title: In situ quantitative1H nuclear magnetic resonance spectroscopy discriminates between raw and steam cooked potato strips based on their metabolites.
abstract: A direct quantitative proton nuclear magnetic resonance spectroscopy method was developed for the measurement of saccharides, organic acids and amino acids in potato (Solanum tuberosum L.) tuber filaments, a complex gel-like food matrix. The method requires minimal sample preparation. It is thus a faster alternative compared to liquid sample matrices, as well as an extension to methods analyzing only selected metabolites in the sample. The samples in this study were either raw or steamed potato strips that were either measured as D2O extracts or directly without extraction or derivatization steps (in situ technique). A total of 22 compounds were identified in extracts and 18 in potato strips. Of these, 20 compounds were quantifiable in potato extracts and 13 compounds in potato strips. The effect of thermal processing was reflected in the profile of analyzed compounds. One example was fumaric acid, which was completely lost in steamed samples in both measurement techniques. Additionally, the content of γ-aminobutyric acid in steamed potato strips was lower. In potato extracts, the contents of additional 7 compounds were statistically different. The raw and steamed samples separated into two groups with multivariate models both in extracts and potato strips, and these groups were linked to changes in aforementioned compounds. These results demonstrated that the in situ quantitative1H NMR technique is a useful tool to analyze potato metabolites. This technique could be further applied to any gel-like complex matrix, meaning that lengthy sample pretreatment could be skipped.
authors: Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; Functional Foods Forum, University of Turku, FI 20014 Turku, Finland. Electronic address: heikki.aisala@utu.fi.
authors: Heikki
authors: H
authors: Aisala
authors: Instrument Centre, Department of Chemistry, University of Turku, Turku, FI-20014 Finland. Electronic address: jatasi@utu.fi.
authors: Jari
authors: J
authors: Sinkkonen
authors: Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland. Electronic address: mslass@utu.fi.
authors: Marika
authors: M
authors: Kalpio
authors: Functional Foods Forum, University of Turku, FI 20014 Turku, Finland. Electronic address: masaarim@utu.fi.
authors: Mari
authors: M
authors: Sandell
authors: Groupe de gastronomie moléculaire, Inra-AgroParisTech International Centre for Molecular Gastronomy, Paris, F-75005 France; UMR GENIAL, AgroParisTech, Inra, Université Paris-Saclay, Massy, 91300 France. Electronic address: herve.this@agroparistech.fr.
authors: Hervé
authors: H
authors: This
authors: Functional Foods Forum, University of Turku, FI 20014 Turku, Finland. Electronic address: anuhop@utu.fi.
authors: Anu
authors: A
authors: Hopia
mesh_terms: D000144:Acids, Acyclic / Q000032:analysis; D000596:Amino Acids / Q000032:analysis; D003296:Cooking; D005632:Fructose / Q000032:analysis; D005947:Glucose / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry*; D035281:Plant Tubers / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D011198:Solanum tuberosum / Q000737:chemistry*; D013395:Sucrose / Q000032:analysis
chemical_list: D000144:Acids, Acyclic; D000596:Amino Acids; D010936:Plant Extracts; D005632:Fructose; D013395:Sucrose; D005947:Glucose
keywords: Amino acids; Heat treatment; In situ quantitative NMR; Organic acids; Saccharides; Solanum tuberosum L.