苦味西葫芦果实木脂素类成分研究

采用色谱技术对苦味西葫芦果实的抗炎活性部位的化学成分进行分离,应用1HNMR、13CNMR确定化合物的结构.从正丁醇萃取部位分离得到4个木脂素化合物:Larisiresinol 4'-O-β-D-glucopyranoside(Ⅰ)、( )-5'-Methoxyisolarisiresinol 3α-O-β-D-glucopyranoside(Ⅱ)、Lyoniside(Ⅲ)、Isolariciresinol-9-O-β-D-xylopyranoside(Ⅳ).化合物Ⅰ、Ⅱ、Ⅲ和Ⅳ均为首次从南瓜属植物中分离得到.     

三华李酒生产工艺研究

研究了菌种、三华李原汁含量、不同缓冲剂、不同碳源等因素对三华李原汁发酵果酒的影响,并对三华李酒的澄清工艺进行了研究,最终得到澄清透明三华李味浓郁的三华李酒。     

Analysis of tannins in seeds and skins of Shiraz grapes throughout berry development

The flavan-3-ol and proanthocyanidin composition of both seeds and skin of Vitis vinifera L. cv. Shiraz grapes was determined by reversed-phase HPLC after acetone extraction and acid-catalysis in the presence of excess phloroglucinol. Samples were taken at weekly intervals from fruit-set until commercial harvest. The main period of proanthocyanidin accumulation in grape seeds occurred immediately after fruit-set with maximum levels observed around veraison. Over two seasons there was variation in both the timing and content of proanthocyanidins in seeds. In skin, proanthocyanidin accumulation occurred from fruit set until 1–2 weeks after veraison. Proanthocyanidin subunit composition was different in seeds and skin and changed during berry development but the mean degree of polymerisation of the tannin polymers in skins was higher than in the seeds at all stages of berry development. Proanthocyanidin levels in both seeds and skin decreased between veraison and harvest. Additional proanthocyanidin subunits were released when the residues remaining after acetone extraction were subjected to direct acid-catalysis in the presence of phloroglucinol. In the seeds, these accounted for much of the post-veraison decrease, but not in grape skin. At harvest, 75% of extractable berry proanthocyanidin was in the seeds. Accumulation of proanthocyanidins in the seeds appears to be independent of that in the skins, but in both tissues synthesis occurs early in berry development and maximum levels are reached around veraison.     

香榧籽油对高脂膳食SD大鼠脂质代谢的影响及机理

为推进对香榧籽油生物功效的认知,以高脂膳食大鼠模型评估香榧籽油的降脂、抗氧化功效及其作用机理。将40只SD大鼠随机分为正常对照组（NF组）、2%香榧籽油正常组（NFO组）、高脂对照组（HF组）、2%香榧籽油高脂组（HFO组）。每周记录SD大鼠体重,分别在第4周和第7周检测血清中总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）、血糖（Glu）、超氧化物歧化酶（SOD）、丙二醛（MDA）、谷胱甘肽过氧化物酶（GSH-Px）、总抗氧化能力（T-AOC）、C反应蛋白（CRP）、白介素6（IL-6）、白介素4（IL-4）水平。在第7周处死大鼠,解剖取肝脏、十二指肠、脂肪组织,采用油红O、苏木精-伊红（HE）染色观察组织形态,并采用qRT-PCR检测肝脏脂质代谢相关基因的表达。结果表明：实验第4周,与NF组相比,香榧籽油能极显著降低SD大鼠体重（P<0.01）,整个实验周期内HF、HFO组大鼠体重无显著差异;与NF组相比,NFO组大鼠血清TG、Glu、MDA水平显著下降（P<0.05）,HDL-C水平显著提高（P<0.05）;与HF组相比,香榧籽油能显著降低大鼠血清TC、LDL-C和Glu水平（P<0.05）,显著提高SOD、GSH-Px的活性和T-AOC（P<0.01,P<0.05）。实验第7周,与NF组相比,NFO组大鼠血清LDL-C水平极显著上升（P<0.01）,TC、MDA水平显著下降（P<005）;与HF组相比,香榧籽油能显著升高大鼠血清TG、LDL-C、MDA、CRP、IL-4水平（P<0.05,P<001）;长期食用香榧籽油,大鼠肝脏、十二指肠组织中偶有炎性细胞浸润,脂肪组织细胞形态大小不均。NFO组大鼠肝脏AMPKα、SREBP-1c基因表达水平极显著高于NF组（P<0.01）,HFO组大鼠肝脏FAS、ACC、AMPKα基因表达水平极显著低于HF组（P<0.01）。香榧籽油可能通过调节AMPKα/SREBP-1c信号通路实现调节大鼠血脂、提高抗氧化水平的生物功效。     

大久保桃的催熟条件研究

本文研究了冷藏后的大久保桃适宜的催熟方式、温度和时间对桃果实和软白桃罐头感官品质和理化指标的影响,并分析了原料利用率。结果表明:大久保桃采用打孔的PE袋包装,催熟效果较好,此时桃的腐败指数和褐变指数低,风味浓郁;有效冷藏18 d内的大久保桃,30℃催熟3 d后,生产的软白桃罐头感官和理化指标均达到国标要求;原料利用率均保持在83.31%以上。该研究为软白桃罐头加工中的桃催熟处理提供了技术依据。     

Isolation,purification, and antioxidant activities of polysaccharides from Ziziphus Jujuba cv. Muzao

In the present study, crude polysaccharides from Ziziphus Jujuba cv. Muzao were isolated and purified using DEAE cellulose-52 and Sephadex G-100 size-exclusion chromatography; four fractions were collected, namely GZMP-1, GZMP-2, GZMP-3, and GZMP-4. The molecular weights of these four fractions were measured to be 111.2, 95.1, 84.2, and 571.4 kDa, respectively, using high-performance gel permeation chromatography. Gas chromatography analysis of the monosaccharide composition confirmed that GZMP-1 was composed of rhamnose, arabinose, glucose, and galactose. Rhamnose, arabinose, and galactose were the main components present in GZMP-2 and GZMP-3, whereas GZMP-4 was composed of only rhamnose and arabinose. Scanning electron microscopy showed relatively smooth surfaces for GZMP-1 and GZMP-4, whereas GZMP-2 and GZMP-3 had more folds on their surfaces. Fourier transform infrared spectroscopy analyses indicated that GZMP-1 and ZMP mainly had α-type glycosidic linkages. The in vitro antioxidant activities of the polysaccharides revealed that jujube polysaccharides exhibit remarkable antioxidant activity, and can scavenge DPPH radical and OH radical in a concentration-dependent manner. The results of this work suggest that polysaccharides from Z. Jujuba cv. Muzao have potential to be used as functional food and in the development of natural antioxidant drug carriers.     

白肉番石榴总黄酮提取工艺优化及体外抗氧化活性分析

对白肉番石榴中总黄酮的提取工艺进行优化,并研究其体外的抗氧化活性。以珍珠番石榴(白肉)的叶、皮为原料,在单因素实验的基础上,以总黄酮提取量为指标,采用正交试验优化获得了番石榴叶、皮中总黄酮的提取工艺。在此基础上提取番石榴果肉中的总黄酮,然后比较番石榴叶、皮、果肉中黄酮的体外抗氧化作用。结果表明,番石榴叶、皮的总黄酮的最优提取工艺略有差异。番石榴叶总黄酮的提取最优工艺为:乙醇浓度50%,提取温度65 ℃,料液比1:20 (g/mL),提取时间135 min。番石榴皮总黄酮提取最优工艺为:乙醇浓度60%,提取温度45 ℃,料液比1:7 (g/mL),提取时间105 min。在最优条件下番石榴叶、皮总黄酮的提取量分别为(188.66±0.23)、(48.03±0.16) mg/g。番石榴叶、皮、果肉总黄酮在ABTS自由基及羟基自由基清除实验、铁还原力及总抗氧化力测定分析中显示良好的抗氧化活性,其中番石榴叶总黄酮的体外抗氧化能力最强。由此说明番石榴黄酮有望成为一种良好的天然抗氧化剂。     

Loss of ascorbic acid during storage of Conference pears in relation to the appearance of brown heart

To investigate the causes of brown heart (BH) in Conference pears, the contents of ascorbic acid (AA) and dehydroascorbic acid (DHAA) in fruits were studied during the first period of storage. AA was studied in 1999 and 2000, DHAA in 1999 only. Pears from normal and very late harvest stored immediately or after a delay in a controlled atmosphere with 2% O₂ and low (0.7%) or high (5%) CO₂ were compared. DHAA content did not change during storage in any treatment. AA decreased in storage according to an exponential model. The rate of AA loss was different in the two years and was higher in late‐harvest fruits and in those stored in 5% CO₂. BH appeared in different treatments when AA decreased below a threshold, which was about 2 mg kg^?1 fresh weight, corresponding to 5% of the AA content at harvest. The frequency and severity of symptoms depended linearly on the time spent by fruits in low‐ascorbate conditions. Advanced maturity at harvest and storage in high CO₂ determine the appearance of BH and increase the rate of AA loss, probably through a reduction in the turnover of antioxidants. © 2002 Society of Chemical Industry     

海南4种茶水提物的抗氧化及抑菌活性比较

为比较海南苦丁茶、白沙绿茶、大叶种茶及鹧鸪茶4种茶水提物的抗氧化及抑菌活性,本实验通过水浸提法获得4种茶的水提物,利用分光光度法测试其体外抗氧化活性;并以5株酿酒酵母及5种致病细菌为靶标,分别测定了4种茶水提物的抗氧化活性及抑菌活性。结果表明:苦丁茶、白沙绿茶、大叶种茶及鹧鸪茶水提物的提取率分别为29.31%、23.02%、27.07%和16.18%;总多酚含量分别为(251.48±12.30)、(315.05±10.98)、(395.05±27.70)、(420.05±25.65)mg GAE/g DW;总黄酮含量分别为(691.60±19.47)、(292.60±18.36)、(524.93±1.53)、(217.60±7.00)mg RE/g DW;4种茶的总抗氧化能力结果由强到弱为:大叶种茶>鹧鸪茶>白沙绿茶>苦丁茶;特别是鹧鸪茶和大叶种茶对二苯基苦酰肼基(Diphenyl picryl hydrazinyl radical,DPPH)自由基、2'-联氨-双-3-乙基苯并噻唑啉-6-磺酸(2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)自由基及超氧阴离子的清除率均高于标准品芦丁和特丁基对苯二酚(Terbutyl hydroquinone,TBHQ)。同时4种茶对H₂O₂氧化应激胁迫下的5株酿酒酵母模式菌株的存活率均有提高,其中苦丁茶对基因缺陷型菌株gsh1Δ的存活率提高最明显,为30.21%。4种茶对致病细菌有较好的抑制作用,其中大叶种茶对金黄色葡萄球菌抑制效果最优,最小抑菌浓度(Minimum inhibitory concentration,MIC)为1.56 mg/mL。由此表明,4种茶水提物具有不同的抗氧化活性和抑菌活性,且多酚含量与活性之间具有较好的相关性。