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1.
Conditions for growing spirulina (Spirulina platensis) were developed. The amino-acid and carbohydrate compositions were determined. Lipids and vitamins of the culture biomass were studied.  相似文献   

2.
The possibility of preparing feed from wheat straw via fermentation by cellulolytic enzymes from the fungusTrichoderma harzianumis demonstrated. The water- and salt-soluble fractions of the fermented feed contain the largest quantity of essential amino acids (22.93%). The predominant essential amino acids are lysine, leucine, methionine, and threonine. The total essential amino acids in the water- and salt-soluble fractions represent 31.44% of the total amount of protein in the fermented feed  相似文献   

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《Analytical letters》2012,45(5):725-736
Abstract

This study was designed to evaluate free amino acid (FAA) composition and total protein in mature human milk from Turkish mothers. Free amino acid concentrations in mature human milk were determined in all subjects using a high‐performance liquid chromatography (HPLC) with postcolumn derivatization system, with a fluorescence detector. Total protein content was determined by the classical biuret method. Total protein concentration was found to be 1.3±0.4 mg/dl. Glutamic asid plus glutamine is the most abundant amino acid (1275 µmol/L), followed by taurine (353 µmol/L) and alanine (261 µmol/L). Glutamic acid plus glutamine accounts for the most free amino acids in mature human milk and their sum represents 40% of total FAA. On the other hand, some amino acid derivatives such as citrulline, ethanolamine, ammonium, ornithine, ortophosphoserine, and phosphoethanolamine, not usually a part of protein, are determined and this fraction represented ~21% of the total FAA in mature human milk in the present study.  相似文献   

4.
Essential oil (1.1%) is isolated fromSalvia officinaliscultivated in Georgia. Its properties are: 20 0.921, n D 20 1.463, [] D 20 +24.91 , acid number 2.8, ketone content 65.4% (oxime method). GLC showed the presence of 11 terpenes, among which -thujone (31.56%), -thujone (17.55), camphor (16.48), and 1,8-cineol (17.53) are present in the highest amounts.  相似文献   

5.
Abstract

Trace amounts of iodine in thirty-eight cereal grain samples cultivated at different locations in Austria were determined for the first time in this study by radiochemical neutron activation analysis. For the dissolution of cereal grain samples and standard reference materials, two different procedures, alkaline and acidic dissolution, were applied in the presence of an iodine carrier. Rapid and simple dissolution procedure with acidic solution was demonstrated in this study. The analytical values in the cereal grain as well as in the standard reference materials obtained by the different dissolution procedures were in good agreement within one standard deviation. The iodine in cereal grains and the standard reference materials ranged from 0.002 to 0.03 μg g?-1 and 0.0015 to 0.30 μg g?-1, respectively. The distribution of relative standard deviation (RSD) for iodine concentration below 0.01 μg g?-1 were 21% and 24% of all data for the range 1–10% RSD and 11–20% RSD, respectively. The RSD for 0.1 μg g?1 of iodine concentrations were around 10%  相似文献   

6.
The hemp seed contains protein fractions that could serve as useful ingredients for food product development. However, utilization of hemp seed protein fractions in the food industry can only be successful if there is sufficient information on their levels and functional properties. Therefore, this work provides a comparative evaluation of the structural and functional properties of hemp seed protein isolate (HPI) and fractions that contain 2S, 7S, or 11S proteins. HPI and protein fractions were isolated at pH values of least solubility. Results showed that the dominant protein was 11S, with a yield of 72.70 ± 2.30%, while 7S and 2S had values of 1.29 ± 0.11% and 3.92 ± 0.15%, respectively. The 2S contained significantly (p < 0.05) higher contents of sulfhydryl groups at 3.69 µmol/g when compared to 7S (1.51 µmol/g), 11S (1.55 µmol/g), and HPI (1.97 µmol/g). The in vitro protein digestibility of the 2S (72.54 ± 0.52%) was significantly (p < 0.05) lower than those of the other isolated proteins. The intrinsic fluorescence showed that the 11S had a more rigid structure at pH 3.0, which was lost at higher pH values. We conclude that the 2S fraction has superior solubility, foaming capacity, and emulsifying activity when compared to the 7S, 11S, and HPI.  相似文献   

7.
Fish maws are commonly recommended and consumed in Asia over many centuries because it is believed to have some traditional medical properties. This study highlights and provides new information on the proximate composition, amino acid and fatty acid composition of fish maws of Cynoscion acoupa, Congresox talabonoides and Sciades proops. The results indicated that fish maws were excellent protein sources and low in fat content. The proteins in fish maws were rich in functional amino acids (FAAs) and the ratio of FAAs and total amino acids in fish maws ranged from 0.68 to 0.69. Among species, croaker C. acoupa contained the most polyunsaturated fatty acids, arachidonic acid, docosahexaenoic acid and eicosapntemacnioc acid, showing the lowest value of index of atherogenicity and index of thrombogenicity, showing the highest value of hypocholesterolemic/hypercholesterolemic ratio, which is the most desirable.  相似文献   

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蛋白质水解液中氨基酸组成的定量分析   总被引:12,自引:0,他引:12  
丁雅韵  谢孟峡  康娟 《分析化学》2002,30(4):418-421
以氯甲酸-9-芴基甲酯(FMOC-Cl)为柱前衍生化试剂在液相色谱上分离17种常见氨基酸的衍生物并测定其摩尔吸光系数。用绝对分析法和标准曲线法对标准氨基酸溶液进行了定量分析,除组氨酸外两种方法测定结果的相对偏差为5.00%以内。对氨基酸的稳定性进行了模拟水解实验,发现在110℃/24h的水解条件下,丝氨酸等不稳定氨基酸的降解较在150℃/1.5h条件下小。用绝对分析法测定测定了牛胰岛素不同水解条件下水解液中氨基酸的含量,大部分氨基酸的相对收率都接近100%。  相似文献   

12.
Most insecticides commonly used in storage facilities are synthetic, an issue that generates concerns about food safety and public health. Therefore, the development of eco-friendly pest management tools is urgently needed. In the present study, a 6% (w/w) Hazomalania voyronii essential oil-based nanoemulsion (HvNE) was developed and evaluated for managing Tribolium confusum, T. castaneum, and Tenebrio molitor, as an eco-friendly wheat protectant. Larval and adult mortality was evaluated after 4, 8, and 16 h, and 1, 2, 3, 4, 5, 6, and 7 days, testing two HvNE concentrations (500 ppm and 1000 ppm). T. confusum and T. castaneum adults and T. molitor larvae were tolerant to both concentrations of the HvNE, reaching 13.0%, 18.7%, and 10.3% mortality, respectively, at 1000 ppm after 7 days of exposure. However, testing HvNE at 1000 ppm, the mortality of T. confusum and T. castaneum larvae and T. molitor adults 7 days post-exposure reached 92.1%, 97.4%, and 100.0%, respectively. Overall, the HvNE can be considered as an effective adulticide or larvicide, depending on the target species. Our results highlight the potential of H. voyronii essential oil for developing green nanoinsecticides to be used in real-world conditions against key stored-product pests.  相似文献   

13.
李军  于一茫  田苗  王宏伟  卫锋  李莉  王雄 《色谱》2006,24(6):581-584
建立了同时检测粮谷中黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A的免疫亲和柱净化-柱后光化学衍生-高效液相色谱方法。样品经过甲醇-水(体积比为80∶20)提取,通过免疫亲和柱富集和净化,采用Waters Nova-Pak色谱柱(3.9 mm i.d.×150 mm,4 μm),以甲醇、乙腈和1%的磷酸溶液为流动相,梯度洗脱,柱后光化学衍生、改变波长荧光检测。黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A检出限分别为0.24,4.0和0.5 μg/kg,标准曲线的线性范围分别为0.24~6.0,4.0~100.0和0.5~40.0 μg/L;在小麦、玉米、黑麦样品中,平均加标回收率为70.8% ~94.0%,相对标准偏差为2.79% ~9.38%。  相似文献   

14.
The recognition of some globular proteins was carried out in aqueous solution, at micromolar concentrations, by using an uncharged symmetrical cobalt–porphyrin (Co–P). By means of UV/Vis, induced circular dichroism, and fluorescence spectroscopy techniques, it was ascertained that the interactions between specific amino acid residues and Co–P occurred on the protein surface. In particular, spectroscopic evidence showed the formation of supramolecular complexes without disruption of the native structure of the proteins and, furthermore, that signal changes were characteristic of each Co–P/protein system, so that they could be used as a highly sensitive analytical tool for protein recognition. The relative association constants were proportional to the protein molecular masses (and then to the number of amino acid residues).  相似文献   

15.
After being harvested, cacao beans are usually subjected to very complex processes in order to improve their chemical and physical characteristics, like tastefulness with chocolate characteristic flavors. The traditional process consists of three major processing stages: fermentation, drying, and roasting, while most of the fermentation is carried out by an on-farm in-box process. In Taiwan, we have two major cocoa beans, the red and the yellow. We proposed that the major factor affecting the variation in tastes and colors in the finished cocoa might be the difference between cultivars. To uncover this, we examined the effect of the three major processes including fermentation, drying and roasting on these two cocoa beans. Results indicated that the two cultivars really behaved differently (despite before or after processing with fermentation, drying, and roasting) with respect to the patterns of fatty acids (palmitic, stearic, oleic, and arachidonic); triacylglycerols:1,2,3-trioleoyl-glycerol (OOO); 1-stearoyl-2,3-oleoyl-glycerol (SOO); 1-stearoyl-sn-2-oleoyl-3-arachidoyl- glycerol (SOA); 1,3-distearyol-sn-2-oleoyl-glycerol (SOS); organic acids (citric, tartaric, acetic, and malic); soluble sugars (glucose and fructose); amino acids; total phenolics; total flavonoids; and volatiles. Our findings suggest that to choose specific processing conditions for each specific cocoa genotype is the crucial point of processing cocoa with consistent taste and color.  相似文献   

16.
The authors have recently reported on the design of a protein (MB-1) enriched in methionine, threonine, lysine, and leucine. The protein is intended to be produced by rumen bacteria, in a way that would provide high producing lactating cows with limiting amino acids. In this report, MB-1 stability in the rumen is assessed, i.e., where the protein might be found after cell lysis or after being secreted by rumen bacteria. Current in vitro methods used to predict proteolytic degradability in the rumen were used for MB-1, as well as other natural proteins for comparison. MB-1 was found to be more susceptible to degradation than cytochrome c and ribonuclease A. Data indicate that MB-1 will be rapidly degraded if exposed to the rumen environment without protection. The contribution of folding stability to proteolytic stability was also examined. Rumen liquor components were selected to formulate a solution compatible with constraints of thermal denaturation studies. Denaturation curves show that the natural proteins were folded at rumen temperature. The MB-1 denaturation curves indicated that MB-1 does not unfold in a cooperative transition when heated from 20 to 70‡C. This suggests that MB-1 structure may be progressively modified as temperature increases, and that a continuum of conformations are available to MB-1. At 39‡C, a significant (50%) portion of MB-1 molecules had their tertiary structure unfolded, contributing to proteolytic degradability. Despite the unusual constraints used in MB-1 design (i.e., a maximized content in selected essential amino acids), results show that MB-1 has structural properties similar to previously reportedde novo designed proteins.  相似文献   

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Marine feed ingredients derived from cephalopods (e.g., squid) and crustaceans (e.g., krill) are commercially used to improve the palatability of shrimp diets. Increase in global demand for shrimps has resulted in overfishing of these marine organisms and is a matter of concern. Insect protein hydrolysate could be a sustainable alternative for the possible replacement of these marine feed ingredients. During this study, four formulations: diet A (control: not containing any palatability enhancer), diet B (containing squid meal and krill oil), diet C (containing 1% insect protein hydrolysate), and diet D (containing 2% insect protein hydrolysate) were tested for (1) time required by first subject to begin feeding (time to strike) and (2) palatability in Litopenaeus vannamei. Additionally, the chemical composition of all four diet formulations was also analyzed. Results indicate that all diets had similar crude composition. The major essential amino acids in all diets were leucine and lysine, whereas eicosapentaenoic acid was the major omega-3 fatty acid in all diets. There were no significant differences between the mean time to strike for all the tested formulations. Palatability of tested formulations was found in the following order: diet D > diet C > diet B = diet A (p < 0.05), indicating that addition of squid meal and krill oil has no effect on palatability in comparison to control, whereas inclusion of insect protein hydrolysates significantly improves the palatability of formulations. Palatability enhancement potential of insect protein hydrolysate could be attributed to the high free amino acid content and water solubility in comparison to squid meal.  相似文献   

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隋凯  李军  卫锋  赵守成 《分析化学》2005,33(11):1643-1646
建立了谷物中脱氧雪腐镰刀菌烯醇DON的高效液相色谱检测和质谱确证方法。样品用水提取,通过免疫亲和柱进行富集和净化,以Hypersil BDS C18柱为分离柱,乙腈-水(10:90,V/V)混合溶剂为流动相进行高效液相色谱分离和检测,利用大气压化学电离质谱(APCI)进行阻性结果的鉴定和确认。在小麦、大麦和面粉等样品中,本方法在0.1~10μg/g添加范围内的回收率为82.4%-103%,相对标准偏差1.4%-7.6%,检出限0.1μg/g。  相似文献   

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