Keywords
wheat flour
derivative spectrophotometry
method validation
How to Cite
Abstract
The aim of this paper was the validation of a methodology for determination of L-phenylalanine (Phe) in wheat fl our by second derivative spectrophotometry. For this purpose, 0.525g of wheat flour was hydrolyzed with HCl 5.7 mol/L at 110°C for 24 h. This material was diluted to 50 mL with 0.1 mol/L sodium phosphate buffer, pH 7.0. The solutions prepared from this hidrolyzed were measured on UV/VIS spectrophotometer at wavelength range from 230 nm to 280 nm. The second derivative spectrophotometry’s spectra were plotted and the values of the negatives peaks areas were used for estimating the Phe contents. Linearity was demonstrated in the range of 0.010 mg/mL to 0.035 mg/mL (corresponding to 251 mg/100g to877 mg/100g of Phe in flour). Matrix effects were observed. The Phe determination was not affected by similar compounds such as L-tyrosine and L-tryptofan. The recoveries ranged from 81 % to 118 % and the relative standard deviation under repetitivity and within-reproducibility conditions were 11 % and 15 %, respectively, for samples at 354 mg/100g, showing the adequate recovery and precision of the methodology. The limits of detection and quantification were 63 mg/100gand 175 mg/100g, respectively. The studied parameters indicated that this methodology is suitable for monitoring and controlling of Phe contents in wheat flour.References
1. Ramaswami U, Smith I. Phenylketonuria. Curr Paediatrics. 1997; 7: 251-255.
2. Starling ALP, Aguiar MJB, Kanufre VC, Soares SF. Fenilcetonúria. Rev Méd Minas Gerais. 1999; 9: 106-10.
3. Mira NVM, Marquez UML. Importância do diagnóstico e tratamento da fenilcetonúria. Rev Saúde Publ. 2000; 34: 86-96.
4. Hendriksz CJ, Walter JH. Update on phenylketonuria. Curr Paediatrics. 2004; 14: 400-6.
5. Marco D, Waitzberg DL. Erros congênitos do metabolismo – fenilcetonúria. In: Waitzberg DL. Nutrição oral, enteral e parenteral na prática clínica. 3.ed. São Paulo: Atheneu; 2004. p. 449-57.
6. Lopez-Bajonero LJ, Lara-Calderon P, Galvez-Mariscal A, Velasquez-Arellano A, Lopez-Munguia A. Enzymatic production of a low-phenylalanine product from skim milk powder and caseinate. J Food Sci. 1991; 56: 938-42.
7. Martins AM, Fisberg RM, Schmidt BJ. Fenilcetonúria: abordagem terapêutica. São Paulo: Nestlé; 1993.
8. Shimamura S, Tamura Y, Miyakawa H, Saito H, Kawaguchi Y, Isomura N, et al. Peptide mixture and products thereof. Morinaga Milk Industry Co., Ltd., Tokio, Japan, Patents US 5952193, A23C 21/02; A23C 21/04; A23C 21/06; A61K 38/01. 1997 Apr 14; 1999 Sep 14.
9. Piecyk M, Srama A, Bzducha A, Obiedzinski M. Application of HPLC and GC/MS to quantifi cation of phenylalanine in chosen kinds of food for particular nutritional uses. Acta Sci Pol Technol Aliment. 2007; 6( 2): 5-18.
10. Keohane PP, Grimble GK, Brown B, Spiller RC. Infl uence of protein composition and hydrolysis method on intestinal absorption of protein in man. Gut. 1985; 26: 907-13.
11. Grimble GK, Keohane PP, Higgins BE, Kaminsk Jr MV, Silk DBA. Effect of peptide chain length on amino acid and nitrogen absortion from two lactoalbumin hydrolysates in the normal human jejunum. Clin Sci. 1986; 71: 65-9.
12. Carreira RL, Barbosa CMS, Junqueira RG, Motta S, Silvestre MPC. Emprego da cromatografi a líquida de alta efi ciência hidrofílica na determinação dos aminoácidos de hidrolisados de caseína. Ciênc Tecnol Aliment. 2002; 22 (3): 229-32.
13. O’Haver TC, Green GL. Numerical error analysis of derivative spectrometry for the quantitative analysis of mixtures. Anal Chem. 1976; 48 (2).
14. Ragone R, Colonna G, Balestrieri C, Servillo L, Irace G. Determination of tyrosine exposure in proteins by second derivative spectroscopy. Biochem. 1984; 23: 1871-5.
15. Grant A, Bhattacharyya PK. Application of derivative spectroscopy to the determination of chromatographic peak purity. J Chromatog A. 1985; 347: 219-35.
16. Rojas FS, Ojeda CB, Pavon JMC. Derivative ultraviolet-visible region absorption spectrophotometry and its analytical applications. Talanta. 1988; 35: 753-61.
17. Ichikawa T, Terada H. Second derivate spectrophotometry as an effective tool for examining phenylalanine residues in proteins. Biochim Biophys Acta. 1977; 494: 267-70.
18. Ichikawa T, Terada H. Estimation of state and amount of phenylalanine residues in proteins by second derivative spectrophotometry. Biochim Biophys Acta. 1979; 580: 120-8.
19. Ichikawa T, Terada H. Determination of phenylalanine, tryptophan and tyrosine in a mixture of amino acids by second derivative spectrophotometry. Chem Pharm Bull. 1981; 29 (2): 438-44.
20. Ichikawa T, Terada H. Effect of dodecyl sulfate on the spectral properties of phenylalanil residues in serum albumin detected by second derivative spectrophotometry. Biochim Biophys Acta. 1981; 671 (1): 33-7.
21. Brandts JF, Kaplan LJ. Derivate spectroscopy applied to tyrosiyl chromophores. Studies on ribonuclease, lima bean inhibitors, insulin, and pancreatic trypsin inhibitor. Biochem. 1973; 12 (10): 2011-24.
22. Matsushima A, Inoue Y, Shibata K. Derivate absortion spectrophotometry of native proteins. Anal Biochem. 1975; 65 (3): 362-68.
23. Cahill JE, Padera FG. Derivative analysis of UV/visible spectra. American Laboratory. 1980; 12: 101-12.
24. Morais HA, Marco LM, Oliveira MC, Silvestre MPC. Casein hydrolysates using papain: peptide profi le and encapsulation in liposomes. Acta Alim. 2005; 34 (1): 59-69.
25. Soares RDL, Biasutti EAR, Capobiango M, Vieira CR, Silva VDM, Januário JN, Aguiar MJB, Silvestre MPC. Preparation of enzymatic skim milk hydrolysates with low phenylalanine content. Acta Farmac Bonaer. 2006; 25: 325-32.
26. Lopes DCF, Delvivo FM, Silvestre MPC. Hydrolysates of skim milk powder: peptide profi les for dietetic purposes. Brit Food J. 2005; 107 (1): 42-53.
27. Capobiango M, Lopes DCF, Carreira RL, Afonso WO, Segall SD, Silvestre MPC. Optimization of enzyme assisted processes for extracting and hydrolysing corn proteins aiming phenylalanine removal. Int J Food Eng. 2007; 3: 1-19.
28. Lopes DCF, Bizzotto CS, Silva VDM, Afonso WO, Lopes Jr CO, Silvestre MPC. Obtention of low-phenylalanine protein hydrolysates from rice: use of two pancreatins. J Food Technol. 2008; 6: 57-65.
29. Vieira CR, Lopes Jr CO, Ramos CS, Capobiango M, Silvestre MPC. Extração enzimática das proteínas da farinha de arroz. Ciênc Tecnol Alimen. 2008; 28: 599-606.
30. NUPAD – Núcleo de ações e pesquisas em apoio diagnóstico. [acesso em: 15 de outubro de 2008]. Disponível em: < http://www.nupad.medicina.ufmg.br>.
31. King B. In-house method validation. A guide for chemical laboratories. LGC Limited. 2003.
32. Thompson M, Ellison SLR, Wood R. Harmonized guidelines for single-laboratory validation of methods of analysis. Pure Appl Chem. 2002; 74: 835-55.
33. Souza SVC, Lima JA, Teodoro JC, Junqueira RG. Validação intralaboratorial de método quantitativo para determinação múltipla de resíduos de avermectinas em leite bovino por cromatografia líquida de alta eficiência com detecção de fl uorescência. Ciênc Tecnol Aliment. 2007; 27 (4): 787-92.
34. Souza SVC, Pinto CT, Junqueira RG. In-house method validation: application in arsenic analysis. Journal of Food Composition and Analysis. 2007; 20: 241-47.
35. Souza SVC, Junqueira RG, Ginn R. Analysis of semicarbazide in baby food by liquid chromatography tandem mass spectrometry (LC-MS-MS) - In-house method validation. J Chromatogr A. 2005; 1077: 151-8.
36. Souza SVC, Junqueira RG. A procedure to assess linearity by ordinary least squares method. Analytica Chimica Acta. 2005; 552: 25-35.
37. Meyer PC, Zund RE. Statistical methods in analytical chemistry. New York: John Wiley & Sons; 1993.
38. Belsley DA, Kuh E, Welsch RE. Regression diagnostics: identifying infl uential data and sources of collinearity. New York: Wiley; 1980.
39. Horwitz W. Protocol for the design, conduct and interpretation of method-performance studies. Pure Appl Chem. 1995; 67: 331-43.
40. Ryan TA, Joiner BL. Normal probability plots and tests for normality. The State College: Pennsylvania State University; 1976.
41. Levene H. Robust tests for equality of variances. In: Olkin I, Ghurye SG, Hoeffding W, Madow WG, Mann HB. (Ed.) Contributions to probability and statistics. Stanford: Stanford University Press; 1960. p. 278-92.
42. Brown MB, Forsythe AB. Robust tests for the equality of variance. J Am Stat Assoc. 1974; 69: 364-7.
43. Durbin J, Watson GS. Testing for serial correlation in least squares regression ii. Biometrika. 1951; 38: 159-78.
44. Draper N, Smith H. Applied regression analysis. New York: Wiley; 1998.
45. Snedecor GW, Cochran WG. Statistical methods. Ames: Iowa State University; 1989.
46. Armitage P, Berry G. Statistical methods in medical research. Oxford: Blackwell Science Ltd.; 1994.
47. USDA (United States Department of Agriculture). Human Nutrition Information Service. Agriculture Handbook. Composition of Foods: Cereal Grains and Pasta. Number 8-20, 1989. Modifi ed From Drake, D.L., S.E. Gebhardt, R.H. Matthews. Updated: Friday, May 26, 2006. [acesso em: 08 de junho de 2008]. Disponível em: <http://food.oregonstate.edu/g/comp/ compa.html>.
48. Grubbs F. Procedures for detecting outlying observations in samples. Technometrics. 1969; 11: 1-21.
49. Barret V, Lewis T. Outliers in statistical data. 3 ed. New York: John Wiley; 1994.
50. Burke S. Missing values, outliers, robust statistics & non-parametric methods. LC GC. 2001; 19-24.
51. EC (European Commission). Commission decision 2002/657/EC of 12 August 2002. Implementing Council Directive 96/23/EC concerning performance of analytical methods and the interpretation of results. Official Journal of the European Communities, 2002, L 221/8.
52. ISO (International Standards Organization). ISO 5725-1. Accuracy (trueness and precision) of measurement methods and results - Parts 1, 2, 3, 4 and 6. Geneva: ISO; 1994.
53. ISO (International Standards Organization). ISO 5725-5. Accuracy (trueness and precision) of measurement methods and results - Part 5. Geneva: ISO; 1998.
54. Kuttatharmmakul S, Massart DL, Smeyers-Verbeke J. Comparison of alternative measurement methods. Anal Chim Acta. 1999; 391: 203-25.
55. Maroto A, Riu J, Boqué R, Rius FX. Estimating uncertainties of analytical results using information from the validation process. Anal Chim Acta. 1999; 391: 173-85.
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