Stability of phenolic and protein measures in excised oak foliage

The stability of protein and phenolic measures in excised foliage from two oak species was measured under conditions that simulated the handling and treatment of foliage during insect rearing trials. Excised foliage kept hydrated under refrigeration or insect-rearing conditions maintained stable levels of protein content, proanthocyanidins, gallotannins, total phenolics, and protein-binding capacity for up to 48 hr following field sampling. Measures of protein content, total phenolics, protein-binding capacity, and proanthocyanidins were significantly greater 48–72 hr after field sampling, followed by declines to near field levels within 120 hr.     

Differential Activity of Peroxidase Isozymes in Response to Wounding, Gypsy Moth, and Plant Hormones in Northern Red Oak (Quercus rubra L.)

We measured total peroxidase activity and the activities of peroxidase isoforms in leaves of red oak (Quercus rubra L.) seedlings exposed to wounding and plant hormones in the greenhouse. Activity of specific peroxidase isoforms was induced differentially by gypsy moth wounding, mechanical wounding, and the wound-associated plant hormone jasmonic acid. Activity of one isoform was enhanced modestly by treatment with salicylate. A study of peroxidase activity in naturally occurring galls elicited on red oak leaves by 12 hymenopteran and dipteran insect species found 16 POD isoforms, 11 of which were differentially induced or suppressed in galls compared with leaves. In both studies, total peroxidase activity as measured spectrophotometrically was not clearly related to activity of these isoforms. These results indicate that red oak seedlings and trees may respond specifically to wounding, particular insects, and plant signals through changes in the activities of individual isozymes.     

柞木磺化化机浆的研究（Ⅱ）：本色柞木磺化化机浆的漂白

为了确定柞木磺化化机浆 (SCMP)的可漂性及较适宜的漂白工艺条件 ,并对配抄新闻纸做初步探讨 ,进行了柞木SCMP的H2 O2 漂白研究。研究结果表明 ,影响漂白的各因素显著程度是H2 O2 用量 >漂白时间 >漂白温度。在H2 O2用量 2 %、温度 5 0℃、时间 12 0min的最佳条件下 ,可使柞木SCMP的白度升高 17.7% ,最终白度达 5 0 .2 %SBD。用漂后浆配抄新闻纸 ,其配比是漂白针叶木浆 2 0 % ,杨木磨木浆 6 4% ,柞木SCMP16 % ,手抄片抗张指数为 2 4.5 3N·m/g ,白度为 5 5 .8%SBD ,达到 2号新闻纸的国家标准。     

Discriminant Analysis of Geographical Origin of Cork Planks and Stoppers by Near Infrared Spectroscopy

Abstract

The objective of this study was to assess the potential of visible and near infrared spectroscopy (VIS+NIRS) combined with multivariate analysis for identifying the geographical origin of cork. The study was carried out on cork planks and natural cork stoppers from the most representative cork-producing areas in the world. Two training sets of international and national cork planks were studied. The first set comprised a total of 479 samples from Morocco, Portugal, and Spain, while the second set comprised a total of 179 samples from the Spanish regions of Andalusia, Catalonia, and Extremadura. A training set of 90 cork stoppers from Andalusia and Catalonia was also studied. Original spectroscopic data were obtained for the transverse sections of the cork planks and for the body and top of the cork stoppers by means of a 6500 Foss-NIRSystems SY II spectrophotometer using a fiber optic probe. Remote reflectance was employed in the wavelength range of 400 to 2500 nm. After analyzing the spectroscopic data, discriminant models were obtained by means of partial least square (PLS) with 70% of the samples. The best models were then validated using 30% of the remaining samples. At least 98% of the international cork plank samples and 95% of the national samples were correctly classified in the calibration and validation stage. The best model for the cork stoppers was obtained for the top of the stoppers, with at least 90% of the samples being correctly classified. The results demonstrate the potential of VIS + NIRS technology as a rapid and accurate method for predicting the geographical origin of cork plank and stoppers.     

蒙古栎橡子中单宁的脱除工艺

研究超声波脱除蒙古栎橡子中单宁的工艺。通过单因素试验选择对单宁脱除效果影响较大的因素进行正交试验,确定的最佳脱除条件为乙醇溶液体积分数40%、料液比1:30(g/mL)、颗粒度80目以上、超声温度55℃、超声功率400W、超声时间60min。在此条件下可以使单宁脱除量达到69.99mg/g。     

栓皮栎橡子淀粉的加工特性研究

本文以市售马铃薯、红薯、绿豆、玉米淀粉为对照,采用电子显微镜、粘度分析仪、质构仪研究了秦巴山区栓皮栎橡子淀粉的颗粒形貌、直支链淀粉含量、糊化特性、冻融稳定性、凝胶特性。结果表明:栓皮栎橡子淀粉颗粒呈肾形、三角形、卵圆形、球形等,平均粒径9.4μm,均小于对照淀粉颗粒;栓皮栎橡子淀粉糊化温度71.23℃,糊化粘度值大于玉米而小于马铃薯、绿豆和红薯淀粉,热糊稳定性优于红薯、绿豆、马铃薯而劣于玉米淀粉,回生速度快于马铃薯、玉米、红薯而慢于绿豆淀粉,冻融稳定性优于马铃薯淀粉而劣于绿豆、玉米、红薯淀粉;在同浓度下,栓皮栎橡子淀粉凝胶的硬度、胶着性、咀嚼性小于绿豆淀粉而大于玉米、马铃薯、红薯淀粉,其凝胶弹性大于马铃薯淀粉凝胶,而与玉米和绿豆淀粉凝胶相当,小于红薯淀粉凝胶,粘聚性和恢复性均大于对照淀粉凝胶,宜作为面条、粉条、粉皮、凉粉和等凝胶类食品的辅助品质改良材料以及作为稳定剂应用于糖果和烘焙工业当中,不宜用于冷冻食品。     

麻栎叶黄酮的大孔树脂分离及其对α-葡萄糖苷酶活性的抑制作用

研究麻栎叶黄酮的大孔吸附树脂分离纯化工艺,并考察其对α-葡萄糖苷酶活性的抑制作用。通过大孔树脂静态吸附动力学实验,在确定大孔树脂类型的基础上,探索其最佳纯化工艺,结果表明,X-5是适用于麻栎叶黄酮吸附分离的较理想的树脂类型。X-5大孔吸附树脂分离纯化麻栎叶黄酮的最佳条件为:上柱液浓度52.79μg/mL左右,上柱液量为50mL,上柱液流速为0.5mL/min,上柱液pH为5。用95%乙醇进行洗脱,洗脱液流速为1.0mL/min,洗脱液量为30mL。在上述最佳条件下,X-5大孔吸附树脂分离纯化麻栎叶黄酮的纯度达58.33%。麻栎叶黄酮具有很强的抑制α-葡萄糖苷酶活性,IC为13.11μg/mL。     

白栎淀粉加工技术研究

白栎是壳斗科（Fagaceae）栎属（Quercus）落叶树种,其果实营养丰富,是我国传统食品的原料之一。目前对白栎淀粉的加工技术研究较少,因此本文主要进行白栎淀粉提取工艺技术、栎粉保藏工艺技术以及栎粉豆腐加工技术的研究,探讨成本低、技术实用、产品质量较好的加工工艺,为进一步的开发利用和产业化提供参考