Chemische Zusammensetzung und sensorisches Profil von UFA/CLA angereicherter Butter im Vergleich zu konventioneller Butter

In the last years, there has been a growing demand by consumers for foods combining an increased nutritional value and benefits on human health. Butter enriched in unsaturated fatty acids/conjugated linoleic acids (UFA/CLA) could become a food with added value for its increased content in essential fatty acids, in vitamins and CLA, which has been reported to show potential anticarcinogenic and cholesterol lowering effects. The aim of the present study was to evaluate the chemical composition and the sensory and odour profiles of UFA/CLA enriched butter in comparison to conventional butter. Their fatty acid composition, vitamin and metal ion contents were determined in both kinds of butter. Descriptive sensory analysis and gas chromatography-mass spectrometry coupled to olfactometry (GC/MS/O) were applied to UFA/CLA enriched and conventional butter. The UFA/CLA enriched butter contained significantly higher CLA than conventional butter. α-Tocopherol and iron contents were also significantly higher in UFA/CLA enriched butter. The sensory profile of the UFA/CLA enriched butter showed a less intense creamy odour and cooked milk aroma than conventional butter. UFA/CLA enriched butter revealed a better spreadability. The olfactometric results of the fresh butter samples indicated that the enriched butter had more intense green, sulphury and fruity notes, due to (Z)-3-hexenol, dimethyl disulphide, 2-phenylethyl acetate and δ-decalactone, respectively, compared to conventional butter

HLA-G: expression in human keratinocytes in vitro and in human skin in vivo

Classical, polymorphic major histocompatibility complex class I molecules are expressed on most nucleated cells.They present peptides at the cell surface and, thus, enable the immune system to scan peptides for their antigenicity. The function of the other, nonclassical class I molecules in man is controversial. HLA-G which has been shown by transfection experiments to be expressed at the cell surface, is only transcribed in placental tissue and in the fetal eye.Therefore, a role of HLA-G in the control of rejection of the allogeneic fetus has been discussed. We found that HLA-G expression is induced in keratinocytes by culture in vitro. Three different alternative splicing products of HLA-G can be detected: a full length transcript, an mRNA lacking exon 3 and a transcript devoid of exon 3 and 4. Reverse transcription followed by polymerase chain reaction also revealed the presence of HLA-G mRNA in vivo in biopsies of either diseased or healthy skin

Assessment of processing technologies which may improve the nutritional composition of dairy products – Overview of progress

Among consumers there is a growing demand for food products with a natural nutritional-physiological advantage over comparable conventional products. As part of an EU funded project, ALP is examining the possible impact of processing on nutritionally valuable milk components, using the example of conjugated linoleic acids (CLA). The extent to which processing influences the CLA content of the end product was determined by literature research and own investigations of organic and conventional butter. Furthermore, new chemical, sensory-based and bio crystallization methods were evaluated by ALP and the University of Kassel to determine the oxidation stability of butter. In a further step the storage stability of CLA enriched and conventional butter was examined and the different methods will be compared. As a third objective a process for low-input CLA enrichment of milk fat (with a focus on alpine butter) has been developed. Since the process selected for the work is a physical enrichment process, it is accepted by international organic farming and food groups. Among the many benefits ascribed to CLA, it is believed to be an effective agent against cancer. The demand for foods with properties that promote human health is growing. The dairy industry has the opportunity to meet this demand by developing new dairy products with a nutritional-physiological function for the functional food market

Characterization of Propionibacterium plasmids.

Plasmid DNAs from 15 Propionibacterium strains were characterized by using restriction endonuclease analyses, DNA-DNA hybridizations, and curing experiments. Restriction endonuclease analysis identified seven distinct plasmids (pRGO1 through pRGO7). Detailed restriction maps were constructed for four of these plasmids. DNA-DNA hybridization analysis revealed that plasmids pRGO1 and pRGO2 had extensive sequence homology and that both were homologous to pRGO7 and to similar sequences of pRGO5. Plasmids pRGO4 and pRGO6 did not have any significant sequence homology with any of the other plasmids. Plasmid pRGO3 had partial sequence homology only with pRGO7. Curing of plasmids pRGO1, pRGO2, and pRGO5 was achieved by treatment with acriflavin, but we failed to identify any plasmid-encoded bacteriocin production, carbohydrate fermentation, or antibiotic resistance. However, physical evidence was obtained that tentatively linked the clumping phenotype of Propionibacterium jensenii P38 with plasmid pRGO5

Determination of storage stability of butter enriched with unsaturated fatty acids/conjugated linoleic acids (UFA/CLA) using instrumental and sensory methods

The oxidative stability of butter enriched with unsaturated fatty acids and conjugated linoleic acids (UFA/CLA butter) was evaluated by chemical, sensory and microbiological analyses during 8 weeks of storage at 6 °C and compared with that of conventional butter. The odour-active compounds were analyzed by gas chromatography–mass spectrometry combined with olfactometry, using solid phase microextraction. Olfactometric analysis showed that both, fresh UFA/CLA butter and fresh conventional butter had similar aroma profiles. After 6–8 weeks of storage, UFA/CLA butter showed stronger fatty (butanoic and 3-methyl butanoic acid), metallic [(E,E)-2,4-nonadienal], green [(E)-2-hexenol] and creamy (2-pentanone) notes compared with the conventional samples. A sensory panel described the two fresh butter types as having a similar sensory profile, except for a stronger creamy aroma, a less intense cooked milk aroma and a significantly higher spreadability of the UFA/CLA butters. Sensory descriptive analysis showed also that both butter types aged in a very similar way, with an increase in rancid and oxidized notes. (c) 2008 Elsevier Ltd. All rights reserved