Franco Battistutta

Determination of biogenic amines in alcoholic and non-alcoholic beers by HPLC

Abstract Eight biogenic amines (histamine, tyramine, tryptamine, 2-phenyl-ethylamine, putrescine, cadaverine, spermine and spermidine) in alcoholic and non-alcoholic beers have been determined by HPLC. The results obtained ranged between 0.1 and 17.2 ppm. Only six amines were found because histamine and spermine were not present in detectable amounts. Spermidine was detected in all samples (0.3–1·4 ppm) despite absence of references in the literature about the content of this amine in beers. Non-alcoholic beers did not have significantly lower amounts of biogenic amines than alcoholic beers.

Modified Nondestructive Colorimetric Method To Evaluate the Variability of Oxygen Diffusion Rate through Wine Bottle Closures

Some modifications to a previous nondestructive colorimetric method that permits evaluation of the oxygen diffusion rate through wine closures were proposed. The method is based on the reaction of indigo carmine solution with oxygen and the tristimulus measurement of the consequent color change. Simplified preparation and measurement procedures were set up, allowing the analysis of a large number of samples simultaneously. The method was applied to the evaluation of the variability within the lot of 20 different types of stoppers (synthetic, produced by molding, and natural cork). The closures were tested at a storage temperature of 26 degrees C. With regard to oxygen permeability, the natural cork stopper showed a low homogeneity within the lot, especially during the first month after bottling, whereas the synthetic closure showed a greater steadiness in the performance. The limits of the colorimetric method were also analyzed, and three possible causes of degradation of the indigo carmine solution were identified: oxygen, light, and heat.

Antioxidant properties of different products and additives in white wine.

Different winemaking products (ascorbic acid, glutathione, yeast lees and a yeast autolysate) were tested in comparison with sulphur dioxide, concerning radical scavenging activity (measured by DPPH assay), oxygen consumption capacity and ability to reduce wine colour and predisposition to browning. Trials were performed in white wines and model solution. SO2 was the most active in reducing wine colour development. Fresh lees and ascorbic acid were very effective in oxygen and free radical scavenging, but they both induced browning during wine storage, the former, by releasing phenolic compounds. Glutathione was also able to scavenge DPPH in wine, but less effective against oxygen, and it induced browning during storage. Surprisingly, the yeast derivative preparation was the treatment that behave more similarly to sulphiting; it was very active in scavenging DPPH, and, even without modifying oxygen consumption rate, it protected quite well wine colour over an 8months storage time.

Effect of Different Lysis Treatments on the Characteristics of Yeast Derivatives for Winemaking

The effects of three preparation techniques on the oenological properties of a yeast autolysate were investigated: enzymatic autolysis, thermolysis, and the combination of a slow freezing-defrosting and mechanical disruption were carried out on a commercial formulation of active dry yeasts (Saccharomyces cerevisiae). The powders obtained by freeze drying, were characterized: volatile compounds were analyzed by SPME-GC with mass spectrometric (MS) and olfactometric detection (O); the release of colloids in winelike solution was studied by SDS-PAGE and size exclusion chromatography (SEC). Finally, the effects of the powders addition on the aroma composition of a white wine were investigated by SPME-GC-MS, SPME-GC-O, and sensory evaluation. The products obtained were quite different from each other. In particular, enzymatic autolysis led to higher contents of nonglycosilated soluble proteins in the powders and determined a higher retention of wine aroma compounds. On the contrary, thermal autolysate was richer in glycoproteins, and it was able to increase the wine aroma intensity; nevertheless, in the wines treated with such preparation, a slight yeastlike olfactory note was perceived.

Interactions between yeast autolysates and volatile compounds in wine and model solution

The addition of a commercial yeast autolysate to a model solution of five typical wine aroma compounds (ethyl octanoate, linalool, 2-phenylethanol, β-ionone and octanoic acid) was investigated considering different variables, such as temperature, pH and the presence of highly concentrated natural volatile substances in wine (e.g. 3-methyl-1-butanol). The interactions of such compounds with both yeast walls and released colloids were studied using gas chromatography, with liquid-liquid extraction and solid-phase microextraction. The results were compared with those obtained by adding the commercial product to a white table wine, spiked with the five standard compounds. The data confirmed that yeast walls mainly bind less polar molecules: their loss in synthetic medium seemed to increase at higher pH values. Temperature and pH affected differently the interactions between yeast colloids and volatile compounds in wine and model solution: in complex solutions (as the addition of 3-methyl-1-butanol demonstrated) the interaction mechanisms could be influenced by competitive or other matrix-related effects, which can reduce the binding of single compounds, or even enhance their volatility.

Effects of raw material on the partition of some volatile compounds of grappa, a typical Italian spirit

Abstract Fractional distillation was used to study the effect of raw materials on grappa composition. Grape marc and grape marc with the addition of an amount of wine lees (42%) greater than the European Community regulations limit (25%) permits were investigated. The concentration of all the volatile compounds considered, the percentage of extraction of acetalde‐hyde, methanol, ethylacetate and ethyl lactate, but not the kinetics of extraction of higher alcohols, acetic acid and ethyl lactate, are affected by this addition of lees to marc. Overall, the hygienic characteristics of grappa are improved.

Oxidative behavior of (+)‐catechin in the presence of inactive dry yeasts: A comparison with sulfur dioxide, ascorbic acid and glutathione

BACKGROUND The antioxidant capacity of an inactive dry yeast preparation (YD) was investigated by conventional analytical methods (spectrophotometry, high-performance liquid chromatography) as well as by cyclic voltammetry in a (+)-catechin model wine and compared with that of some of the most common antioxidants found in wine: sulfur dioxide, ascorbic acid and glutathione. RESULTS Sulfur dioxide was the highest-performing substance in protecting (+)-catechin against browning, followed by ascorbic acid and the YD preparation. Sulfites were the only antioxidant whose activity was clearly detectable in the model wines after 29 days of storage. Voltammetric studies demonstrated that the antioxidant capacity of the products tested was connected to their intrinsic characteristics and their molar concentrations (catechin/antioxidant molar ratio). CONCLUSION The YD preparation displayed a certain ability to protect polyphenols against browning. The antioxidant activity of YDs towards (+)-catechin appeared to be based on different mechanisms with respect to that of the other products tested: the insoluble portion of these preparations (cell wall residues) might have a non-negligible role, even if the ability of YDs to release compounds able to suppress oxidation cannot be rejected. Direct comparison of the different antioxidants led to interesting indications concerning their mechanism of action in wine-like solution, depending on their concentration and intrinsic characteristics.

Effects of an unconventional oenological technique on the evolution of free and glycosidically bound terpenols of Muscat of Ganelli grapes: preliminary results

In order to increase the flavour compounds of fermented Muscat of Canelli grapes, which are the raw material of an alcoholic beverage, an unconventional oenological technique was carried out, using an extended maceration time combined with the addition of Aspergillus niger glycosidases. The evolution of free linalool, nerol, geraniol, α‐terpineol, s‐citronellol, trans‐furanic linalool oxide, cis‐furanic linalool oxide and of the corresponding glycosidically bound terpenols was studied using regression analysis. Results have shown that the concentrations of glycosidically bound linalool, geraniol, nerol and of free geraniol and s‐citronellol can be highly correlated with maceration time.