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排序方式: 共有188条查询结果,搜索用时 49 毫秒
81.
Bean TH 《Science (New York, N.Y.)》1899,9(220):416-417
82.
Julia E. Cremer Liman Liu Scott R. Bean Jae‐Bom Ohm Michael Tilley Jeff D. Wilson Rhett C. Kaufman Thanh H. Vu Edward K. Gilding Ian D. Godwin Donghai Wang 《Cereal Chemistry》2014,91(3):218-227
Seed protein and starch composition determine the efficiency of the fermentation process in the production of grain‐based ethanol. Sorghum, a highly water‐ and nutrient‐efficient plant, provides an alternative to fuel crops with greater irrigation and fertilizer requirements, such as maize. However, sorghum grain is generally less digestible because of extensive disulfide cross‐linking among sulfur‐rich storage proteins in the protein– starch matrix. Thus, the fine structure and composition of the seed endosperm directly impact grain end use, including fermentation performance. To test the hypothesis that kafirin (prolamin) seed storage proteins specifically influence the efficiency of ethanol production from sorghum, 10 diverse genetic lines with allelic variation in the β‐, γ‐, and (δ‐kafirins, including three β‐kafirin null mutants, were tested for ethanol yield and fermentation efficiency. Our selected lines showed wide variation in grain biochemical features, including total protein (9.96–16.47%), starch (65.52–74.29%), and free amino nitrogen (FAN) (32.84–73.51 mg/L). Total ethanol yield (ranging from 384 to 426 L/metric ton), was positively correlated to starch content (R2 = 0.74), and there was a slight positive correlation between protein digestibility and ethanol yield (R2 = 0.52). Increases in FAN content enhanced fermentation efficiency (R2 = 0.65). The highest ethanol producer was elite staygreen breeding line B923296, and the line with the highest fermentation efficiency at the 72 h time point was inbred BT×623. A large‐seeded genotype, KS115, carrying a novel γ‐kafirin allele, was rich in FAN and exhibited excellent short‐term fermentation efficiency at 85.68% at the 20 h time point. However, the overall ethanol yield from this line was comparatively low at 384 L/metric ton, because of insufficient starch, low digestibility, and high crude protein. Multivariate analysis indicated an association between the β‐kafirin allele and variation in grain digestibility (P = 0.042) and FAN (P = 0.036), with subsequent effects on ethanol yield. Reversed‐phase HPLC profiling of the alcohol‐soluble kafirin protein fraction revealed diversity in protein content and composition across the lines, with similarities in peak distribution profiles among β‐kafirin null mutants compared with normal lines. 相似文献
83.
Novel food and non-food uses for sorghum and millets 总被引:4,自引:3,他引:4
Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity. 相似文献
84.
A new class of zein additives was investigated, thiocyanate salts. Ammonium, potassium, guanidine (GTC), and magnesium thiocyanate salts were added to solutions of zein in with various amounts of tri(ethylene glycol) (TEG), cast as films, and then tested to determine the impact that each salt had on properties. The presence of these salts affected solution rheology and intrinsic viscosity, demonstrating that the salts interacted with the protein. It was found that these salts acted as plasticizers, as they lowered the glass transition temperature of zein when evaluated with differential scanning calorimetry. In zein films in which TEG was present, these salts increased elongation and reduced tensile strength. However, unlike traditional plasticizers (such as TEG), when the salts were used as the only additive, elongation was not increased and tensile strength was not decreased. Of the salts tested, GTC in combination with TEG was found to increase elongation the most. The impact of salts on elongation was greatly affected by the relative humidity in which the samples were stored. 相似文献
85.
Bean RB 《Science (New York, N.Y.)》1928,67(1723):1-5
Tropic jungle life has an influence that decreases stature, and so has Arctic cold and waste. In each there is difficulty in procuring proper food, and discomfort in the extreme. The active life of the temperate zone with its comforts and abundant food supply produces the tallest statures. The greatest extremes of small stature are found among the Negrillos of Central Africa and the Aymaras of Central South America, in the jungles of excessive heat and poor food supply. Next to these come the Eskimos, Lapps and Siberians, with ice and excessive cold and poor food supply. On the other hand, the littoral and southern Baltic regions in Europe, the western part of Asia, eastern Africa, and the plains and pampas of the Americas with their active life, abundant food supply and temperate climate produce the tallest statures. Certain stocks may move into areas for which they are not fitted and remain for a time, and such conditions exist throughout the world to-day where recent movements of peoples have taken place, but ultimately there is a survival of the stock best fitted for the environment, and the unfitted stocks disappear by amalgamation, eradication or dispersal. Sea areas and probably sea food have an influence in reducing stature. The present Mediterranean peoples and the primordial British have small statures and so does Japan, yet they came from taller continental stocks. The Central Americans and Fuegians are smaller than the continental peoples near-by. The Malays and southern Asiaties are smaller than the peoples of the interior of the continent. Other instances might be cited. There is some evidence that the seaboard statures of the United States are less than those of the interior, but other factors enter here. Looked at in its broadest sense, environment molds the individual, selection retains the fittest under different environments, and heredity carries on the results. 相似文献
86.
Observed sequences of large earthquakes are not consistent in either recurrence time or energy release; long-term prediction has been impossible even in areas, such as Parkfield, with well-defined recurrence intervals. The seismic gap hypothesis, which predicts characteristic earthquakes in areas of the circum-Pacific belt that have not produced recent great earthquakes, has also failed to predict the observed clustering of high-energy events. Models in which fractal scaling is broken at high magnitude predict that characteristic events and recurrence behavior will be unstable in time. The central predictions of these models are supported by recent observations at Landers and Big Bear in California. 相似文献
87.
88.
AK Ghosh D Sarkar DC Nayak P Bhattacharyya 《Archives of Agronomy and Soil Science》2013,59(6):583-591
A sequential fractionation scheme, based on a soil phosphorous fractionation, was developed to assess the chemical nature, and thus the potential bioavailability and mobility of As, at the sites. Soil As was separated into five fractions with (i) anion exchange resin, (ii) NaHCO3, (iii) NaOH, (iv) HCl, (v) residual. Most sites contained relatively low concentrations of As in the two most labile fractions. The bulk of the contaminant As at the sites seemed to be associated with soil amorphous Fe and Al minerals and the dominant clay minerals which help in As sorption are montmorillonite and mica. Resin-extractable As in particular might provide a good index of potential As bioavailability and mobility. 相似文献
89.
Ákos Horváth Béla Urbányi Steven D. Mims William B. Bean Boris Gomelsky Terrence R. Tiersch 《Journal of the World Aquaculture Society》2006,37(4):356-362
Experiments were performed to improve protocols for sperm cryopreservation of paddlefish (Polyodon spathula), a species for which there has been limited study. The first experiment was conducted to investigate the effects of two extenders (modified Tsvetkova’s extender: mT and modified Hanks’ balanced salt solution: mHBSS) in combination with methanol (MeOH) and dimethyl sulfoxide in two concentrations (5 and 10%) on the postthaw motility and fertilization rates of cryopreserved sperm. The highest postthaw motility (85 ± 5%) was observed when sperm were frozen using mT extender with 10% MeOH as cryoprotectant. Extenders (P = 0.0018) and cryoprotectants (P = 0.0040) each had a significant effect on the postthaw motility of paddlefish sperm. The highest fertilization (80 ± 3%) was found when eggs were fertilized with sperm frozen with mT extender in combination with 10% MeOH. However, there was no significant difference among fertilization rates when MeOH was used as a cryoprotectant in either concentration or in combination with either mT or mHBSS extenders. In the second experiment, 4000 eggs were fertilized with the pooled contents of five straws of thawed sperm (total volume of 1.25 mL) using mT extender in combination with 5% MeOH, and hatch rates as high as 79 ± 5% were observed. A third experiment was also conducted to clarify the role of MeOH concentration; however, no significant difference was found among fertilization and hatch rates when either 5 or 10% MeOH was used as a cryoprotectant. These results suggest that MeOH is a safe and reliable cryoprotectant for freezing of paddlefish sperm and obtaining viable postthaw sperm for consistent fertilization and hatch rates. Further, this experimental protocol is relatively simple and applicable for commercial hatchery production of paddlefish. 相似文献