Chemical characterization of asturian cider.

Ninety-four samples of Asturian natural cider were analyzed for titratable and volatile acidities, pH, alcoholic, total polyphenol, and acidic polysaccharide contents, nonvolatile acids, polyalcohols, residual sugars, and major volatile compounds. A partial least-squares regression analysis (PLR-1) was performed to correlate the chemical composition and the origin of the raw material, the cider samples being grouped into two categories: an "odd" class, cider made from foreign apples (1995 and 1997), and an "even" class, ciders made from Asturian apples (1996 and 1998). The mathematical model has a multiple linear correlation coefficient of 80%.

Study of the phenolic profile of cider apple cultivars at maturity by multivariate techniques.

Phenolic compounds in 46 Spanish cider apple varieties were determined by RP-HPLC with direct injection. Several pattern recognition procedures, including principal component analysis (PCA), linear discriminant analysis (LDA), and partial least squares (PLS-1), were applied to the data in an attempt to classify the samples into bitter and nonbitter categories. Reliable decision rules were obtained by both LDA and PLS-1. LDA achieved 91.3 and 85.7% correct classification respectively, for internal and external evaluation of the model.

Analysis of polysaccharides in cider: their effect on sensory foaming properties.

A feasible spectrophotometric method for determining acidic and neutral polysaccharides in cider is described, and the advantages of this method are examined with respect to precision, accuracy, and detection and quantitation limits. The concentration of nonvolatile and volatile components in cider, together with chemometric techniques such as principal component analysis (PCA), soft independent modeling of class analogy (SIMCA), and partial least squares (PLS), allowed us to typify the ciders on the basis of their foaming properties. Acidic polysaccharide and 1-propanol were the most relevant variables for this purpose.

Determination of acaricides in honey by liquid chromatography with ordinary, narrow-bore, and microbore columns.

Narrow-bore and microbore columns packed with octadecylsilane were used to compare their sensitivity and efficiency in the separation of coumaphos, fluvalinate, bromopropylate, and 4,4'-dibromobenzophenone from honey with those of ordinary columns. The best sensitivity for acaricides was accomplished by using a 150 mm × 0.32 mm i.d., 5 µm Spherisorb ODS-2 capillary column, methanol-water (90:10 v/v) as the mobile phase, and 5 µL/min as the flow rate. Detection limits for individual acaricides using a UV detection range from 0.40 to 0.74 µg/kg of honey were comparable to those obtained by gas chromatography using an electron capture detector. All acaricides were separated in <12 min. The coefficients of variations on real samples were <6.2%.

Dynamics of Yeast Populations during Cider Fermentation in the Asturian Region of Spain.

The influence of different cidermaking systems and apple mixtures on the dynamics of yeast populations in cider manufactured in Asturias (northern Spain) were studied. Results obtained in an experimental pilot plant were compared with those found in Asturian cider plants by using traditional techniques. Saccharomyces cerevisiae and Kloeckera apiculata were found in all cases.