Preparation,characterisation and antioxidant activities of litchi (Litchi chinensis Sonn.) polysaccharides extracted by ultra‐high pressure

Litchi (Litchi chinensis Sonn.) is a fruit containing many nutrients. Based on a three level, three‐variable Box‐Behnken design, response surface methodology, was used to optimise the process of ultra‐high pressure (UHP) assisted extraction of litchi polysaccharides (LCP). The optimal extraction conditions were as follows: pressure 460 MPa, treatment time 17 min and liquid–solid ratio 15. The experimental yield for extracting LCP was 12.01% under the optimal conditions. The LCP had a high polysaccharide and low protein content. GC results showed that LCP was composed of rhamnose, fucose, mannose and galactose with the corresponding molar percentages of 7.89, 46.45, 9.71 and 19.63. Infrared analysis showed that LCP had a typical spectrum of an α‐configuration pyranose ring. Antioxidant activity analysis revealed that LCP possessed a strong reducing power and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging activity and could protect against the damage of hydroxyl radicals. The investigations demonstrated that UHP could be a valuable way to separate polysaccharides from litchi pulp, and LCP may be potentially developed to an antioxidant for food industries.     

Characterization of Male and Female Jojoba Plants Employing Antioxidants,Lipid Peroxidation and Physiological Studies

Jojoba, [Simmondsia chinensis (Link) Schneider] is a commercially important dioecious, desert shrub which is mainly cultivated for liquid wax (oil) present in its seeds (40–60 %). The oil is being utilized by the cosmetic, pharmaceuticals, and other industries for certain formulations. In this study, gender based differences in biochemical and physiological parameters were examined in relation to natural drought conditions. The amount of protein, proline, cysteine, chlorophyll a and b, carotenoids and enzymatic activities were evaluated in leaves of male and female Jojoba genotypes. Significant differences between genders were found which was attributed to higher drought tolerance of males than females. Males showed higher contents of protein (113.05 ± 0.88 mg g^?1 FW), proline (95.13 ± 2.33 µmol g^?1 FW), cysteine (42.47 ± 2.69 µmol g^?1 FW) than females (proteins: 70.77 ± 0.52 mg g^?1 FW, proline: 66.61 ± 1.75 µmol g^?1 FW, cysteine: 17.84 ± 3.00 µmol g^?1 FW). Malondialdehyde (MDA) content was lower in male genotypes (18.29 ± 0.53 µmol g^?1 FW) than female genotypes (23.02 ± 0.70 µmol g^?1 FW). Higher activities of catalase (CAT) [0.088 ± 0.005 nkat mg^?1 protein], guaiacol peroxidase (GPX) [0.006 ± 0.001 nkat mg^?1 protein], glutathione reductase (GR) [9.02 ± 0.04 nkat mg^?1 protein], ascorbate peroxidase (APX) [4.28 ± 0.08 nkat mg^?1 protein] and superoxide dismutase (SOD) [151.75 ± 3.58 nkat mg^?1 protein] were found in males compared to females [CAT: 0.007 ± 00 nkat mg^?1 protein, GPX: 0.003 ± 00 nkat mg^?1 protein, GR: 6.40 ± 0.06 nkat mg^?1 protein, APX: 3.08 ± 0.06 nkat mg^?1 protein, SOD: 52.51 ± 1.73 nkat mg^?1 protein]. Chlorophyll b content was also higher in males than females.     

郊区农村月季专类园规划设计研究——以崇明东禾九谷开心农场为例

月季是中国传统名花,具有悠久的栽培历史且栽培品种繁多,其花色鲜艳,有较高的观赏价值。以上海市崇明东禾九谷开心农场月季专类园为例,参考专类园的设计原则及周边建设环境,引入多个月季栽培品种,运用花海、花廊、花柱等设计形式,讨论如何因地制宜地组织合理的景观架构以营造植物空间。同时研究阐述了月季在栽培养护过程中的注意要点,以及如何在保证品种月季生长良好的前提下,在郊区农村打造可供游人游憩的月季专类品质园。     

菟丝子总黄酮超声提取工艺的研究

优选菟丝子总黄酮的最佳提取工艺。采用L9(34)正交实验,对影响因素提取温度、乙醇浓度、料液比和提取时间进行优化,以总黄酮含量为评价指标,并采用分光光度法测定含量。菟丝子总黄酮的最佳提取工艺为加入药材量30倍65%乙醇在40℃下超声提取15 min。优选得到的工艺稳定可行。     

从红豆杉中提取紫杉醇的工艺研究

紫杉醇(Taxol)是从红豆杉树皮中分离得到的一种二萜化合物,具有独特疗效的抗癌物,现已被多个国家批准应用于临床治疗卵巢癌和乳腺癌等疾病。由于红豆杉中的紫杉醇含量非常低(仅为0.010%~0.013%),而且大量结构类似的紫杉烷类物质存在,使得紫杉醇的分离纯化非常困难。本文通过对比5种不同提取方法 (液液萃取、固相萃取、硅胶层析、氧化铝层析、薄层层析),提出一种新的以氧化铝层析结合固相萃取工艺,具有紫杉醇高回收率的特点。     

粤产射干挥发油的水蒸气蒸馏提取及气相色谱-质谱联用分析

对水蒸气蒸馏提取射干挥发油的提取条件进行了研究。获得最佳提取条件为:射干粉末(40目)150 g加入1000 mL的水,浸泡2 h后,水蒸气蒸馏提取10 h。用气相色谱-质谱联用技术测定了所得射干挥发油的化学成分,鉴定出其中41种成分,有机酸类化合物(38.74%)以及醛类化合物(9.77%),含量最高的成分分别为月桂酸(15.05%),癸酸(11.07%),雪松醇(6.99%),桃醛(5.36%),正辛酸(5.18%);肉豆蔻酸甲酯(3.78%)和1-乙基己酸酐(3.20%)等天然有效成分。     

金莲花糖苷酸解香味组分分析及卷烟加香应用研究

采用酸解法对金莲花糖苷的香气前体物进行降解,运用GC-MS 技术对其酸解物香气成分进行分析,并进行了卷烟加香试验。GC-MS共鉴定了其中15种香气成分,主要有芳樟醇、脱氢芳樟醇、α-松油醇、棕榈酸等,这些成分是构成卷烟香味的重要物质。在烟丝中加入适量金莲花糖苷可以起到改善香气质、增加香气量、降低刺激性和杂气的作用。     

五倍子中有效成分提取方法研究进展

五倍子中草药在我国分布广泛,其中有效成分使用领域也较广,因此对于其有效成分的提取成为目前研究的热点。文章介绍了五倍子中药材中存在的各种化学成分,包括鞣质、没食子酸、焦性没食子酸等,并重点阐述了目前鞣质和没食子酸活性成分的提取方法,进一步比较了各种提取技术优缺点,并对今后中草药有效成分的提取方法进行了展望。     

中国石蒜淀粉提取工艺的研究

以中国石蒜鳞茎为试验材料,分别对比了以水、Ca(OH)2、NaOH作为浸提液时的淀粉提取率,确定NaOH为最佳浸提液。在此基础上,通过单因素试验研究了NaOH浸提液的pH值、料液比、浸泡时间、沉降时间对中国石蒜淀粉提取率的影响,并用正交试验确定了中国石蒜淀粉提取的最佳工艺为:NaOH作为浸提液,pH 9.0,料液比1∶4,浸泡时间6 h,沉降时间4 h。利用此方法,中国石蒜淀粉的提取率超过80%。     

华根霉脂肪酶催化合成乙酸香茅酯的研究

研究了华根霉菌丝结合脂肪酶(RCL)非水相直接酯化合成乙酸香茅酯的反应条件。在醇酸比为1.2∶1,反应温度40℃时得到较高的转化率。但由于底物乙酸较强的抑制性,使得高底物浓度下RCL催化能力受限。通过采用分批流加的方法使在底物浓度0.2mol/L时转化率提高至94%。与10种商品化脂肪酶进行了比较,发现在相同条件下RCL表现出较高的转化效率。产物乙酸香茅酯的色泽好,气味纯正。