基于GC-QTOF-MS代谢组学技术研究饲喂不同糖饲料对蜜蜂所产蜂王浆中代谢物组成成分的影响

为研究饲喂不同糖饲料对蜜蜂所产蜂王浆品质的影响,基于气相色谱-四极杆飞行时间质谱代谢组学技术对3?种不同糖饲料饲喂条件下（白糖、蜂蜜、高果糖浆）蜜蜂所生产的蜂王浆进行分析。结果表明：与白糖组相比,蜂蜜组脯氨酸、异亮氨酸、缬氨酸、乳糖、癸酸、L-磺基丙氨酸等含量显著较高（P＜0.05）;与蜂蜜组相比较,高果糖浆组蔗糖、麦芽糖含量显著较高（P＜0.05）,而甘油、纤维二糖、异亮氨酸、木糖、羟脯氨酸、乳糖、L-磺基丙氨酸含量显著较低（P＜0.05）;高果糖浆组与白糖组比较,软脂酸、麦芽糖、苏氨酸、半乳糖含量显著较高（P＜0.05）,而纤维二糖、松二糖、木糖、乳糖、赤藓糖含量显著较低（P＜0.05）。这种由于不同糖饲料饲喂条件而导致的差异可能会对蜜蜂及蜜蜂幼虫生长发育以及蜂王浆品质产生一定的影响,同时为蜂农饲喂方式的选择以及进一步研究影响蜂王浆组成差异的因素提供理论依据。     

基于气相色谱-质谱和液相色谱-质谱技术的冷鲜滩羊肉贮藏中脂肪差异代谢物检测

以宁夏滩羊脂质为研究对象,基于OmicsBean组学数据整合分析云平台,采用气相色谱-质谱和液相色谱-质谱技术检测冷鲜贮藏期为0、4、8、12?d滩羊脂肪的差异代谢物,找出风味物质的前体、中间体。结果表明：差异代谢物的种类随贮藏时间的延长总体呈下降趋势。游离氨基酸的种类随贮藏期延长呈先升后降趋势。贮藏8?d时,次黄嘌呤、丙氨酸及苏氨酸的含量显著上升,说明与甜味、苦味有关的风味物质前体在贮藏中已产生。而脂肪产生的多种风味物质前体如油酸、棕榈酸、硬脂酸含量显著下降,说明在此期间脂肪酸代谢活跃。因此,研究宰后脂肪代谢随贮藏时间的推移变化,能为冷鲜滩羊肉生产技术改进提供理论指导。     

Epigenetic Manipulation Induces the Production of Coumarin‐Type Secondary Metabolite from Arthrobotrys foliicola

Pursuing epigenetic manipulation approach in fungi led to the isolation of an unusual coumarin metabolite from fungi. An addition of the histone deacetylase inhibitor, suberohydroxamic acid (SBHA), to the culture medium of Arthrobotrys foliicola induced production of the coumarin‐type secondary metabolite represented by a single intensive peak in the HPLC profile of the ethyl acetate extract. The compound which was identified as 4‐ethyl‐7‐hydroxy‐8‐methyl‐2H‐chromen‐2‐one ( 1 ) was isolated from nature for the first time. Moreover, the investigation on the remaining part of the HPLC profile led to the separation of 6‐ethyl‐2,4‐dihydroxy‐3‐methylbenzaldehyde ( 2 ) and ten 2,5‐diketopiperazine compounds ( 3 – 12 ). The structures of isolates were deduced by their mass and NMR spectroscopic data. The coumarin‐type secondary metabolite ( 1 ) with peculiar smell induced by epigenetic stimulation is found for the first time in the Arthrobotrys species and the family Orbiliaceae. We evaluated 1 for the cytotoxic, anti‐inflammatory, anti‐allergic and nematocidal activities, however, it was found inactive.     

Wheat Qu and Its Production Technology,Microbiota, Flavor,and Metabolites

Chinese rice wine (CRW) is an ancient wine with a moderate alcohol content; it has been prized in China for its color, sweet flavor profile, and is a national beverage typically used in banquets. Wheat Qu is the starter used to make CRW, and plays a vital role in the quality and flavor profile. This review details the raw materials and the wheat Qu manufacturing process, and recent information on wheat Qu microbiotas. The volatile compounds in wheat Qus and its flavor are also reviewed. Finally, the enzymes, and metabolites contained in wheat Qu, such as biogenic amines, are also discussed.     

高效液相色谱法同时定量分析紫苏不同部位的植物代谢物

该研究旨在建立一种同时测定中国紫苏不同部位中代谢物含量的分析方法,明确紫苏不同部位中代谢物的种类与含量,为此类物质的高效利用提供一定科学依据。利用溶剂提取结合高效液相色谱技术,分别对紫苏叶、紫苏壳、紫苏杆中19种植物代谢物进行测定分析。结果表明,19种物质在55 min内完全分离,峰型和分离度良好,检出限在0.05~0.40 mg/L之间,标准曲线R2均在0.997 6以上,回收率和精密度分别在61.65%~111.42%和1.02%~17.20%之间。应用该方法对12种紫苏样品进行了检测,发现19种化合物在不同紫苏部位中的含量差异较大,在0.04~24.05 mg/g之间。12个样品中均检出2种酚酸和5种黄酮及黄酮苷。紫苏壳和杆中均检出木犀草素,含量为0.05~0.18 mg/g;紫苏叶中化合物含量顺序为迷迭香酸>野黄芩苷>芹菜素-7-O-葡萄糖苷。此外,在紫苏壳中首次检出HMF和糠醛两种呋喃环衍生物。该方法简单高效,仪器要求低,适用于紫苏及其他植物型样品中代谢物的定量检测。     

油茶籽乙醇提取物代谢物组成及其抗炎活性

为探究油茶籽油抗炎机制,采用超高效液相色谱-串联质谱技术检测分析了15?个批次油茶籽乙醇提取物中所有小分子代谢物,并通过“蓝精灵”实验评估油茶籽乙醇提取物对果蝇肠炎的抑制活性,将油茶籽乙醇提取物中小分子代谢物与抗炎活性进行相关性分析并与脂氧合酶进行分子对接,筛选鉴定其关键代谢产物,最后通过“蓝精灵”实验进行验证。结果表明：油茶籽乙醇提取物具有良好的果蝇肠炎抑制活性,抑制率为15.06%～61.71%,其代谢物主要包括多酚类、氨基酸类、有机酸类、核苷酸类、糖类、脂类等,发现7?种多酚类化合物以前未在油茶籽中报道过。初步筛选出具有良好抗肠炎活性的代谢物为：鸦胆子素B、丹参新酮、8-香叶草氧基补骨脂素、异芒果苷、5,7,4’-三羟基-6-异戊烯基异黄酮、山柰苷和山柰酚-3-O-芸香糖苷。5,7,4’-三羟基-6-异戊烯基异黄酮是首次被证实具有抗炎活性,0.1 mg/mL给药量时,果蝇肠炎抑制率为64%,远大于阳性对照柳氮磺胺吡啶（27.99%）。本研究为进一步探究油茶籽提取物内外抗肠炎活性及其机制奠定了基础。     

Gaseous ozone to preserve quality and enhance microbial safety of fresh produce: Recent developments and research needs

Fresh fruits and vegetables are highly perishable and are subject to large postharvest losses due to physiological (senescence), pathologic (decay), and physical (mechanical damage) factors. In addition, contamination of fresh produce with foodborne human pathogens has become a concern. Gaseous ozone has multiple benefits including destruction of ethylene, inactivation of foodborne and spoilage microorganisms, and degradation of chemical residues. This article reviews the beneficial effects of gaseous ozone, its influence on quality and biochemical changes, foodborne human pathogens, and spoilage microorganisms, and discusses research needs with an emphasis on fruits. Ozone may induce synthesis of a number of antioxidants and bioactive compounds by activating secondary metabolisms involving a wide range of enzymes. Disparities exist in the literature regarding the impact of gaseous ozone on quality and physiological processes of fresh produce, such as weight loss, ascorbic acid, and fruit ripening. The disparities are complicated by incomplete reporting of the necessary information, such as relative humidity and temperatures at which ozone measurement and treatment were performed, which is needed for accurate comparison of results among studies. In order to fully realize the benefits of gaseous ozone, research is needed to evaluate the molecular mechanisms of gaseous ozone in inhibiting ripening, influence of relative humidity on the antimicrobial efficacy, interaction between ozone and the cuticle of fresh produce, ozone signaling pathways in the cells and tissues, and so forth. Possible adverse effects of gaseous ozone on quality of fresh produce also need to be carefully evaluated for the purpose of enhancing microbial and chemical safety of fresh produce.     

Strategies to Modulate Specialized Metabolism in Mediterranean Crops: From Molecular Aspects to Field

Plant specialized metabolites (SMs) play an important role in the interaction with the environment and are part of the plant defense response. These natural products are volatile, semi-volatile and non-volatile compounds produced from common building blocks deriving from primary metabolic pathways and rapidly evolved to allow a better adaptation of plants to environmental cues. Specialized metabolites include terpenes, flavonoids, alkaloids, glucosinolates, tannins, resins, etc. that can be used as phytochemicals, food additives, flavoring agents and pharmaceutical compounds. This review will be focused on Mediterranean crop plants as a source of SMs, with a special attention on the strategies that can be used to modulate their production, including abiotic stresses, interaction with beneficial soil microorganisms and novel genetic approaches.