Improving storability,physiological disorders,and antioxidant properties of ‘Bartlett’ and ‘d’Anjou’ pears (Pyrus communis L.) by pre-harvest 1-methylcyclopropene spraying

Ethylene continues to be a major factor influencing quality of European pears during storage. Although research has been done on the effect of pre-harvest 1-methylcyclopropene (1-MCP) on physiological characteristics in pears, a full understanding of cultivar response and antioxidant metabolism remains elusive. Spraying 1-MCP on ‘Bartlett’ and ‘d’Anjou’ pears was studied with respect to physiology, storage and eating quality, disorders, and antioxidant properties at two harvest date (H1 and H2) during storage and ripening. Treatment with 1-MCP extended the harvest window of ‘Bartlett’ and ‘d’Anjou’ pears 3 and 4 days, respectively, without reducing storage or eating quality. Treatment with 1-MCP reduced ethylene production (EPR) and respiration rates (RR), maintained fruit firmness and green colour during storage and retarded development of desirable melting texture in both cultivars. Additionally, 1-MCP lowered the incidence of disorders by alleviating membrane lipid peroxidation, retaining high total flavonoids (TF) and antioxidant capacity, and enhancing superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity in both cultivars. Overall, pre-harvest 1-MCP applications could extend storage time of ‘Bartlett’ and ‘d’Anjou’ pears to 5 and 6 months, respectively, at −1.1 ± 0.5 °C, by reducing ethylene synthesis and enhancing antioxidant metabolism.     

黑果腺肋花楸中花色苷超声辅助提取工艺优化研究

目的优化超声辅助提取黑果腺肋花楸中花色苷工艺的方法。方法在单因素的基础上,研究提取温度、液料比和提取时间对花色苷提取率的影响,并利用响应面法对花色苷的提取条件进行优化。结果黑果腺肋花楸中花色苷提取的最佳工艺条件为:乙醇溶液(含0.5%的乙酸)浓度为40%,提取温度为43℃,超声时间为23 min,料液比为89:1(V:m),此条件下,黑果腺肋花楸中花色苷提取得率为(0.79±0.010)g/100g。结论本方法可以快速有效地提取黑果腺肋花楸中的花色苷。     

RT-FQPCR法快速检测葡萄酒中醋酸菌群

建立一种快速、灵敏的检测葡萄酒中醋酸菌群的检测技术。通过改进葡萄酒中脱氧核糖核酸（DNA）提取方法，设计醋酸菌通用引物，优化实时荧光定量聚合酶链式反应（RT-FQPCR）条件，确定葡萄酒中醋酸菌的快速检测方法，同时利用7种醋酸菌对该方法的通用性、特异性以及灵敏度进行了验证。结果表明，7种醋酸菌均具有明显扩增曲线；非目的菌在该种条件下未见扩增，综合检测灵敏度为124 CFU/mL。以10种市售葡萄酒为基质，在其中添加醋酸菌均可检测出目标添加菌株。该方法通用性强，可用于葡萄酒中醋酸菌群的检测。     

Macaroon-like FeCo2O4 modified activated carbon anode for enhancing power generation in direct glucose fuel cell

Macaroon-like FeCo₂O₄ nanomaterial was prepared and used as electrocatalyst in direct glucose alkaline fuel cell (DGAFC), which exhibited high catalytic activity towards glucose oxidation reaction. Maximum power density of 35.91 W m⁻² was achieved in the DGAFC equipped with a FeCo₂O₄ modified activated carbon (AC) anode, which was almost 151% higher than the control. Physical and electrochemical characterizations were performed to provide further understanding of the origin of its high activity. Our results show that the introduction of FeCo₂O₄ into the AC anode remarkably increase the exchange current density and reduce the charge transfer resistance. It is supposed that there is a synergistic effect between Fe (III) and Co (III), which accelerates electron transfer from glucose to external circuits. This study will promote the development of cost effective and environmentally benign catalysts for electrochemical energy applications.     

山楂果胶低聚半乳糖醛酸提取物对中波紫外线辐射HaCaT细胞氧化损伤和光老化的保护作用

探讨了山楂果胶低聚半乳糖醛酸提取物对中波紫外线(ultraviolet B,UVB)辐射后人永生化表皮角质形成细胞(HaCaT)的氧化损伤和光老化的保护作用。体外培养HaCaT细胞,分为对照组(HaCaT细胞不照射UVB,不给予山楂果胶低聚半乳糖醛酸提取物处理)、UVB辐射组(30 mJ/cm~2)、低剂量(5μg/mL)山楂果胶低聚半乳糖醛酸+30 mJ/cm~2 UVB辐射组、高剂量(10μg/mL)山楂果胶低聚半乳糖醛酸+30 mJ/cm~2 UVB辐射组。以噻唑蓝比色法检测细胞活力,采用试剂盒检测超氧化物歧化酶(superoxide dismulase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)、过氧化氢酶(catalase,CAT)和乳酸脱氢酶(lactate dehydrogenase,LDH)活力,丙二醛(malondialdehyde,MDA)含量,羟脯氨酸(hydroxyproline,Hyp)质量浓度和活性氧(reactive oxygen species,ROS)水平。采用酶联免疫吸附测定实验检测肿瘤坏死因子-α(tumor necrosis factor alpha,TNF-α)、白细胞介素-6(interleukin-6,IL-6)质量浓度和基质金属蛋白酶-1(matrix metalloproteinase 1,MMP-1)含量。结果表明,经UVB照射后,Ha Ca T细胞活力明显降低。低、高剂量的山楂果胶低聚半乳糖醛酸提取物对经UVB辐射的HaCaT细胞具有显著的增殖作用(P0.05);SOD、GSH-Px、CAT活力增加;LDH活力、ROS水平和MDA含量下降;Hyp质量浓度增加;MMP-1含量和TNF-α、IL-6质量浓度下降,且与辐射组比较均具有显著或极显著差异(P0.05或P0.01)。实时荧光定量聚合酶链式反应检测MMP-1、TNF-α及IL-6 m RNA表达水平与其含量或质量浓度检测结果一致。因此,山楂果胶低聚半乳糖醛酸对UVB辐射Ha Ca T细胞的氧化损伤及光老化具有保护作用。     

蔓越莓中膳食纤维的结构性质和功能性质研究

目的 考察蔓越莓中膳食纤维的结构性质和功能性质。方法 利用酶解法提取蔓越莓总膳食纤维、不溶性膳食纤维和可溶性膳食纤维, 并采用红外光谱和高效液相色谱测定其官能团结构和分子量, 采用质构仪和粘度计测定其凝胶性质和粘度, 同时对膳食纤维吸附亚硝酸根离子、交换阳离子、胆固醇、重金属和葡萄糖的能力进行研究。结果 总膳食纤维和不溶性膳食纤维的提取率较高, 分别为54.67%和38.70%, 膳食纤维具有凝胶和粘度的性质, 同时在功能上有吸附亚硝酸根离子, 交换阳离子, 吸收胆固醇, 重金属离子和葡萄糖的性能。结论 蔓越莓膳食纤维具有特殊的结构性质和很好的功能活性, 可以开发蔓越莓新功能食品。     

超高压处理对蓝靛果抗氧化物提取量及活性的影响

研究超高压处理对蓝靛果中总抗氧化物、花色苷、多酚、VC提取量及总抗氧化活性的影响,探索细胞微观结构与总抗氧化物提取量的关系。结果表明:提取压力为300 MPa时总抗氧化物提取量最高,为85.20 mg/g(以鲜果计);总抗氧化物冻干粉中总酚、花色苷、VC含量分别在300、400 MPa和对照组中最高,分别为136.48、4.12 μg/mg和27.14 μg/mg。提取压力为400 MPa时,总抗氧化物对2,2’-联氨-双-(3-乙基苯并噻唑啉-6-磺酸)二胺盐自由基清除能力(0.37 mmol/L)、Fe~(3+)还原能力(0.84 mmol/L)、1,1-二苯基-2-三硝基苯肼自由基清除能力(91.5%)最大,表明400 MPa压力条件下提取的抗氧化物活性最高。观察电子显微镜图片发现400 MPa处理对蓝靛果细胞破坏巨大,有利于抗氧化物的提取,从细胞微观结构角度证明超高压处理可以提高蓝靛果抗氧化物提取量;差异显著性分析表明VC、花色苷含量部分组之间不显著,其他组之间差异显著。通过本实验证实:超高压处理可以促进蓝靛果细胞破碎,有利于溶剂与抗氧化物接触,提高抗氧化物的提取量及抗氧化活性。