Effect of Dehydration on Raspberries: Polyphenol and Anthocyanin Retention, Antioxidant Capacity, and Antiadipogenic Activity

ABSTRACT:  Fresh and dried raspberries prepared by freeze drying (FD), microwave-vacuum (MIVAC), hot-air drying (HAD), and a combination of hot-air drying and microwave-vacuum (HAD/MIVAC) drying methods were evaluated for polyphenol retention, total polyphenol and anthocyanin contents, total antioxidant capacity, and antiadipogenic activity (the inhibition of fat cell development). Ellagic acid and quercetin were present in the largest concentrations in fresh and dehydrated raspberries. Dehydration led to a loss of polyphenols and anthocyanins and antioxidant capacity. Polyphenols (aglycone form) were retained in the greatest amount: 20% (freeze dried) to 30% (HAD/MIVAC) (fresh = 100%). A total of 30% of polyphenols (glycoside form) were retained in raspberries dried by the HAD/MIVAC methods with 5% of retention observed for raspberries dried by FD, HAD, or MIVAC. FD and MIVAC resulted in higher retention of anthocyanins (aglycone form) than other drying methods. It was also observed that antioxidant activity was reduced by dehydration. Adipogenesis was inhibited by polyphenolic glycosides (30%) and aglycones (30% to 40%) in fresh and HAD/MIVAC raspberries. Extracts from dried raspberries by HAD/MIVAC methods were relatively more effective at inhibiting adipogenesis compared to HAD and FD dried raspberries.     

超声波辅助复合酶法提取枸杞多糖工艺研究

以枸杞为试验材料,研究了超声波辅助复合酶（脂肪酶/蛋白酶/纤维素酶/果胶酶=1:1:1:1）提取枸杞多糖的工艺条件。以枸杞多糖得率为评价指标,通过正交试验确定了最佳提取条件为料液比1∶40（g∶mL）,提取温度50 ℃,超声时间50 min,复合酶添加量0.5%。在此最佳条件下,枸杞多糖平均得率为58.910%。     

酸果蔓提取物的抗氧化活性及稳定性研究

利用分光光度法对酸果蔓提取物的抗氧化活性进行了检测,并研究了在不同条件下提取物的稳定性。结果表明,酸果蔓提取物对羟自由基、超氧阴离子自由基的清除率分别是78．4%、91．5%,对脂质过氧化的抑制率为85．7%。在酸性及氯化钠溶液中能稳定存在,有较好的光稳定性,在75℃下有较好的热稳定性。     

Alterations in antioxidant status of rats following intake of ginger through diet

Ginger is known to possess potent antioxidant and anti-inflammatory properties. Therefore, in vivo studies in rats were initiated to investigate if ginger fed through diet can improve their antioxidant status. Inbred male Wistar/NIN rats were divided into four groups containing six animals per group. The 1st group received a stock diet whereas the 2nd, 3rd and 4th groups were fed with a diet incorporating ginger powder at 0.5%, 1% and 5% levels for a period of one month. After one month of feeding, rats were sacrificed and their livers and kidneys collected for the analysis of antioxidant enzymes like superoxide dismutase (SOD), catalase and glutathione peroxidase (GSHPx), and to estimate lipid peroxidation and protein oxidation. The levels of all the three enzymes, which are the important components of antioxidative defenses, were significantly stimulated in the livers of groups fed with ginger. The significant reduction in lipid peroxidation in livers and kidneys and inhibition of protein oxidative products in livers indicated the antioxidant potential of ginger when consumed naturally through diet. The findings reported suggest that regular intake of ginger through diet can protect against oxidative tissue damage.     

干腌火腿中肽的形成机理研究进展

干腌火腿加工过程中,在肌肉中内源酶和微生物的共同作用下,产生多种具有特定生物活性或对产品风味具有提升作用的肽。抗氧化肽、降血压肽和抗菌肽等生物活性肽提升火腿的营养价值;呈味肽如鲜味肽、甜味肽、苦味肽、酸味肽、咸味肽及浓厚感肽,有助于形成火腿独特的风味。该文综述了干腌火腿中肽的功能特性,重点对加工过程中肽的影响因素及形成机理进行介绍,为干腌火腿品质特性提升和新工艺设计提供理论参考依据。     

固相萃取-加压毛细管电色谱法测定酵素中敌螨普的残留

该研究建立了一种快速、高效的加压毛细管电色谱法检测酵素中敌螨普残留的分析方法,并依据所建立的方法研究不同酵素中敌螨普残留的情况。样品经体积分数20%的乙腈提取,PRiME HLB小柱净化后检测。以乙腈-15 mmol/L磷酸钾缓冲液（pH 4.7）(15∶85,V/V)为流动相,在电压强度+2 kV条件下,外标法峰面积定量。结果表明,敌螨普标准溶液在0.001～0.200μg/mL质量浓度范围内线性良好,相关系数R为0.999 1,检出限（LOD）为1.0μg/kg,定量限（LOQ）为3.0μg/kg,加标回收率达到85.6%～92.9%,精密度试验结果相对标准偏差（RSD）为2.83%～5.12%。该方法具有前处理简单、快速的优点,适用于多种酵素中敌螨普残留分析。     

Biocatalysis with Thermostable Enzymes: Structure and Properties of a Thermophilic ‘ene’‐Reductase related to Old Yellow Enzyme

We report the crystal structure of a thermophilic “ene” reductase (TOYE) isolated from Thermoanaerobacter pseudethanolicus E39. The crystal structure reveals a tetrameric enzyme and an active site that is relatively large compared to most other structurally determined and related Old Yellow Enzymes. The enzyme adopts higher order oligomeric states (octamers and dodecamers) in solution, as revealed by sedimentation velocity and multiangle laser light scattering. Bead modelling indicates that the solution structure is consistent with the basic tetrameric structure observed in crystallographic studies and electron microscopy. TOYE is stable at high temperatures (T_m>70 °C) and shows increased resistance to denaturation in water‐miscible organic solvents compared to the mesophilic Old Yellow Enzyme family member, pentaerythritol tetranitrate reductase. TOYE has typical ene‐reductase properties of the Old Yellow Enzyme family. There is currently major interest in using Old Yellow Enzyme family members in the preparative biocatalysis of a number of activated alkenes. The increased stability of TOYE in organic solvents is advantageous for biotransformations in which water‐miscible organic solvents and biphasic reaction conditions are required to both deliver novel substrates and minimize product racemisation.     

Enzymatic membrane reactors: the determining factors in two separate phase operations

A two separate phase‐enzymatic membrane reactor is an attractive process since it has a large interfacial area and exchange surfaces, simultaneous reaction and separation and other benefits. Many factors influence its successful operation, and these include characteristics of the enzyme, membrane, circulating fluids and reactor operations. Although the operating conditions are the main factor, other factors must be considered before, during or after its application. At the initial stage of reactor development, the solubility of substrates and products, type of operation, membrane material and size, enzyme preparation and loading procedure, and cleanliness of the recirculated fluids should be specified. The immobilization site, reactor arrangement, dissolved or no‐solvent operation, classic or emulsion operation and immobilized or suspended enzyme(s) are determined later. Some factors still need further studies. Utilization of the technology is described for use from multigram‐ to plant‐scale capacity to process racemic and achiral compounds. The racemates were resolved primarily by kinetic resolution, but dynamic kinetic resolution has been exploited. The technology focused on hydrolytic reactions, but esterification processes were also exploited. Copyright © 2011 Society of Chemical Industry     

Genistein Inhibits Osteoclastic Differentiation of RAW 264.7 Cells via Regulation of ROS Production and Scavenging

Genistein, a phytoestrogen, has been demonstrated to have a bone-sparing and antiresorptive effect. Genistein can inhibit the osteoclast formation of receptor activator of nuclear factor-κB ligand (RANKL)-induced RAW 264.7 cells by preventing the translocation of nuclear factor-κB (NF-κB), a redox-sensitive factor, to the nucleus. Therefore, the suppressive effect of genistein on the reactive oxygen species (ROS) level during osteoclast differentiation and the mechanism associated with the control of ROS levels by genistein were investigated. The cellular antioxidant capacity and inhibitory effect of genistein were confirmed. The translation and activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (Nox1), as well as the disruption of the mitochondrial electron transport chain system were obviously suppressed by genistein in a dose-dependent manner. The induction of phase II antioxidant enzymes, such as superoxide dismutase 1 (SOD1) and heme oxygenase-1 (HO-1), was enhanced by genistein. In addition, the translational induction of nuclear factor erythroid 2-related factor 2 (Nrf2) was notably increased by genistein. These results provide that the inhibitory effects of genistein on RANKL-stimulated osteoclast differentiation is likely to be attributed to the control of ROS generation through suppressing the translation and activation of Nox1 and the disruption of the mitochondrial electron transport chain system, as well as ROS scavenging through the Nrf2-mediated induction of phase II antioxidant enzymes, such as SOD1 and HO-1.