摘要 :
Our country was heavily dependent on impors of wheat (Triticum spp) during fifties, sixties and seventies before it attained self-sufficiency. Occasionally imports are necessitated even now; for instance, in 1986-89 to tide over t...
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Our country was heavily dependent on impors of wheat (Triticum spp) during fifties, sixties and seventies before it attained self-sufficiency. Occasionally imports are necessitated even now; for instance, in 1986-89 to tide over the tight food situation imposed by severe drought and in 1991-92 and 1996 to ensure proper working of public distribution system and to discourage hoarders and unscrupulous traders. On the whole, thanks to Green Revolution, the production of foodgrains especially wheat has increased remarkably. As a result of enhancement of production over a period of time, the per caput net availability of wheat per annum has increased form 42.5 kg in 1970 to 67.0 kg in 1997 (Table 1).
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Wheat is the third largest crop globally and an essential source of calories in human diets. Maintaining and increasing global wheat production is therefore strongly linked to food security. A large geographic variation in wheat y...
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Wheat is the third largest crop globally and an essential source of calories in human diets. Maintaining and increasing global wheat production is therefore strongly linked to food security. A large geographic variation in wheat yields across similar climates points to sizeable yield gaps in many nations, and indicates a regionally variable flexibility to increase wheat production. Wheat is particularly sensitive to a changing climate thus limiting management opportunities to enable (sustainable) intensification with potentially significant implications for future wheat production. We present a comprehensive global evaluation of future wheat yields and production under distinct Representative Concentration Pathways (RCPs) using the Environmental Policy Integrated Climate (EPIC) agro-ecosystem model. We project, in a geographically explicit manner, future wheat production pathways for rainfed and irrigated wheat systems. We explore agricultural management flexibility by quantifying the development of wheat yield potentials under current, rainfed, exploitable (given current irrigation infrastructure), and irrigated intensification levels. Globally, because of climate change, wheat production under conventional management (around the year 2000) would decrease across all RCPs by 37 to 52 and 54 to 103 Mt in the 2050s and 2090s, respectively. However, the exploitable and potential production gap will stay above 350 and 580 Mt, respectively, for all RCPs and time horizons, indicating that negative impacts of climate change can globally be offset by adequate intensification using currently existing irrigation infrastructure and nutrient additions. Future world wheat production on cropland already under cultivation can be increased by ～35% through intensified fertilization and ～50% through increased fertilization and extended irrigation, if sufficient water would be available. Significant potential can still be exploited, especially in rainfed wheat systems in Russia, Eastern Europe and North America.
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The present study investigated effects of germination and fermentation on protein quality of the wheat flour. The wheat seeds were obtained locally and were divided into three portions and processed as raw wheat flour (RWF), germi...
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The present study investigated effects of germination and fermentation on protein quality of the wheat flour. The wheat seeds were obtained locally and were divided into three portions and processed as raw wheat flour (RWF), germinated wheat flour (GWF) and fermented wheat flour (FWF) respectively. The samples were analysed for chemical and protein qualities using standard methods. Protein content (g/100g) varied between 10.77±0.66 (RWF) and 13.70±0.30 (FWF). Mineral composition of RWF, GWF and FWF had potassium as the highest while zinc (RWF and FWF) and nickel (GWF) were the least. For amino acid, glutamic acid was the most abundant; while cysteine (RWF and FWF) and methionine (GWF) were the least. Total essential amino acid plus histidine and arginine range between 26.4% (FWF) and 37.9% (GWF). For protein efficiency ratio (PER), RWF had the highest value (1.99), while GWF had the least (0.86), while for? the essential amino acid index (EAAIs), RWF was higher than that of GWF and FWF. Similarly, the biological value of RWF (31.8%) was higher than those of GWF (29.4%) and FWF (29.1%) sample respectively. The anti-nutrient compositions of the wheat flour samples were low, while phytate:zinc, phytate:calcium, (Ca)(phytate):zinc and phytate:iron molar ratios? were lower than the critical values. Bulk density (BD) ranged between 0.80±0.04 and 0.86±0.02, swelling capacity (SC) 0.0±0.03 and 1.23±0.21, water absorption capacity (WAC) 315 and 415% and least gellation 3.33±1.10 and 14.6±1.16%. The finding concluded that the employed processing methods, particularly fermentation, influenced the chemical composition of the wheat flour in terms of protein content and reduction of anti-nutrient composition.
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The purpose of this research was to develop a simple method for measuring lipase activity as an indicator of wheat and wheat bran storage quality. This simplified method does not require the separation or purification of lipase. O...
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The purpose of this research was to develop a simple method for measuring lipase activity as an indicator of wheat and wheat bran storage quality. This simplified method does not require the separation or purification of lipase. Optimal conditions for lipase activity measurements were determined by varying the substrate (olive oil) and water concentrations, temperature, and incubation time. Following incubation, FFA were quantified spectrophtometrically using a copper soap assay, and lipase activity was expressed as units/gram (U/g), where 1 U was defined as the microequivalents of oleic acid liberated per hour. The method was tested on one commercial and four pure wheat cultivars. The lipase activity was also correlated with the development of FFA during actual storage of heat-treated commercial bran. Lipase activity in wheat bran ranged from 2.17 to 9.42 U/g, and in whole kernel wheat from 1.05 to 3.54 U/g. Optimal olive oil and water concentrations were 0.4 to 0.8 mL and 0.15 to 0.20 mL per g of defatted sample, respectively. Optimal incubation temperature was 40°C, and incubation times of up to 8 h were linear. Lipase activity was highly correlated with the buildup of FFA in stored wheat bran (R 2=0.97).
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摘要 :
The purpose of this research was to develop a simple method for measuring lipase activity as an indicator of wheat and wheat bran storage quality.This simplified method does not require the separation or purification of lipase.Opt...
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The purpose of this research was to develop a simple method for measuring lipase activity as an indicator of wheat and wheat bran storage quality.This simplified method does not require the separation or purification of lipase.Optimal conditions for lipase activity measurements were determined by varying the substrate (olive oil) and water concentrations,temperature,and incubation time.Following incubation,FFA were quantified spectrophotometrically using a copper soap assay,and lipase activity was expressed as units/gram (U/g),where 1 U was defined as the microequivalents of oleic acid liberated per hour.The method was tested on one commercial and four pure wheat cultivars.The lipase activity was also correlated with the development of FFA during actual storage of heat-treated commercial bran.Lipase activity in wheat bran ranged from 2.1 7 to 9.42 U/g,and in whole kernel wheat from 1.05 to 3.54 U/g.Optimal olive oil and water concentrations were 0.4 to 0.8 mL and 0.15 to 0.20 mL per g of defatted sample,respectively.Optimal incubation temperature was 40 deg C,and incubation times of up to 8 h were linear.Lipase activity was highly correlated with the buildup of FFA in stored wheat bran (R~2 = 0.97).
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The aim of this work was to evaluate the effects of wheat germ - stabilized by toasting or by sourdough fermentation - on dough and bread properties. Doughs were produced by adding increasing amounts of each type of stabilized ger...
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The aim of this work was to evaluate the effects of wheat germ - stabilized by toasting or by sourdough fermentation - on dough and bread properties. Doughs were produced by adding increasing amounts of each type of stabilized germ, starting with the current recommended level of 3 g/100 g up to 20 g/100 g. Sourdough fermentation ensured the presence of lactic acid bacteria LAB in amounts comparable to those found in conventional sourdough. The acidification induced by LAB inactivates lipase and lipoxygenase, as does the toasting process. These results account for the decrease in rancidity, as demonstrated by the low development of hexanal during storage. Fermentation significantly decreased the content of glutathione, responsible for the deterioration of the rheological characteristics and workability of dough containing high levels of germ. Dough enriched with fermented germ exhibited high stability during mixing and development. Positive effects high specific volume and low firmness associated with the use of germ stabilized by fermentation have been detected both in fresh bread and in samples stored up to 4 days in controlled conditions of humidity and temperature. Finally, the sensory consumers' test confirmed that the addition of fermented germ did not diminish the liking of the sample.
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This paper describes a novel principle for the separation of wheat flour into starch and gluten in a concentrated medium. The process is based on the use of simple shear flow in a cone-and-cone device. The separation takes place i...
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This paper describes a novel principle for the separation of wheat flour into starch and gluten in a concentrated medium. The process is based on the use of simple shear flow in a cone-and-cone device. The separation takes place in two steps. Initially, local segregation of gluten and starch phases occurs, leading to formation of macroscopically visible gluten patches distributed throughout the dough. This local segregation can be understood by considering the dough as a visco-elastic matrix containing an inert filler (starch). Further shearing leads to aggregation of those patches and migration (large-scale separation) towards the apex of the cone. As a result, the wheat dough is separated into a protein-poor fraction, containing less than 4% protein, and a protein-rich fraction containing almost 50% protein on a dry weight basis. However, under the process conditions used, upon a very long shearing, a redistribution of the aggregated gluten structures in the starch phase was observed, demonstrating a processing limit for the separation performance. Compared to traditional processing, the separation process presented shows opportunities for producing high quality gluten accompanied with significant water savings. Considering the fact that simple shear flow in steady rate is less harmful to gluten quality, such a separation process could benefit gluten quality
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Grain storage plays a vital part in social stability as well as people's daily lives. By virtue of its unique storage advantages, wheat has become one of the most important grain reserves in the world. Wheat kernels continue consu...
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Grain storage plays a vital part in social stability as well as people's daily lives. By virtue of its unique storage advantages, wheat has become one of the most important grain reserves in the world. Wheat kernels continue consuming their own energy to maintain lives during the whole process of storage, which will lead to deterioration of their edible qualities as well as may be infected by certain mold provided that the surrounding conditions are suitable. Thus, establishing an efficient and accurate method to assess wheat kernel's storage status is necessary for the sake of shaping a shelter to human beings as well as animals. For that reason, various wheat aging and wheat moldy detection methods have been summarized in this chapter. Up to now, study of aging and mold detection in wheat kernels can be divided into conventional chemical techniques and newly proposed physical detection methods. This review has analyzed in detail the limitations of conventional technologies, and then probes into some promising physical technologies for better detecting stored status of wheat kernels.
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With the growing population pressure and expected 20% increase in per capita availability of wheat, India now faces a challenge of producing extra 40 million tonnes, which requires a growth rate of 1.8% per year as against the cur...
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With the growing population pressure and expected 20% increase in per capita availability of wheat, India now faces a challenge of producing extra 40 million tonnes, which requires a growth rate of 1.8% per year as against the current 1%. Research efforts are in progress to increase yield levels by developing hybrid wheats, breeding cultivars with durable resistance to newly emerged diseases and pests, introgressing the higher yielding alien genes in the background of present cultivars, etc. but nothing seems to bring in the desired impetus since national average of production has been stalemating for the last few years. At this juncture, it has been envisaged to derive the genes offering promise of higher yields and robust disease resistance from various sources on a hit and trial basis and the winter wheats are the most revealing in this context. Winter wheats have already served this cause by donating Norin 10 dwarfing gene to spring wheat cultivars which harbingered green revolution in the latesixties. Pace of higher productivity of wheat was further maintained through nineties and till date by Veery cultivars adapted for spring cultivation also find their origin in winter wheat sources. Therefore why not to tap the available winter wheat germplasm again through attempting winter x spring crosses for identifying cultivars with significantly higher yield potential as compared to the present ones. Growing winter wheats in a crossing block in Indian plains during normal wheat season (rabi) is an arduous task involving huge investments for artificial fulfillment of vernalisation, a prerequisite for flowering. However, the winter wheats sown in the month of October at ICAR's regional station at Lahaul-Spiti situated in temperate Himalaya of Himachal Pradesh flower in the ensuing month of July and synchronize for crossing with the spring wheat cultivars sown at the same location in the month of May. Therefore, transfer of superior traits from winter wheats to spring wheat cultivars or vice versacan be achieved economically with more feasibility.
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