Os alimentos funcionais probióticos e/ou prebióticos estão em grande expansão no mercado e encontram-se disponíveis em diversas formas de apresentação, principalmente como produtos lácteos, na forma de iogurtes e leites fermentados. Porém, aproximadamente 70% da população mundial tem seu consumo ameaçado, em virtude da incapacidade de produzir a enzima &#946;-galactosidase em quantidades suficientes para a digestão de lactose, característica esta que torna esses indivíduos intolerantes a esse açúcar. O arroz (Oryza sativa) é um cereal consumido por cerca de dois terços da população mundial, que apresenta um baixo sabor residual e que faz parte da cultura alimentar de diversos países, inclusive o Brasil. Suas propriedades favorecem o seu uso em géis, pudins e sobremesas, principalmente devido à sua aparência, sabor suave, além de resultar em certos efeitos benéficos à saúde, como prevenção e controle de doenças crônicas, também consequentes da presença de proteínas hipoalergênicas. O presente trabalho teve como objetivo desenvolver um produto novo que sirva de alternativa para indivíduos intolerantes à lactose - uma sobremesa não láctea potencialmente simbiótica à base de arroz, elaborada com a adição da cultura ABT (composta dos microrganismos comprovadamente probióticos Lactobacillus acidophilus La-5, Bifidobacterium animalis subsp. lactis Bb-12 e da cultura starter Streptococcus thermophilus) e com os ingredientes prebióticos inulina e fruto-oligossacarídeo (FOS) e enriquecida com cálcio e com isolado protéico de soro de leite. Três tratamentos foram realizados (em triplicata): T1 (sobremesa não fermentada), na qual o produto final foi diretamente resfriado, sem a sua fermentação prévia, T2 (sobremesa fermentada) na qual se aguardou a fermentação por parte da cultura adicionada (a 37 &#176;C/ 2 horas) e T3 (controle), sem a adição da cultura. Os produtos foram mantidos a 4-5 &#176;C por até 21 dias. As sobremesas foram avaliadas sensorialmente por provadores não treinados, após 7, 14 e 21 dias de armazenamento, através de teste de aceitabilidade, com escala hedônica de nove pontos. Também foram monitorados o pH, a firmeza instrumental (em analisador de textura TA-XT2) e a viabilidade de Bb-12, La-5 e Streptococcus thermophilus e a população de contaminantes, no produto recém-preparado (1 dia) e após 7, 14 e 21 dias de armazenamento. Adicionalmente, a determinação de pH foi realizada durante a elaboração dos produtos e a composição centesimal foi efetuada no produto mantido congelado. A sobremesa T1 (não fermentada) apresentou redução de pH durante os 21 dias de armazenamento, enquanto que T2 (fermentada) e T3 (controle) não diferiram significativamente (p>0,01). A firmeza de T2 foi ligeiramente menor (entre 0,46 N - dia 1 e 0,23 N - dia 21) que a de T1 (entre 0,55 N - dia 1 e 0,25 N - dia 21). A avaliação sensorial revelou que as sobremesas desenvolvidas obtiveram notas entre 6,4 e 7,4, sendo que não foram detectadas diferenças significativas (p<0,05) na preferência entre os diferentes tratamentos realizados e para os diferentes dias de armazenamento, com exceção do tratamento T3 ao 14º dia, o qual obteve notas significativamente inferiores aos demais. A viabilidade de Bb-12 foi superior à de La-5 em ambos os tratamentos adicionados de cultura ABT. Entretanto, a fermentação influenciou cada microrganismo de modo distinto. A viabilidade de La-5 foi maior em T1, tendo diminuído de 8,1 log UFC/g (dia 1 - pH 5,1) para 7,3 log UFC/g (dia 21 - pH 4,9), enquanto que Bb-12 apresentou viabilidade ligeiramente superior em T2, tendo diminuído de 8,8 log UFC/g (dia 1 - pH 4,7) para 8,1 log UFC/g (dia 21 - pH 4,5). Em T2, a população de La-5 foi inferior a 5,0 log UFC/g após 21 dias de armazenamento. A população de S. thermophilus se manteve superior a 8,0 log UFC/g durante todos os períodos, em ambos os tratamentos. A sobremesa não láctea à base de arroz potencialmente simbiótica desenvolvida apresenta boas perspectivas como alimento funcional e obteve boa aceitação por parte dos provadores. A fabricação do produto não fermentado poderia ser a sobremesa de escolha, de preparo mais curto, levando-se em consideração as questões econômicas envolvidas durante a sua produção. O estudo sugere que cada cepa deve ser testada separadamente, quanto ao comportamento no produto, em diferentes condições. Sugere, ainda, que a inclusão da etapa fermentativa na preparação de uma sobremesa pode afetar diferentemente cepas probióticas distintas. / Functional foods containing probiotic strains and/or prebiotic ingredients are available in different forms, and most of them are dairy products, such as yogurts and fermented milk. Nevertheless, the milk content in these products may restrict their intake by a considerable proportion (approximately 70%) of the worldwide population that is incapable of producing &#946;-galactosidase in enough quantity for digesting lactose. Rice (Oryza sativa) is an alternative crop with low residual taste, which is extremely abundant, being the basic food for more than half of world´s population. Its properties favor its use in puddings and desserts, mainly due to its appearance, light taste, and resulting in certain beneficial effects to health, such as prevention and control of chronic diseases, also due to the hypoallergenic proteins present. This study aimed to develop a new product to serve as an alternative for individuals who are lactose intolerant - a non-dairy rice-based potentially synbiotic dessert, prepared with the addition of an ABT culture (containing Bifidobacterium animalis subsp. lactis Bb-12, Lactobacillus acidophilus La-5, and Streptococcus thermophilus), with inulin and fructo-oligosaccharide (FOS), and enriched with calcium and milk whey protein isolate. Three different trials were prepared (in triplicates): T1 - without the previous fermentation stage after the addition of the ABT culture, and directly cooled for storage; T2 - desserts were previously fermented, at 37 °C for 2h, after the addition of the culture; and T3 (control) - without the addition of culture. The products were stored at 4-5 °C for up to 21 days. The desserts were submitted to sensory evaluation by an untrained panel, employing the acceptability test, with a 9-point structured hedonic scale, after 7, 14 and 21 days of storage. Moreover, pH, and instrumental firmness (TA-XT2 texture analyzer), and viability of Bb-12, La-5, and Streptococcus thermophilus, and populations of contaminants were also monitored during the storage period (days 1, 7, 14, and 21 of storage) for each trial. In addition, pH was also determined during production, and chemical composition proceeded from frozen samples. Trial T1 (non fermented) showed a decrease in pH during the whole storage period of 21 days, whereas T2 (fermented), and T3 (control) did not change significantly (p>0,01). T2 presented a slightly lower firmness (between 0.46 N - day 1, and 0.23 N - day 21) than T1 (between 0.55 N - day 1, and 0.25 N - day 21). The sensory evaluation revealed that the desserts obtained grades between 6.4 and 7.4, and no differences (p<0,05) for sensory acceptability between the trials, and the different days of storage were observed, except for trial T3 on the 14th day, which obtained significantly lower grades, when compared to the others. Viability of Bb-12 was higher than of La-5 in both trials with ABT culture. Nevertheless, the fermentation stage had implications on growth in different ways for each microorganism. Viability of La-5 was significantly higher (p<0.05) in T1, decreasing from 8.1 log cfu/g (day 1 - pH 5.1) to 7.3 log cfu/g (day 21 - pH 4.9), whereas viability of Bb-12 was just slightly higher in T2, decreasing from 8.8 log cfu/g (day 1 - pH 4.7) to 8.1 log cfu/g (day 21 - pH 4.5). Trial T2 revealed La-5 populations below 5.0 log cfu/g, after 21 days of storage. S. thermophiles maintained population above 8.0 log cfu/g during all storage times for both trials. This study indicated that the non-dairy rice-based potentially synbiotic dessert developed has a great potential as a functional food, and was well accepted by the panelists. The production of the non-fermented dessert could be the best choice, for economical questions and because of the shorter time during the production. This study suggests each strain must be evaluated independently for a specific product and condition. Moreover, the inclusion of a fermentation stage during production may affect the viability of probiotic strains in different ways.

O presente estudo investigou a aplicação de dois tipos de AnSBBR (reatores anaeróbio com biofilme e operados em batelada e batelada alimentada sequenciais: com recirculação da fase líquida e com agitação) para produção de biohidrogênio tratando água residuária sintética (a base de soro de leite e lactose, respectivamente). O AnSBBR com recirculação da fase líquida, que foi o estudo principal do presente trabalho, apresentou problemas na produção de hidrogênio utilizando soro de leite como substrato. Algumas alternativas, como adaptação da biomassa com substratos puros de degradação mais fácil, controle do pH em valores muito baixos e diferentes formas de inoculação foram testadas, entretanto, sem obtenção de sucesso. A solução do problema foi obtida ao refrigerar o meio de alimentação a 4ºC para evitar a fermentação no frasco de armazenamento, retirar a ureia e a suplementação de nutrientes, e realizar lavagens periódicas do material suporte para retirada de parte da biomassa. Dessa forma eliminaram-se indícios de produção de H2S por possível ação de bactérias redutoras de sulfato (BRS) e atingiu-se uma produção estável de hidrogênio sem, entretanto, eliminar completamento o metano, que foi produzido em baixas concentrações. Depois de atingida a estabilidade, investigou-se a influência da concentração afluente de substrato, do tempo de enchimento e da temperatura na produção de biohidrogênio no AnSBBR com recirculação da fase líquida tratando soro de leite. O estudo da concentração afluente apresentou um ponto ótimo para a concentração de 5400 mgDQO.L-1, atingindo valores de 0,80 mol H2.mol-1 lactose e de 660 mL H2.L-1.d-1. O estudo do tempo de enchimento apresentou resultados similares para as condições analisadas. Com relação à temperatura, os melhores resultados foram obtidos com a temperatura mais baixa testada de 15ºC (1,12 mol H2.mol lactose-1 e 1080 mL H2.L-1.d-1), sendo que na temperatura mais alta testada (45&#176;C) não ocorreu produção de hidrogênio. Para o AnSBBR com agitação mecânica, que foi um estudado complementar realizado pelo fato da lactose ser o principal complemento do soro de leite, o desempenho do biorreator foi avaliado de acordo com influência conjunta do tempo de ciclo (tC &#8211; 2, 3 e 4 h), da concentração afluente (CSTA &#8211; 3600-5400 mgDQO.L-1) e da carga orgânica volumétrica aplicada (COAV &#8211; 9,3, 12,3, 13,9, 18,5 e 27,8 mgDQO.L-1.d-1). Foram obtidos excelentes resultados: consumos de carboidratos (lactose), com valores médios sempre acima de 90&#37; e uma produção estável de biohidrogênio em todas as condições estudadas, com metano em baixas concentrações apenas na condição de maior COAV. A diminuição do tC apresentou tendência clara de melhora sobre o RMCRC,n (rendimento molar entre hidrogênio produzido e carboidrato removido) apenas para as condições com menor concentração CSTA, havendo uma relação direta entre CSTA, e RMCRC,n em todos os valores de tC, exceto para o tempo de ciclo de 3 h, exatamente onde ocorreu produção de metano. O melhor valor de RMCRC,n obtido na operação com lactose (1,65 mol H2.mol Carboidrato-1) foi superior aos obtidos em outros trabalhos utilizando a mesma configuração de reator e sacarose como substrato. As análises filogenéticas mostraram que a maioria dos clones analisados foi semelhante à Clostridium. Além destes, clones filogeneticamente semelhantes com a Família Lactobacilaceae, especificamente Lactobacillus rhamnosus foram observados em menor porcentagem no reator, assim como clones com sequências semelhantes a Acetobacter indonesiensis. / The present study investigated the application of two types of AnSBBR (anaerobic reactors with biofilm and operated in batch and fed-batch sequences: with recirculation of the liquid phase and with agitation) for biohydrogen production treating synthetic wastewater (cheese whey and lactose-based, respectively). The AnSBBR with recirculation of the liquid phase, which was the main study of this work, presented problems in the hydrogen production using cheese whey as substrate. Some alternatives, such as adaptation of the biomass with pure substrates of easier degradation, pH control at very low values and different forms of inoculation were tested but without achieving success. The solution of the problem was obtained by cooling the feed medium at 4ºC to prevent fermentation in the storage flasks, removing the urea and the nutrient supplementation, and performing periodic washing of the support material for the removal of part of the biomass. Thus, H2S production evidences by possible action of sulphate-reducing bacteria (SRB) were eliminated, reaching a stable production of hydrogen without eliminate the presence of methane completely, which was produced in low concentrations. After reaching the stability, it was investigated the influence of the influent concentration of the substrate, the influence of the filling time and the influence of the temperature on the production of biohydrogen in an AnSBBR with recirculation of the liquid phase treating cheese whey. The study of the influent concentration showed an optimum point for the concentration of 5400 mgDQO.L-1, reaching values of 0.80 mol H2.mol-1lactose and 660 mL H2.L-1.d-1. The study of the filling time showed similar results for the analyzed conditions. With respect to the temperature, the best results were obtained with the lowest temperature tested of 15ºC (1.12 mol H2.mol-1lactose and 1080 mL H2.L-1.d-1), while the highest temperature tested (45ºC) didn\'t produce hydrogen. For the AnSBBR with mechanical stirring (which was an additional study that was performed by the fact that the lactose is the main component of the cheese whey) the performance of the bioreactor was evaluated in accordance with the joint influence og the cycle time (tC - 2, 3 and 4 h ), the influent concentration (CSTA - 3600-5400 mgDQO.L-1) and the applied volumetric organic load (COAV - 9.3, 12.3, 13.9, 18.5 and 27.8 mgDQO.L-1.d-1). Excellent results were obtained: consumption of carbohydrates (lactose) always above 90% and a stable production of biohydrogen in all conditions studied, with low methane concentrations just in the condition with the biggest COAV. The decrease in the tC showed a clear trend of improvement of the RMCRC,n (molar yield between the hydrogen produced and removed carbohydrate) only for the conditions with the low influent concentration (CSTA). There was a direct relationship between CSTA and RMCRC,n in all values of tC, except for the cycle time of 3 hours, exactly in which there was methane production. The best value of RMCRC,n obtained in the operation with lactose (1.65 mol H2.mol-1Lactose) was superior to those obtained in other studies using the same reactor configuration and sucrose as substrate. Phylogenetic analysis showed that the majority of the analyzed clones was similar to Clostridium. In addition, clones phylogenetically similar to Lactobacilaceae family, specifically Lactobacillus rhamnosus, were observed in a small proportion in the reactor, as well as clones with similar sequences of Acetobacter indonesiensis.

Le lactosérum est un résidu liquide laitier qui a lieu pendant la fermentation du fromage. Il est composé par lactose (le solide principal de substance sèche), protéines, vitamines et minéraux. À cause de ces éléments, sa demande biologique et chimique d’oxygène (DBO) et (DCO) est grande (30 < DBO < 50 g/L; and 60 < DCO < 80 g/L). Il est nécessaire donc de traiter le lactosérum avant d’en jeter dans les lacs, les rivières, etc. La valorisation du lactosérum par des bactéries est d’un grand potentiel technique non seulement pour la réduction de DBO et DCO mais aussi pour obtenir des produits comme le 2,3-butanediol (2,3-BD). Des bactéries comme Enterobacter cloacae, Klebsiella pneumoniae et Paenibacillus polymyxa consomment et transforment des saccharides comme lactose en 2,3-BD. Il en est d’autres, comme Escherichia coli, qui doivent être génétiquement modifiées car elles n’ont pas le chemin enzymatique pour produire 2,3-BD. De cette manière l’objectif principal de cette recherche est celui de tester l’habilité d’une souche génétiquement modifié d’E. coli pour transformer le lactose (un disaccharide) en 2,3-BD afin de savoir le potentiel du lactosérum comme une source de lactose. La souche d’E. coli JFR12 (ECGM12) a été utilisée pour fermenter trois concentrations de glucose, galactose et lactose (12.5, 25 and 50 g/L) enrichirent M9. Le rendement de 2,3-BD le plus grand (36% environ, g 2,3-BD/g saccharide) fut obtenu en présence de 25 g/L de glucose et lactose; quoique l’usage de n’importe quelle concentration de galactose produisît des rendements plus pauvres de 2,3-BD. En plus, 2 mélanges de glucose-galactose ont été testés (1:1, w/w) à une concentration finale du 25 et 50 g/L de mélange. Les rendements de 2,3-BD obtenus ont été très similaires à les obtenus avec du galactose comme l’unique source de carbone. Par conséquent, une hypothèse a été formulée: l’usage de galactose entrave la formation de 2,3-BD, alors que les enzymes impliquent dans l’hydrolyse du lactose pourraient neutraliser l’effet du galactose et de cette manière, les rendements de 2,3-BD ont pu être hauts / Whey is a dairy effluent generated during the cheese manufacturing. Its composition presents lactose (the main solid of dry matter), proteins, vitamins and minerals. Due to these compounds, its biological (BOD) and chemical oxygen demand (COD) are high (30 < BOD < 50 g/L; and 60 < COD < 80 g/L). Therefore, it is necessary to treat the whey before releasing it into lakes, rivers, etc. The valorization of whey by bacteria is a potential technique not only for reducing the BOD and COD, but also to obtain products like 2,3-butanediol (2,3-BD). Bacteria like Enterobacter cloacae, Klebsiella pneumoniae and Paenibacillus polymyxa consume and transform saccharides like lactose into 2,3-BD. Other bacteria such as Escherichia coli have to be genetically modified since they do not possess the enzymatic pathway to produce 2,3-BD. In this way, the main objective of this research is to test the ability of a genetically modified strain of E. coli to transform lactose (a disaccharide) into 2,3-BD in order to know the potential of whey as a lactose source. In this way, the E. coli JFR12 (ECGM12) was used to ferment three concentrations of glucose, galactose and lactose (12.5, 25 and 50 g/L) supplemented M9. The highest 2,3-BD yield (around 0.36 g 2,3-BD/g saccharide) was obtained in the presence of 25 g/L of glucose and lactose; whereas the use of whatever galactose concentration provided poorer yields of 2,3-BD compared to those obtained using glucose and lactose. Moreover, 2 mixture of glucose-galactose was tested (1:1, w/w) at a final concentration of 25 and 50 g/L of mixture. The 2,3-BD yields obtained were very similar to those using galactose as a sole carbon source. Therefore, it was hypothesized that galactose impedes the formation of 2,3-BD, whereas enzyme involved in the lactose hydrolysis might counteract the effect of galactose, leading to high 2,3-BD yields

Resumo: Vacas com alto potencial para produção de leite requerem suplementação com alimentos concentrados para suprir suas exigências nutricionais. A utilização do milho como parte desses alimentos torna-se freqüente, já que é a fonte de amido mais utilizada. Com o objetivo de avaliar os efeitos da substituição dos grãos secos de milho (GSM) pela silagem de grãos úmidos de milho (SGUM) sobre a produção e composição do leite, foram utilizadas cinco vacas da raça Holandesas (HPB), primíparas com média de 112 dias pós-parto, confinadas em Tie Stall, no setor de Bovinocultura Leiteira da Universidade de Marília - UNIMAR. Foram avaliadas cinco rações balanceadas de acordo com o NRC (2001) para 17,5% PB (MS) e 2,4 Mcal EM/kg MS, contendo farelo de soja, GSM e/ou SGUM, silagem de cana de açúcar e feno. Níveis de substituição dos GSM pela SGUM estão descritos nos tratamentos: 1) 0%; 2) 25%; 3) 50%; 4) 75% e 5) 100%. O período experimental teve duração de 70 dias, divididos em cinco fases de 14 dias cada. A produção de leite e o consumo de matéria seca foram registrados diariamente. Os animais foram submetidos a duas ordenhas diárias (6:00 e 18:00 h), sendo as amostras de leite coletadas nas ordenhas consecutivas de cada fase experimental (quatro dias de coleta). O delineamento experimental utilizado foi o Quadrado Latino 5x5 e os dados analisados pelo programa estatístico SAS. O peso corporal (508 kg), produção de leite (23,6 kg), produção de leite corrigida (22,7 kg), consumos de matéria seca (17,13 kg), não apresentaram diferença com a inclusão da SGUM na dieta, porém os consumos de FDN (6,67 kg), FDA (3,39 kg) e eficiência alimentar para produção de leite (1,41 kg leite/dia), apresentaram diferença. Para a composição do leite, apenas o nitrogênio uréico (17,67 mg/dL) apresentou diferença com a inclusão de SGUM na dieta, indicando desta forma... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cows with high potential for milk production require extra concentrated food in order to supply their nutritional demands. The use of corn as part of their feeding has been frequent, since it is the most used source of starch. Intended for evaluating the effects of the substitution of the dry shelled corn (DSC) for the high moisture corn silage (HMCS) on the production and composition of the milk, five Holstein cows (BWH) were used. They were primiparous, with a postpartum time of around 112 days, confined in Tie Stall, in the dairy cattle sector of the University of Marília - UNIMAR. It was evaluated five rations balanced in agreement with NRC (2001) to 17.5% CP (DM) and 2.4 Mcal ME/kg DM, containing soybean meal, DSC and/or HMCS, sugar silage and hay. Levels of substitution of DSC for the HMCS are described in the treatments: 1) 0%; 2) 25%; 3) 50%; 4) 75% and 5) 100%. The experimental period was 70 days, divided into five phases of 14 days each. The production of milk and consumption of dry matter were registered daily. The animals were submitted to two milk daily rates (6h00 and 18h00), and the milk samples were collected in the following milking of each experimental phase (four days of collection). It was used the method of Latin Square 5x5 and the data analyzed by the SAS statistical program. Body weight (508 kg), production of milk (23.6 kg), production of milk corrected for 4% of fat (22.7 kg), and dry matter consumptions (17.13 kg) did not present any difference with the inclusion of HMCS in the diet, unlike the FDN (6.67 kg), FDA (3.39 kg) intake and feed efficiency production of milk (1.41 kg milk/day) presented difference. As for the composition of the milk, only the urea nitrogen (17.67 mg/dL) presented difference with the inclusion of HMCS in the diet, thus indicating that HMCS... (Complete abstract click electronic access below) / Orientador: Ciniro Costa / Coorientador: Gercílio Alves de Almeida Júnior / Banca: Paulo Roberto de Lima Meireles / Banca: Mauro Dal Secco de Oliveira / Mestre

Objetivo: Determinar a prevalência de má absorção de lactose e sua associação com a cor da pele e a idade em crianças e adolescentes de escolas públicas do município de Porto Alegre. Material e Métodos: Foi realizado um estudo transversal que incluiu 225 indivíduos de 8 a 18 anos, freqüentadores de escolas públicas do município de Porto Alegre. Os participantes foram classificados segundo a cor e a faixa etária. A má absorção de lactose foi diagnosticada através do teste do hidrogênio expirado após ingestão de 250 ml de leite. O teste teve duração de 3 horas e foi considerado como critério de positividade o aumento ≥ 20 partes por milhão na concentração de hidrogênio em relação ao nível basal. Resultados: Foram estudados 225 alunos, com uma média e desvio padrão de idade de 12,2 ± 2,0 anos. Cento e cinqüenta e quatro alunos eram de cor branca (68,4%) e os restantes, de cor não-branca (preta ou parda). A má absorção de lactose foi evidenciada em 19/225 casos (8,4%). Foram diagnosticados 8/154 casos (5,2%) nos alunos de cor branca e 11/71 casos (15,5%) nos alunos de cor não-branca (p = 0,02). Em relação à faixa etária, ocorreram 15/143 casos (10,5%) nos alunos entre 8 e 12 anos e 4/82 casos (4,9%) entre 13 e 18 anos (p = 0,227). Conclusões: A prevalência de má absorção de lactose encontrada em alunos de escolas pú-blicas de Porto Alegre é alta, especialmente se considerarmos que foram utilizadas doses fi-siológicas (250 ml de leite) para o diagnóstico. As taxas de má absorção foram maiores entre as crianças de cor não-branca em relação às crianças de cor branca, confirmando a influência racial na hipolactasia primária do tipo adulto. / Objective: To determine the prevalence of lactose malabsorption and its association with skin color and age in children and teenagers attending public schools in Porto Alegre, Brazil. Materials and Methods: A cross-sectional study was performed with 225 subjects between 8 and 18 years of age attending public schools in the municipality of Porto Alegre, Brazil. Subjects were classified according to skin color and age group. Lactose malabsorption was diagnosed using the breath hydrogen test after ingestion of 250 ml of milk. The test lasted 3 hours; malabsorption was determined in the presence of an increase of ≥ 20 ppm in hydrogen concentration in relation to the basal levels. Results: A total of 225 students were studied, with a mean age ± standard deviation of 12.2 ± 2.0 years. Of these, 154 students were white (68.4%); the remaining were black or brown. Lactose malabsorption was observed in 19/225 cases (8.4%): 8/154 cases (5.2%) in white students, and 11/71 cases (15.5%) among dark-skinned students (p = 0.02). In relation to age group, 15/143 cases (10.5%) occurred in students between 8 and 12 years of age, and 4/82 cases (4.9%) occurred in students between 13 and 18 years of age (p = 0.227). Conclusions: The prevalence of lactose malabsorption observed in students attending public schools in Porto Alegre was high, especially since physiological doses (250 ml of milk) were used for the diagnosis. Malabsorption rates were higher among black or brown-skinned children when compared to white children, which confirms the influence of race on primary adult type hypolactasia.

Actuellement, 70 % de la population mondiale est concernée par la baisse génétiquement programmée de l’activité de la lactase. Pour ces sujets, la consommation de lactose peut entrainer de sévères troubles digestifs. Les produits diététiques étudiés, réhydratés à l’aide de lait par le consommateur, sont donc potentiellement source d’inconforts. La première partie de ce projet s’est par conséquent attachée à développer des moyens permettant l’obtention de produits convenant à la majorité de la population intolérante au lactose. Dans le même temps, de plus en plus conscient du lien étroit liant alimentation, santé et bien être, le consommateur tend depuis quelques années à modifier ses habitudes alimentaires. Cela se traduit par un intérêt grandissant pour les aliments « santé ». La formulation de tels produits se heurte toutefois encore au manque de connaissances quant à la biodisponibilité de certains macro et micronutriments. Ce projet à visée industrielle propose par conséquent d’optimiser la digestibilité de l’amidon et des protéines contenus dans différents produits diététiques destinés à remplacer l’intégralité de la ration journalière. Pour ce faire, la digestibilité de différentes sources d’amidon (blé, maïs, maïs cireux, manioc, pomme de terre, riz et riz cireux) et de différentes protéines (caséines, concentrat de protéines de lait, isolat de protéines de pois, poudre de blanc d’œuf, concentrat de protéines sériques et isolat de protéines de soja) a été étudiée in vitro et comparée / Currently, 70% of the world population is affected by the genetically programmed decline in lactase activity. For these subjects, lactose consumption can cause severe digestive disorders. The studied dietetic products, usually rehydrated with milk by the consumer before use, are hence a potential source of digestive discomfort. The first part of this project deals therefore with development ways in order to obtain suitable products for the majority of lactose intolerant population. Laterraly, increasingly aware of the close link between food and health, consumers tend to change their eating habits. This is reflected by a growing interest in "healthy" foods. The formulation of these products is however still hampered by a lack of knowledge about some macro and micronutrients bioavailability. This industrial project aims to maximize the digestibility of starch and protein contained in dietary products replacing the entire daily ration. The digestibility of different starch sources (wheat, corn, waxy maize, cassava, potato, waxy rice and rice) and different food proteins (caseins, milk protein concentrate, pea protein isolate, egg white powder, whey protein concentrate and soya protein isolate) has thus been studied and compared in vitro

This study aimed to obtain 15% total solids and reduced mineral content in milk UF permeate by nanofiltration, hydrolysing the lactose content of nano-concentrate enzymically, partially substituting sucrose in ice cream formulations with hydrolysed lactose nano-concentrate (HLNC), and investigating the effects of HLNC on the physio-chemical and sensory characteristics of ice cream. The desired 15% total solids in the nano-concentrate was achieved after three fold concentration of milk UF permeate. The colour of milk permeate changed, pH and mineral content decreased, and crude protein content, lactose content and titratable acidity increased. The lactose content was hydrolysed by enzyme lactase. HLNC was used to replace 25% and 50% of sucrose in ice cream formulations. Springiness, cohesiveness, chewiness, adhesiveness, hardness, iciness, Ph and colour were not significantly affected. Viscosity, freezing point, glass transition temperature, melting temperature, gumminess and sweetness were significantly decreased, whereas freezing time, saltiness and cooked flavour were significantly increased. The overall acceptability of ice cream significantly decreased at 50% but was insignificantly affected at the 25% level. These results indicate that about one quarter of sucrose could be replaced by HLNC. / Master of Science (Hons) (Food Technology)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Much of the world population has problems in consuming milk and dairy products because some people are lactose intolerant. To be absorbed in the intestine lactose needs to be hydrolyzed by lactase enzyme. People with lactose intolerance do not produce lactase and therefore can not enjoy milk and dairy products benefits. This work aim to prepare requeijões cremosos by two different processes (direct acidification and enzymatic coagulation) by adding lactase enzyme at different concentrations (0.2; 0.5 and 0.8 g of lactase enzyme per liter of milk, respectively) and evaluating their physico-chemical, microbiological and sensory properties compared with requeijões control sample. In relation to physical and chemical characteristics the requeijões prepared are in accordance with current law. The lactose was hydrolyzed in more than 70 % for the treatments with adding of the lactase enzyme, enough to alleviate symptoms of intolerance in people who not well absorb lactose. Lactose found in "requeijões" with added lactase are considered low, within the standards regulated by the laws of foods for special purposes. The requeijões were sensoring accepted, no difference was detected statistic by Tukey test (p<0.05) in testing by a hedonic scale among treatments. The lipid profile of requeijões , the total saturated fatty acids ranged from 62.76% to 64.70%, while total unsaturated ranged from 34.36% to 38.36%. In the texture profile analysis only the firmness and elasticity parameters differed significantly (p< 0,05) during the storage period (60 days). Considering the results it is possible conclude that the enzyme lactase used in the experiment efficiently hydrolyzed the lactose of the requeijões , and, did not affect the physico-chemical and sensory characteristics of the product, then this is a viable option for the lactose intolerant people. / Grande parte da população mundial tem problemas em consumir leite e seus derivados por serem intolerantes à lactose. Para ser absorvida, a lactose necessita ser hidrolisada no intestino pela enzima lactase. As pessoas intolerantes à lactose não produzem a lactase e, portanto, não podem desfrutar dos benefícios do leite e de seus derivados. O presente estudo teve como objetivo elaborar requeijões cremosos com baixo teor de lactose obtidos por dois diferentes processos (acidificação direta e coagulação enzimática) a partir de leites adicionados de enzima lactase em diferentes concentrações (0,2; 0,5 e 0,8g de enzima por litro de leite) e avaliar as suas características físico-químicas, microbiológicas e sensoriais em comparação com requeijões cremosos controle. Quanto às características físicoquímicas os requeijões elaborados estão de acordo com a legislação vigente. A lactose foi hidrolisada em mais de 70% para os tratamentos com adição de enzima lactase, suficiente para amenizar os sintomas de intolerância em pessoas que possuem má absorção da lactose. Os teores de lactose encontrados nos requeijões com adição de lactase foram considerados baixos, dentro dos padrões regulamentados pela legislação de alimentos para fins especiais. As contagens de micro-organismos se mantiveram dentro do exigido pela legislação brasileira. Os requeijões foram aceitos sensorialmente, não sendo detectada diferença estatística entre os tratamentos pelo teste de Tukey (p< 0,05) no teste por escala hedônica. No perfil lipídico dos requeijões, o total de ácidos graxos saturados variou 62,76% a 64,70%, enquanto o total de insaturados variou de 34,36% a 38,36%. Na análise do perfil de textura apenas os parâmetros firmeza e elasticidade diferiram significativamente (p<0,05) durante o período de armazenamento (60 dias). Considerando os resultados obtidos pode-se concluir que a enzima lactase utilizada hidrolisou eficientemente a lactose dos requeijões e não comprometeu as características físico-químicas e sensoriais do produto, sendo este então uma opção viável para indivíduos intolerantes a lactose.

Le procédé d’agglomération permet d’améliorer les propriétés de réhydratation des poudres de lait par formation de structures poreuses favorisant la pénétration de l’eau par capillarité. Une meilleure compréhension de la contribution des caractéristiques des matières premières et des paramètres du procédé aux mécanismes d'agglomération est nécessaire pour maîtriser les propriétés de réhydratation résultantes. Cette thèse CIFRE a été conduite afin de combler ce manque. Une étude statistique des données de production industrielle de l’entreprise partenaire du projet a d’abord permis de contextualiser la problématique et de proposer des hypothèses sur des mécanismes potentiels. Une étude paramétrique du procédé a été conduite sur un équipement pilote original d’agglomération par injection de vapeur.Les matières premières et poudres agglomérées ont été caractérisées au plan de leur composition, de l'état physico-chimique des constituants, des caractéristiques physiques des particules et des propriétés de réhydratation des agglomérats. Les résultats montrent une influence déterminante des phénomènes de transition vitreuse et de cristallisation du lactose sur le processus d’agglomération et les propriétés de réhydratation des agglomérats. L'optimum des propriétés de réhydratation est fonction de la réactivité de la matière (teneur en eau, température de transition vitreuse, quantité de lactose amorphe), du taux de mouillage lors de l'agglomération et des conditions de séchage. Les constituants amorphes et la transition vitreuse semblent contribuer plus au déterminisme des p / The agglomeration process makes it possible to improve the rehydration properties of milk powders by forming porous structures that favour the water penetration by capillarity. A better understanding of the contribution of raw materials characteristics and process parameters to the agglomeration mechanisms is needed to control the rehydration properties of the agglomerates. This PhD project has been led to fill this gap. A statistical analysis of the data of industrial production obtained from the partner company of the project allowed first to contextualize the issue and formulate hypothesis on the potential underlying mechanisms of agglomeration. Experimental studies of the process were then performed on an original steam-jet agglomeration equipment at a pilot scaleThe raw materials and agglomerated powders were characterized regarding their composition, the physicochemical state of their components, the physical characteristics of the particles and the agglomerates rehydration properties. The results showed a crucial influence of the glass transition and the lactose crystallization phenomena on both the agglomeration process efficiency and the resulting agglomerates rehydration properties. The optimum of rehydration properties depends on the reactivity of the materials (water content, glass transition temperature, quantity of amorphous lactose), the particles wetting during agglomeration and the drying conditions. The amorphous contents and the glass transition seem to contribute more significantly to the determinism of the rehydration properties than the physical

L’augmentation de la demande en lait infantile génère une forte croissance de la production mondiale de lactose. En raison d’exigences accrues sur la qualité du produit, le mottage, ou prise en masse spontanée de la poudre, est une non-conformité pouvant s’avérer très coûteuse. En utilisant une approche procédé – produit, ce projet vise à identifier les paramètres critiques et comprendre les mécanismes de mottage du lactose, pour donner les moyens aux industriels de prévenir le mottage. Les résultats obtenus sur des poudres produites à l’échelle pilote montrent le rôle déterminant des impuretés (i.e. composés autres que le lactose) et de la granulométrie. En effet, les impuretés renforcent l’hygroscopicité et le mottage. De plus, en augmentant la teneur en impuretés, la surface spécifique et le nombre de points de contact, une diminution de la taille des particules et une hétérogénéité de tailles accrue intensifient le mottage. L’analyse des poudres commerciales a confirmé ces résultatUn autre résultat marquant de ce travail est le développement d’un test de mottage accéléré, qui permet de classer des poudres de lactose en fonction de leur tendance au mottage en moins d’une journée, après un stockage à 50°C et 60% d’HR. Un test similaire implémenté sur chaque site de production permettrait l’identification rapide des lots à risque avant expédition. Grâce à la meilleure compréhension des mécanismes de mottage fourni par ce travail, les industriels peuvent cibler les étapes critiques du procédé à optimiser pour prévenir le mottage du lactose. / Driven by the growth in the infant formula market, lactose production is increasing worldwide, and the requirements for the product quality are becoming stricter. Caking, or the unwanted agglomeration of lactose powder particles, is synonym of poor quality for the customers and should therefore be prevented to avoid large economic loss. Focusing on the process–product relationship, this PhD project aimed at finding the critical parameters and understanding the caking mechanisms in lactose powder in order to establish means to limit caking. In samples from pilot production, impurities (i.e. non-lactose components) were shown to increase moisture sorption and caking. The particle size distribution of the powder also exhibited a large effect on caking. Indeed, smaller particles and a broader distribution were characterized by enhanced moisture sorption and stronger caking, which were explained by a larger impurity content and surface area and more contact points.Analyses on the commercial powder confirmed these results and revealed the instability of the water activity during storage of the powder after drying, which was linked to caking in the bags. This PhD project also addressed an essential need in the dairy industry, i.e. the development of an accelerated caking test. Samples from different production sites were discriminated in terms of caking in less than a day, using appropriate test conditions (50°C and 60% RH). A similar test implemented at all sites would highlight batches with a high caking tendency before shipment to the customers. The better understanding of th