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1.
This study compared the compositional changes in mushrooms exposed to sunlight with those occurring after commercial ultraviolet (UV) light processing. Button mushrooms (75 kg) were processed in the presence or absence of UVB light; a third group was exposed to direct sunlight. Mushroom composition was evaluated using chemical analyses. Vitamin D concentrations were 5, 410, and 374 μg/100 g (dw) in control, UVB, and sunlight groups, respectively. On a dry weight basis, no significant changes in vitamin C, folate, vitamins B(6), vitamin B(5), riboflavin, niacin, amino acids, fatty acids, ergosterol, or agaritine were observed following UVB processing. Sunlight exposure resulted in a 26% loss of riboflavin, evidence of folate oxidation, and unexplained increases in ergosterol (9.5%). It was concluded that compositional effects of UVB light are limited to changes in vitamin D and show no detrimental changes relative to natural sunlight exposure and, therefore, provide important information relevant to the suitability and safety of UVB light technology for vitamin D enhanced mushrooms.  相似文献   

2.
The objectives of this research were to study the effects of high intensity (0.5, 0.75, and 1.0 mW/cm (2)), dose (0.5, 1.0, and 1.5 J/cm (2)), and postharvest time (1 and 4 days) on the vitamin D 2 formation in Portabella mushrooms ( Agaricus bisporus) as a result of UV-B exposure, as well as the vitamin D 2 degradation in treated mushrooms during storage. Within each intensity application, dose had the largest effect where more exposure converted more vitamin D 2 from ergosterol. Similar dose across each intensity application resulted in similar vitamin D 2 concentration. Practical commercial production requires as short a treatment time as possible, and intensity was a major factor from this standpoint where the time it took to achieve a similar vitamin D 2 concentration for similar dose exposure was significantly reduced as intensity increased. By using an intensity of 1.0 mW/cm (2) at a dose of 0.5 J/cm (2), the concentration of vitamin D 2 produced was 3.83 microg/g dry solids of mushrooms in 8 min, whereas using an intensity of 0.5 mW/cm (2) at a dose of 0.5 J/cm (2), the concentration of vitamin D 2 produced was 3.75microg/g dry solids of mushrooms in 18 min. Also, postharvest time did not have a significant effect on vitamin D 2 formation in mushrooms that were treated 1 and 4 days after harvest. Vitamin D 2 degraded in treated mushrooms during storage by apparent first-order kinetics, where the degradation rate constant was 0.025 h (-1). The information provided in this study will help mushroom producers develop commercial-scale UV treatment processes to add value to their crop while improving consumer health.  相似文献   

3.
Phytosterols were quantified in nuts and seeds commonly consumed in the United States. Total lipid extracts were subjected to acid hydrolysis and then alkaline saponfication, and free sterols were analyzed as trimethylsilyl derivatives by capillary GC-FID and GC-MS. Delta5-Avenasterol was quantified after alkaline saponification plus direct analysis of the glucoside. Sesame seed and wheat germ had the highest total phytosterol content (400-413 mg/100 g) and Brazil nuts the lowest (95 mg/100 g). Of the products typically consumed as snack foods, pistachio and sunflower kernel were richest in phytosterols (270-289 mg/100 g). beta-Sitosterol, Delta5-avenasterol, and campesterol were predominant. Campestanol ranged from 1.0 to 12.7 mg/100 g. Only 13 mg/100 g beta-sitosterol was found in pumpkin seed kernel, although total sterol content was high (265 mg/100 g). Phytosterol concentrations were greater than reported in existing food composition databases, probably due to the inclusion of steryl glycosides, which represent a significant portion of total sterols in nuts and seeds.  相似文献   

4.
Vitamin A (vitamin A palmitate) and vitamin E (alpha-tocopheryl acetate) levels were determined in 77 samples of fortified infant formulas manufactured by 4 firms in the United States from 1981 to 1983 and were compared by formulation base (soy, milk) and manufacturing firm. For vitamin A and vitamin E, the mean values (IU/100 kcal) were 454 +/- 95 (range 248-614) and 2.0 +/- 0.7 (range 1.1-5.0), respectively. No significant differences (alpha = 0.05) were found in levels (IU/100 kcal) of vitamin A and vitamin E between milk- and soy-based formulas. When the mean vitamin A and vitamin E levels of formulas produced by the various firms were compared on an IU/100 kcal or percent of label declaration basis, significant differences (alpha = 0.05) were found among firms. Mean vitamin A levels for the various products compared to label declarations ranged from 126% of declared for the ready-to-use formulas to 139% of declared for the powders. Mean vitamin E levels ranged from 97% of declared for ready-to-use formulas to 118% of declared for concentrates. Except for one sample that contained 248 IU vitamin A/100 kcal, the formulas met the requirements of the 1980 Infant Formula Act.  相似文献   

5.
Mobile sources are significant contributors to ambient particulate matter (PM) in the United States. As the emphasis shifts from PM10 to PM2.5, it becomes particularly important to account for the mobile source contribution to observed particulate levels since these sources may be the major contributor to the fine particle fraction. This is due to the fact that most mobile source mass emissions have an aerodynamic diameter less than 2.5 µm, while the particles of geological origin that tend to dominate the PM10 fraction generally have an aerodynamic diameter greater than 2.5 µm. A common approach to assess the relative contributions of sources to observed particulate mass concentrations is the application of source apportionment methods. These methods include material balance, chemical mass balance (CMB), and multivariate receptor models. This paper describes a number recent source attribution studies performed in the United States in order to evaluate the range of the mobile source contribution to observed PM. In addition, a review of the methods used to apportion source contributions to ambient particulate loadings is presented.  相似文献   

6.
The basic composition (moisture, total carbohydrates, dietary fiber, crude fat, ash, nitrogen, and protein) and amino acid contents were determined in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinula edodes, and Pleurotus ostreatus. In addition, nitrogen-to-protein conversion factors were calculated for each species by dividing the sums of amino acid residues with total (Kjeldahl) nitrogen contents. The dry matter contents of mushrooms varied from 7.7% to 8.4%. The dry matter of mushrooms contained large amounts of carbohydrates, from 4.5 (A. bisporus/white) to 5.8 g/100 g fresh weight (L. edodes). L. edodes proved to be an especially good source of dietary fiber (3.3 g/100 g fresh weight); the other mushrooms contained 1.5-2.4 g/100 g fresh weight. Crude fat, ash, and protein (based on amino acid analysis) contents of the mushrooms varied 0.31-0.35, 0.49-0.78, and 1.8-2.09 g/100 g fresh weight, respectively. Mushrooms proved to be good sources of almost all essential amino acids when compared with common vegetables. The mean nitrogen-to-protein conversion factor analyzed in the present study was 4.7 +/- 0.21. When using this factor, a very good estimation of protein contents could be obtained for the main species of mushrooms cultivated in Finland.  相似文献   

7.
Source profiles (fractional mass abundances and uncertainties) for use in chemical mass balance (CMB) source apportionment are reported for soil dust from unpaved roads and desert lands. The objectives were to add to the library of source composition profiles available for CMB studies, and to provide data on the variation in wind-blown dust composition between particle sizes and geographical locations. Samples were resuspended and sampled through PM1, PM2.5 and PM10 inlets onto filters, then chemically analyzed for 40 elements, seven ions and eight carbon fractions. Air quality management would benefit from technology that can distinguish soil dust from sites in different geographical locations and sites with different land uses. Five geographical clusters representing Ft Bliss, TX, Dona Ana County, NM, Ft Irwin, CA, the west desert and the Canyonlands, UT, were examined. Distinctive differences were found between sites within a cluster and these differences were comparable to the differences between cluster averages. Some sites showed small differences in chemical composition between particle sizes, but these differences were less than the differences observed between nearby geographical locations. Dust emissions from sites with uniform geology have distinctive source profiles that may be useful for CMB receptor modeling. Heterogeneous regions, defined by land management boundaries, will require extensive field sampling to develop representative composite source profiles.  相似文献   

8.
《CATENA》2001,44(1):1-11
Distributed process-based hydrologic models have been used to describe and predict the movement of sediment on small watersheds. However, to parameterize these models requires an understanding of the spatial variability of erosion processes and the particle sizes of the sediment being moved. In this study, a high resolution digital elevation model (DEM) and detailed sediment particle sampling allowed a comparison of hillslope characteristics and particle sizes of surficial armoring in a semiarid watershed. Individual particle size classes on hillslopes are correlated with the underlying sediment type, local slope, aspect, and area draining through a grid element. The strongest correlations are between the underlying sediment and overlying sediment. However, the distribution of the particle size classes is consistent with a hydrodynamic explanation for sorting. In particular, increased area draining through a grid node and increased slope are correlated with higher concentrations of the 16–64-mm particle size class. Both the coarsest and finest particle size classes are significantly correlated with the aspect of flow from a grid cell, with increased coarse particles and decreased fines on east-facing slopes. These spatial differences with aspect are attributed to dry season prevailing winds. These observations about process and spatial distribution are useful in predicting the spatial distribution of particles on the watershed for applications such as distributed hydrologic models.  相似文献   

9.
Within the United States, a nationwide debate has been raging over how to best provide quality education for all learners. Much of this debate, spurred by poor test scores and other measures of achievement, has centered on the development of national, state and local standards and assessments for the core disciplines (e.g., mathematics, science, geography). For the most part, environmental education has been left out of this debate and out of the various standards development initiatives. Whether one agrees philosophically with academic standards or not, these standards are determining what is being taught in the classroom. By 1993, environmental education in the United States found itself in a conundrum. It has always been argued that environmental education should be interdisciplinary, infused throughout the curriculum. However, with the new standards, environmental education was in real danger of becoming marginalized. To address this situation, the North American Association for Environmental Education (NAAEE) initiated the National Project for Excellence in Environmental Education.  相似文献   

10.
In the United States, more farms are composting than municipalities, commercial/institutional establishments, and other private sector groups combined. To obtain an overview of agricultural composting in the United States, industry, government, and university representatives from the top 10 beef and dairy cattle, poultry, and swine producing states were contacted between January and April of 1995. These states represent at least 70 percent of the nation's production of these commodities (except for beef cattle at 52 percent). The representatives provided information about the number of farms composting, the materials composted, composting methods, how the compost is used, and motivating and impeding factors for farms to compost. In addition, information was gathered concerning composting crop residues. In this case, specific applications of crop residue composting were identified and individuals knowledgeable about the applications were contacted for background information.

Note the estimated numbers of composting operations presented here represent a best attempt to quantify the composting activity taking place on various types of farms. In many cases, the numbers are rough estimates, based on the assessments of the representatives contacted in each state. Also, they only include the composting operations in the top 10 producing states. A considerable amount of composting occurs outside of these states. Therefore, Tables 1 and 2 underestimate the number of farms that compost.  相似文献   

11.
A survey of residual nitrite (NO(2)(-)) and nitrate (NO(3)(-)) in cured meats available at retail was conducted to verify concentrations in conventional (C) products and establish a baseline for organic/natural/uncured/indirectly cured (ONC) products. In this study, 470 cured meat products representing six major categories were taken from retail outlets in five major metropolitan cities across the United States. Random samples representing both C and ONC type products were analyzed for NO(2)(-) and NO(3)(-) content (ppm) using an ENO-20 high-performance liquid chromatography system equipped with a reverse phase column. Generally, there were no differences in NO(2)(-) concentrations between C and ONC meat categories, but a few ONC products surveyed in certain cities were lower in NO(3)(-) content. Pairwise comparisons between cities indicated that NO(2)(-) and NO(3)(-) contents of all C type products were not appreciably different, and the same was true for most ONC products. Numerical NO(2)(-) values were less variable than NO(3)(-) concentrations within each meat product category. NO(2)(-) concentrations were similar to those previously reported by Cassens ( Cassens , R. G. Residual nitrite in cured meat . Food Technol. 1997a , 51 , 53 - 55 ) in 1997. Residual NO(2)(-) and NO(3)(-) values in this study were numerically lower than those reported by NAS ( National Academy of Sciences . The Health Effects of Nitrate, Nitrite, and N-Nitroso Compounds ; National Academy Press : Washington, DC , 1981 ) in 1981. Data from this survey provide a benchmark of NO(2)(-) and NO(3)(-) concentrations for ONC products available at retail.  相似文献   

12.
The need to conserve United States populations of Lepidoptera has been recognised for a century, but intensive programmes to do so have only recently come into being. The evolution of the butterfly and moth conservation movement in the United States is followed from the earliest instances to the present state of progress. The origin and growth of the Xerces Society as the chief body for terrestrial arthropod conservation in America are described. Currently, ecological research and political action aimed at specific lepidopteran protection issues are under way. Several of these are examined and the most acute needs for further study and action indicated. Habitat alteration emerges dramatically as the chief problem in the decline of butterfly and moth populations. The relative importance of pesticides and overcollecting is discussed and reinforces the conclusion that the habitat is paramount. Introductions of organisms for purposes of conservation likewise receive consideration, showing this strategy to be problematical and subject to careful review prior to its use. The various levels of government as well as private bodies and individuals have distinct roles in insect conservation. Greater public awareness of beneficial insects must precede optimal effectiveness of conservation schemes. The appointment of an official federal insect conservator is announced along with his initial proposal for endangered species listings for certain North American butterflies. The prognosis for a national programme is suggested. Lepidoptera conservation in the United States has become a fully fledged movement with numerous successes and with many difficult problems to face. The situation is viewed with immediate alarm but cautious long-term optimism as well.  相似文献   

13.
14.
This article summarizes the trends in agricultural injuries and illnesses in the past decade, as well as the needs for surveillance in the future. Agriculture is one of the most hazardous industries in the U.S. The fatality rate in agriculture remained high (about 22/100,000 workers) through the 1990s. and tractors remained the leading source of death, causing approximately 300 fatalities each year. Non-fatal injuries and illnesses decreased in the employed agricultural worker population. There are no adequate injury and illness data for self-employed farmers and family members to show trends over time. The reported injury rates have been 0.5 to 16.6/100 workers, based on the source of information. Many studies have shown high rates of respiratory and musculoskeletal symptoms, hearing loss, and skin disorders in agriculture. The overall cancer rate is lower; however, certain cancers are elevated in farmers. Surveillance information has not improved significantly in the past decade; however, many studies have provided more insight into the prevalence, incidence, and risk factors for injury and illness. Further efforts are needed to better define the populations at risk, including farmers and ranchers, family members, workers, migrant and seasonal workers, and others exposed to farm hazards. Fatalities are well documented, and it is important to continue existing surveillance in the future. Surveillance systems should be developed to collect information on agriculture-related non-fatal injuries and illnesses.  相似文献   

15.
Organochlorine residues were analyzed in brook trout (Salvelinus fontinalis) collected from six undisturbed lakes in Maine, New Hampshire and Vermont. The residues (whole body) were compared among age groups of fish and were correlated by regression analyses with water chemistry factors that might be affected by acid precipitation. There were significant differences in the organochlorine content of fish from different lakes but not among age groups of fish within each lake or among all lakes. There were no significant correlations between the water chemistry values measured and organochlorine content of the fish. Inasmuch as no organochlorine pesticides have been used within the lake watersheds, the compounds must have reached these lakes by atmospheric transport.  相似文献   

16.
17.
The Atlantic salmon (Salmo salar) was formerly abundant in northeast coastal rivers in the United States from the Canadian border to the Connecticut River, and possibly as far south as the Delaware River. It was eliminated from most of its former range by a combination of overfishing, construction of dams impassable to migrating fish, and municipal and industrial pollution. Reproducing populations are now limited to a few rivers in Maine, but attempts are under way to reintroduce the species to some rivers where populations formerly existed. Most of the native Atlantic salmon rivers are low in acid neutralizing capacity and receive acidic precipitation. The third order streams are not now acidic; however, in some first and second order streams in Maine, pH episodically declines to 4.7 and Al increases to 350 μg g?1. These conditions could be toxic to sensitive early life history stages of Atlantic salmon. Comparison of chemical conditions in two Maine rivers in 1980–1982 with those in 1969–1970 indicated that the streams have not become more acidic during this interval. Data on the sport catch of Atlantic salmon indicated that populations have generally remained stable or recently increased in the Maine rivers having naturally reproducing populations. The recent increase probably resulted from introductions of hatchery smolts to supplement natural reproduction, and the occurrence of strong year classes in 1978 and 1980. The population in one stream has declined significantly in recent years, but the cause of the decline is probably not related to acidic precipitation. Atlantic salmon resources in the U.S. have apparently not been adversely affected by atmospheric deposition at the present time.  相似文献   

18.
Mercury (Hg) contamination from a variety of point and non-point sources, including atmospheric inputs, is currently considered to be the most serious environmental threat to the well being of fish and wildlife resources in the southeastern United States. Fish consumption advisories have been issued in all ten states comprising the U.S. Fish and Wildlife Service's Southeast Region. Both freshwater and marine species have been affected with levels ranging as high as 7.0 ppm in some individuals. Many other species, including various species of reptiles, birds and mammals (including humans) are also contaminated. Impacts noted range from reproductive impairment to mortality.  相似文献   

19.
Sediment samples collected in 1980-1982 from riverine and pothole wetlands at 17 locations in the north central United States were analyzed for organochlorine pesticides, certain of their metabolites, and polychlorinated biphenyls (PCBs). Concentrations were above minimum detection levels (5 ng/g of organochlorines and 20 ng/g of PCBs) in less than 4% of the samples taken. Fish samples taken at 9 of these 17 locations, and analyzed for the same compounds, showed a higher frequency of detectable contaminants. The most common compound found in fish was DDE, which was found in 51% of the samples at levels up to 512 ng/g. alpha-BHC was present at concentrations of 5 to 27 ng/g in 36% of the fish samples, and DDD was found at levels of 5 to 60 ng/g in 14%. Four other compounds, DDT, dieldrin, PCB, and trans-nonachlor, were detected in fish at relatively low concentrations in less than 10% of the samples. This survey, thus, indicated little contamination by organochlorine pesticides or PCBs in the wetland habitats of this region.  相似文献   

20.
Vitamin C and elemental analysis of a range of indigenous bushfruit from the Northern Territory, Darwin, Australia, was carried out. The results suggest that bushfruit may be a valuable food resource. In the majority of cases, vitamin C and elemental composition of bushfruits were comparable to those of western fruits in the same fruit category. Billy goat plums (Terminalia fertinandiana) have the highest vitamin C content, while K concentration is generally high as compared to other elements. Morinda citrifolia gave strong test for the presence of terpenes.  相似文献   

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