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1.
ABSTRACT

Combined practice of sulfuration and drying is widely applied for extending shelf life of fruits. The differences in fruit size are not taken into consideration during these applications and during fresh fruit consumption. In this study, effect of fruit size and drying methods (hot air-drying and sun drying) on the chemical composition of fresh and sulfurated apricot was investigated. Total drying times for sun drying and hot air-drying were 11?d and 51?h, respectively. A temperature gradient was applied during hot air-drying. The fruit size substantially affects the composition of both fresh and dried apricots. The results were subjected to principal component analysis. The small-sized fresh apricots discriminate themselves from large ones with higher amounts of phenolic compounds, whereas the large-sized fresh apricots contain more sugar and organic acids. Size classification and hot air-drying are advisable for high-quality dried apricot production.  相似文献   

2.
The photooxidation of soybean oil was determined and correlated with triacylglycerol composition and structure. Purified triacylglycerols were photooxidized at room temperature under fluorescent light. Rates of peroxide formation and total headspace volatiles were related positively (P<0.5 significance) to oxidizability (r=0.75, r=0.76); content of linolenic acid (r=0.80, r=0.85) and linoleic acid (r=0.61, r=0.57); linoleic acid on carbon 2 (r=0.64, r=0.64); and average number of double bonds (r=0.76, r=0.76). Negative correlations were observed with respect to oleic acid (r=−0.70, r=−0.70). Soybean oil stability was decreased by linolenic acid-containing triacylglycerols and increased by oleic acid-containing triacylglycerols. Trilinoleoylglycerol and dilinoleoyl-oleoylglycerol were the most important oxidation product precursors. However, for high-linolenic acid soybean oil, dilinoleoyl-linolenoylglycerol and trilinoleoylglycerol were the most important oxidation product precursors. The most abundant volatile produced from thermal decomposition at 140°C of photooxidized triacylglycerols was 2-heptenal, except for high-linolenic acid oils, where the most abundant volatile was propanal. The photooxidative stability of soybean oil triacylglycerols with respect to composition and structure is of interest for the development of soybean varieties with oils of improved odor and flavor stability. Presented at the 20th ISF World Congress 83rd Annual American Oil Chemists’ Society Meeting, May 10–14, 1992, Toronto, Canada.  相似文献   

3.
Environmental and genetic influences on the chemical composition and lipoxygenase activity of 24 soybean genotypes (groups IV-S and V) were determined. The soybeans were grown at two climatically different locations within the state of Georgia. Oil and protein contents and fatty acid composition of the oil in soybeans were affected by the environment. Five genotypes from group IV-S has a fatty acid composition of the oil different from the other genotypes in the group. These differences appeared to be genetically controlled. The level of lipoxygenase activity in soybeans also appeared to be genetically controlled and not influenced by the environment. The study indicated that soybean genotypes could be selected for a specific climatic region based on oil fatty acid composition and lipoxygenase activity.  相似文献   

4.
This study analyzed eight cooked species of fish and one species of shrimps (grilled, curried, fried and cooked in rice) commonly consumed in Bahrain for their proximate, mineral and heavy metal content. The results reveled that the protein content was in the range of 22.8-29.2 g/100 g, while the fat content was between 2.9-11.9 g/100 g. The energy content was the highest in the fried Scomberomorus commerson being 894.2 KJ/100 g, followed by Scomberomorus commerson cooked in rice (867.3 KJ/100 g). The samples also had a considerable content of sodium ranging from 120-600 mg/100 g, potassium (310-560 mg/100 g) phosphorous (200-330 mg/100 g), magnesium (26-54 mg/100 g) and zinc (0.4-2.0 mg/100 g), while the other minerals were present to a lower extent. Lead was present to an extent of 0.30 microg/g in the grilled Plectorhinchus sordidus while Lethrinus nebulosus cooked in rice contained 0.35 microg/g of mercury. Cadmium levels were constant at <0.02 microg/g. It can be concluded the traditional methods of cooking fish and shrimps have an effect on their nutrient composition and heavy metal content hence, it is advisable to avoid excessive frying and use minimal salt. In addition, consuming of a wide variety of species of fish and alternating between the various modes of cooking is the best approach to achieve improved dietary habits, minimizing mercury exposure and increasing omega-3 fatty acid intake.  相似文献   

5.
“Al8B4C7” and Al3BC3 powders were synthesized, and the formation of secondary phases was suppressed during the densification of the ternary aluminum borocarbides. The so-called “Al8B4C7” was Al3BC3 containing excess Al and B. The excess components in “Al8B4C7” promoted the densification of Al3BC3. The formation of secondary phases could not be controlled when using the reactive hot pressing method during the densification of Al3BC3. In contrast, monolithic Al3BC3 was obtained by separating calcination and hot pressing stage. The hardness, Young's modulus and fracture toughness of the sintered Al3BC3 were 13.9 GPa, 136 GPa and 2.2 MPa m1/2, respectively.  相似文献   

6.
7.
The aim of the study was to quantify the differences in meat and fat quality and lipid metabolism of pigs with either high or medium capacity for lipid accretion. A total of 58 castrated males of the breeds German Saddle Back (SB) and German Landrace (DL) were included in the experiment. Animals were housed individually and fed twice daily semi ad libitum. Saddle Back pigs indicated a lower lean meat content (41.4% vs 52.6%) and a higher fat percentage (40.9% vs 28.2%) in comparison to DL as a result of high lipid accumulation. The larger fat content of SB was related to an increased intramuscular fat concentration of longissimus muscle. A significant correlation between intramuscular fat content and fatty acid composition was estimated in both breeds. The relative concentration of saturated fatty acids was significantly increased in SB pigs. The percentage of polyunsaturated fatty acids (8.3%) in SB muscle fat was significantly lower than in DL muscle fat (10.7%). The de novo biosynthesis of fatty acids resulted in mostly saturated fatty acids and oleic acid. The higher activities of lipogenetic enzymes in backfat of SB proved a higher lipogenetic capacity. There were no significant differences in meat quality traits of longissimus muscle between the two breeds.  相似文献   

8.
Proximal composition was determined in meat's Creole cattle (CGBC). For this purpose, four raw cuts of CGBC were analyzed: buttock, flank, loin blade steak, and shoulder blade steak. The mentioned names of the meat cuts come from the National Meat Bureau from the Republic of Argentina. These cuts were taken from an experimental lot of Creole cattle (n = 11) in Jujuy province. Comparisons were made with data extracted from Argentine Table of Food Composition, edited by National Nutrition Institute, Buenos Aires, Argentina (1942). The results show that the level of protein is slightly inferior (in the case of CGBC varies between 18.44 +/- 0.30 and 21.06 +/- 0.11 g/100 g, while in the CTE varies between 20 and 23.8 g/100 g). The content of lipids in the cuts without visible fat is variable (1.06 +/- 0.01 to 2.74 +/- 0.61 g/100 g in the cuts of CGBC and 1.4 to 8.4 for the cuts of CTE). The content of minerals is similar (Fe 2.26 +/- 0.18 to 2.35 +/- 0.23 mg/100 g in CGBC, while in the CTE varies between 3.15 and 3.46 mg/100 g; Phosphorous varies between 142 +/- 10 and 170 +/- 11 mg/100 g in CGBC and 186 to 213 mg/100 g in CTE). These outcomes allow to affirm that the quality of CGBC beef is very similar to CTE beef with regard to principal nutrients.  相似文献   

9.
Summary Observation nurseries including 24 varieties of sesame were grown at 23 locations in 16 states. Data for yield, oil and protein content of the seed, and for iodine value of the oil were obtained from certain locations. Sesame seems reasonably well adapted on the better soils of most of the southern one-half of the United States. Average seed yield for varieties at 14 locations was 506 pounds per acre. Average yield of seed, oil, and protein per acre for seven varieties grown at eight locations was 662, 344, and 163 pounds per acre, respectively. The chemical composition of the seed was found to be well within the acceptable range but was markedly influenced both by the varieties and by the locations where they were grown. The average oil and protein contents on a moisture-free basis were 53.53% and 26.25%, respectively. The average iodine value of the oil was 110.0. Average protein content on the moisture- and oil-free basis was 57.28%. The genetic and environmental influences that affect protein content of the seed also inversely affected the oil content. It was suggested that in sesame protein synthesis is favored over oil synthesis as the nitrogen supply to the seed increases. Contribution of the Division of Tobacco, Medicinal, and Special Crops, Bureau of Plant Industry, Soils, and Agricultural Engineering, and the Southern Regional Research Laboratory, Bureau of Agricultural and Industrial Chemistry, U. S. Department of Agriculture. Agronomist, Division of Tobacco, Medicinal, and Special Crops in cooperation with the Department of Agronomy, Texas Agricultural Experiment Station; and chemist, Southern Regional Research Laboratory, New Orleans, La., respectively. The authors wish to acknowledge the assistance of workers in the various state agricultural experiment stations and government agencies who grew the tests and made data and seed samples available.  相似文献   

10.
Canola oil triacylglycerols from genetically modified canola lines (InterMountain Canola Co., Cinnaminson, NJ) have been evaluated for their photooxidative and autoxidative stabilities, as influenced by their fatty acid compositions and their triacylglycerol compositions and structures. Purified canola oil triacylglycerols were oxidized in duplicate in fluorescent light at 25°C and in the dark at 60°C under oxygen, and their oxidative deterioration with time was monitored by determining colorimetric peroxide values. Also monitored with time, oxidation products were determined by reversed-phase high-performance liquid chromatography with ultraviolet absorbance detection. Total volatiles, generated by thermal decomposition of the oxidized triacylglycerols, were quantitated by static-head-space gas chromatography. These experimental parameters were statistically correlated with predicted oxidizability, fatty acid composition, position of fatty acids on glycerol carbons and triacylglycerol composition. Oxidative deterioration of canola triacylglycerols correlated negatively with oleic acid composition, with oleic acid content at carbon 2 and with trioleoylglycerol content of the oil. Deterioration was positively correlated with the amount of linolenic acid on nonspecific locations on glycerol carbons 1,2 and 3, the amount of linoleic acid on glycerol carbon 2 and withsn-oleoyllinoleoyllinolenoyl glycerol content. Differences in character or quantity of volatile product and triacylglycerol hydroperoxides were low, whether generated during autoxidation or photooxidation of the canola triacylglycerols. Presented at the joint meeting of the American and Japan Oil Chemists' Societies, April 25–28, 1993, Anaheim, California.  相似文献   

11.
Summary The data presented show that the filtration-extraction process can be applied to the extraction of oil from flaxseed. General conditions for preparing the material and for extraction have been established. Adequate comminution, cooking, and crisping yielded materials having necessary characteristics for the successful application of the filtration-extraction process. Mass velocities in excess of 2,000 and residual lipides contents below 1% were obtained when these materials were slurried and extracted at slightly elevated temperatures (130°F.). The conditions of rolling had an appreciable effect upon the efficiency of extraction of flaxseed. One pass through five-high rolls with clearances of 0.002 in., 0.002 in., 0.002 in., and 0.000 in. between respective rolls proved satisfactory. Apparent optimum cooking moisture levels for efficient oil extraction fall between 17 and 24% maximum initial, and 8.0 to 10.5% as discharged from the cooker. Mass velocities were significantly lowered when maximum initial cooking moisture contents were below 14% since at these moisture levels it becomes necessary to reduce the moisture content to below 8%, as discharged from the cooker, to achieve suitable cooking. At these low moisture levels crisping by evaporative cooling is not effective. The versatility of the filtration-extraction process, which had been previously adapted to the extraction of oil from cottonseed, soybeans, sesame seed, peanuts, and rice bran, has been extended, with some minor but important modifications in the preparation and extraction conditions, to the extraction of oil from flaxseed. Presented at the fall meeting of the American Oil Chemists’ Society, Philadelphia, Pa., Oct. 10–12, 1955. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.  相似文献   

12.
Chlorophyll was added to refined and bleached canola oil before hydrogenation, and the effects on hydrogena-tion rate, fatty acid composition and the percentagetrans isomers were determined. The hydrogenation rate was greatly slowed down by chlorophyll under selective (200 C and 48 kPa) and nonselective conditions (165 C and 303 kPa). Higher levels of chlorophyll reduced the reaction rate more than the lower levels under both conditions. Dropping points were slightly higher for the nonselectively hydrogenated samples than for the selectively hydrogenated ones. Addition of 1 mg/kg or more chlorophyll decreased the solid fat content under nonselective conditions. Addition of chlorophyll reduced thetrans isomer content under nonselective conditions. Nonselective conditions also resulted in a greater decrease of 18:3 and faster production of 18:0 than selective conditions at all levels of chlorophyll addition.  相似文献   

13.
In this paper we investigate the behavior of a fluidized bed of silica nanoparticles under the influence of externally applied vibrations and an electrostatic field. We have observed that the application of these fields separately has opposite effects on bed expansion. On one hand, vertical vibrations enhance bed expansion as the vibration intensity is increased up to a critical value. On the other hand, an electrostatic field applied in the horizontal direction, hinders bed expansion. In previous research papers, it has been suggested that the size of nanoparticle agglomerates could be affected either by vibration or by the action of the electric field. Using the modified Richardson-Zaki method to analyze our experimental data we find that vertical vibration tends to decrease the average agglomerate size in agreement with previous research. However, in this work we look further into the physical mechanisms which affect the response of the fluidized bed. Our results suggest that both vibration and the electric field produce a significant perturbation to the flow of agglomerates within the fluidized bed. Vibration transmits a vertical motion to the agglomerates that enhances bed expansion until the vibration velocity becomes of the order of the expected rising velocity of macroscopic bubbles. At this critical point, bubble growth is stimulated by vibration. A horizontal electrostatic field produces a drift of the charged agglomerates toward the walls that gives rise to fluidization heterogeneity and bed collapse. When both fields are simultaneous applied, these opposed effects can be practically compensated.  相似文献   

14.
15.
Gas liquid chromatography was used to determine fatty acid composition of oil obtained from corn (Zea mays L.) inbred lines by different extraction procedures. Kernels were separated into endosperm and germ fractions for nine inbreds which had a considerable range in fatty acid composition of oil. Oil obtained from the endosperm by different extraction procedures was significantly different in composition for all fatty acids. Oil obtained from the germ by different extraction procedures was similar in fatty acid composition. The differences in response of endosperm and germ oils to extraction procedures were attributed to the type of lipid found in each fraction. It was concluded that choice of extraction procedures was of little importance in studies of oil from the corn germ, but that specific extraction procedures must be recognized as a factor when studying oil composition of the endosperm. Approved as Journal Series Paper No. 696, University of Georgia, College of Agriculture Experiment Stations.  相似文献   

16.
The nutritional qualities of soybean proteins are basically determined by amino acid patterns, amino acid availabilities (digestibility) and contents of biologically active components. Of these factors, the last two are most affected by processing conditions, whereas amino acid analysis is least affected, although it too may be modified in those cases in which soybean proteins are fractionated. In the preparation of the large variety of soya products presently available, soybeans are subjected to many different processes, all of which are discussed. Heat treatment appears to be the process which most affects protein nutritional quality; generally, quality first increases with heat treatment due to inactivation of biologically active factors, passes through a maximum and then decreases due to destruction and/or inactivation of essential amino acids such as cystine and lysine. Other processes affect protein nutritional quality to different degrees, inasmuch as they affect amino acid analysis, digestibility and content of biologically active components. When soybean proteins are used to extend animal proteins, supplement other vegetable proteins, or in vegetable protein mixtures, nutritional quality of the combined proteins appears to be affected in the same manner as that of soya proteins alone.  相似文献   

17.
The performance of continuous solid state bioreactors having two different solid substrate flow patterns, namely plug flow and completely mixed flow, is quantified for both steady-state and transient operation using a simple mathematical model. The core assumption is that each substrate particle acts as an infinitesimal bioreactor. The residence time distribution of the particles is considered in the formulation of the equations for the mixed-flow bioreactor and the error that results from neglecting it is investigated by comparing the simulation results with those of a completely mixed, continuous bioreactor for submerged liquid fermentation (a chemostat). The model is extended to include autolysis, inter-particle inoculation and contamination. Plug flow is shown to have superior performance when high product concentration is needed, if autolysis or other undesirable late emerging phenomena occur, and when non-sterile fermentation using slow-growing microorganisms is undertaken.  相似文献   

18.
Cotton root growth as affected by P fertilizer placement   总被引:1,自引:0,他引:1  
Growth chamber studies were conducted to evaluate root growth and P uptake by cotton (Gossypium hirsutum L.) as affected by the proportion of the soil volume that is treated with fertilizer P. Cotton seedlings were grown in a Dewey silty clay loam (Typic Paleudult) and a Marvyn loamy sand (Typic Paleudult). The Dewey soil had a low-P status and the Marvyn soil had a high-P status (7 and 44 mg kg–1 Mehlich I extractable P, respectively). Phosphorus was added at a constant or base rate which was added to decreasing proportions of the soil volume (i.e. 1.0, 0.5, 0.25 and 0.125). The addition of the same amount of P to decreasing proportions of the soil volume resulted in a stimulation of root growth in the P-fertilized soil volume relative to the nonfertilized soil. The degree of stimulation was similar for the two soils which differed in P status. Phosphorus uptake reached a maximum when 0.25 and 0.50 of the soil volume was treated with P on the Marvyn and Dewey soils, respectively.  相似文献   

19.
Two feeding experiments (i, ii) were conducted to investigate the influence of different dietary fats on the fatty acid (FA) composition of phospholipids as well as meat quality in pigs. In each experiment 12�4 siblings of Swiss Landrace or Large White breed were allocated to one of four feeding treatments according to sex, breed, and litter and fattened from about 25 to 105 kg liveweight. Pigs were fed a control diet (barley, wheat, soybean meal) or the control diet supplemented with 7% pork fat, 4.95% olive oil or 3.17% soybean oil (i) or 5% of olein or stearin fraction of pork fat or hydrogenated fat (ii). The dietary FA composition was reflected in the FA composition of phospholipids in M. long. dorsi and triceps brachii. However, the unsaturated to saturated ratio was not affected by the dietary intake of polyunsaturated FAs and was only slightly increased by the olive oil supplementation. Trans FAs including conjugated linoleic acid were incorporated into phospholipids only to a small extent. The dietary altered fatty acid composition of phospholipids did not cause any effect on pH, cooking loss, texture, or colour of pork, but meat quality as well as the proportion of saturated FA, arachidonic acid, and n‐3 fatty acids were significantly influenced by genetic effects.  相似文献   

20.
Abstract

Contents of fructooligosaccharides and inulin along with those of selected sugars in fresh banana of different ripening stages were first determined. Banana was then processed into snacks either by hot air drying (HD) or low-pressure superheated steam drying (LPSSD). Selected physicochemical properties of both fresh banana (moisture content, water activity, flesh-to-peel ratio, total soluble solids content, pH, titratable acidity and firmness) and its snacks (microstructure, texture and color) were investigated. Fresh banana of ripening stage 5 exhibited higher fructooligosaccharides, inulin and sugar contents; its snacks also possessed maximum fructooligosaccharides and inulin contents. Drying methods did not have any significant effect on the contents of these prebiotics. Although snacks from banana of ripening stage 5 possessed higher sugar contents, such contents, when snacks are consumed at the recommended amount, are still lower than the recommend daily intake. Stage-5 LPSSD snack exhibited better texture and color than its HD counterpart, so the former has a potential of being a prebiotic-based snack.  相似文献   

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