ANTHOCYANIN PIGMENTS OF SOUR CHERRIES

Fresh fruits of tart cherries (Prunus cerasus L. var. Montmorency) were extracted with acidic methanol. The anthocyanin pigments were isolated and purified by conventional paper chromatography. They were identified by spectral and R_f data and by acid hydrolysis. The pigments were cy anidin-3-glucosylrutinoside, cyanidin-3-glucosylsambubioside, cyani-din-3-sophoroside, cyanidin-3-rutinoside, cyanidin-3-glucoside and peoni-din-3-rutinoside. No free cyanidin or peonidin was found. Cyanidin-3-glucosylsambubioside, reported in cherries for the first time, was also found in the varieties of English Morello, Early Richmond and Meteor     

QUANTITATIVE METHODS FOR ANTHOCYANINS

SUMMARY –A qualitative technique for the determination of the individual flavonol pigments of cranberries was developed, based on cellulose thin-layer chromatography. The method was such that it was suitable for quantitative use by removing the pigment spots and measurement of the selected pigments by spectrophotometry. A quantitative technique for total flavonols, expressed as quercetin, based on spectrophotometry at 374 nm was developed. Total flavonols and total anthocyanins can be determined on the same extract.     

STABILIZATION OF CARROT JUICE BY DILUTE ACID TREATMENT

SUMMARY– A problem arises if juice extracted from raw carrots is heated to about 180° before or during conventional canning practices. An unsightly, unappetizing coagulum forms and the color of the juice precipitates with the coagulum. The coagulum is not as evident if the carrots are heated 5 min in water prior to juice extraction, but the juice loses some of its bright-orange color. The canned juice extracted from carrots heated 5 min in a .05 N acetic acid solution does not coagulate and the amount of juice which can be extracted from the carrots is 3.3% greater than that from carrots heated 5 min in water. The centrifuged juice from acid-treated carrots had a brighter orange color than juice from the water-treated carrots. The color notation was Rd, 23.7, a, 30.4 and b, 34.8 for juice from acid-treated carrots compared with a notation of Rd, 19.2, a, 24.4 and b, 31.4 for the juice from water-treated carrots. The canned juice extracted from raw carrots had less pectic substances and starch and about the same amount of protein as the canned juice from the carrots heated in water or .05 N acetic acid, but the canned juice from raw carrots coagulated. The juice from carrots heated in acid does not form a coagulum and maintains its orange color, probably because of the action of the heat and acid on the protoplasmic liquid of the cell before or immediately after the cell is ruptured.     

Phase Relationships in the System Zirconia—Ceria

The phase relationships in the system zirconia-ceria were investigated by X-ray diffraction and dilatometric methods. The specimens were prepared by mixing and compacting the oxide powders and firing at 2000°C. At 2000°C. zirconia and ceria are miscible in each other from about 24 to 100 mole % ceria. The range of solid solubility decreases markedly with temperature, so that near 1000°C. the solubility of zirconia in ceria is only about 10 mole %. The addition of 0 to 1.5 mole % ceria lowers the temperature at which zirconia transforms from the tetragonal to the monoclinic form. Near 15%, therefore, this temperature is below room temperature and zirconia is stabilized. On the basis of these results, a tentative phase diagram of the system zirconia-ceria is presented. Experiments also have been conducted with zirconia containing 13.8 mole % magnesia (stabilized zirconia). In this case the solubility between stabilized zirconia and ceria is complete at high temperature (2000°C.). At lower temperature, however, the solid solution breaks down and a two-phase region appears in the center of the diagram.     

挤压AZ31B镁合金的低周疲劳性能(英文)

通过外加总应变幅控制的拉-压对称疲劳试验,研究常温下挤压AZ31B镁合金在不同应变幅下的疲劳性能。结果表明,除了在低应变幅0.5%外,样品均呈现循环应变硬化;应变幅为0.5%时,样品在初始阶段呈现循环硬化,随后保持应力恒定;在压缩过程中孪晶的产生以及随后的卸载和反向拉伸过程中的去孪晶行为导致了高应变幅下的滞回环形状拉-压不对称现象,而低应变幅0.5%下的滞回环形状基本对称,说明低应变幅下孪生-去孪生现象不明显。在整个疲劳过程中,高应变和低应变下的应力—应变曲线呈现2种不同的滞回环形状,这是由不同疲劳阶段孪生和位错滑移2种不同的变形机制所导致。     

Free and Bound Volatile Secondary Metabolites of Vitis Vhifera Grape cv. Sauvignon Blanc

Free volatiles, and those hydrolytically released from glycosidic forms, were analyzed for Sauvignon Blanc juices from three successive vintages. Most of the 213 compounds identified were in one of the bio-genetic categories: norisoprenoids, benzene derivatives, monoterpenes or aliphatics. Several have not been previously reported as grape components. Monoterpenes were in lower concentration than normally found in floral grape varieties, but at higher levels than reported in Chardonnay juices. A notable proportion (40–50%) of the bound monoterpenes were monocyclic. Hydration of α-terpineol at pH 3 gave c-4-(1-hydroxy-1-methyIethyl)-1-methyl-r-1-cyclohexanol (cis-p-men-thane-1,8-diol) and t-4-(1-hydroxy-1-methylethyl)-1-methyl-r-1-cy-clohexanol (trans-p-menthane-1,8-diol) as the main products and a low yield of t-4-(1-methylethyl)-r-1-methylcyclohexane-1,4-diol (trans-p-menthane-1,4-diol). These were confirmed as major components of the acid hydrolysates of the bound fraction.