title: Determination of free amino acids in African gourd seed milks by capillary electrophoresis with light-emitting diode induced fluorescence and laser-induced fluorescence detection.
abstract: A CE technique coupled to LIF detection (488 nm) or LED-induced fluorescence detection (470 nm) has been evaluated to acquire a cheap way to analyze amino acids (AAs) whilst maintaining the best sensitivity. To quantitate AAs in milk of Cucurbitaceae of Sub-Saharan Africa, they were labeled with FITC. We used an optimized separation buffer composed of 30 mM boric acid buffer adjusted to pH 9.3 with NaOH (1 M) containing 12 mM SDS and 5% ethylene glycol v/v; prior to the injections, the derivatized samples are diluted 100 times. The LOQs in the sample are Arg: 1.1 μM, Ala: 3.5 μM, and Glu 8.9 μM. Cucumeropsis mannii (CM) Naudin and Citrullus lanatus (CL) are vegetable sources rich in proteins and AAs of high quality. Our analyses have led to the identification of 11 AAs in CL and CM milks. Phe, Trp, and Ala are predominant in the two types of lyophilized milks, while Asp and Val demonstrate very low contents. Six essential AAs (Phe, Thr, Val, Trp, Ile, and Leu) are present in both types of extracts, but lysine was not detected, indicating that this AA is missing in gourd milk. These results should be useful in efforts to complement or replace very expensive cow milk or the less-appreciated soya milk with milk from available local agroressources.
authors.affiliation: Laboratoire de Transformation et Qualité des Aliments, IDR, Université Marien Ngouabi, Brazzaville, Congo; Equipe pluridisciplaire en Alimentation et Nutrition, Faculté de Sciences, Université Marien Ngouabi, Brazzaville, Congo.
authors.forename: Josiane
authors.initials: J
authors.lastname: Enzonga
authors.forename: Varravaddheay
authors.initials: V
authors.lastname: Ong-Meang
authors.forename: François
authors.initials: F
authors.lastname: Couderc
authors.forename: Audrey
authors.initials: A
authors.lastname: Boutonnet
authors.forename: Véréna
authors.initials: V
authors.lastname: Poinsot
authors.forename: Michel Mvoula
authors.initials: MM
authors.lastname: Tsieri
authors.forename: Thomas
authors.initials: T
authors.lastname: Silou
authors.forename: Jalloul
authors.initials: J
authors.lastname: Bouajila
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D019662:Cucurbitaceae / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D041941:Milk Substitutes / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D000596:Amino Acids; D010936:Plant Extracts
keywords: Amino acid; Capillary electrophoresis; Light-emitting diode induced fluorescence; Seed milk