European Food Research and Technology

We have established an electrophoretic method to evaluate proteolysis in Parmesan cheese by means of an objective ripening index. The separation of caseins by alkaline polyacrylamide gel electrophoresis (PAGE) (12% T, 2.6% C, pH 8.9, 5 M urea) is followed by the densitometric analysis of theγ- andβ-casein fractions. The relationship between the resulting coefficients (γ-Cn/β-Cn) and the age of reference samples of Original Italian Grana Padano (6–22 months) was linear up to 15 months, allowing an evaluation of the extent of proteolysis and therefore a deduction of the age of the Parmesan samples analysed. Based on this calibration we propose to use a threshold level of 1.3 (γ-Cn/β-Cn) to verify the required age, i.e. 12 months, of Parmesan cheese, retailed as a loaf or prepacked slices. Commercially grated Parmesan samples may contain ≤20% cheese rind, which has a very low degree of casein breakdown. So a threshold level of 0.8 (γ-Cn/β-Cn) is proposed for all grated Parmesan products. The preparation of reference solutions with defined coefficients (γ-Cn/β-Cn), corresponding to the proteolysis indices of reference samples of different aged Grana Padano is described. The coefficients (γ-Cn/β-Cn) as well as theβ-casein content of two additional series of reference samples and of 49 commercial Parmesan samples taken from retail outlets in Austria and Italy are presented.

Mittels der indirekten Hämagglutination kann Milcheiweiß auch in hocherhitzten Fleischerzeugnissen (115° C) notwendigenfalls sogar quantitativ differenziert werden. Die erforderlichen Antiseren gegen erhitztes Milcheiweiß wurden durch Immunisierung mittels Metallverbindungen gewonnen. Zur Gewinnung von serologisch noch reaktionsfähigen Eiweißkomponenten sind Dialyse und Lyophilisierung des hocherhitzten Materials notwendig. Unter Anwendung der im einzelnen beschriebenen Methode konnte Milcheiweiß auch in bis auf 115° C erhitztem Material in Konzentrationen ab 0,1% quantitativ erfaßt werden.

The aim of this study was to determine and evaluate the amounts of major elements (Ca, Fe, K, Na and P), essential trace elements (Cu, Zn, Fe and Mn) and some other trace metals (Ag, Al, Co, Ni, Cr, Sr, Se, Bi, Rb) in eleven species of wild-grown common edible mushrooms from family Boletaceae (Boletus appendiculatus, Boletus edulis, Boletus regius, Boletus fechtneri, Boletus impolitus, Boletus purpureus, Boletus rhodoxanthus, Leccinum crocipodium, Leccinum pseudoscaber, Xerocomellus chrysenteron, Xerocomus badius) from Serbia. The measurements of major elements (Ca, Fe, K, Na and P) were carried out by inductively coupled plasma optical emission spectrometer (ICP-OES), while analytical measurements of the rest of studied elements were performed using an inductively coupled plasma mass spectrometer (ICP-MS), after microwave digestion. The results showed that the element concentrations were species-dependent. Potassium and phosphorous concentrations were found to be greater than those of the other mineral constituents in all tested species. Multivariate analysis included principal component analysis (PCA) and hierarchical cluster analyses (HCA). HCA grouped mushrooms in three statistically significant clusters, while PCA indicated connection between analyzed metals. Also, this paper highlights the importance of essential and nonessential elements of human health and their daily intake.

Benzoesäure, Sorbinsäure und PHB-Ester lassen sich auf Mischschichten von 80% Polyamid und 20% Cellulose gut voneinander trennen. Die remissionsphotometrische Auswertung der Chromatogramme ermöglicht eine schnelle Identifizierung und quantitative Bestimmung aller drei Konservierungsstoffe mit relativ hoher Genauigkeit.