨果汁中棒曲霉素(patulin,PAT)的方法。方法以硅藻土作为吸附剂对梨果汁中棒曲霉素进行吸附,分析了吸附等温线,吸附热力学和动力学特征。结果在35℃下AG-3000#型硅藻土对梨果汁中棒曲霉素具有较好的吸附作用,最高吸附量为1066.152μg/g,最大吸附率为88.8%,且吸附为自发吸热过程。吸附等温线结果显示,棒曲霉素的吸附量随着棒曲霉素初始浓度的增大而增大;吸附热力学特征符合Langmiur吸附等温线模型。吸附动力学结果显示,硅藻土对梨果汁中棒曲霉素的吸附符合准二级速率方程模型。结论 AG-3000#硅藻土适合梨果汁中棒曲霉素的吸附。     

大孔吸附树脂吸附浓缩苹果汁中棒曲霉素的研究

研究DB101 B、DM-130、AB-8、HPD-850、HPD-200L、ATF.3树脂对棒曲霉素的吸附性能及对果汁主要理化性质的影响.比较6种树脂对棒曲霉素的吸附作用,筛选出最适吸附树脂,对其进行静态和动态吸附试验,研究其吸附性能.结标明,ATF-31型树脂对棒曲霉素的吸附率为60.41%,果汁的透光率和色值分别提高4.4%和88.3%,吸附最佳操作条件为:pH 4.2,吸附流速为10 mL/min,棒曲霉素初始浓度为35.20μg/L.ATF-31型树脂是棒曲霉素的良好吸附材料,并能较好的提高浓缩苹果汁的色值与透光率.     

Fate of patulin in the presence of the yeast Saccharomyces cerevisiae

Patulin is known to become analytically non-detectable during the production of cider from contaminated apple juice. The fate of [¹⁴C]-labelled patulin during the alcoholic fermentation of apple juice was studied. Three commercial cider strains of Saccharomyces cerevisiae degraded patulin during active fermentative growth, but not when growing aerobically. The products of patulin degradation were more polar than patulin itself and remained in the clarified fermented cider. Patulin did not appear to bind to yeast cells or apple juice sediment in these model experiments. HPLC analysis of patulin-spiked fermentations showed the appearance of two major metabolites, one of which corresponded by both TLC and HPLC to E-ascladiol prepared by the chemical reduction of patulin using sodium borohydride. Using a diode array detector, both metabolites had a λ_max = 271nm, identical to that of ascladiol. Thenmr spectrum of a crude preparation of these metabolites showed signals corresponding to those of the E-ascladiol prepared chemically and a weaker set of signals corresponding to those reported in the literature for Z-ascladiol.     

Patulin reduction in apple juice from concentrate by UV radiation and comparison of kinetic degradation models between apple juice and apple cider

Patulin, a mycotoxin produced by several genera of fungi, including Byssochlamys, Aspergillus, and Penicillium, has been an important concern in apple cider and apple juice due to its toxicity and health consequences. In this study, the effects of UV on the patulin level, physical and chemical properties, and sensory attributes in apple juice from concentrate were investigated. Kinetic modeling of patulin reduction by UV radiation in apple juice from concentrate was calculated and compared with the degradation rate observed previously in apple cider. From an initial patulin contamination of approximately 1,000 ppb (μg/liter), the UV exposure, ranging from 14.2 mJ/cm(2) (one pass) to 99.4 mJ/cm(2) (seven passes), was successful in reducing patulin levels by 72.57% ± 2.76% to 5.14% ± 0.70%, respectively. Patulin reduction by UV radiation followed first-order kinetic modeling in a fashion similar to first-order microbial inactivation. An exponential correlation between UV exposure and the percentage of patulin remaining was observed, giving an r(2) value of 0.9950. Apple juice was repeatedly exposed to 14.2 mJ/cm(2) for each treatment, and patulin levels were significantly decreased when compared with the level obtained with the previous UV exposure treatment. While there were no significant differences in the percentages of titratable acidity and ascorbic acid (P > 0.05), there were minor yet random sampling differences in pH and degrees Brix (1 °Brix is 1 g of sucrose in 100 g of solution; the °Brix represents the soluble solids content of the solution as percentage by weight [%, wt/wt]) (P ≤ 0.05). A significant difference (P ≤ 0.05) in sensory perception for the finished apple juice was detected between the control and the full seven-pass UV radiation treatment using an experienced consumer panel and a triangle test. Patulin reduction by UV radiation from both the current study and a previous study involving apple cider was compared, which showed that both matrices strongly fit a first-order kinetic degradation model. However, the kinetic constant for degradation in apple juice was approximately 5.5 times greater than that observed in an apple cider matrix.     

Detection of patulin in apple juices marketed in the Tohoku district, Japan

Patulin is a mycotoxin mainly produced by Penicillium and Aspergillus. We investigated the incidence of patulin contamination in 179 samples of apple juice and 9 samples of mixed juice (containing apple juice concentrate as an ingredient) commercially available in the Tohoku district of Japan. Patulin was detected in 3 of 143 samples containing domestic fruits and in 6 of 45 samples containing imported products and products produced in Japan using imported apple juice concentrate. Patulin analyses were carried out using high-pressure liquid chromatography with a detection limit of 4 microg/liter. The patulin content of contaminated domestic samples (three samples with concentrations ranging from 6 to 10 microg/liter), imported samples (one sample with a concentration of 15 microg/liter), and domestic samples produced containing imported concentrate (five samples with concentrations ranging from 6 to 9 microg/liter) was lower than the maximum limit of 50 microg/liter currently adopted by many countries, including Japan.     

Long-term survey of patulin in apple juice concentrates produced in Turkey.

A liquid chromatographic method described by us elsewhere was evaluated for a long-term survey of patulin in apple juice concentrates. Patulin was separated on a reversed phase C18 LC column with water-acetonitrile (99:1) as the mobile phase and quantitated with a photodiode array (PDA) detector. Relatively low amounts of patulin (< 5 micrograms/l for single strength juice at 11.2 degrees Bx) were detected in apple juice concentrates and confirmed by PDA detector, comparing the corresponding UV spectra with that of patulin standard. Four hundred and eighty two apple juice concentrates produced through 1996-99 were analysed for their patulin contents. Year-to-year variations in patulin levels of apple juice concentrates were found out to be statistically significant. Patulin contamination levels of apple juice concentrates tended to decrease through the years and averaged 63, 43, 19 and 31 micrograms/l in 1996, 1997, 1998 and 1999, respectively. Percentages of concentrates exceeding the maximum permitted concentration of 50 micrograms/l were 52%, 34%, 8% and 8% for 1996, 1997, 1998 and 1999, respectively.     

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.     

Incidence of patulin in apple juices marketed in Turkey.

The purpose of this study was to investigate the patulin contamination of apple juices consumed by the Turkish population. Patulin was detected using high-performance liquid chromatography (HPLC) with a UV detector at 280 nm, and the identification of patulin was further confirmed by thin-layer chromatography (TLC). Using HPLC, the recoveries were 79.9 +/- 6.7% and 83.7 +/- 4.6%, and the coefficients of variation were 8.4 and 5.5% for apple juices spiked with the known amounts of patulin (60 and 120 microg/liter. respectively). The minimum patulin level detected was 5 ng in a standard solution and 5 microg/liter in apple juices. The TLC method was used only to confirm patulin levels higher than 20 microg/liter (100 ng/spot) in apple juices. The total number of samples was 45. Patulin was present in detectable levels in 60% of apple juices at concentrations ranging from 19.1 to 732.8 microg/liter. Forty-four percent of the apple juice samples had patulin contamination levels higher than 50 microg/ liter, which is the allowable upper limit in Turkey.     

CONTAMINATION OF PATULIN IN CLEAR APPLE JUICE IN MASHHAD, IRAN

Patulin is a frequent contaminant of moldy and rotten apples and apple products. The aim of this study was to evaluate patulin contamination in 58 apple juices collected from a retail market in Mashhad during winter and spring of 2006.
Samples were assayed for patulin by high-performance liquid chromatography. Fifty-four samples were positive for patulin at levels that ranged from 10.5 to 121.8 µg/L, and six samples had patulin levels higher than 50 µg/L. The overall mean of patulin concentration was 29.2  ±  19.5 µg/L. Forty-eight samples had patulin concentration between 5 and 50 µg/L. Although the mean concentration of patulin samples was lower than Iranian maximum tolerated level of 50 µg/L, contamination of 10% of the samples at levels higher than 50 µg/L indicated the need for improving production techniques by the industry.

PRACTICAL APPLICATIONS

Studies have shown that the concentration of patulin may exceed the determined limits in apple juice and in other fruit products. Its presence can be a potential threat to the health of consumers, particularly children. The results may help us in understanding what should be the level of patulin in apple juice. The awareness of the apple industry of patulin contamination in fruit and the implementation of improved techniques for the production of apple products with reduced patulin concentrations have contributed to the quality of apple juice that are available on the Iranian market.     

Contamination of food products with patulin

Based on the method for patulin determination designed by the authors the rate and level of contamination of fruit, vegetables and foods manufactured from them (juices, purees, jams) with this mycotoxin were studied. Patulin was found in 8 out of 160 samples of fruit and vegetables, the highest concentration of patulin was identified in the berries of sea buckthorn (up to 54 000 micrograms/kg). Patulin was found in 28 out of 185 samples of foods manufactured from fruit. The concentration of patulin in juices did not exceed the allowable concentrations on the average. Patulin was largely identified in apple, sea buckthorn and plum juices.     

Biomass and Patulin Production by Byssochlamys nivea in Apple Juice as Affected by Sorbate, Benzoate, SO2 and Temperature

The effects of potassium sorbate, sodium benzoate, SO₂ and incubation temperature on biomass and patulin production by Byssochlamys nivea in apple juice were determined. Growth at 21, 30 and 37°C over a 25-day incubation period was significantly retarded by 75 ppm SO₂, 150 ppm potassium sorbate and 500 ppm sodium benzoate. Biomass accumulated to approximately 500 mg/100 ml in control samples of apple juice. Patulin was produced in the highest concentrations at 21°C after 20 days incubation. After reaching a maximum concentration at 30 and 37°C, a rapid decline in patulin content was observed. Patulin production was also observed at 12°C. On the basis of concentration, SO₂ had the most significant effect on the rate of biomass and patulin production by B. nivea followed by potassium sorbate and sodium benzoate, respectively.