Mycotoxins in botanicals and dried fruits: A review

Botanicals are used in many countries for medicinal and general health-promoting purposes. Numerous natural occurrences of mycotoxins in botanicals and dried fruits have been reported. Aflatoxins or ochratoxin A (OTA) have been found in botanicals such as ginseng, ginger, liquorice, turmeric, and kava-kava in the USA, Spain, Argentina, India, and some other countries, while fumonisins have been found in medicinal wild plants in South Africa and in herbal tea and medicinal plants in Turkey. Zearalenone was identified in ginseng root. Dried fruits can be contaminated with aflatoxins, OTA, kojic acid, and, occasionally, with patulin or zearalenone. One main area of concern is aflatoxins in dried figs; bright greenish yellow fluorescence under ultraviolet light is associated with aflatoxin contamination. OTA in dried vine fruits (raisins, sultanas, and currants) is another concern. There are also reports of aflatoxins in raisins and OTA in dried figs, apricots, dried plums (prunes), dates, and quince. Maximum permitted levels in the European Union include 4 µg kg^-1 for total aflatoxins in dried fruit intended for direct consumption and 10 µg kg^-1 for OTA in dried vine fruit. This review discusses the occurrence of mycotoxins in botanicals and dried fruits and analytical issues such as sampling, sample preparation, and methods for analysis. Fungal contamination of these products, the influence of sorting, storage, and processing, and prevention are also considered.     

Incidence of patulin in fruits and fruit juices marketed in Campinas, Brazil

One hundred and eleven samples of processed fruit juices (apple, grape, pineapple, papaya, guava, banana and mango) and 38 samples of sound fruits (apple, papaya, mango, pear and peach) produced and marketed in Brazil, were analysed for patulin by HPLC. Only one out of 30 samples of apple juice was found positive at 17 mug/l. Patulin was not detected in the other foodstuffs. It was found in 14 samples of spoiled fruit samples of apple (150-267 mug/kg), pear (134-245 mug/ kg) and peach (92-174 mug/kg). Confirmation of the identity of patulin was based on the UV spectrum obtained by the HPLC diode array detector, compared with thatof standard patulin, TLC developed by several solvent systems and sprayed with 3-methyl-2-benzothiazolinone hydrazone , and by acetylation with acetic anhydride.     

Second order derivative spectrophotometric method for determination of vitamin C content in fruits,vegetables and fruit juices

A second-order derivative UV spectrophotometric method for determination of vitamin C [ascorbic acid (AA)] content in a variety of natural samples is described. The method is based on the measurement of a peak–baseline amplitude in the second derivative of the AA spectrum at 267.5 nm. The following corresponding regression equation was obtained within the concentration range 2×10^-5 to 1×10^-4 M AA (3.5–17.6 g/cm³ AA) in 1.0 M HCl solution: ²D_267.5=2.420×10⁴ c+0.025; the correlation coefficient was 0.9993 and the detection limit 4.2×10^-6 M. The results obtained by analysing 21 different species of fruits, vegetables and juices indicated a possibility for a more extensive application of the proposed method. This method is rapid, simple and requires no pretreatment of the analysed material, which makes it suitable for routine analyses. The reliability of the method was confirmed by comparative determinations with the generally accepted 2,6-dichloroindophenol method.     

Effects of food processing and fruit juices on in-vitro estimated iron availability from cereals,vegetables and fruits

Selected processed foods were digested in vitro under simulated physiological conditions. The proportion of iron diffusing across a semi-permeable membrane was used as an index of bioavailability. Certain food processing procedures appeared to greatly enhance the proportion of diffusible iron. Many of the foods that were canned, dried, pickled, fermented, refined, or which contained certain additives, displayed enhanced iron diffusibility compared with unprocessed foods. Iron diffusibility from wheat flour was found to be enhanced by the addition of fruit juices. The constituent organic acids in the fruit juices, namely citric, ascorbic and malic, were found to be potentially responsible for this enhancement. These three compounds are also important examples of a sequestrant, an antioxidant, and an acidulant. These and similar compounds are added to many processed foods in order to improve their quality and preservation. All such additives have the potential to influence the chemical form, and probably the bioavailability, of food iron.     

Determination of mycotoxins in biscuits,dried fruits and fruit jams: an assessment of human exposure

ABSTRACT

A reliable, fast and simple method using UHPLC-MS/MS was developed for the determination of aflatoxins B₁ (AFB1), G₁ (AFG1), B₂ (AFB2) and G₂ (AFG2), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA), HT-2 toxin and T-2 toxin in crude extracts of biscuits with fruit filling, cookies, dried fruits and fruit jams. The method was successfully demonstrated on 39 samples of biscuits with fruit filling, 34 cookies, 14 dried fruits and 10 fruit jams. The mycotoxins detected in biscuits samples were ZEA, OTA, T-2 and AFB1 with an average concentrations of positive samples of 2.64, 4.10, 8.13 and 1.32 µg kg^?1, respectively; while the mycotoxins detected in jam samples were AFB1, OTA, T-2 and AFB2 with an average concentrations of positive samples of 2.00, 17.7, 4.37 and 1.15 µg kg^?1, respectively. The results showed that the majority of samples were in compliance with relevant regulations. However in eight samples of biscuits and three samples of fig jam the contents of OTA were higher than the existing OTA limits. The combined dietary exposure of selected mycotoxins was estimated for the first time for children, adolescents and adults. The estimated combined dietary exposures were all lower than the proposed value assumed to predict a possible risk scenario.     

Moulds and yeasts in fruit salads and fruit juices

Thirty-eight fruit salad samples including cantaloupe, citrus fruits, honeydew, pineapple, cut strawberries and mixed fruit salads, and 65 pasteurized fruit juice samples (apple, carrot, grapefruit, grape and orange juices, apple cider, and soy milk) were purchased from local supermarkets in the Washington, DC area and tested for fungal contamination. The majority of fruit salad samples (97%) were contaminated with yeasts at levels ranging from <2.0 to 9.72 log10 of colony forming units per gram (cfu/g). Frequently encountered yeasts were Pichia spp., Candida pulcherrima, C. lambica, C. sake, Rhodotorula spp., and Debaryomyces polymorphus. Low numbers of Penicillium spp. were found in pineapple salads, whereas Cladosporium spp. were present in mixed fruit and cut strawberry salads. Twenty-two per cent of the fruit juice samples tested showed fungal contamination. Yeasts were the predominant contaminants ranging from <1.0 to 6.83 log10 cfu/ml. Yeasts commonly found in fruit juices were C. lambica, C. sake, and Rhodotorula rubra. Geotrichum spp. and low numbers of Penicillium and Fusarium spp. (1.70 and 1.60 log10 cfu/ml, respectively) were present in grapefruit juice.     

Preparation and processing of fruit juices, cordials and drinks

The techniques and equipment for the production of fruit juices and non-carbonated drinks, and for the production of carbonated drinks, are described.     

Freeze concentration of fruit juices

Concentration of aqueous foods such as fruit juices, milk, beer, wine, coffee, and tea, is a major unit operation in the food industry. Technically feasible processes that are commercially available for the concentration of liquid foods include evaporation, freeze concentration, reverse osmosis, and ultrafiltration. Evaporation is considered to be the most economical and most widely used method of concentration. However, it is not suited for food products with very delicate flavors. Commercial processes for the concentration of such products by membrane separation techniques are not yet available. As compared to the conventional evaporation processes, concentration by freezing is potentially a superior and economic process for aroma-rich liquid foods. In the past, the process, however, was seldom used because of the investment cost and the considerable loss of concentrate in the withdrawn ice, and hence, the quality. Recent technological developments have minimized these two drawbacks associated with the earlier freeze concentration processes. In the coming decade, freeze concentration is seen as a potentially attractive method for the concentration of aroma-rich liquid foods, including fruit juices, coffee, tea, and selected alcoholic beverages. In this article, several aspects of the theoretical considerations behind freeze concentration of fruit juices, the development of new and cheaper designs, and commercially available freeze concentration processes are reviewed. The economics of the process and its application to several other areas of the food industry are also discussed.     

全球果汁及果汁饮料消费状况

来自Euromonitor的资料显示,自1992年至2007年,全球果汁及果汁饮料消费市场大多呈现平稳的增长势头.     

Analysis of 5-hydroxymethylfurfual in coffee, dried fruits and urine

5-Hydroxymethylfurfural has become a substance of interest since recent results showed a possible carcinogenic potential in consequence of a metabolic activation by sulfotransferases. 5-Hydroxymethylfurfural is formed either by acid catalysed degradation of reducing sugars or via the Maillard reaction. This work provides an overview of foods potentially containing high amounts of 5-hydroxymethylfurfural. It comprises dried fruits with a high sugar content that were exposed to heat for a long time. The concentration ranges from very low in, e. g. figs (1 mg/kg) to plums that contained up to 2,200 mg/kg. Several types of roasted coffee were analysed that contained from 300 to 2,900 mg/kg of 5-hydroxymethylfurfural. In a small human study with seven healthy volunteers the urine excretion of unmetabolised 5-hydroxymethylfurfural was investigated. After uptake of 20 g of plum jam containing 24 mg of 5-hydroxymethylfurfural, 163 microg (mean) were excreted within 6 h, an equivalent of 0.75% of the ingested 5-hydroxymethylfurfural.     

Heat-resistant fungi in Nigerian heat-processed fruit juices

Sixty packaged heat-processed Nigerian fruit juices consisting of 15 each of mango, orange, pineapple and tomato, were screened for the presence of heat-resistant fungi after storage at approximately 28°C for 30 days. The resulting fungal growth was purified on potato dextrose agar. Approximately 17% of all the fruit juice packages and 27% of mango and tomato juices contained heat-resistant fungi. These were identified as Paecilomyces variotii, Aspergillus tamarii, A. flavus and A. ochraceus , the latter being predominant.     

果蔬及其制品真菌毒素的控制研究进展

真菌毒素是真菌在生长过程中所产生的一些次级代谢产物,广泛存在于谷物和饲料中,对人畜健康危害极大。近年研究表明果蔬在采后与加工环节中也易污染真菌毒素,已经引起了公众的广泛关注。本文主要从物理方法、化学方法、生物方法等方面综述了果蔬及其产品中真菌毒素控制方法的研究进展,其中生物防治果蔬及其产品中真菌毒素的方法由于安全、高效及环境友好,具有潜在的应用前景。      

果汁生产中膜技术的应用

膜技术是一种高效、低能耗和易操作的分离技术,在果汁的生产中得到越来越广泛的应用。概述了膜技术在苹果汁、柑桔汁、山楂汁、葡萄汁、草莓汁等果汁生产中的应用和特点,并展望了膜技术在果汁加工中的应用前景。     

Role of ion-selective electrodes in studies on vegetation, vegetables, fruits, juices and oils.

Ion-selective electrodes constitute an important means of determining many of the ions, for example, nitrate, chloride, bromide, cyanide, fluoride, sulphate, ammonium, sodium, potassium, calcium, magnesium and boron, that occur in vegetation, vegetables, fruits, juices and oils. Their scope is outlined together with associated experimental problems and the results compared with those obtained by alternative analytical methods.     

Furan formation during UV-treatment of fruit juices

Furan is a suspected human carcinogen and reported to be produced by thermal or ultraviolet light (UV-C) treatment of various foods, such as fruit juices and sugar solutions. This study explores the formation of furan during UV-treatment of high fructose corn syrup (HFCS) solution and simulated juices containing it and validates the results with two real juices, apple juice and apple cider. Studies performed on individual components of fruit juices revealed fructose to be the main constituent in fruit juices that is responsible for furan formation during UV-treatment. Furan formation was promoted at acidic pH, yet was suppressed in the presence of ascorbic acid. Furan synthesis is strongly influenced by absorbance of the treated solution, with increasing absorption coefficient leading to reduced furan formation. Formation of furan in fruit juices sweetened with HFCS when subjected to UV-treatment has been firmly established.     

Heat of sorption of water in dried fruits

The heats of moisture adsorption and desorption in four dried fruits (sultana raisins, figs, prunes and apricots) were estimated from equilibrium sorption data, using the Clausius-Clapeyron equation in the temperature range 15–60°C. The net isosteric heat of sorption ( q st) decreased sharply from about 20 kJ mol⁻¹ water to near zero when the moisture content was increased from 0.05 to 0.50kg water kg⁻¹ dry matter. An exponential function was fitted to the experimental q st values at various moisture contents (X) , yielding two characteristic constants ( q 0 and X 0) for each fruit. Mean and total heats of sorption were calculated from the proposed empirical equation, which are useful for enthalpy prediction in food dehydration. The heats of desorption were higher than the heats of adsorption, indicating significant hysteresis in the sorption of water, especially in dried apricots.     

水溶性壳聚糖在果汁澄清中的应用研究

研究水溶性壳聚糖对果汁的澄清作用,测定果汁经壳聚糖澄清后主要成分的变化。结果表明,2%壳聚糖水溶液能提高果汁的透光率,且不影响果汁的营养成分,是一种有效的果汁澄清剂。     

Clarification of fruit juices by fungal pectinases

This study analyses the efficiency of fungal pectinolytic preparations produced in laboratory and commercial products used in the clarification process of apple, butia palm fruit, blueberry, and grape juices. Two crude enzymatic extracts, produced by Aspergillus niger T0005007-2 (TE1) and Aspergillus oryzae IPT 301 (TE2), were tested in solid-state and submerse cultures, respectively, in comparison to the commercial preparations Pectinex^®Clear and Pectinex^®BE Colour, used for the clarification of clear (apple, butia palm fruit) and dark (blueberry and grape) juices, respectively. With pectinases total activity at 1 U/mL of fruit juice, reactions were conducted at 30 and 50 °C, for 30 and 60 min. Time increase resulted in an improved clarification, whereas temperature increase could not be clearly linked to a greater clarification. When compared to the commercial products, the use of the crude preparation TE1 resulted in similar clarification of apple and blueberry juices. For butia palm and grape juice, however, TE1 presented the highest clarification results, revealing the potential of A. niger T0005007-2 enzymes for commercial application.