title: A microcalorimetric sensor for food and cosmetic analyses: l-Malic acid determination.
abstract: Enzymatic microcalorimetry has been successfully employed in the reliable determination of the l-malic acid concentration in some foods and cosmetic products. The l-malic acid concentration during the wine-making process is particularly useful in order to control the progress of the malo-lactic fermentation. Total acidity, taste and flavour characteristics of wine depend on the l-malic acid quantity still present. To point out the analytical methodology the dehydration process of l-malic acid, in the presence of Fumarase enzyme, has been used. The new method has been compared with a common spectrophotometric one. By the proposed calorimetric method the l-malic acid concentration in different types of food (white and red wines, fruits and soft beverages) has been determined. In some cosmetic products too the l-malic acid was quantified. The method outlined resulted simple, direct and reliable (good accuracy and precision), in particular it does not require any pre-treatment or clean up of the samples, save the dilution in buffer.
authors: Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy.
authors: Marta Letizia
authors: ML
authors: Antonelli
authors: Claudio
authors: C
authors: Spadaro
authors: Rosalia Fortunata
authors: RF
authors: Tornelli
mesh_terms: D002151:Calorimetry / Q000379:methods* / Q000639:trends*; D003358:Cosmetics / Q000032:analysis; D005285:Fermentation; D005504:Food Analysis / Q000379:methods* / Q000592:standards; D005649:Fumarate Hydratase / Q000378:metabolism; D008293:Malates / Q000032:analysis* / Q000378:metabolism; D008832:Microchemistry; D014920:Wine / Q000032:analysis
chemical_list: D003358:Cosmetics; D008293:Malates; C030298:malic acid; D005649:Fumarate Hydratase