title: Time-Domain Nuclear Magnetic Resonance (TD-NMR) and Chemometrics for Determination of Fat Content in Commercial Products of Milk Powder.
abstract: This study shows the use of time-domain (TD)-NMR transverse relaxation (T2) data and chemometrics in the nondestructive determination of fat content for powdered food samples such as commercial dried milk products. Most proposed NMR spectroscopy methods for measuring fat content correlate free induction decay or echo intensities with the sample's mass. The need for the sample's mass limits the analytical frequency of NMR determination, because weighing the samples is an additional step in this procedure. Therefore, the method proposed here is based on a multivariate model of T2 decay, measured with Carr-Purcell-Meiboom-Gill pulse sequence and reference values of fat content. The TD-NMR spectroscopy method shows high correlation (r = 0.95) with the lipid content, determined by the standard extraction method of Bligh and Dyer. For comparison, fat content determination was also performed using a multivariate model with near-IR (NIR) spectroscopy, which is also a nondestructive method. The advantages of the proposed TD-NMR method are that it (1) minimizes toxic residue generation, (2) performs measurements with high analytical frequency (a few seconds per analysis), and (3) does not require sample preparation (such as pelleting, needed for NIR spectroscopy analyses) or weighing the samples.
authors.affiliation: Universidade Estadual Paulista "Júlio de Mesquita Filho," Instituto de Química, Departamento de Química Analítica, Rua Professor Francisco Degni, 55, Araraquara, SP 14800-060, Brazil.
authors.forename: Paloma Andrade Martins
authors.initials: PA
authors.lastname: Nascimento
authors.affiliation: Universidade Estadual Paulista "Júlio de Mesquita Filho," Instituto de Química, Departamento de Química Analítica, Rua Professor Francisco Degni, 55, Araraquara, SP 14800-060, Brazil.
authors.forename: Paulo Lopes
authors.initials: PL
authors.lastname: Barsanelli
authors.affiliation: Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos, Departamento de Ciência de Alimentos, Campinas, SP 13083-962, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Rebellato
authors.affiliation: Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos, Departamento de Ciência de Alimentos, Campinas, SP 13083-962, Brazil.
authors.forename: Juliana Azevedo Lima
authors.initials: JA
authors.lastname: Pallone
authors.affiliation: Embrapa Instrumentação, Rua Quinze de Novembro 1452, São Carlos, SP 13561-206, Brazil.
authors.forename: Luiz Alberto
authors.initials: LA
authors.lastname: Colnago
authors.affiliation: Universidade Estadual Paulista "Júlio de Mesquita Filho," Instituto de Química, Departamento de Química Analítica, Rua Professor Francisco Degni, 55, Araraquara, SP 14800-060, Brazil.
authors.forename: Fabíola Manhas Verbi
authors.initials: FM
authors.lastname: Pereira
mesh_terms: D003611:Dairy Products / Q000032:analysis*; D006801:Humans; D041943:Infant Formula / Q000032:analysis*; D016018:Least-Squares Analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D014280:Triglycerides / Q000032:analysis*
chemical_list: D014280:Triglycerides