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571.
572.
Sinagawa-García SR Rascón-Cruz Q Valdez-Ortiz A Medina-Godoy S Escobar-Gutiérrez A Paredes-López O 《Journal of agricultural and food chemistry》2004,52(9):2709-2714
Prospective testing for allergenicity of proteins obtained from sources with no prior history of causing allergy has been difficult to perform. Thus, the objective of this work was to assess the food safety of genetically modified maize with an amaranth globulin protein termed amarantin. Transgenic maize lines evaluated showed, in relation to nontransgenic, 4-35% more protein and 0-44% higher contents of specific essential amino acids. Individual sequence analysis with known amino acid sequences, reported as allergens, showed that none of these IgE elicitors were identified in amarantin. Amarantin was digested within the first 15 min by Simulated Gastric Fluid treatment as observed by Western blot. Expressed amarantin did not induce important levels of specific IgE antibodies in BALB/c mice, as analyzed by ELISA. We conclude that the transgenic maize with amarantin is not an important allergenicity inducer, just as nontransgenic maize. 相似文献
573.
Isolation and properties of a Kunitz-type protein inhibitor obtained from Pithecellobium dulce seeds
Delgado-Vargas F López-Valdés HE Valdés-Rodríguez S Blanco-Labra A Chagolla-López A López-Valenzuela Ede J 《Journal of agricultural and food chemistry》2004,52(20):6115-6121
We report for the first time the isolation and characterization of a protease inhibitor from the seeds of Pithecellobium dulce, which is a Leguminosae tree native to Mexico. The purification of the P. dulce trypsin inhibitor (PDTI) was a direct process. After its extraction (pH 8.0) and precipitation (80% (NH(4))(2)SO(4)), the pH was adjusted to 4.0, the supernatant was loaded onto a CM-Sepharose column, and a single peak of trypsin inhibitory activity was eluted (CM-TIA). The main component of CM-TIA was PDTI, a protein composed of two polypeptide chains joined by disulfide bridge(s), with a pI of 4.95 and a molecular weight determined by electrospray mass spectrometry of 19 614 Da. The N-terminal sequence of PDTI has the highest similarity with the seed inhibitor of Acacia confusa. PDTI lacks chymotrypsin inhibitory activity. A low rate of cytotoxicity of CM-TIA toward RINm5F cells contrasted with a high rate of the active fraction G75-TIA (gel filtration chromatography; LC(50) of 0.04 mg/mL). 相似文献
574.
In this work a new method to detect the existence of chiral amino acids in orange juice is presented. The method employs beta-cyclodextrins and micellar electrokinetic chromatography with laser-induced fluorescence (MEKC-LIF) to separate and detect L- and D-amino acids (L-aa and D-aa) previously derivatized with fluorescein isothiocianate (FITC). A systematic optimization of the chiral-MEKC conditions is done bringing about in less than 20 min a good separation of the main amino acids found in orange juice (i.e., Pro, Asp, Ser, Asn, Glu, Ala, Arg, and the nonchiral GABA, i.e., gamma-aminobutyric acid). Using this procedure, the analysis time reproducibility for the 15 standard compounds (L-aa, D-aa, and GABA) has been determined to be better than 0.2% (n = 5) for the same day and better than 0.7% (n = 15) for three different days. Corrected peak area reproducibility is somewhat lower, providing values better than 3.3% (n = 5) for the same day and 6.9% (n = 15) for three different days. The limit of detection using this procedure was determined to be 0.86 attomoles for L-Arg. The optimized FITC derivatization method allows the easy and straightforward detection of amino acids in orange concentrates and juices (i.e., only centrifugation of diluted samples for 5 min is needed prior to their derivatization). D-Ala, D-Asp, D-Arg, and D-Glu were determined in orange juices and orange concentrates from different geographical origins using this new method. Moreover, the effect of different temperature treatments (50, 92, and 150 degrees C) on the content of D-aa in orange juice was evaluated. 相似文献
575.
Cortez Lucas Aguilar Marques Júnior José Peluco Rafael Gonçalves Siqueira Diego Silva Siansi Frederico Luiz Barbosa Ronny Sobreira Furlani Carlos Eduardo Angeli Camargo Lívia Arantes Silva Laércio Santos Gomes Romário Pimenta 《Precision Agriculture》2020,21(6):1351-1365
Precision Agriculture - Knowledge of the spatial variability of compaction would minimize the movement of soil and optimize the operation and economic viability of sugarcane activities. The present... 相似文献
576.
In Argentina, Eleusine tristachya has been recently reported as a problematic weed that can occur at high densities in spring and summer in fallows and in maize and soyabean. The reason for the increase in E. tristachya populations is that once the weed is established, it is difficult to eliminate because it produces a high number of seeds and plant regrowth occurs after herbicide treatments. The aim of this study was to determine the effect of post-emergence application of herbicides (glyphosate, haloxyfop-methyl and clethodim) at the seedling, vegetative and reproductive stages on the short-term (biomass 30 days after treatment—30 DAT) and long-term (tiller number and height and seed production—regrowth at 330 DAT) control of E. tristachya selected biotypes in outdoor pot experiments. Data fitted to a log-logistic model. For all the herbicides considered, at the seedling and vegetative stages, short-term control was achieved with low ED50 and ED90 values, whereas at the reproductive stage, ED90 values were three- to sixfold (glyphosate), six- to 52-fold (haloxyfop-methyl) and five- to 13-fold (clethodim) higher. Long-term control at the recommended dose or lower was not possible at the reproductive stage as tiller regrowth and seed production occurred with all herbicides. It is advisable to control Eleusine tristachya when plants are small at the beginning of the growing season using the recommended herbicide dose. A delayed application will produce tiller regeneration the following year, and consequently, control would only be achieved applying an overdose, which can cause risks to health and the environment. We concluded that a management programme based on the combination of glyphosate with post-emergence graminicides applied at early stages will be effective to control future infestations. 相似文献
577.
Fiz da Costa Susana Darriba Dorotea Martínez‐Patiño Alejandro Guerra 《Aquaculture Research》2011,42(10):1549-1557
This study investigated razor clam Ensis arcuatus culture from larval rearing to commercial size to assess it's aquaculture potential. Broodstock was spawned several times in hatchery facilities to demonstrate that larval availability is not a constraint for hatchery production. Larval culture lasted 20 days, showing an average survival of 14.35%. The razor clam seed reached a size of 28.5 mm at 4 months. Seed culture is feasible; however, it is constrained by the fact that razor clams need to be buried. Higher survival was observed when culturing razor clam seed with a substrate (82–83%), irrespective of the substrate grain size, while containers held without a substrate showed a significantly lower survival (56.5%). We showed that it is possible to rear E. arcuatus juveniles in bottles, with survival as high as 94–95% being achieved. The length increase of the hatchery‐produced E. arcuatus over 600 days was described by the equation Ln L=4.5+(?141.17/t), where L is length in mm and t is time in days. On‐growing showed adequate survival rates and it took 2–3 years to reach commercial size. 相似文献
578.
J. Alejandro Buentello Jonathan B. Goff Delbert M. Gatlin III 《Journal of the World Aquaculture Society》2009,40(5):687-694
Zinc is a trace mineral element that plays an essential role in numerous biochemical processes, and has been shown to affect growth and health of several fish species. However, the dietary zinc requirement of hybrid striped bass has not been defined. Therefore, a feeding trial was conducted to determine the dietary requirement for zinc by this fish and to compare zinc bioavailability of two chemically different forms (zinc sulfate and zinc proteinate). Six experimental diets were formulated with purified ingredients and supplemented with ZnSO4 to provide total zinc concentrations of 7, 12, 16, 26, 42, and 80 mg/kg diet which were determined by analysis. Each diet contained 32% crude protein, 6% lipid, and approximately 14.2 kJ of digestible energy per gram. The experimental diets were fed twice daily for 10 wk to triplicate groups of 15 hybrid striped bass initially weighing 0.86 ± 0.05 g/fish in 38‐L glass aquaria, connected as a recirculating system. Finally, after the feeding period, the fish were evaluated for weight gain, feed efficiency, protein efficiency ratio, and survival, as well as blood serum zinc, bone zinc, and hematocrit. All fish thrived during the feeding trial and not even the fish fed the basal diet displayed any apparent deficiency signs, although weight gain steadily increased with escalating levels of dietary zinc up to 42 mg/kg diet. On the basis of the most responsive indicators–bone zinc and serum zinc–the minimum dietary zinc requirement of hybrid striped bass was determined to be 17.0 and 17.3 mg Zn/kg diet, respectively, based on broken‐line regression. This estimate is similar in magnitude to dietary zinc requirements reported for other fish species. In addition, the bioavailability of zinc proteinate versus that of ZnSO4 was estimated by deriving the ratio of the slopes of the regression lines fitted to bone zinc and serum zinc data. This analysis indicated that hybrid striped bass utilized zinc proteinate ~1.7 times more efficiently than ZnSO4. 相似文献
579.
Marsili NR Lista A Fernandez Band BS Goicoechea HC Olivieri AC 《Journal of agricultural and food chemistry》2004,52(9):2479-2484
Two widely employed antimicrobials, benzoic and sorbic acids, were simultaneously determined in commercial orange juices employing a combination of a flow injection system with pH gradient generation, diode array spectrophotometric detection, and chemometric processing of the recorded second-order data. Parallel factor analysis and multivariate curve resolution-alternating least-squares were used for obtaining the spectral profiles of sample components and concentration profiles as a function of pH, including provisions for managing rank-deficient data sets. An appropriately designed calibration with a nine-sample set of binary mixtures of standards, coupled to the use of the second-order advantage offered by the applied chemometric techniques, allowed quantitation of the analytes in synthetic test samples and also in commercial orange juices, even in the presence of unmodeled interferents (with relative prediction errors of 8.7% for benzoic acid and 2.5% for sorbic acid). No prior separation or sample pretreatment steps were required. The comparison of results concerning commercial samples with a laborious reference technique yielded satisfactory statistical indicators (recoveries were 99.0% for benzoic acid and 101.4% for sorbic acid). 相似文献
580.
Blenkinsop RW Copp LJ Yada RY Marangoni AG 《Journal of agricultural and food chemistry》2002,50(16):4545-4553
A four-year study of a number of compositional parameters of potato tubers during low-temperature storage was conducted to examine the compositional differences between cold-tolerant (low sugar-accumulating) and cold-sensitive (high sugar-accumulating) tubers in relation to potato chip processing quality. Compositional parameters analyzed included sucrose, reducing sugars, nitrogen, protein, ascorbic acid, and dry matter content. Pearson correlation analysis of the data illustrated that chip color was most closely correlated with reducing sugar concentration. Multiple regression analysis revealed that the relative contribution of each parameter to chip color varied greatly among the cultivars and selections evaluated and from season to season. This analysis demonstrates that the quantitative relationships between the measured compositional parameters and chip color were not sufficient to provide a general predictive index of chip color quality for tubers processed directly from low-temperature storage. 相似文献