Dissertation 'consists of a selection of 71 publications produced over the period 1975-2001, which were drawn from the more complete list of 198 original research papers, review articles and books published over the same period' -- declaration. / Thesis (PhD Food Sc )--Stellenbosch University, 2001. / ENGLISH ABSTRACT: One of the curious facts about the food industry is that many of the processes in use today were being practised, in some form or other, by the Roman legions as they marched across Europe and beyond. Certainly they were familiar with the basic techniques of fermentation, and much current research into fermented foods is concerned with understanding the fundamental nature of these traditional processes, and how the individual stages in a particular fermentation can be better controlled. Recent developments in the dairy industry have tended to reflect this pattern and, over the years, my research group has done much to support the expanding markets for yoghurt and similar fermented milks. Our evaluation of the polysaccharide-producing characteristics of starter cultures, for example, encouraged yoghurt manufacturers to match physical properties to the perceived demands of consumers, and most culture suppliers followed this lead by labelling their products with precise designations as to their potential for imparting viscosity to a retail item. Similarly, my group was the first to record the unique physical properties of the concentrated yoghurt, labneh, C 230 g 1-1 total solids) that had been made for hundreds of years by draining whey from natural yoghurt hanging in a cloth or animal-skin bag. This detailed analysis of the product facilitated the application of ultra-filtration to natural yoghurt to generate a product with a quality that matched traditionallabneh and, today, factories in the Middle East, Greece and elsewhere are using modern membrane-filtration plants to satisfy a growing market demand. Our success in publicising the attractive properties of concentrated yoghurt encouraged me to devote time to yet another 'historical' concept, namely the apparent 'health benefits' derived by small communities in Eastern Europe from consuming kefir and koumiss. In the West, the flavour and texture of these latter products have never been accepted, but employing similar cultures to produce 'health-promoting' bio-yoghurts opened an entirely new avenue for research. As clinical evidence in support of the prophylactic and therapeutic properties of Lactobacillus acidophilus and a species of Bifidobacterium became available, so it became apparent that the therapeutic advantage that accompanies the regular ingestion of 'bio-yoghurts' depended on the survival of these microfloras over the stipulated shelf-lives of the retail vehicles. However, no laboratory medium was immediately available for the simultaneous enumeration of Lb. acidophilus and Bifidobacterium along with the yoghurt cultures, i.e. Streptococcus thermophilus and Lactobacillus delbrueckii sub-sp. bulgaricus. Designing such a medium became a priority for one of my students, and, even today, the procedures that he derived are being used by consumer groups that monitor the performance of the major dairy companies in England. If the improved quality of yoghurts and 'bio-yoghurts' had a major impact on consumer perceptions of fermented milks, the food sector in England gradually became aware of an even more dramatic change in consumer attitudes. Thus twenty years ago, cheese meant 'Cheddar' but, following a 'deluge' of television publicity about the attractions of 'exotic' catering, housewives began demanding mozzarella and mascarpone for lavish desserts, Feta to sprinkle over salads and Halloumi to grill or fry. In turn, exporting countries like Italy, Greece and Cyprus came under intense pressure to increase supplies of top quality products. Local manufacturers soon realised, however, that there was little information available concerning the scientific basis to the procedures employed to make some of these traditional cheeses, and my research group was selected by Funding Agencies in Greece and Cyprus to act as a focus for a series of studies of Feta and Halloumi cheese. The need to eliminate pathogens from the storage brines of Feta cheese without killing the yeasts and bacteria associated with maturation became an important consideration for exporters, and one of my students exploited a novel procedure employing furocoumarins and long-wave ultra-violet light to achieve the desired selective inactivation. At present, the economics of commercial application are somewhat dubious but, as soon as cheap, synthetic, non-toxic furocoumarins become more readily available, the system may well merit re-evaluation. We did confirm, however, that the metabolic activities of the yeasts and bacteria typically isolated from storage brines are essential for flavour development in Feta cheese, and that similar microfloras are instrumental in the development of the important charactistics of traditional Halloumi cheese. In particular, a new species of lactic acid bacterium, Lactobacillus cypricasei, was isolated from samples of the traditional ovine cheese, but whether or not the species has a unique role(s) in the maturation process remains an open question. Clearly there is still much to learn but, if the activities of my reseach group have added just a little to the scientific background essential for future studies of cheese and fermented milks, then their completion will have been worthwhile. / AFRIKAANSE OPSOMMING: Een van die merkwaardigste feite omtrent die voedselindustrie is dat baie van die prosesse wat vandag gebruik word, in een of ander vorm deur die Romeinse magte gebruik is toe hulle deur Europa marsjeer het. Basiese fermentasie tegnieke was aan hulle bekend, en heelwat huidige navorsing oor gefermenteerde voedsel is gemik daarop om die fundamentele natuur van hierdie tradisionele prosesse te verstaan en hoe die individuele stappe in 'n spesifieke fermentasie beter beheer kan word. Onlangse ontwikkelinge in die suiwelindustrie reflekteer hierdie patroon, en my navorsingsgroep het oor die jare heelwat gedoen om die groeiende markte vir joghurt en soortgelyke gefermenteerde melk te ondersteun. Ons evaluasie van die polisakkariedproduserende eienskappe van suursels het byvoorbeeld joghurtvervaardigers gehelp om fisieke eienskappe daar te stel wat verbruikers tevrede sal stel. Meeste verskaffers van kulture het hierdie voorbeeld gevolg deur hul produkte so te etiketteer dat duidelik gewys word watter potensiaal dit het om viskositeit aan die finale produk te verleen. Verder was my groep die eerste om die unieke fisiese eienskappe van die gekonsentreerde joghurt, labneh (230 g 1-1 totale vastestowwe) te bepaal, wat vir honderde jare gemaak is deur die wei van natuurlike joghurt te dreineer deur dit in "n materiaal- of diervelsak te hang. "n Gedetailleerde analise van hierdie tradisionele produk het bygedra tot die gebruik van ultrafiltrasie op natuurlike joghurt om "n produk te gee met dieselfde kwaliteit as tradisionele labneh. Vandag gebruik fabrieke in die Midde Ooste, Griekeland en elders moderne membraan-filtrasie aanlegte om in die groeiende vraag na die produk te voorsien. Ons sukses met die bekendmaking van die aantreklike eienskappe van gekonsentreerde joghurt het my aangespoor om tyd te spandeer aan nog 'n sogenaamde "historiese" konsep, naamlik die skynbare gesondheidsvoordele van klein gemeenskappe in Oos-Europa wat kefir en koumiss verbruik. In die Weste is die smaak en tekstuur van hierdie produkte nooit werklik aanvaar nie, maar om soortgelyke kulture te gebruik om "gesondheidsbevorderende" bio-joghurt te produseer, het 'n hele nuwe navorsingsveld daargestel. Soos kliniese bewyse van die terapeutiese en voorkomende voordele van Lactobacillus acidophilus en 'n spesie van Bifidobacterium bekend gemaak is, het dit duidelik geword dat die terapeutiese voordele wat saamgaan met die gereelde inname van "bio-joghurts", afhang van die oorlewing van hierdie mikroflora oor die gestipuleerde rakleeftyd van die kommersiële produkte. Geen laboratorium medium was egter onmiddellik beskikbaar vir die gelyktydige telling van Lb. actdophilus en Bifldobacterium tesame met die joghurt kulture Streptococcus thermophilus en Lb. delbrueckii sub-sp. bulgaricus. Die ontwikkeling van so 'n medium het een van my studente se prioriteit geword, en selfs vandag word die prosedures wat deur hom ontwikkel is, gebruik deur verbruikersgroepe wat die optrede van groot suiwelmaatskappye in Engeland monitor. lndien die verbeterde kwaliteit van joghurts en bio-joghurts 'n groot impak gehad het op verbruikers se persepsie van gefermenteerde melk oor Wes-Europa heen, het die voedselsektor in Engeland bewus geraak van selfs 'n meer dramatiese verandering in verbruikers se houding. Twintig jaar terug het kaas "Cheddar" beteken, maar na 'n stortvloed televisie advertensies oor die aanloklikheid van eksotiese geregte, het daar by huisvroue 'n vraag ontstaan na Mozzarella en Mascarpone vir nageregte, Feta oor slaai en Halloumi om te bak of te braai. Italië, Griekeland en Siprus wat hierdie produkte uitgevoer het, het onder kwaai druk gekom om groter hoeveelhede, top-kwaliteit produkte te lewer. Plaaslike vervaardigers het gou agtergekom dat min inligting beskikbaar was oor die wetenskaplike basis van die prosedures wat gebruik word om hierdie tradisionele kase te maak en my navorsingsgroep is deur befondsingsagentskappe in Griekeland en Siprus genader om studies te doen oor sekere aspekte van die vervaardiging van Feta en Halloumi kaas. Dit het vir beide in- en uitvoerders belangrik geword om die patogene te elimineer uit die soutoplossing waarin Fetakaas gestoor word, sonder om die giste en bakterieë wat rypwording aanhelp, te dood. Een van my studente het 'n innoverende prosedure ontwikkel wat furocoumarins en lang-golf-ultra-violet lig gebruik om selektiewe inaktivering te kry. Op die oomblik is daar effense onsekerheid oor die ekonomiese implikasies van die kommersiële toepassing, maar sodra goedkoop, sintetiese, nie-toksiese furocoumarins geredelik beskikbaar word, moet die sisteem weer geëvalueer word. Ons het egter bevestig dat die metaboliese aktiwiteite van die giste en bakterieë in die stooroplossing noodsaaklik is vir geurontwikkeling in Feta kaas en dat soortgelyke mikrofloras instrumenteel is in die ontwikkeling van die belangrike karaktereienskappe van tradisionele Halloumi kaas. 'n Unieke melksuurbakterium, Lactobacillus cypricasei, is uit monsters tradisionele skaap Halloumi geïsoleer, maar of hierdie spesie 'n unieke rol speel in die verouderingsproses is nog 'n ope vraag. Duidelik is daar nog baie om te leer, maar indien my navorsingsgroep se aktiwiteite slegs 'n klein bydrae gemaak het tot die wetenskaplike agtergrond wat essensieel is vir toekomstige navorsing, was die voltooiing daarvan die moeite werd.

O objetivo deste estudo foi avaliar o efeito da inclusão de leite em pó desnatado e de açúcar sobre a viabilidade de microrganismos probióticos e a qualidade do leite fermentado desnatado. Para isso, foram constituídos 8 tratamentos, a saber: 1. leite desnatado (LD) e padronizado com 0,2% de gordura (LD 0,2%G); 2. LD 0,2%G + 5% de leite em pó (Lp); 3. LD 0,2%G + 10% de Lp; 4. LD 0,2%G + 15% de Lp; 5. LD 0,2%G + 5% de Lp + 10% de açúcar (A); 6. LD 0,2%G + 10% de Lp + 10% de A; 7. LD 0,2%G + 15% de Lp + 10% de A; 8. LD 0,2%G + 10% de A. Foi preparada a cultura láctea mista DVS ABT-4 (Chr-Hansen) contendo Streptococcus thermophilus, Bifidobacterium animalis e Lactobacillus acidophilus, que foi aplicada em todos os tratamentos para a fermentação e produção do leite fermentado. O produto foi então envasado e armazenado a 5ºC para as análises subseqüentes. Os leites fermentados foram submetidos à avaliação físico-química, microbiológica e sensorial nos dias 1, 10 e 21 após a fabricação. Os resultados mostraram que todos os tratamentos permaneceram de acordo com a legislação brasileira no que diz respeito aos aspectos físico-químicos, além de os mesmos terem permanecido constantes durante os 21 dias de armazenamento, com exceção do pH, que diminuiu nos dias seguintes a fabricação em decorrência da pós-acidificaçao dos leites fermentados. Quanto às características microbiológicas, observou-se maiores contagens nos tratamentos com maior teor de leite em pó (tratamentos 3, 4, 6 e 7), principalmente para as bactérias probióticas, com diferença estatisticamente significativa entre todos os tratamentos. Entretanto, a adição de açúcar não interferiu nas contagens de probióticos dos leites fermentados. As contagens microbiológicas permaneceram constantes durante todos os 21 dias de armazenamento. O tratamento 6 (LD 0,2%G + 10% de Lp + 10% de A) foi o que obteve melhores notas na avaliação sensorial nos dias 1, 10 e 21 de armazenamento, indicando ser esta formulação a melhor dentre as estudadas para a aceitação do produto com maior viabilidade de bactérias probióticas. / The aim of this study was to evaluate the effect of skimmed milk powder and sugar inclusion on the viability of probiotic microorganisms and on the quality of skimmed fermented milk. Eight different treatments were prepared: 1. Skimmed and standardized milk (SM) at 0,2% of fat (SM 0,2%F); 2. SM 0,2%F + 5% of milk powder (MP); 3. SM 0,2%F + 10% MP; 4.SM 0,2%F + 15% MP; 5. SM 0,2%F + 5% MP + 5% of sugar (S); 6. SM 0,2%F + 10% MP + 5% S; 7. SM 0,2%F + 15%MP + 10%S; 8. SM 0,2%F + 10%S. The mixed lactic culture DVS ABT-4 (Chr-Hansen) containing Streptococcus thermophilus, Bifidobacterium animalis and Lactobacillus acidophilus was prepared and placed in all the treatments for the fermented milk fermentation and production. The product was bottled and stored at 5°C for the subsequent analyses. The fermented milks were submitted to physical-chemical, microbiological and sensory analyses on the 1st, 10th and 21st days after production. Results for the physic-chemical analyses showed that all the treatments comprised the requirements as adopted in Brazilian regulations. All the physical-chemical variables were constant during the 21 days of storage, except for the pH, which decreased during storage because of the fermented milks post-acidification. For the microbiological analyses, greater numbers, especially the probiotic bacteria, were obtained in treatments with higher milk powder content (treatments 3, 4, 6 and 7), with significant statistical differences among all the treatments. However, the sugar addition did not interfere with the recovery of probiotic bacteria in the fermented milks. The microbiological data were constant during the 21 days of storage. Results obtained in the sensory analyses showed that treatment 6 was the one with higher grades on days 1, 10 and 21 of storage, hence indicating that this composition is the best one among those studied for acceptability of the product with greater viability of probiotic bacteria.

Neste trabalho duas espécies de grãos, de kefir e do tibet, popularmente conhecidas e utilizadas para fermentar o leite, foram estudados neste trabalho, no que se refere aos produtos formados durante a fermentação. O grão de kefir é uma associação simbiótica de microganismo pertencente a diversas espécies incluindo no geral bactérias ácidas láticas (Lactobacillus, Lactococcus, Leuconostoc), leveduras (Saccharomyces cereviseae) e bactérias ácidas acéticas (Acetobacter). O grão de tibet é, também composto por uma associação simbiótica de leveduras e bactéria ácida lática. No entanto, grãos de kefir e tibet são muitos similares em quantidade microbiológica, procedimento de cultivo, muito similar em estrutura e produtos de fermentação, mas diferem em aspecto visual. A voltametria cíclica e cromatografia líquida de alta eficiência, em fase reversa (HPLC) com detecção no UV em 210nm operando no modo de eluição isocrático, foram aplicadas para determinar ácidos orgânicos em leite fermentados pelos grãos kefir e do Tibet e em amostra de iogurte comercial. Em ambos os métodos utilizados os resultados obtidos mostraram a presença de ácidos orgânicos em leite e no leite fermentado pelos grãos kefir e do Tibet e em amostra comercial de iogurte. Essas matrizes mostraram eletroatividade em ultramicroeletrodo de ouro. E nas análises por HPLC foi comprovado a presença de ácidos orgânicos e em grandes quantidades para cinco ácidos dos oito presentes nas amostras. Neste trabalho, foi efetuada a determinação de 8 ácidos orgânicos. Nas amostras citadas foram identificados os ácidos lático, oxálico, pirúvico, acético, úrico, cítrico, succínico e fórmico. Esta identificação foi feita por comparação entre os tempos de retenção dos compostos nas amostras de leite fermentado com os tempos de retenção dos padrões dos ácidos injetados individualmente para a técnica de HPLC. E quanto a aplicação da voltametria na análise de leite fermentado, o grão de Tibet demonstrou maior resposta analítica entre corrente e concentração, comparado ao grão de kefir e amostra comercial de iogurte. Fazendo uma análise comparativa das duas técnicas a HPLC tornou-se mais adequada devido a maior seletividade. / The products formed during the milk fermentation using the kefir and tibet grains (popularly known species) were studied in this work. The kefir grain is a symbiotic association of microorganisms that includes several species of lactic acid bacteria (Lactobacillus, Lactococcus, Leuconostoc), yeasts (Saccharomyces cereviseae) and acetic acid bacteria (Acetobacter). The tibet grain is also composed by a symbiotic association of yeasts and lactic acid bacteria. In spite of, the kefir and tibet grains are very similar in microbiologic components, cultivation procedure, structure and fermentation products, they differ in visual aspect. For the determination of the organic acids contained in fermented milk by the kefir or tibet grains and in a sample of commercial yogurt, the cyclic voltammetry and high performance liquid chromatography (HPLC) in reverse phase techniques were applied, the later was operated in isocratic elution mode with detection in the UV (210nm) region. In both techniques used, the obtained results showed the presence of organic acids in milk and in the fermented milk by the grains kefir and tibet and in the sample of commercial yogurt. Those matrixes showed electroactivity on a gold ultramicroelectrode and their analyses using HPLC was also possible. Thus, the presence of organic acids in great amounts for five acids of the eight presents in the samples was confirmed. In this work, the detection of 8 organic acids was carried out. In the mentioned samples were identified the lactic, oxalic, pyruvic, acetic, uric, citric, succinic and formic acids. This identification was performed by comparison among the retention times of the compounds in the samples of fermented milk with the retention times of the patterns of the acids, injected individually for the HPLC technique. Nevertheless, in the voltammetry application for the analysis of the fermented milk, the tibet grain demonstrated larger analytical signals (current – concentration relationship), compared to the kefir grain and the commercial sample of yogurt. Making a comparative analysis of the two techniques, HPLC became more appropriate due its larger selectivity.

A crescente preocupação com tecnologias sustentáveis e a procura de novos alimentos funcionais despertam o interesse para o desenvolvimento de novos produtos alimentícios que proporcionem, além da nutrição, benefícios à saúde do consumidor. Assim, esse trabalho visa propor o leite orgânico como potencial matéria-prima para a fabricação de leites fermentados probióticos. Para tanto, estudou-se o perfil tecnológico de cepas de bifidobactéria em cultura pura e em co-cultura com Streptococcus thermophilus em leites orgânico e convencional, analisando a composição química dos leites, determinando o perfil de acidificação de quatro cepas de Bifidobacterium animalis subsp. lactis em cultura pura e em co-cultura com Streptococcus thermophilus, verificando a contagem microbiológica das culturas probióticas e iniciadoras nos leites fermentados, examinando o perfil de ácidos graxos e o teor de ácido linoléico conjugado dos leites fermentados e determinando o perfil de textura dos leites fermentados. A maior velocidade de acidificação foi observada para as cepas B94 e BL04 em leite orgânico e para a cepa HN019, para ambos os tipos de leite. As contagens de todas as cepas de B. animalis subsp. lactis foram superiores a 8,58 log10 unidades formadoras de colônia (UFC).mL-1</SUP. O leite orgânico apresentou maiores teores de ferro e proteína, enquanto o leite convencional apresentou maiores teores de gordura e lactose. Os principais ácidos graxos foram pouco influenciados pelo tipo de leite e as maiores quantidades de ácido linoléico conjugado (65 % maior do que o controle) foram encontradas em leite orgânico fermentado com a cepa BB12 em co-cultura com S. thermophilus. Assim, verificou-se que o leite orgânico pode ser empregado como matéria-prima na fabricação de leites fermentados probióticos, agregando qualidade nutricional ao produto final. / The concern about sustainable technologies and demand for new functional foods arouses the interest for the development of new food products in addition to provide nutrition and health benefits to the consumer. Thus, this work aims to offer organic milk as a potential raw material for the manufacture of probiotic fermented milk. Therefore, studying the technological profile of strains of bifidobacteria in pure culture and in co-culture with Streptococcus thermophilus in organic and conventional milks, analyzing the chemical composition of milk; determining the profile of acidification of four strains of Bifidobacterium animalis subsp. lactis in pure culture and in co-culture with Streptococcus thermophilus; checking the counts of starter and probiotic cultures in fermented milks; examining the profile of fatty acids and conjugated linoleic acid content of fermented milks and the profile of texture of fermented milks. The highest rate of acidification profile was observed for the strains BL04 and B94 in organic milk and for the strain HN019 in both milks. The counts of all strains of B. animalis subsp. lactis were higher than 8.58 log10 colony forming units (CFU). mL-1. The organic milk had higher levels of iron and protein, whereas conventional milk had higher levels of fat and lactose. The main fatty acids were not influenced by the type of milk and higher amounts of conjugated linoleic acid (65% higher than the control) were found in organic fermented milk with the strain BB12 in co-culture with S. thermophilus. Thus, it was found that organic milk can be used as raw material in the manufacture of probiotic fermented milk, increasing nutritional quality to final product.

O trato gastrointestinal de humanos é rico em microrganismos que, podem tanto ser benéficos para a saúde do hospedeiro, prevenindo e/ ou tratando a intolerância à lactose, constipação intestinal, síndrome do intestino irritável, entre outras, quanto podem prejudicá-lo, afetando a aquisição de nutrientes e produção de mediadores inflamatórios. Estes distintos papéis da microbiota intestinal são tão marcantes que podem, inclusive, influenciar no desenvolvimento da obesidade em algumas pessoas, podendo levar até mesmo à Síndrome Metabólica. Probióticos e prebióticos podem conferir alterações nas propriedades da microbiota, afetando o crescimento bacteriano e seu metabolismo e, até mesmo, o uso de nutrientes. Assim, o objetivo geral deste trabalho foi avaliar o efeito do uso de leite fermentado simbiótico na obesidade e nos indicadores de Síndrome Metabólica, como circunferência de cintura, TGL, HDL-c, glicemia e pressão arterial, em pacientes com predisposição a esta doença, selecionados de acordo com os critérios de diagnóstico para síndrome metabólica. Para esta pesquisa foram desenhados quatro produtos, três deles inoculados com uma cultura comercial de probiótico - Bifidobacterium lactis (BL420), adicionados ou não de casca de maracujá em pó (prebiótico), sendo um deles preparado com uma emulsão de óleos vegetais, que apresenta efeito em prolongar a saciedade; e o quarto produto, fermentado apenas com a cultura clássica Streptococcus thermophilus. Avaliaram-se as propriedades tecnológicas dos produtos - físico-química, sensorial, microestrutura, microbiológica, e estudaram-se seus aspectos funcionais. Finalmente, os produtos foram testados em consumidores ao longo de um ensaio clínico durante 12 semanas, período no qual os voluntários tiveram que consumir 100 mL do produto, duas vezes ao dia, todos os dias. A avaliação dos voluntários foi feita antes do início do ensaio e também aos ao final dos 90 dias. / The gastrointestinal tract of humans is rich in microorganisms which can both be beneficial to host health, preventing and / or treating lactose intolerance, constipation, irritable bowel syndrome, among others, as they can harm, affecting nutrient acquisition and the production of inflammatory mediators. These distinctive roles of intestinal microbiota are so striking that can even influence the development of obesity in some people and may even lead to metabolic syndrome. Probiotics and prebiotics can confer alterations in the microbiota properties, affecting the bacteria growth and their metabolism, and the use of nutrients. Thus, the aim of this study was to evaluate the use of innovative symbiotic fermented milk in obesity and metabolic syndrome indicators such as waist circumference, TGL, HDL-C, blood glucose and blood pressure in patients with a predisposition to this disease, selected according to the diagnostic criteria for metabolic syndrome. For this, four fermented mik were designed, three of them inoculated with a commercial probiotic culture - Bifidobacterium lactis (BL420), added or not by passion fruit peel powder (prebiotic), one of them being prepared with an emulsion of vegetable oil, which has effect on prolonguing satiety; and the fourth product, fermented only with the classical culture Streptococcus thermophilus. Products´ technological properties were evaluated - physico chemical, sensory, microstructure, microbiology, and functional aspects were studied. Finally products were tested in consumers throughout a clinical trial during 12 weeks, period in which the volunteers had to consume 100 mL of the product twice a day, every day. The evaluation of the volunteers was done before the start of the test and also at the end of the 90 days.

A crescente preocupação com tecnologias sustentáveis e a procura de novos alimentos funcionais despertam o interesse para o desenvolvimento de novos produtos alimentícios que proporcionem, além da nutrição, benefícios à saúde do consumidor. Assim, esse trabalho visa propor o leite orgânico como potencial matéria-prima para a fabricação de leites fermentados probióticos. Para tanto, estudou-se o perfil tecnológico de cepas de bifidobactéria em cultura pura e em co-cultura com Streptococcus thermophilus em leites orgânico e convencional, analisando a composição química dos leites, determinando o perfil de acidificação de quatro cepas de Bifidobacterium animalis subsp. lactis em cultura pura e em co-cultura com Streptococcus thermophilus, verificando a contagem microbiológica das culturas probióticas e iniciadoras nos leites fermentados, examinando o perfil de ácidos graxos e o teor de ácido linoléico conjugado dos leites fermentados e determinando o perfil de textura dos leites fermentados. A maior velocidade de acidificação foi observada para as cepas B94 e BL04 em leite orgânico e para a cepa HN019, para ambos os tipos de leite. As contagens de todas as cepas de B. animalis subsp. lactis foram superiores a 8,58 log10 unidades formadoras de colônia (UFC).mL-1</SUP. O leite orgânico apresentou maiores teores de ferro e proteína, enquanto o leite convencional apresentou maiores teores de gordura e lactose. Os principais ácidos graxos foram pouco influenciados pelo tipo de leite e as maiores quantidades de ácido linoléico conjugado (65 % maior do que o controle) foram encontradas em leite orgânico fermentado com a cepa BB12 em co-cultura com S. thermophilus. Assim, verificou-se que o leite orgânico pode ser empregado como matéria-prima na fabricação de leites fermentados probióticos, agregando qualidade nutricional ao produto final. / The concern about sustainable technologies and demand for new functional foods arouses the interest for the development of new food products in addition to provide nutrition and health benefits to the consumer. Thus, this work aims to offer organic milk as a potential raw material for the manufacture of probiotic fermented milk. Therefore, studying the technological profile of strains of bifidobacteria in pure culture and in co-culture with Streptococcus thermophilus in organic and conventional milks, analyzing the chemical composition of milk; determining the profile of acidification of four strains of Bifidobacterium animalis subsp. lactis in pure culture and in co-culture with Streptococcus thermophilus; checking the counts of starter and probiotic cultures in fermented milks; examining the profile of fatty acids and conjugated linoleic acid content of fermented milks and the profile of texture of fermented milks. The highest rate of acidification profile was observed for the strains BL04 and B94 in organic milk and for the strain HN019 in both milks. The counts of all strains of B. animalis subsp. lactis were higher than 8.58 log10 colony forming units (CFU). mL-1. The organic milk had higher levels of iron and protein, whereas conventional milk had higher levels of fat and lactose. The main fatty acids were not influenced by the type of milk and higher amounts of conjugated linoleic acid (65% higher than the control) were found in organic fermented milk with the strain BB12 in co-culture with S. thermophilus. Thus, it was found that organic milk can be used as raw material in the manufacture of probiotic fermented milk, increasing nutritional quality to final product.

O trato gastrointestinal de humanos é rico em microrganismos que, podem tanto ser benéficos para a saúde do hospedeiro, prevenindo e/ ou tratando a intolerância à lactose, constipação intestinal, síndrome do intestino irritável, entre outras, quanto podem prejudicá-lo, afetando a aquisição de nutrientes e produção de mediadores inflamatórios. Estes distintos papéis da microbiota intestinal são tão marcantes que podem, inclusive, influenciar no desenvolvimento da obesidade em algumas pessoas, podendo levar até mesmo à Síndrome Metabólica. Probióticos e prebióticos podem conferir alterações nas propriedades da microbiota, afetando o crescimento bacteriano e seu metabolismo e, até mesmo, o uso de nutrientes. Assim, o objetivo geral deste trabalho foi avaliar o efeito do uso de leite fermentado simbiótico na obesidade e nos indicadores de Síndrome Metabólica, como circunferência de cintura, TGL, HDL-c, glicemia e pressão arterial, em pacientes com predisposição a esta doença, selecionados de acordo com os critérios de diagnóstico para síndrome metabólica. Para esta pesquisa foram desenhados quatro produtos, três deles inoculados com uma cultura comercial de probiótico - Bifidobacterium lactis (BL420), adicionados ou não de casca de maracujá em pó (prebiótico), sendo um deles preparado com uma emulsão de óleos vegetais, que apresenta efeito em prolongar a saciedade; e o quarto produto, fermentado apenas com a cultura clássica Streptococcus thermophilus. Avaliaram-se as propriedades tecnológicas dos produtos - físico-química, sensorial, microestrutura, microbiológica, e estudaram-se seus aspectos funcionais. Finalmente, os produtos foram testados em consumidores ao longo de um ensaio clínico durante 12 semanas, período no qual os voluntários tiveram que consumir 100 mL do produto, duas vezes ao dia, todos os dias. A avaliação dos voluntários foi feita antes do início do ensaio e também aos ao final dos 90 dias. / The gastrointestinal tract of humans is rich in microorganisms which can both be beneficial to host health, preventing and / or treating lactose intolerance, constipation, irritable bowel syndrome, among others, as they can harm, affecting nutrient acquisition and the production of inflammatory mediators. These distinctive roles of intestinal microbiota are so striking that can even influence the development of obesity in some people and may even lead to metabolic syndrome. Probiotics and prebiotics can confer alterations in the microbiota properties, affecting the bacteria growth and their metabolism, and the use of nutrients. Thus, the aim of this study was to evaluate the use of innovative symbiotic fermented milk in obesity and metabolic syndrome indicators such as waist circumference, TGL, HDL-C, blood glucose and blood pressure in patients with a predisposition to this disease, selected according to the diagnostic criteria for metabolic syndrome. For this, four fermented mik were designed, three of them inoculated with a commercial probiotic culture - Bifidobacterium lactis (BL420), added or not by passion fruit peel powder (prebiotic), one of them being prepared with an emulsion of vegetable oil, which has effect on prolonguing satiety; and the fourth product, fermented only with the classical culture Streptococcus thermophilus. Products´ technological properties were evaluated - physico chemical, sensory, microstructure, microbiology, and functional aspects were studied. Finally products were tested in consumers throughout a clinical trial during 12 weeks, period in which the volunteers had to consume 100 mL of the product twice a day, every day. The evaluation of the volunteers was done before the start of the test and also at the end of the 90 days.

O objetivo deste estudo foi avaliar o efeito da inclusão de leite em pó desnatado e de açúcar sobre a viabilidade de microrganismos probióticos e a qualidade do leite fermentado desnatado. Para isso, foram constituídos 8 tratamentos, a saber: 1. leite desnatado (LD) e padronizado com 0,2% de gordura (LD 0,2%G); 2. LD 0,2%G + 5% de leite em pó (Lp); 3. LD 0,2%G + 10% de Lp; 4. LD 0,2%G + 15% de Lp; 5. LD 0,2%G + 5% de Lp + 10% de açúcar (A); 6. LD 0,2%G + 10% de Lp + 10% de A; 7. LD 0,2%G + 15% de Lp + 10% de A; 8. LD 0,2%G + 10% de A. Foi preparada a cultura láctea mista DVS ABT-4 (Chr-Hansen) contendo Streptococcus thermophilus, Bifidobacterium animalis e Lactobacillus acidophilus, que foi aplicada em todos os tratamentos para a fermentação e produção do leite fermentado. O produto foi então envasado e armazenado a 5ºC para as análises subseqüentes. Os leites fermentados foram submetidos à avaliação físico-química, microbiológica e sensorial nos dias 1, 10 e 21 após a fabricação. Os resultados mostraram que todos os tratamentos permaneceram de acordo com a legislação brasileira no que diz respeito aos aspectos físico-químicos, além de os mesmos terem permanecido constantes durante os 21 dias de armazenamento, com exceção do pH, que diminuiu nos dias seguintes a fabricação em decorrência da pós-acidificaçao dos leites fermentados. Quanto às características microbiológicas, observou-se maiores contagens nos tratamentos com maior teor de leite em pó (tratamentos 3, 4, 6 e 7), principalmente para as bactérias probióticas, com diferença estatisticamente significativa entre todos os tratamentos. Entretanto, a adição de açúcar não interferiu nas contagens de probióticos dos leites fermentados. As contagens microbiológicas permaneceram constantes durante todos os 21 dias de armazenamento. O tratamento 6 (LD 0,2%G + 10% de Lp + 10% de A) foi o que obteve melhores notas na avaliação sensorial nos dias 1, 10 e 21 de armazenamento, indicando ser esta formulação a melhor dentre as estudadas para a aceitação do produto com maior viabilidade de bactérias probióticas. / The aim of this study was to evaluate the effect of skimmed milk powder and sugar inclusion on the viability of probiotic microorganisms and on the quality of skimmed fermented milk. Eight different treatments were prepared: 1. Skimmed and standardized milk (SM) at 0,2% of fat (SM 0,2%F); 2. SM 0,2%F + 5% of milk powder (MP); 3. SM 0,2%F + 10% MP; 4.SM 0,2%F + 15% MP; 5. SM 0,2%F + 5% MP + 5% of sugar (S); 6. SM 0,2%F + 10% MP + 5% S; 7. SM 0,2%F + 15%MP + 10%S; 8. SM 0,2%F + 10%S. The mixed lactic culture DVS ABT-4 (Chr-Hansen) containing Streptococcus thermophilus, Bifidobacterium animalis and Lactobacillus acidophilus was prepared and placed in all the treatments for the fermented milk fermentation and production. The product was bottled and stored at 5°C for the subsequent analyses. The fermented milks were submitted to physical-chemical, microbiological and sensory analyses on the 1st, 10th and 21st days after production. Results for the physic-chemical analyses showed that all the treatments comprised the requirements as adopted in Brazilian regulations. All the physical-chemical variables were constant during the 21 days of storage, except for the pH, which decreased during storage because of the fermented milks post-acidification. For the microbiological analyses, greater numbers, especially the probiotic bacteria, were obtained in treatments with higher milk powder content (treatments 3, 4, 6 and 7), with significant statistical differences among all the treatments. However, the sugar addition did not interfere with the recovery of probiotic bacteria in the fermented milks. The microbiological data were constant during the 21 days of storage. Results obtained in the sensory analyses showed that treatment 6 was the one with higher grades on days 1, 10 and 21 of storage, hence indicating that this composition is the best one among those studied for acceptability of the product with greater viability of probiotic bacteria.

Today approximately 10 % of fermented milk products stick to the packaging material inner surface, and therefore it is not possible to pour all of the dairy product from the package. This is both an economical and environmental issue. The product loss is expensive for consumer and makes recycling of package less effective. As they do not yet exist the development of packaging materials to which fermented milk products stick less, it would make it possible to both save money and protect our environment. The aim of this work was to provide knowledge and understanding of the important factors involved in the phenomenon when fermented milk products adhere to the inner surface of a packaging material. Studies were done on materials having different surface properties, such as polarity and relative oxidation. They were incubated in fermented milk and other dairy products varying in fat concentration and protein type up to 168 h. The systems were investigated gravimetrically, with Fourier Transform Infra Red/Attenuated Total Reflectance Spectroscopy, Scanning Electron Microscopy and Contact Angle measurements. Fermented milk contains amphiphilic components and therefore can interact both with polar and non-polar surfaces, such that the relative oxidation of the surface does not contribute to the adhesion. The adhesion of fermented milk is an equilibrium reaction, which depend on the fat concentration before equilibrium as well as the protein concentration after equilibrium. The adhesion seems to follows the Vroman effect, with smaller molecules associating faster and thereby adhering to the surface initially, but are displaced by larger molecules that associates slower as times passes.

Tyrimo metu naudotos laktobacilų išskyrimo, lactobacilų padermių rūgščių gamybos aktyvumo nustatymo, rauginto pieno klampumo nustatymo, bei riebalų rūgščių gamybos aktyvumo nustatymo metodikos. Darbo tikslas: Nustatyti skirtingų laktobacilų rūšių karvės ir ožkos pieno fermentacijos aktyvumą. Darbo uždaviniai: 1.Nustatyti Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum ir L. fermentum rūgščių gamybos aktyvumą rauginant karvės ir ožkos pieną. 2.Nustatyti ir įvertinti surauginto karvės ir ožkos pieno klampą; 3.Nustatyti skirtingų laktobacilų riebalų rūgščių gamybos aktyvumą. 4.Nustatyti Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum ir L. fermentum gyvybingumą rauginant pieną dvi paras. Išvados: Skirtingos laktobacilų rūšys karvės ir ožkos piene rūgštis gamino aktyviai. Didžiausiu rūgščių gamybos aktyvumu raugintame karvės piene pasižymėjo L. acidophilus, šios kultūros titruojamasis rūgštingumas 6 - ąją para buvo 220 oT, ožkos piene – L. planarum, 6 – ąją parą buvo 228 oT. Didžiausias rauginto karvės ir ožkos pieno klampumas nustatytas pieną rauginant 24 val. L. bulgaricus kultūra (atitinkamai 344,797 mPa.s ir 167,313 mPa.s). Didžiausias sočiųjų riebalų rūgščių (RR) kiekis, nuo bendro riebalų rūgščių kiekio, nustatytas karvės piene raugintame su L. bulgaricus (66,7 proc) ir L. acidophilus (62,6 proc). Didžiausias polinesočiųjų RR kiekis nustatytas pieną rauginant su L. plantarum (71,1 proc). Didžiausias sočiųjų RR kiekis... [toliau žr. visą tekstą] / During the research the following methods had been used: extraction of lactobacillus, identification of production activeness in lactobacillus tribe acids, tests of acidified milk tenacity and establishments in production activeness of fatty acids. Work aim: Determine fermentation activeness of different lactbacillus tribes in cow‘s and goat‘s milk. Work goals: 1.Determine activeness of production of Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum and L. fermentum in cow‘s and goat‘s milk. 2.Identyfy and evaluate cow‘s and goat‘s acidified milk of viscosity. 3.Determine production activeness of different lactobacillus fatty acids. 4.Identify Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum and L. fermentum viability fermentation milk for two days. Conclusions: Different types of lactobacillus in cow‘s and goat‘s milk produced acids actively. The biggest production of acids in acidified milk was performed by L. acidophilus, titrated acidity of this culture after 6 days was 220 oT, in goat‘s milk – L. planarum, after 6 days - 228 oT. The biggest cow‘s and goat‘s actified milk tenacity was found when milk was fermented for 24 h with the help of L. bulgaricus culture (accordingly 344,797 mPa.s and 167,313 mPa.s). The biggest ammount of fatty acids, from the overall fatty acid ammount, found in cow‘s milk which was fermented with L. bulgaricus (66,7 %) and L. acidophilus (62,6 %). The biggest ammount of polyunsaturates was found... [to full text]