玉米赤霉烯酮毒素降解酶基因的克隆及在毕赤酵母中的高效表达

以粉红黏帚霉菌株总RNA为模板,采用RT-PCR技术克隆得到玉米赤霉烯酮降解酶基因cD-NA序列,插入pPIC9K载体后,转化毕赤酵母。经MD板筛选,得到His+型重组子,进行甲醇诱导表达,并进行了降解玉米赤霉烯酮能力测定。克隆得到的cDNA序列全长795 bp,连续编码编码264个氨基酸;阳性克隆子在甲醇诱导培养3~5 d后,HPLC检测证实,经表达后的酶液能完全降解液体中玉米赤霉烯酮(ZEN)。     

芋的贮藏与保鲜

由于芋水分含量高、酚类物质存在,整芋特别是鲜切芋的贮藏与保鲜很重要。我国常见芋艿品种的贮藏与保鲜技术,整芋的贮藏与保鲜涉及室内外贮藏差异、不同的贮存介质差异、不同的品种差异、不同的芋艿部位差异以及贮藏温度的要求;鲜切芋的贮藏与保鲜涉及不同的包装材料、不同的涂膜处理、不同的加工方法、不同的保鲜剂对鲜切芋艿的影响。为芋艿贮藏与保鲜开辟新蹊径提供新思路。     

芦笋下脚料中黄酮类物质分离纯化及鉴定

通过研究大孔吸附树脂的吸附和解吸性能,确定了AB-8型树脂分离纯化芦笋下脚料中黄酮类物质的条件为:吸附流速2mL/min,洗脱流速1.5mL/min;吸附原液pH6,洗脱剂为体积分数大于70%乙醇溶液,洗脱剂用量为200mL。纯化后的黄酮类物质经颜色反应和紫外光谱鉴定,主要为黄酮醇类。     

Functional properties of different Korean sweet potato varieties

Eight different varieties of Korean sweet potatoes (SPs) were investigated to develop new healthy foods. The purple-fleshed SPs, ‘Shinjami’ and ‘Borami’, the orange-fleshed SPs, ‘Juwhangmi’ and ‘Shinwhangmi’, and the white/cream-fleshed dry-type SPs, ‘Shinyulmi’, ‘Shinchunmi’, ‘Yeonwhangmi’, and ‘Jeungmi’, were used. Alcohol insoluble solids (AIS), total dietary fiber (TDF), anthocyanin, carotenoid, and phenolic compounds contents for SP powders vary significantly (p<0.05) between different varieties. The TDF, anthocyanin, and the total phenolic compounds of SPs had the highest values in the purple-fleshed SPs (10.11–10.87%, 2.43–3.35 mg/g, and 454.13–638.79%, respectively) and the lowest values in the white/cream-fleshed dry-type SPs. The carotenoids of the orange-fleshed SPs were higher in ‘Juwhangmi’ than in ‘Shinwhangmi’. The color differences among the purple-fleshed SPs were 3–4 times larger than those of other SPs. The antioxidant activities of the purple-fleshed SPs were higher than those of other SPs.     

梳棉机加装梳针分梳板对涤纶纱质量的影响

探讨梳棉机刺辊下加装梳针分梳板对涤纶纱质量的影响。在梳棉机刺辊下分别加装小漏底和梳针分梳板,在820 r/min、1 054 r/min和1 290 r/min三档刺辊速度条件下,分别对其所加工的纱进行了条干和强力的检测。结果表明:与刺辊下配置小漏底相比,加装梳针分梳板更有利于成纱条干的改善,对降低成纱千米细节效果较为明显,在刺辊速度为1 054 r/min时对成纱千米棉结有十分明显的改善作用,但对成纱千米粗节并没有改善作用。认为:加装梳针分梳板对成纱强力和强力不匀率在刺辊速度较低时有一定的改善作用。     

芳砜纶混纺防护服织物的设计及性能研究

为改善芳砜纶混纺织物的撕破强力,选用芳砜纶和国产芳纶131 3不同混纺比纱线和织物组织结构,进行了防护服织物设计及试织,并测试了织物撕破强力和阻燃性能。结果表明:随着混纺纱中芳砜纶含量的增加,织物的阻燃性能得以改善;同等规格的织物,防撕裂格子布的撕破强力优于方平组织织物。经综合比较后认为,芳砜纶芳纶1313混纺比为75/25的防撕裂格子组织织物成本最低。     

Antioxidant and <Emphasis Type="Italic">α</Emphasis>-glucosidase inhibitory activities of different solvent extracts of skullcap (<Emphasis Type="Italic">Scutellaria baicalensis</Emphasis>)

In this study, different solvent extracts of skullcap (Scutellaria baicalensis) were assayed for their total phenol content (TPC), antioxidant activity [determined as DPPH radical scavenging activity, superoxide dismutase (SOD)-like activity, oxygen radical absorbance capacity (ORAC) assay, and comet assay], and α-glucosidaseinhibitory activity. The TPC of skullcap ranged from 9.06 mg/g gallic acid equivalents (GAE) for acetone extract (AE) to 91.8 mg/g GAE for methanol extract (ME). AE, which had a low TPC, exhibited the highest DPPH radical scavenging activity and SOD-like activity. TPC positively correlated with the ORAC assay (r=0.96, p<0.001). All skullcap extracts significantly reduced the hydrogen peroxide-induced DNA damage in human leukocytes. ME with a high TPC and ORAC value showed the highest α-glucosidase inhibition. The difference in the biological activities of the extracts may be due to the differences in their chemical structure or polarity. Therefore, the results obtained indicate that might be a potential source of compounds with health-protective effects. ME, in particular, might be a prospective therapeutic agent for diabetes.     

Antioxidant and tyrosinase inhibitory activities of different parts of guava (<Emphasis Type="Italic">Psidium guajava</Emphasis> L.)

The antioxidant and the tyrosinase inhibitory activities of 4 different solvents (acetone, ethanol, methanol, and water) for preparation of extracts from guava (branch, fruit, leaf, and seed) were evaluated by measuring total phenolic contents (TPC), DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power (RP), and tyrosinase inhibitory activity. The extracts of branch and leaf showed relatively higher antioxidant properties than those of fruit and seed. The highest TPC (141.28 mg/g gallic acid equivalents), DPPH radical scavenging activity (IC₅₀=34.01 μg/mL), ABTS radical scavenging activity (IC₅₀=3.23 μg/mL), and RP (IC₅₀= 75.63 μg/mL) were found in acetone extract of leaf, while water extract of seed had the lowest antioxidant activity. The tyrosinase inhibitory activity of ethanol extract from guava leaf was 69.56%, which was the highest activity among the extracts. These results indicate that useful bioactive substances exist in the guava branch as well as leaf extracts.     

Effect of angiotensin I-converting enzyme (ACE) inhibitory peptide purified from enzymatic hydrolysates of <Emphasis Type="Italic">Styela plicata</Emphasis>

Angiotensin I-converting enzyme (ACE) inhibitory peptide was isolated from Styela plicata. The S. plicata was hydrolyzed with various proteases including Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase, trypsin, α-chymotrypsin, pepsin, and papain. The hydrolysate prepared with Protamex had the highest ACE inhibitory activity compared to the other hydrolysates. We attempted to isolate ACE inhibitory peptides from hydrolysate prepared with Protamex using ultra-filtration, gel filtration on a Sephadex G-25 column and reversed-phase high-performance liquid chromatography (RP-HPLC) on an ODS column. IC₅₀ value of the purified ACE inhibitory peptide was 24.7 μM, and Lineweaver–Burk plots suggest that the purified peptide from S. plicata acts as mixed-type inhibitor against ACE. Amino acid sequence of the purified peptide was identified as Met-Leu-Leu-Cys-Ser, with a molecular weight 566.4 Da. The results of this study suggest that peptides derived from S. plicata may be beneficial as anti-hypertension compounds in functional foods resource.