Improved Method for the Analysis of Organic Acids and New Derivatization of Alcohols in Complex Natural Aqueous Matrixes:  Application to Wine and Apple Vinegar

Abstract

An improvement in the procedure for investigation of organic acids and a new derivatization method, amenable to gas chromatographic-mass spectrometric detection of alcohols, are presented. The latter is based on the formation of phenacetyl esters. The simultaneous application of the two methods also allows data to be obtained on some volatile neutrals present in complex natural aqueous fluids. Application to wine and cider vinegars allowed detection of a number of previously unreported components, among which are interesting partially esterified polycarboxylic esters.

New procedures for determination of acids in coffee extracts, and observations on the development of acidity upon ageing

“…The procedure was an ad hoc adaptation of a reported [23] method to the problems posed by this specific matrix. These modifications were the result of our extensive experimentation.…”

“…The methoxy ethers of the methyl esters of malic and citric esters are formed by partial methyl etherification of the free hydroxy function of malic and citric acid with diazomethane [23]; no such methoxy function was present originally. This must be taken into Fig.…”

“…vinegars) [23], to extracts obtained from freshly prepared coffee, from coffee after accelerated ageing, and from coffee beans after different amounts of roasting. To minimize loss of any material GC-MS analysis of the low-molecular-weight (C 1 -C 3 ) acids was performed as their butyl esters, by using diazobutane as derivatizing agent.…”

Rapid Detection of Acetic Acid Bacteria in the Traditional Pot-Fermented Rice Vinegar Kurozu

“…Many different types of vinegars exist worldwide, made from various sources such as grains, fruits, and roots (Horiuch et al, 1999;Giumanini et al, 2001;Terahara et al, 2003;Ye et al, 2004;Masino et al, 2008). The rice vinegar Kurozu is a traditional product of Kagoshima, Japan, which is produced by long manufacturing processes including a ~6-month fermentation step followed by ~3-year maturation step.…”

Flow‐Injection Analysis of Residual Glucose in Wines Using a Semiautomatic Analyzer Equipped with a Prussian Blue‐Based Biosensor

“…Analysis of wines and other beverages attracts a particular attention since it requires only a minor sample preparation procedure. A number of chromatographic, spectrometric and electrochemical detection systems were designed for carbohydrates [10], l-lactate [11,12], l-malate [13], glycerol [14], alcohols [15], phenolic [16], sulfuric [17] and aromatic [18,19] compounds. Spectrometric and chromatographic methods of analysis including mass-spectrometry, HPLC, micro-extraction and electrophoresis in some cases are more sensitive than electrochemical ones but much more laborious and expensive.…”