Recent advances on the use of adsorbent materials for detoxification of Fusarium mycotoxins

The extensive use of adsorbents in the livestock industry has led to the introduction of a wide range of new products on the market, most of them claiming high in vitro mycotoxin adsorption capacity. However, adsorbents that may appear effective in vitro do not necessarily retain their efficacy when tested in vivo. Studies performed in our laboratory during the past few years aiming to evaluate the efficacy of various adsorbent materials in binding Fusarium mycotoxins are reported. Adsorption experiments were performed in in vitro screening tests for Fusarium mycotoxins at different pHs; by in vivo tests using the increase of the sphinganine to sphingosine ratio in rat urine and tissues as a biomarker of fumonisin exposure; and by a dynamic, computer-controlled, gastrointestinal model simulating the gastrointestinal tract of healthy pigs. Most of the commercially available mycotoxin-binders failed in sequestering in vitro Fusarium mycotoxins. Only for a small number of adsorbent materials was the ability to bind more than one mycotoxin demonstrated. Cholestyramine was proven to be an effective binder for fumonisins and zearalenone in vitro, which was confirmed for zearalenone in experiments using a dynamic gastrointestinal model and for fumonisins in in vivo experiments. No adsorbent materials, with the exception of activated carbon, showed relevant ability in binding deoxynivalenol and nivalenol. The in vitro efficacy of activated carbon toward fumonisins was not confirmed in vivo by the biomarker assay. The dynamic gastrointestinal model was a reliable tool to study the effectiveness of adsorbent materials in reducing the bioaccessibility of Fusarium mycotoxins, as an alternative to the more difficult and time-consuming studies with domestic livestock.     

脱皮"双低"油菜籽饼的脱毒脱油工艺研究

采用乙醇醋酸体系对脱皮"双低"冷榨油菜籽饼进行脱毒脱油试验,结果表明,最佳工艺参数为:醋酸:乙醇:水=5∶90∶5(体积比),固液比为1∶10,76℃下搅拌45 min,此条件下,植酸脱除率为84.2%,硫甙含量为0.78%,残油率为2.66%,且干物质损失少,油菜籽饼的营养成分均得到提高.     

脱毒亚麻粕籽粉对面团流变学及面包特性的影响研究

采用粉质仪、拉伸仪、质构仪等分析手段探讨脱毒处理后的亚麻籽粕粉添加到小麦粉中对面团流变学特性(粉质特性、拉伸特性)、面包烘焙特性的影响。结果表明,挤压处理使有毒成分生氰糖苷含量显著降低(从257.85 mg/kg降到18.58 mg/kg);随着脱毒亚麻籽粕粉添加量的增加,面团吸水率、弱化度增加;面团形成时间、稳定时间和粉质评价值降低;面团的R5阻力、最大拉伸阻力、拉伸长度、拉伸能量降低;复合小麦粉所制面包比容下降,感官评分及硬度、弹性等物性指标均无较大的变化。当添加量增大(超过5%时),需同时配合使用小麦粉改良剂。     

蒙脱石对黄曲霉毒素B1的脱毒研究

通过雏鸭急性毒性、肉仔鸡饲养试验研究了蒙脱石在动物体内对黄曲霉毒素B1(AFB1)的脱毒效果和对动物健康与生产性能的影响。结果表明，每只雏鸭一次摄入16μg及以上AFB1时可出现急性中毒死亡。肉仔鸡摄入含AFB1 80μg／kg的饲料，1周后饲料报酬降低，但肝脏中无AFB1残留。蒙脱石能对抗AFB1对动物的急慢性毒性作用，减少动物急性中毒死亡率，恢复动物生产性能。在肉鸡日粮中添加0．5％的蒙脱石对鸡骨骼强度无不良影响．对鸡骨骼钙、磷、铜、铁、锌沉积无影响：使骨骼铅、氟沉积减少，骨骼锰含量降低。     

杏仁脱皮去苦及杏仁油脱色研究

采用正交实验方法研究杏仁脱皮去苦及杏仁油脱色,从中筛选出最佳工艺参数。在沸腾的pH值为9的碱液中浸泡5min杏仁脱皮效果好;在pH值为4的35℃的酸性溶液中浸泡36h,可以完全去除苦杏仁的苦味;粗制杏仁油脱色,用自制的脱色剂,油剂比20∶1,在85℃下搅拌5min后过滤可获得微黄透明的脱色杏仁油。     

储粮中真菌毒素及其防控

该文概述储粮真菌毒素主要种类、化学结构、污染分布、特性及危害等;同时对储粮真菌毒素产毒条件与影响因素、防控及去除毒素等问题进行较详细综述与讨论,并展望储粮真菌毒素未来研究方向和前景。     

Toxic Compounds Formed on Prolonged Heating of Citrinin under Watery Conditions

Citrinin was partially decomposed by heating under aqueous conditions at 90°C for > 10 min and a group of degraded compounds (Group I) was detected by TLC. At 100°C and 110°C, citrinin disappeared rapidly, and the cytotoxicity of the samples increased with prolonged heating. At 120°C, citrinin disappeared more rapidly while TLC spots of Group I compounds also diminished upon >20 min heating and a new group of compounds (Group II) appeared. Cytotoxicity decreased rapidly at > 120°C and was eliminated after 10 min at 130°C. Group I appeared to contain toxic compound(s) but Group II did not. Heating citrinin under conditions similar to cooking may cause formation of additional cytotoxic compounds.     

Strategies to prevent mycotoxin contamination of food and animal feed: a review

Mycotoxins are fungal secondary metabolites that have been associated with severe toxic effects to vertebrates produced by many important phytopathogenic and food spoilage fungi including Aspergillus, Penicillium, Fusarium, and Alternaria species. The contamination of foods and animal feeds with mycotoxins is a worldwide problem. We reviewed various control strategies to prevent the growth of mycotoxigenic fungi as well as to inhibit mycotoxin biosynthesis including pre-harvest (resistance varieties, field management and the use of biological and chemical agents), harvest management, and post-harvest (improving of drying and storage conditions, the use of natural and chemical agents, and irradiation) applications. While much work in this area has been performed on the most economically important mycotoxins, aflatoxin B(1) and ochratoxin A much less information is available on other mycotoxins such as trichothecenes, fumonisin B(1), zearalenone, citrinin, and patulin. In addition, physical, chemical, and biological detoxification methods used to prevent exposure to the toxic and carcinogenic effect of mycotoxins are discussed. Finally, dietary strategies, which are one of the most recent approaches to counteract the mycotoxin problem with special emphasis on in vivo and in vitro efficacy of several of binding agents (activated carbons, hydrated sodium calcium aluminosilicate, bentonite, zeolites, and lactic acid bacteria) have also been reviewed.     

黄曲霉毒素B1的生物脱毒研究进展

简要介绍了黄曲霉毒素的分子结构、理化性质、对人体健康的危害及黄曲霉毒素B1在食品中的限量标准。重点阐述了近几年黄曲霉毒素B1生物脱毒方面的进展,其中微生物主要通过吸附和降解两方面去除黄曲霉毒素B1。     

Enzymic adaptations in leaf-feeding insects to host-plant allelochemicals

Herbivorous insects have the capacity to develop behavioral, physiological, and biochemical resistance mechanisms in response to chemical selection pressures. Among natural insect-plant associations, there are several cases of target-site insensitivity to and enhanced metabolism of plant allelochemicals. There are also known instances of physiological defenses such as extra rapid excretion or storage of toxic compounds. Multiple defenses seem to be prevalent in natural insect-plant interactions that involve toxic compounds, possibly reflecting the long time these interactions have had to evolve compared to insect-synthetic insecticide interactions. Synthetic insecticides were introduced about 45 years ago. Until recently they have been used as single-active-component preparations. As such, they have been and are very effective in producing insect populations with enhanced detoxification ability and target-site insensitivity. Most insecticide-resistant insect populations have one major defense mechanism. This feature makes the synthetic insecticides very useful tools for studies of insect defenses against toxic chemicals. Information gained from studies with insecticides can shed light on the capabilities of insects to adapt to toxicants in their environment. In assessing the validity of work with synthetic insecticides for natural systems, the fundamental differences between these substances and allelochemicals, and in their presentation to the insects, must, however, be considered. The prevalence of multiple defenses and reliance on modified physiological processes in natural interactions may reflect different properties of the natural chemicals in being generally highly biodegradable and often less acutely toxic than synthetic insecticides. In many cases, the plant allelochemicals are presented to the insects as mixtures. It is, however, to be expected that pest insects will evolve effective multiple defenses against synthetic insecticides. About 20% of all resistant populations have already developed multiple defenses, in most cases combinations of enhanced metabolism and target-site insensitivity. This implies that current crop protection practices need to be modified to ensure the continued usefulness of synthetic insecticides. To achieve this, it is important to study intensively not only insect-insecticide interactions but also the interactions operating in natural insect-plant associations.