流动注射分析中获得一阶导数光谱的新方法

本文提出了一种新的导数光谱检测技术。利用自行研制的一套流动注射比色装置。固定在双光束分光光度计的样品光束和参比光束位置,结合流动注射分析技术,实现同时扫描获得响应信号之差(ΔA=A样-A参),即ΔA/Δt≈dA/dt恰为一阶导数光谱。对其实验技术和检测原理进行了探讨。并将方法应用于多糖含量的测定,进样频率高达110次/h,糖含量在0～4.5μg/mL范围内符合比尔定律,分析的灵敏度较单光束光度提高到1.7倍。对南瓜粉糖含量的测定加权平均回收率为97.84%(n=9),实验结果令人满意。     

超声提取南瓜多糖的研究

南瓜多糖是南瓜的活性成分,具有保健、疗疾功效。通过实验研究了预浸时间、超声功率、超声提取温度,超声作用时间以及占空比对超声提取南瓜多糖的影响和效果。结果表明：以水为提取剂,预浸时间10min,超声作用时间20min,提取温度60℃,超声波功率80W,占空比为1时,样品中南瓜多糖提取量最大可达42．6mg／g。     

天然食用色素南瓜黄的稳定性及应用研究

在对南瓜黄的制备及性质研究的基础上，对南瓜黄色素在实际使用时可能遇到的各种环境中的稳定性能进行了探讨，并对色素的实际应用效果作简单介绍     

南瓜多糖提取纯化工艺的研究

为了提高南瓜多糖的提取率,采用冷冻法对南瓜进行前处理,通过正交实验确定了南瓜多糖提取的工艺参数,采用凝胶层析法对南瓜多糖进行了纯化并测定其分子量,采用了红外光谱对南瓜多糖进行了结构分析。实验结果表明,采用冷冻预处理后,南瓜多糖的提取率增加了77%;正交实验确定的南瓜多糖的优化工艺参数为:提取温度65℃,提取时间2 h,料液比1∶16;南瓜粗多糖经SephadexG-200凝胶层析柱后分为2个色谱峰,其平均分子量分别约为21 400和57 500;红外光谱分析显示,南瓜多糖为含有环状结构的多糖。     

南瓜汤宝的研制

对一种即食性的南瓜产品——南瓜汤宝的制作工艺进行了研究。结果表明,南瓜汤宝的最佳工艺参数为:去皮、去瓤的南瓜蒸煮16 min后,加入新鲜南瓜1/2质量的水进行打浆。调配250 mL的南瓜果汁时,最佳配料比为:南瓜浆100 g,白砂糖15 g,柠檬酸0.4 g,复合增稠剂(卡拉胶与CMC-Na按1∶1复合)0.375 g。南瓜浆在100℃下水浴浓缩2 h,然后分3次加入增稠剂,继续浓缩1.5 h,得到的最终产品性状最佳。     

微波辅助提取南瓜皮中果胶的研究

讨论了利用微波辐射萃取法从南瓜皮中提取果胶的不同因素的影响,通过实验确立了微波条件下提取果胶的最佳工艺条件为:用盐酸调pH值为1.8,用水作为溶剂,料液比为1∶20,微波辐射功率为600W,辐射时间为4min,乙醇(体积分数)为60%,提取率可达到16.9%。     

南瓜——保健佳品

南瓜是一种营养丰富，极具开发潜力的天然降糖食品，该文介绍了南瓜的营养成分，药用价值，保健功能以及南瓜有着广阔的开发前景。     

保健型南瓜冰淇淋的研制

研究南瓜汁为辅料生产南瓜冰淇淋的工艺,探讨复合稳定剂的配比对南瓜冰淇淋膨胀率、融化率的影响,通过正交试验确定南瓜汁、白砂糖及复合稳定剂的最佳配比,确定杀菌、均质及老化条件。研究结果表明:复合稳定剂CMC-Na、明胶、卡拉胶、复合乳化剂的比例8∶1∶4∶2;南瓜汁添加量5%,复合稳定剂用量0.70%,白砂糖16%,南瓜冰淇淋混合料经135℃,2 s灭菌,均质压力第一段15 MPa,第二段3 MPa,均质温度55℃,3℃老化20 h,可得品质优良的产品。     

Abscisic Acid Mediates Salicylic Acid Induced Chilling Tolerance of Grafted Cucumber by Activating H2O2 Biosynthesis and Accumulation

Grafting is widely applied to enhance the tolerance of some vegetables to biotic and abiotic stress. Salicylic acid (SA) is known to be involved in grafting-induced chilling tolerance in cucumber. Here, we revealed that grafting with pumpkin (Cucurbita moschata, Cm) as a rootstock improved chilling tolerance and increased the accumulation of SA, abscisic acid (ABA) and hydrogen peroxide (H₂O₂) in grafted cucumber (Cucumis sativus/Cucurbita moschata, Cs/Cm) leaves. Exogenous SA improved the chilling tolerance and increased the accumulation of ABA and H₂O₂ and the mRNA abundances of CBF1, COR47, NCED, and RBOH1. However, 2-aminoindan-2-phosphonic acid (AIP) and L-a-aminooxy-b-phenylpropionic acid (AOPP) (biosynthesis inhibitors of SA) reduced grafting-induced chilling tolerance, as well as the synthesis of ABA and H₂O₂, in cucumber leaves. ABA significantly increased endogenous H₂O₂ production and the resistance to chilling stress, as proven by the lower electrolyte leakage (EL) and chilling injury index (CI). However, application of the ABA biosynthesis inhibitors sodium tungstate (Na₂WO₄) and fluridone (Flu) abolished grafting or SA-induced H₂O₂ accumulation and chilling tolerance. SA-induced plant response to chilling stress was also eliminated by N,N′-dimethylthiourea (DMTU, an H₂O₂ scavenger). In addition, ABA-induced chilling tolerance was attenuated by DMTU and diphenyleneiodonium (DPI, an H₂O₂ inhibitor) chloride, but AIP and AOPP had little effect on the ABA-induced mitigation of chilling stress. Na₂WO₄ and Flu diminished grafting- or SA-induced H₂O₂ biosynthesis, but DMTU and DPI did not affect ABA production induced by SA under chilling stress. These results suggest that SA participated in grafting-induced chilling tolerance by stimulating the biosynthesis of ABA and H₂O₂. H₂O₂, as a downstream signaler of ABA, mediates SA-induced chilling tolerance in grafted cucumber plants.     

早餐工程——南瓜小米营养粥的研制

以南瓜、小米为主要原料,配以木糖醇、红枣等,经不同条件的适当处理生产出风味独特、营养价值高于同类产品的营养红糖姜汁麦米粥,通过对比实验确定了最佳工艺条件及配方,并以黏度和悬浮时间这两项指标作为性能评价指标,对常见的几种增稠稳定剂进行复配增稠实验的研究评价,筛选出一种高黏度的复合增稠稳定剂.