Advisor(s)
Abstract(s)
Serra da Estrela cheese is a high-value Portuguese Protected Designation of Origin cheese, produced with raw
ewe milk. Thus, information regarding its composition is of utmost relevance for both consumers and certified
producers. In this work, the chromatographic profiles of free amino acids in cheeses (45 days of maturation, 6
producers located in 5 municipalities and produced from November 2017 to March 2018) were established by
UPLC-DAD-MS/MS. The proposed method allowed detecting 19 free amino acids and cystine with overall limits
of detection and quantification lower than 44 μmol/L (1.4 mg/100 g cheese, wet matter) and than 134 μmol/L
(4.2 mg/100 g cheese, wet matter), respectively. In all cheeses, 17 free amino acids were quantified including 8
essential amino acids (histidine, leucine-isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan
and valine) and 9 non-essential amino acids (arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine,
proline, serine and tyrosine). The amounts of the free amino acids, essential free amino acids, branched
chain free amino acids (leucine, isoleucine and valine) plus the free amino acids ratios (mg/g protein) were
further used to identify the producer of Serra da Estrela cheeses. Linear discriminant analysis coupled with the
simulated annealing variable selection algorithm was used allowing the correct classification of 96% and
90 ± 8% of the samples, for leave-one-out and repeated K-fold cross-validation procedures, respectively. The
satisfactory predictive performance pointed out the possibility of using cheeses’ amino acids profiles as origin
biomarkers for authenticity control, warranting the correctness identification of the cheese producer/brand,
which is quite relevant for ensuring the consumer confidence and satisfaction when purchasing this high-value
dairy food.
Description
Keywords
Amino acids profiles Chemometrics Origin assessment Serra da Estrela cheese UPLC-DAD-MS/MS
Pedagogical Context
Citation
Reis Lima, M. J.; Santos, Andréia O.; Falcão, Soraia; Fontes, Luísa; Teixeira-Lemos, Edite; Vilas-Boas, Miguel; Veloso, Ana C.A.; Peres, António M. (2019). Serra da Estrela cheese's free amino acids profiles by UPLC-DAD-MS/MS and their application for cheese origin assessment. Food Research International. ISSN 0963-9969. 126, p. 1-8