The theme of this thesis is to determine the aroma active compounds in fermented dairy products. These substances significantly influence the palatability of these dairy products. Five kinds of dairy products were analyzed. Two types of creamy yogurts, and three types of yoghurt milks were produced at the dairy Ekomilk Ltd. in Frydek - Mistek and four types of acidified milk, five kinds of creamy yogurts, two kefir milks and two clabbered milks come from production of the company Kunin, Inc. Ostrava - Martinov. The SPME extraction method was used for the determination of aromatics, subsequent analysis was performed using gas chromatography. Compounds contained in fermented milk products were identified and quantified on the basis of the measured standards. Total 39 compounds, including 16 alcohols, 7 acids, 6 aldehydes, 6 ketones and 4 esters were identified. Fermented dairy products were twice subjected to sensory evaluation by the ranking test and scale test. The assessors were chosen from students, postgraduate students and staff of faculty of chemistry BUT. Consumers evaluated very positively yogurts, yogurt drinks and acidified milks, while kefir milks and clabbered milks did not suit in some aspects.

Tout au long du processus de transformation et de stockage, les matières premières alimentaires sont susceptibles d’être colonisées par des micro-organismes. On estime que 5 à 10 % de la production alimentaire mondiale est perdue du fait de la prolifération de levures et/ou moisissures au sein de ces matrices. L’industrie laitière est la deuxième filière agro-alimentaire au monde et celle-ci n’est pas épargnée par ces contaminations. Pour résoudre cette problématique et répondre à la demande grandissante des consommateurs visant à éliminer les conservateurs chimiques dans les produits alimentaires, la biopréservation par des ferments bactériens représente la meilleure alternative. Dans cette étude, la capacité antifongique de 18 souches de lactobacilles a été analysée vis-à-vis de la croissance de souches fongiques isolées de produits laitiers contaminés. Quatre souches de Lactobacillus présentant le spectre d’inhibition le plus large ont ainsi été sélectionnées. La caractérisation des molécules antifongiques produites a été réalisée à partir de cultures en milieu MRS, milieu lait et fromages frais, révélant la synergie de l’acide lactique avec d’autres molécules. Ces molécules se sont révélées faiblement produites et correspondent à des acides organiques issus de la dégradation d’acides aminés (acide phényllactique, acide benzoïque, …), des acides gras (C12, C14, C16 saturé ou non, C18 saturé ou non) et des molécules volatiles ou semi-volatiles (diacétyle, acide acétique, …). L’augmentation de l’activité antifongique par surproduction de ces molécules a par la suite été tentée par différentes approches : mutagénèse aléatoire, ajout de précurseurs dans le milieu, etc, malheureusement sans succès. / Throughout the processing and storage process, food raw materials are likely to be colonized by micro-organisms. It is estimated that 5 to 10% of global food production is lost due to the proliferation of yeasts and/or molds within these matrices. The dairy industry is the second largest food industry in the world and is not immune to this contamination. To solve this problem and meet the growing consumer demand to eliminate chemical preservatives in food products, biopreservation with bacterial ferments is the best alternative. In this study, the antifungal capacity of 18 strains of Lactobacillus was analyzed with respect to the inhibition of growth of fungal strains isolated from contaminated dairy products. Four Lactobacillus strains with the broadest inhibition spectrum were selected. The characterization of the antifungal molecules produced was carried out from cultures in MRS medium, milk medium and fresh cheese, revealing the synergy of lactic acid with other molecules. These molecules have been found to be weakly produced and correspond to organic acids resulting from the degradation of amino acids (phenyllactic acid, benzoic acid,...), fatty acids (C12, C14, C16 saturated or unsaturated, C18 saturated or unsaturated) and volatile or semi-volatile molecules (diacetyl, acetic acid,...). The increase in antifungal activity by overproduction of these molecules was subsequently attempted by different approaches: random mutagenesis, addition of precursors to the environment, etc., unfortunately without success.

No description available.

Objective: Diet lifestyle can influence the risk of endometriosis. Therefore, we conducted a systematicmeta-analysis to investigate the association between dairy products and the risk of endometriosis. Besides, we performed a dose-responsemeta-analysis to evaluate the amount of dairy intake affecting the risk of endometriosis. Methods: Relevant studies were searched from Pubmed, Embase databases, Cochrane Library, and Web of Science from the inception to November 6th, 2020. Also, the dose-response meta-analysis was conducted. All the pooled results were performed by risk ratios (RRs). Results: Finally, seven high-quality studies were included in the present meta-analysis. Total dairy intake was inversely associated with the risk of endometriosis, and the risk of endometriosis tended to decrease with a decrease in the risk of endometriosis when dairy products intake was over 21 servings/week (RR 0.87, 95% CI 0.76–1.00; pnon−linearity = 0.04). Similarly, people who consumed more than 18 servings of high-fat dairy products per week had a reduced risk of endometriosis (RR 0.86, 95% CI 0.76–0.96). When stratified-analyses were conducted based on specific dairy product categories, it indicated that people with high cheese intake might have a reduced risk of endometriosis (RR 0.86, 95%CI 0.74–1.00). Other specific dairy products such as whole milk (RR 0.90, 95% CI 0.72–1.12), reduced-fat/skim milk (RR 0.83, 95% CI 0.50–1.73), ice cream (RR 0.83, 95% CI 0.50–1.73), and yogurt (RR 0.83, 95% CI 0.62–1.11) have not shown significant evidence of an association with the risk of endometriosis. However, there is a higher risk of endometriosis in the females with high butter intake compared to females with low butter intake (1.27, 95% CI 1.03–1.55). Conclusions: Overall, dairy products intake was associated with a reduction in endometriosis, with significant effects when the average daily intake 3 servings. When analyzed according to the specific type of dairy product, it was shown that females with higher high-fat dairy and cheese intake might have a reduced risk of endometriosis. However, high butter intake might be associated to the increased risk of endometriosis. More future studies are needed to validate and add to this finding.

An enzyme-linked immunosorbent assay (ELISA) using polyclonal antibodies has been developed for the detection of the fluorescing group of Pseudomonas. The assay was used as a rapid test (6h) for predicting the shelf-life of pasteurized fluid milk. Milk samples were held at 7°C and tested weekly until determined to be unacceptable by daily sensory evaluation. Sterile milk samples were inoculated with target concentrations of 0 (control), 100, and 1000 cells/ml of Pseudomonas fluorescens on day 0. Samples were tested before and after preliminary incubations. Preliminary incubations conducted include milk alone and milk with broth (1:1) for 18h at 21°C. ELISA and plate counts were performed before and after preliminary incubation to determine the number of pseudomonads present and the relationship between ELISA and plate counts. These numbers were correlated to the shelf-life of each sample, as determined by sensory evaluation. Samples undergoing a preliminary incubation with only milk gave the best correlation to shelf-life (R=0.86). / Master of Science

Master of Science

The aim of this investigation is to determine whether there is a correlation between the sanitary condition of milk and dairy products dispensed in Sherman, Texas, and the plate counts, the morphology, and the Gram stain reaction of the organisms in predominant colonies from these.

The general problem to be dealt with in this thesis is that of determining whether the antitrust laws of the state of Texas fulfill their aim of maintaining competition through the prosecution of conspiracies in restraint of trade. The specific problem is the determination of the effect of the antitrust laws on the dairy industry in Texas.

Yes / A study of pottery vessel contents and use was undertaken in order to obtain information on food processed in Subneolithic and Neolithic vessels from Nida and Šventoji (3300–2400 cal BC). The aim is to assess pottery use during major changes in the coastal environment and in material culture. Bulk carbon and nitrogen isotope, lipid biomarker and compound specific carbon isotope analysis was undertaken on ‘foodcrusts’, charred deposits adhering to vessel surfaces, and absorbed residues from different vessel types. In addition, three archaeological seal bones were analysed for bulk collagen and compound specific carbon isotope analysis to establish collagen-lipid offsets to inform interpretation of the data. The results show that the majority of the vessels were used for processing aquatic products. At Nida the data suggest exploitation of freshwater resources and, in the later stages of occupation, dairying. Analysis of a small number of Subneolithic vessels from Šventoji produced results that are also consistent with processing of aquatic products. Other substances identified include Pinaceae sp. resin or tar and beeswax. These data demonstrate that identifying patterns in pottery use contributes to understanding Neolithisation processes.

Historically, consumer perceptions towards dairy products have been measured using a rational cognitive approach. However, recent consumer insights suggest that emotions play a dominant role in consumer decision making. The South African dairy industry therefore identified a need to determine emotive reactions to educational messages in addition to the reasons underpinning dairy consumption. Using a mixed method research approach, reactions from 81 South African dairy consumers were obtained, using three different, but interrelated measuring instruments. Descriptive statistics, hierarchical ladder maps and correlation analyses were used to examine emotive and cognitive consumer reaction to a number of generic dairy messages and products. The findings indicate that certain communication messages appear to have a stronger impact on consumers due to specific emotions that these messages elicit. Personal values underpinning dairy consumption decisions were also identified within the context of emotive reactions to the selected dairy products. / Business Management / M. Com. (Business Management)