Andrea Antonelli

HPLC Determination of Organic Acids in Traditional Balsamic Vinegar of Reggio Emilia

Abstract The major constituents of Traditional Balsamic Vinegar (TBV) of Reggio Emilia (including citric, malic, tartaric, lactic, acetic, gluconic, and succinic acids, fructose, and glucose) were quantified in a single HPLC run. A cation exchange column was used, and the analytes were quantified by the standard addition method. These conditions provided a reliable method, which was applied to twenty‐one samples. Glucose and fructose were the main constituents. Acid concentration showed a great variability, and it was characterized by the presence of gluconic acid. Except in one sample, acetic acid was the main constituent of this class of compounds.

Sensory characterisation of wine vinegars

Abstract Ninety-six samples of vinegars of different sources were subjected to sensory analysis. For white vinegars, Linear Discriminant Analysis showed that sensory analysis could be used to distinguish between the different sources of vinegar, and especially to discriminate between alcohol and apple vinegars from wine vinegars on the basis of only seven sensory parameters. Principal Component Regression showed that the quality level of vinegars could be determined by taste, smell and clarity. Only ‘quality’ red vinegars were appreciated for their vinous character.

Modifications of dried basil (Ocinum basilicum) leaf oil by gamma and microwave irradiation

Dried basil leaves were irradiated with two different doses of gamma rays and with microwaves. Comparison with a blank sample was performed by capillary gas chromatography/mass spectrometry (GC/MS) which identified 47 peaks. Linalool and estragol showed the greatest increases with γ-radiation and dropped with microwaves. The composition of essential oils was different, except for a few compounds which increased or decreased regardless of the treatment. Gamma radiation caused the most evident changes in the composition profiles. A sensory test confirmed significant differences between the extracts. The panellists preferred the gamma treated sample, while the microwaved sample was the least appreciated.

Prediction of compositional and sensory characteristics using RGB digital images and multivariate calibration techniques.

In the present paper, the possibility to use the information contained in RGB digital images to gain a fast and inexpensive quantification of colour-related properties of food is explored. To this aim, we present an approach which consists, as first step, in condensing the colour related information contained in RGB digital images of the analysed samples in one-dimensional signals, named colourgrams. These signals are then used as descriptor variables in multivariate calibration models. The feasibility of this approach has been tested using as a benchmark a series of samples of pesto sauce, whose RGB images have been used to predict both visual attributes defined by a panel test and the content of various pigments (chlorophylls a and b, pheophytins a and b, β-carotene and lutein). The possibility to predict correctly the values of some of the studied parameters suggests the feasibility of this approach for fast monitoring of the main aspect-related properties of a food matrix. The values of the squared correlation coefficient computed in prediction on a test set (R(Pred)(2)) for green and yellow hues were greater than 0.75, while R(Pred)(2) values greater than 0.85 were obtained for the prediction of total chlorophylls content and of chlorophylls/pheophytins ratio. The great flexibility of this blind analysis method for the quantitative evaluation of colour related features of matrices with an inhomogeneous aspect suggests that it is possible to implement automated, objective, and transferable systems for fast monitoring of raw materials, different stages of the manufacture and end products, not necessarily for the food industry only.

Polyalcohols in vinegar as an origin discriminator

Polyalcohol content in vinegars of different botanical and geographical origin was studied by means of capillary gas chromatography. The data were statistically evaluated in order to discriminate the different vinegar types. Wine vinegars did not show a characteristic polyalcohol pattern, while apple vinegars and alcohol vinegars were well recognizable. The former had high sorbitol content and the latter showed the lowest amount of polyalcohols. Statistical analysis showed that polyalcohol determination is a possible tool to discriminate vinegar raw material at least for white products.

Techniques for resveratrol silylation

SummaryResveratrol, a wine stilbene phytoalexin with some pharmacological properties, was extracted from red wines by MeOH elution of a Sephadex LH-20 column, used for its purification. The column extract was dried and silylated by different methods to optimize resveratrol derivatization. The resveratrol analysis was by gas chromatography and gas cromatography-mass spectrometry allowing determination of its two isomers.

Evaluation of the combined effects of enzymatic treatment and aging on lees on the aroma of wine from Bombino bianco grapes.

In this study, two different doses of commercial beta-glucanase enzyme preparation were tested to verify their effect on wines aged on lees. These wines were compared with two samples with no enzymatic treatment. The former was aged on lees (control), and the latter was readily filtered off from the yeast cell biomass (standard). Analysis of variance (one-way ANOVA), the Tukey test, and principal component analysis (PCA) were applied to all of the samples, which were analyzed for aroma composition, along with galacturonic acid, total acidity, pH, and color. Results showed a large number of statistically significant differences among samples. In general, wines treated with beta-glucanase were characterized by higher concentration of many volatile compounds. The presence of lees and even more the exogenous enzymatic action enhanced almost all volatile compounds. Besides the high presence of ethyl esters, it is worth mentioning the behavior of hexanol and trans-3-hexenol, which are strongly enhanced by the presence of lees and by enzymatic treatments.

Determination of phthalate esters in distillates by ultrasound-vortex-assisted dispersive liquid-liquid micro-extraction (USVADLLME) coupled with gas chromatography/mass spectrometry

A method for the extraction of phthalate esters (PAEs) by Ultrasound-Vortex-Assisted Dispersive Liquid-Liquid Micro-Extraction (USVADLLME) approach was optimised and applied for the first time to a historical series of brandies. These contaminants are widely spread in the environment as a consequence of about half century of use in different fields of applications. The concern about these substances and the recent legal restrictions of China in distillates import need a quick and sensitive method for their quantification. The proposed method, moreover, is environmentally oriented due to the disposal of micro-quantities of solvent required. In fact, sub-ppm-limits of detection were achieved with a solvent volume as low as 160μL. The analysed samples were within the legal limits, except for some very ancient brandies whose contamination was probably due to a PAEs concentration effect as a consequence of long ageing and for the use of plastic pipelines no more operative.

Determination of acrylamide in dried fruits and edible seeds using QuEChERS extraction and LC separation with MS detection

Acrylamide is a carcinogenic and neurotoxic process contaminant that is generated from food components during heat treatment, while it is absent in raw foodstuffs. Its level in food arouses great concern. A method for acrylamide extraction and determination in dried fruits (dried prunes and raisins) and edible seeds (almonds, hazelnuts, peanuts, pine nuts, pistachios, and walnuts) using a QuEChERS-LC-ESI-MS-Triple Quadrupole approach was set up. Linearity, sensitivity, accuracy, and precision of the method were satisfactory. Dried prunes and peanuts were the only samples appreciably contaminated, 14.7-124.3 and 10.0-42.9μg/kg, respectively, as a consequence of the drying process. In fact, prunes are dried at 70-80°C for a quite long time (24-36h), while peanuts undergo a roasting process at 160-180°C for 25-30min. The relative standard deviations, accuracy, LOD, and LOQ show that the method provides a reliable approach to acrylamide determination in different matrices.

Essential oils: SPE fractionation

SummaryEssential oil analysis is often characterised by mixtures that are difficult to separate. The components belong to different classes of compounds that range widely in concentration. Hence, a pre-separation technique is often required, at least to evaluate the minor components. This paper reports an SPE method to overcome this problem. The method was developed with a standard solution that yielded 90% mean recovery of the analytes. It was then tested on two different essential oils: tarragon (Artemisia dracunculus) and rose (Rosa damascena). In this way, the essential oil components were pre-separated into three fractions: A, which contained hydrocarbons; B, which contained esters, ethers, oxides, carbonyl compounds and tertiary alcohols; and C, which contained other alcohols, acids and diols.