罗望子挥发性组分的定量结构——色谱保留值关系研究

采用分子电性距离矢量（MEDV）表征罗望子挥发油各组分的分子结构,运用多元线性回归建立定量结构-色谱保留关系（QSRR）模型,同时采用逐步回归结合统计检测对模型进行变量筛选,建立了罗望子挥发油定量结构-色谱保留（QSRR）关系的8变量和5变量模型,两QSRR模型的建模计算值复相关系数（R）分别为0.975和0.974;留一法（leave-one-out）交互校验复相关系数（R）分别为0.951和0.965,表明模型具有良好的估计能力与稳定性。      

酸角饮料的开发研制初探

将酸角打浆后的果肉分别在不同条件下对其浸提，确定其最佳浸提条件为时间90min、温度85℃、料水比1：6。浸提出的果汁色、香、味都较好，且酸角风味突出。用蜂蜜作为调味和澄清剂，红糖增加其风味，其最佳配方为白砂糖5%、柠檬酸0.12%、红糖2%、蜂蜜1%。产品中加入0.02%的乙基麦芽酚可使酸角香气风味色泽更浓郁，纯正。加入10%的梨汁使产品口感柔和。     

紫丁香花精油挥发性成分色谱保留指数的预测模型

定量结构-色谱保留指数相关性(QSRR)方法已成为色谱领域中的有用工具,用于解释与预测各种物质的色谱行为。在分子拓扑理论的基础上,计算了64种紫杉醇花精油挥发性成分化合物的三类拓扑指数值:价分子连接性指数(χi),电性拓扑状态指数(ek)和分子电性距离矢量(mj),并随机选取其中的51个作为训练集,其他分子做检验集,采用多元回归中逐步筛选的方法建立了分子结构和色谱保留指数的最优预测模型(R=0.982),用检验集检验了所建模型的预测能力,并经Jackknife检验,交互检验和外部检验验证了模型的总体稳健性。     

酸角果肉多糖的提取工艺优化与初级结构分析

以酸角果肉为原料,利用响应面分析法改进超声波辅助提取酸角果肉多糖(polysaccharides from Tamarindus indica L. Pulp fruit,PFTP)的条件参数。基于单因素试验结果,设置自变量为提取时间、超声功率、提取温度与液料比,响应值为酸角果肉多糖得率,进行四因素三水平的响应面分析。获得最佳提取参数:提取时间40 min、超声功率200 W、提取温度50℃、液料比30∶1(mL/g),此时得率为31.94%,高于文献优化条件下的热水浸提得率23.44%。结合紫外吸收光谱、红外吸收光谱与高效阴离子交换色谱法分析酸角果肉多糖的初级结构,紫外吸收光谱表明酸角果肉多糖含有少量蛋白质,无核酸;红外吸收光谱表明酸角果肉多糖出现多糖的特征吸收,具有β-糖苷键结构;高效阴离子交换色谱图表明酸角果肉多糖的主要单糖组成为阿拉伯糖、半乳糖、鼠李糖、岩藻糖、木糖、葡萄糖和半乳糖醛酸,对应的摩尔比为45.56∶15.67∶6.41∶1∶5.14∶14.27∶1.95,高效排阻色谱法测得酸角果肉多糖的分子量为8.262×10~5g/mol,且分布均一,其半乳糖醛酸含量为30.02%。     

血橙果实香气成分色谱保留指数预测

应用分子电性距离矢量（MEDV）对血橙中的45种挥发性组分的气相色谱保留指数（RI）进行了定量结构-色谱保留关系（QSRR）研究。通过多元线性回归（MLR）和逐步回归（SMR）得到了该类化合物气相色谱保留指数（RI）的预测模型,模型的复相关系数（R）为0.947,标准误差（SD）为105.039。留一法（Leave-one-out,LOO）交互检验对模型进行了评价,得到的复相关系数（RCV）为0.923,标准误差（SDCV）为126.394。结果表明所建模型具有良好的预测能力和稳定性。      

基于气相色谱-离子迁移谱法分析酸角和甜角中挥发性成分差异

目的 分析酸角和甜角挥发性成分差异。方法 采用气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry, GC-IMS)分析3种酸角和2种甜角挥发性成分及其相对含量,基于指纹图谱和相对气味活度值(relative odor activity values, ROAV),结合聚类热图分析酸角和甜角中挥发性成分差异。结果 3种酸角和2种甜角样品中共鉴定出48种挥发性成分,包括16种醛类、11种醇类、6种酯类、5种酸类、5种酮类、2种烯类、2种硫醚类及1种吡嗪类。酸角样品中醛类(26.38%～31.82%)、酯类(18.81%～23.12%)、酸类(9.27%～12.03%)、烯类(1.05%～1.35%)物质相对含量明显高于甜角,而甜角样品中酮类(25.13%～27.36%)、醇类(19.60%～21.32%)物质相对含量高于酸角。通过构建特征挥发性成分指纹图谱并结合ROAV筛选出16种关键特征挥发性成分,分别为5-甲基糠醛、糠醛、5-羟甲基糠醛、乙酸甲酯、己酸乙酯、苯甲醛、异戊醛、异戊醇、1-戊烯-3-醇、β-罗勒烯、(E)-2-庚...     

Industrial relevance of Tamarindus indica L. by-products as source of valuable active metabolites

Tamarind (Tamarindus indica L.) pulp is highly consumed due to the appreciable sensorial attributes. However, the fruit processing generates from 50 to 70% of residue, corresponding to peel, fiber, and seeds; a biomass still unexplored and usually discarded in the environment. In this perspective, the present review highlights and summarizes the current literature data about the main bioactive compounds associated to by-products from tamarind processing. Then, to balance the lack of information on these residues, an overview on extraction methods is also presented, linked to the recovery of relevant compounds from these residues and possible applications for the resulting products. Phenolic compounds, fatty acids, and polysaccharides are the main classes of substances from tamarind by-products, which, when processed, are submitted to traditional extraction methods (Soxhlet and maceration). To spread the environmental appeal of these residues as viable biomass, non-traditional extraction methods, still underused for tamarind by-products, are valued. These methods are interesting alternatives to obtain valuable compounds adequate for functional foods, packaging formulations, medicines, and cosmetics.     

Antifungal activity of some essential oil components

Fifteen essential oil components were evaluated for antifungal activity towards five spoilage-causing fungi. In liquid shake cultures, unsaturated aldehydes (citral, cinnamic aldehyde and cittronellal) followed by geraniol, an unsaturated alcohol were most inhibitory to Aspergillus niger, Fusarium oxysporum and Penicillium digitatum; their minimal inhibitory concentrations (MIC) was 100 μg ml⁻¹. Menthol, a terpene alcohol was most inhibitory to Rhizopus stolonifer and Mucor sp. with a MIC of 200 μg ml⁻¹. Hydrocarbons like camphene, limonene and α-terpinene were least inhibitory. When incorporated in agar medium different patterns of activity were found. Thus citral, cinnamic aldehyde, citronellal, geraniol and menthol not only failed to completely inhibit A. niger, F. oxysporum and P. digitatum but were more active against R. stolonifer and Mucor sp. than in liquid medium. The differences were due to the vapour of the volatile test compounds which accumulated over the agar medium. The growth inhibition due to the vapours alone was measured by using structurally modified petri-plates. The vapours were more active against R. stolonifer and Mucor sp. than against A. niger, F. Oxysporum and P. digitatum. Fungal growth inhibition by volatile compounds in agar medium reflects the combined activity of the vapour and the compound incorporated in the medium and the inhibition is different from that obtained in liquid medium. Regarding the structure-activity relationship of citral, the-CHO group in conjugation with a carbon to carbon double bond (C=C) was found to be responsible for the antifungal activity of the molecule.     

Antibacterial activity of essential oil components.

Antibacterial activity of fifteen essential oil components towards food borne Staphylococcus sp., Micrococcus sp., Bacillus sp. and Enterobacter sp. was studied by an agar plate technique. Cinnamic aldehyde was the most active compound followed by citral, geraniol, eugenol and menthol. At 500 micrograms/ml, cinnamic aldehyde completely inhibited the bacterial growth for more than 30 days at 30 degrees C that was comparable to 200 micrograms/ml of butylated hydroxy anisole (BHA). At lower temperatures, 25 and 20 degrees C, antibacterial activity of the five essential oil components increased. Addition of sodium chloride at 4% level (w/v) in the medium had no effect on the inhibitory activity of cinnamic aldehyde. In mixtures of cinnamic aldehyde and eugenol or BHA an additive effect was observed.     

细基江蓠挥发油化学成分的研究

海南岛具有十分丰富的海藻资源,海南细基江蓠是海南岛特有的江蓠变种,海南细基江蓠挥发油的研究末见报道.该研究用超临界CO2流体萃取技术对海南细基江蓠进行精油提取研究,萃取过程采用程序加压和程序升温,进一步采用GC-MS联用技术对萃取得到的细基江蓠精油组分进行了分析.共分离出27个组分峰,鉴定出其中21个化学成分,占挥发油总量的95.07%.海南细基江蓠挥发油中含量较高的成分如十六烷酸(24.44%)、γ-榄香烯(11.93%)、11-Z-十六碳烯酸(10.74%)、9-E-十八碳烯酸(7.05%)、十四酸(6.70%)等的混合香气构成了细基江蓠精油的特征香气.海南细基江蓠挥发油研究旨在为进一步开发利用海藻细基江蓠提供了科学依据.