Constituents of nutritional relevance in fermented milk products commercialised in Italy

Rapid Determination of Total Tryptophan in Yoghurt by Ultra High Performance Liquid Chromatography with Fluorescence Detection

Tryptophan (TRP) is an essential amino acid which cannot be synthesized by humans and animals, but has to be supplied by exogenous sources, notably through the diet. The bulk of dietary TRP flows into the synthesis of body’s proteins, but the TRP metabolism also involves several biochemical reactions (i.e., serotonin and kynurenine pathways). Defects in the TRP transport mechanism or catabolism are related to a large number of clinical abnormalities. Therefore, dietary TRP intake is necessary not only for the body’s growth but also for most of the body’s metabolic functions. Among protein-based foods, milk proteins provide a relatively high amount of TRP. In this paper, a rapid chromatographic method for TRP determination in yoghurt, by ultra high performance liquid chromatography on a reversed-phase column with fluorescence detection (280 nm Ex; 360 nm Em), is provided. A linear gradient elution of acetonitrile in water allowed TRP analysis in 8.0 min. The limit of detection and limit of quantification of the method were 0.011 ng/µL and 0.029 ng/µL, respectively, using 5-methyl-l-tryptophan as the internal standard. The analytical method was successfully applied to commercial yoghurts from different animal species, and the TRP values ranged between 35.19 and 121.97 mg/100 g (goat and cow Greek type yoghurt, respectively).

Total carotene content and quality characteristics of pumpkin flavoured buffalo milk

As per the World Health Organization (WHO) and Global Hunger Index, the incidence of malnutrition and Vitamin-A deficiency in preschool-age children is higher in South-East Asian countries. Therefore, this study was envisaged to formulate value-added flavoured buffalo milk and to carry out the sensory evaluation, nutritional analysis, storage characteristics and total carotene content of the developed product. Flavoured buffalo milk was prepared by incorporation of Cucurbita pepo (Pumpkin) pulp and ground sugar at a concentration of 15% and 10%, respectively. The formulation was found preeminent by panellists and then subjected to nutritional analysis and storage studies at room temperature following "in bottle heat treatment". Nutritional analysis revealed that the protein, fat, total carbohydrates, total ash and moisture content of pumpkin flavoured buffalo milk were 3.07%, 5.21%, 12.63%, 0.61% and 78.48%, respectively. The storage study of flavoured buffalo milk showed a significantly (p < 0.05) declined score in colour and appearance as well as flavour only after day 90. The overall acceptability score also declined significantly (p < 0.05) after day 60 of storage. Though the sensory score declined gradually during the storage period, the product was liked by the panellist even till day 180. The carotene content of pumpkin flavoured buffalo milk was 1.2 mg/100 g at day 0 and it decreased significantly as storage prolongs. The nutritional components were not affected significantly during the 180 days storage period. Standard plate counts, coliform counts as well as yeast and mould counts were not detected during storage of pumpkin flavoured buffalo milk.

A proposal for a diet-based local PCDD/F deposition limit

This study proposes a method to estimate the maximal tolerable value for the atmospheric deposition of dioxins (PCDD/Fs) to soil. The case study for the application of this methodology is an Alpine valley where a steel production plant is present. In order to estimate the limit value for the PCDD/F deposition, consolidated food chain models were applied, but were adapted to be run backwards with respect to their original formulation, by starting from the diet of people living in the region and from the PCDD/F Tolerable Daily Intake value proposed by the World Health Organization. For this case study, the estimated limit value was 2.30 pg WHO-TEQ m(-2) d(-1) when only local diary products were taken into account and 1.91 pg WHO-TEQ m(-2) d(-1) when also the role of local cereals and vegetables was considered. The average PCDD/F deposition measured in the same region during a monitoring campaign was lower than the above limit values (1.40 pg WHO-TEQ m(-2) d(-1)). Indications on how to consider the contribution of meat and fish are provided too. The approach proposed in this paper represents a useful tool to assess the acceptable overall deposition for a specific region.

Chemical characteristics, fatty acid compositions, conjugated linoleic acid contents and cholesterol levels of some traditional Turkish cheeses

The chemical characteristics, fatty acid and conjugated linoleic acid (CLA) contents and cholesterol levels of some traditional Turkish cheeses that are consumed mostly in Turkey were determined in this study. The fatty acid and cholesterol contents and CLA amount of cheeses were analysed as methyl esters by gas chromatography. The aim of this study was to determine the nutritional profile of some Turkish cheeses produced by traditional methods. The major fatty acids of the cheeses were palmitic acid (C(16:0)) and oleic acid (C(18:1)). The saturated fatty acid content of samples changed between 60.80% and 76.57%, while the monounsaturated fatty acid content ranged from 21.42% to 34.05% and the polyunsaturated fatty acid content was between 1.47% and 3.59%. The CLA contents of the cheeses ranged from 0.44 to 1.04 g/100 g in fat. The cholesterol levels of the samples were determined as 44.6-147.69 mg/100 g in cheese.

Influence of microorganisms on retinol isomerization in milk

In order to have a deeper insight into the retinol isomerization phenomenon, in this work different milk samples have been analysed for their content of trans retinol and its cis-isomers, by means of reliable HPLC techniques. Levels of the different isomers and the degree of retinol isomerization (13-cis/all-trans ratio, %) have been monitored during milk storage at different temperatures and after addition of specific microorganisms. In raw milk stored at 4°C for 96 h the degree of retinol isomerization shifted from 1·1 to 2·3%, while in raw milk stored at 22°C for 24 h it increased from 1·1 to 12·7%. Among microorganisms tested in pasteurized milk, the most active in causing an increment in the 13-cis/all-trans ratio (%), from 3·4 to 33·4% in 8 h, was Streptococcus thermophilus. The results obtained demonstrated a relationship between microbial evolution and retinol isomerization. Therefore, the determination of retinol isomers is of importance not only for a more precise evaluation of vitamin A activity but also for the evaluation of the microbiological quality of milk.