scholarly journals Determination of Protein Oxidation in Aquaculture Feed

2021 ◽  
Author(s):  
Danka Dragojlović
Keyword(s):  
Protein Oxidation ◽  
Protein Extraction ◽  
Protein Carbonyls ◽  
Trichloracetic Acid ◽  
Complex Samples ◽  
Modified Method ◽  
Aquaculture Feed ◽  
Cheap Method ◽  
Lowry Method

The aim of this research was to develop reliable, easy-to-perform and cheap method for measuring protein oxidation in complex samples such as aquaculture feed within various protein sources. For that purpose modified 2,4-dinitrophenylhydrazyne (DNPH)-based method for quantification of protein carbonyls was employed, while the method modification was consisted of using different solutions for the extraction, time of protein extraction and concentration of trichloracetic acid (TCA) for protein precipitation. It was found that extraction during night, higher TCA concentration  and the use of  0.5 M KCl extraction solution resulted in the highest protein amount measured by Lowry method and 280 nm protein estimation. On the other hand, the lowest protein yield was obtained by using distillated water for the extraction. Furthermore, the lowest amount of protein carbonyls was in the case when extraction was performed with distilled water (DW), while the highest content of protein carbonyls were reached with 0.15 M KCl and 0.5 M KCl extraction solutions. It was observed that the amount of carbonyls compounds were increasing during storage under accelerated conditions, and in comparison to the original (unmodified) method, the modified method for measuring protein oxidation resulted in the higher amount of carbonyls during the all points of storage.

Adaptation of the AOAC Fluorine Method for Determining Fluoride in Fish Protein Concentrate

1970 ◽  
Vol 53 (1) ◽  
pp. 3-6
Author(s):  
R. Bruce Klemm ◽  
Mary E. Ambrose Klemm
Keyword(s):  
Steam Distillation ◽  
Silica Sand ◽  
Official Method ◽  
Protein Concentrate ◽  
Fish Protein ◽  
Direct Titration ◽  
Modified Method ◽  
Aoac Official ◽  
Aoac Official Method

Abstract The AOAC official method, 24.029–24.035, for the determination of fluorine in foods was modified slightly to o btain quantitative recoveries of fluorine from samples of fish protein concentrate (FPC). The most important alterations include the use of steam distillation, the addition of finely ground silica sand in the distillation, a decrease in the distillation temperature, and the utilization of direct titration. Recoveries of fluoride added to FPC before ashing, using this modified method, averaged 96.0 ± 3.0%. Our results are in agreement with those of several other analysts who used a variety of methods.

scholarly journals Comparison of Quality Changes in Eurasian Perch (Perca Fluviatilis L.) Fillets Originated from Two Different Rearing Systems during Frozen and Refrigerated Storage

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1405
Author(s):  
Nima Hematyar ◽  
Jan Mraz ◽  
Vlastimil Stejskal ◽  
Sabine Sampels ◽  
Zuzana Linhartová ◽  
...  
Keyword(s):  
Protein Oxidation ◽  
Sodium Dodecyl ◽  
Frozen Storage ◽  
Storage Conditions ◽  
Quality Parameters ◽  
Protein Carbonyls ◽  
Main Concern ◽  
Refrigerated Storage ◽  
Eurasian Perch ◽  
Recirculating Aquaculture Systems

The current knowledge on how different Eurasian perch rearing systems impact the final fillet quality is scant. Therefore, two domestic storage conditions were investigated—10 months frozen (-20 °C) and 12 days refrigerated (+4 °C) storage conditions—in order to determine (i) how the choice of rearing system affects fillets quality during different processing conditions and (ii) if oxidative changes and other quality parameters were interactive. For the proposed idea, proteome analysis, oxidative changes, and some quality parameters were considered in this study. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) indicated a higher loss of protein in the frozen fillets from ponds (PF) than the fillets from recirculating aquaculture systems (RAS) (RF). Western blot showed a higher protein carbonyls level in RF compared to PF, which was confirmed by the total protein carbonyls during frozen storage. PF indicated less liquid loss, hardness, and oxidation progress than RF in both storage conditions. The biogenic amines index (BAI) in the fillets from either origin showed acceptable levels during storage at +4 °C. Furthermore, the n-3/n-6 ratio was similar for both fillets. The deterioration of fillets during frozen storage was mainly caused by formation of ice crystals followed by protein oxidation, while protein oxidation was the main concern during refrigerated storage confirmed by principal component analysis (PCA) analysis.

Improved Method for the Determination of Ethylenebisdithiocarbamate Residues in Plants, Fruits, and Vegetables

1967 ◽  
Vol 50 (5) ◽  
pp. 1102-1108
Author(s):  
Charles F Gordon ◽  
Richard J Schuckert ◽  
William E Bornak
Keyword(s):  
Sulfuric Acid ◽  
Fruits And Vegetables ◽  
Analytical Procedure ◽  
Improved Method ◽  
Modified Method ◽  
Fungicide Residues ◽  
Crop Types ◽  
Large Representative

Abstract A modified method for the determination of dithiocarbamate fungicide residues on crops is presented. A large representative subsample of the frozen crop is blended in ice-cold deaerated water and an aliquot of the homogenate is added to the analytical apparatus containing hot 5 0% sulfuric acid. Dithiocarbamates are decomposed to evolve CS2 which is removed by a continuous gentle air-sweep from the digestion flask. Variations in technique allow the analysis of dithiocarbamate fungicide residues in several ranges, 1-10, 10-200, and 200-1000 /ig maneb. Recoveries from a wide variety of crops averaged 70 to 103%. Certain crop types present low recoveries and/or high apparent control values, but modifications in the analytical procedure are successful in solving these problems.

scholarly journals Animal and Plant Protein Oxidation: Chemical and Functional Property Significance

Foods ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 40
Author(s):  
Youling L. Xiong ◽  
Anqi Guo
Keyword(s):  
Protein Oxidation ◽  
Food Systems ◽  
Muscle Protein ◽  
Plant Protein ◽  
Enzymatic Oxidation ◽  
Protein Carbonyls ◽  
Amino Acid Side Chain ◽  
Food Protein ◽  
Protein Radicals ◽  
The Impact

Protein oxidation, a phenomenon that was not well recognized previously but now better understood, is a complex chemical process occurring ubiquitously in food systems and can be induced by processing treatments as well. While early research concentrated on muscle protein oxidation, later investigations included plant, milk, and egg proteins. The process of protein oxidation involves both radicals and nonradicals, and amino acid side chain groups are usually the site of initial oxidant attack which generates protein carbonyls, disulfide, dityrosine, and protein radicals. The ensuing alteration of protein conformational structures and formation of protein polymers and aggregates can result in significant changes in solubility and functionality, such as gelation, emulsification, foaming, and water-holding. Oxidant dose-dependent effects have been widely reported, i.e., mild-to-moderate oxidation may enhance the functionality while strong oxidation leads to insolubilization and functionality losses. Therefore, controlling the extent of protein oxidation in both animal and plant protein foods through oxidative and antioxidative strategies has been of wide interest in model system as well in in situ studies. This review presents a historical perspective of food protein oxidation research and provides an inclusive discussion of the impact of chemical and enzymatic oxidation on functional properties of meat, legume, cereal, dairy, and egg proteins based on the literature reports published in recent decades.

scholarly journals Concurrent chromatographic determination of pseudoephedrine and loratadine from combination syrups and tablets

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Imad Osman Abu Reid
Keyword(s):  
Ammonium Acetate ◽  
Chemical Properties ◽  
Chromatographic Determination ◽  
Analytical Challenge ◽  
Intermediate Precision ◽  
Box Behnken Design ◽  
Complex Samples ◽  
System Suitability ◽  
Nonpolar Compounds

Abstract Background Chromatographic separation of polar and nonpolar compounds when presented in combined dosage forms has always been considered as great analytical challenge. Separation and retention of both polar and nonpolar compounds by the same stationary phase can be a useful approach for analyses of complex samples with such a difference in chemical properties. Loratadine (nonpolar) and pseudoephedrine (polar) are typical examples of this situation. Results The Box–Behnken design was used to optimize the separation process, an efficient separation of loratadine and pseudoephedrine was achieved within 6 min; employing a mixture of 16.0 mM ammonium acetate buffer (pH 4.5) and acetonitrile (23:77, v/v) as isocratic mobile phase, pumped at 1.0 mL/min through a Zorbax cyanopropyl column (250 mm × 4.6 mm, 5 μm), the analytes were detected at 250 nm. Under the same conditions, separation of sodium benzoate preservative co-formulated with the two analytes in syrup formulation was also achieved. The calibration curve demonstrated excellent linearity in the range of 24.6–123.2 μg/mL and 594.8–2974.0 μg/mL for loratadine and pseudoephedrine, respectively with determination coefficient (r2) > 0.999. Conclusion The method’s accuracy bias < 2.0%, repeatability and intermediate precision (%RSD < 2.0%) were verified. In addition, system suitability parameters were found within the acceptable limits. Satisfactory results were obtained upon the application of the validated method to the analysis of commercial tablet and syrup formulations.

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