高效液相色谱-质谱法分析植物玛咖中的玛咖烯和玛咖酰胺

采用6224液相色谱-飞行时间器串联质谱仪对植物玛咖中的玛咖烯和玛咖酰胺成分进行分析研究,在25分钟内分离出14种玛咖烯和玛咖酰胺,质量准确度误差不超过3×10^-6（3ppm）,准确度高。对比分析了3个不同品种的玛咖,结果表明云南产的黑色玛咖中的玛咖烯和玛咖酰胺总的相对含量最高。     

Postharvest Ultrasound‐Assisted Freeze‐Thaw Pretreatment Improves the Drying Efficiency,Physicochemical Properties,and Macamide Biosynthesis of Maca (Lepidium meyenii)

A novel technique of ultrasound‐assisted freeze‐thaw pretreatment (UFP) was developed to improve the drying efficiency of maca and bioactive amide synthesis in maca. The optimal UFP conditions are ultrasonic processing 90 min at 30 °C with 6 freeze‐thaw cycles. Samples with freeze‐thaw pretreatment (FP), ultrasound pretreatment (UP), and UFP were prepared for further comparative study. A no pretreatment (NP) sample was included as a control. The results showed that UFP improved the drying efficiency of maca slices, showing the highest effective moisture diffusivity (1.75 × 10^?9 m²/s). This result was further supported by low‐field nuclear magnetic resonance (LF‐NMR) analysis and scanning electron microscopy (SEM). The rehydration capacity and protein content of maca slices were improved by UFP. More importantly, contents of bioactive macamides and their biosynthetic precursors were increased in 2.5‐ and 10‐fold, respectively. In conclusion, UFP is an efficient technique to improve drying efficiency, physicochemical properties, and bioactive macamides of maca, which can be applied in the industrial manufacture of maca products.     

The metabolic formation profiles of macamides accompanied by the conversion of glucosinolates in maca (Lepidium meyenii) during natural air drying

Macamides, functional compounds found only in Lepidium meyenii Walpers, have gained interest in many fields of research due to its multiple bioactivities. Nevertheless, the mechanism by which macamides are synthesised is not thoroughly understood. In this study, the synthesis of six macamides and the conversion of three glucosinolates were studied systematically during a 6-month natural air drying process. An investigation of synthesis profiles showed that the largest category of macamides, the major constituents of total macamides, has the same benzyl group as benzyl glucosinolate, which has higher content than other glucosinolates. The second largest group of macamides contains the same m-methoxybenzyl group as m-methoxybenzyl glucosinolate which is the second major constituent of total glucosinolates. The results from this study suggest that glucosinolates are one of the most important precursors of macamides. Compared with all other drying methods, natural air drying is the most suitable condition for the formation of macamides.     

基于质谱裂解规律和UPLC-Q-TOF技术的玛咖酰胺类化合物筛查检测

本研究基于电荷或游离基中心诱导理论归纳了典型苄基和间甲氧基苄基玛咖酰胺类化合物的UPLC-Q-TOF质谱裂解规律，搭建了定性筛查谱库，同时建立了4种玛咖酰胺的定量检测技术。谱库包括保留时间、准分子离子及碎片离子的质荷比和分子结构等相关信息。结果表明，玛咖酰胺类化合物(A-J)可充分分离，出峰时间依次为5.83、5.32、5.93、6.50、6.40、5.23、7.32、6.58、6.47、7.32 min，利用谱库筛查时10种玛咖酰胺均可匹配10个以上碎片信息且质量分析误差在10 Mu以内；定量检测时4种玛咖酰胺（Mb18:3、Mo18:2、Mb18:2、Mb16）的检出限分别为0.50、1.20、1.20、0.50 mg/kg，定量限分别为1.50、3.60、3.60、1.50 mg/kg，平均回收率在81.64%~113.00%，且RSD均小于10%。本方法具有高准确性和精密度，对于玛咖及其制品的产地溯源、真假鉴别、质量分级和市场监管具有重要意义。     

基于灭菌效果和活性成分保持的玛咖 灭菌方法研究

目的考察不同灭菌方法对玛咖灭菌效果及其活性成分玛咖酰胺和芥子油苷含量的影响。方法分别用湿热、干热、微波、~(60)Co辐射4种灭菌方法对玛咖粉进行灭菌处理,检测灭菌前后玛咖粉的微生物限度指标,并用高效液相色谱法(HPLC)测定灭菌前后玛咖粉中玛咖酰胺和芥子油苷含量。结果 ~(60)Co辐射灭菌、湿热灭菌和干热灭菌效果均较好,达到96.57%以上,微波灭菌效果不明显,灭菌效果只有78.76%;玛咖活性成分检测结果表明~(60)Co辐射灭菌对玛咖酰胺和芥子油苷含量影响最小,损失率分别为2.61%和2.40%,其次是干热灭菌,损失率分别为10.58%和2.99%,湿热灭菌对玛咖酰胺和芥子油苷含量影响最大,损失率分别达到51.47%和76.05%。结论综合考虑灭菌效果和对玛咖活性成分影响,玛咖粉灭菌方法可选用~(60)Co辐射灭菌或干热灭菌。