Eduardo Guerra Hernández

Analysis of diacetyl in yogurt by two new spectrophotometric and fluorimetric methods

Abstract Two new methods (spectrophotometric and fluorimetric) are reported for the determination of diacetyl in yogurt. The diacetyl was isolated by distillation and condensed with isoniazide. This solution was then treated with Zr(IV) to form a complex, which was measured with these two methods. Average recovery of diacetyl was 96.8% for spectrophotometry and 99.1% for fluorimetry, while precision was RSD = 2.5 and 1.0%, respectively. The concentration of diacetyl in yogurt ranged from 0.79 to 2.77 μg/g. The two procedures gave statistically similar results. The fluorimetric method was compared with a traditional method (gas chromatography), for which acetaldehyde, acetone, methanol, and ethanol were also determined.

Description of indexes based on the adherence to the Mediterranean Dietary Pattern: a review

INTRODUCTIONndiet quality indexes are tools are aimed at quantifying the compliance to a defined dietary pattern. These indexes are a combined measure of dietary factors (food groups, foods, nutrients and ratios) and/ or lifestyles factors. The Mediterranean Diet (MD) is a dietary pattern characterized by their positive effects against chronic diseases. There have been many indexes proposed for the assessment of this dietary pattern. An evaluation of their composition and health benefits is therefore convenient.nnnOBJECTIVEnthe objective is to evaluate indexes of adherence to the MD with regard to their definition, methodological issues and validation as reported in epidemiological studies.nnnMETHODSnwe searched in PubMed for studies that developed MD Indexes up to October 2014.nnnRESULTSna total number of 22 indexes were identified, with differences regarding the number of components (7-28), scoring (0, 1, 2, 3, 4, 5, 8 or 10, in case of compliance), range (0-100) and type of components (which could be food groups/foods or their combination, with nutrients). Among the positive components, fruits and vegetables were the most common and meats, among the negative components. There were also differences with regard to their composition and evaluation (e.g. criteria of moderate alcohol consumption), as well as with the scoring system (in medians, terciles or established servings).nnnCONCLUSIONSnthis review suggests that since there is great heterogeneity in the definition of MD. It would be therefore convenient to establish more clearly the components to be included and to establish commonly defined criteria to quantify this dietary pattern.