Evaluation of physicochemical properties and viability of starter culture of liquid cheese whey-based frozen yogurts supplemented with inulin / Avaliação de propriedades físico-químicas e viabilidade de culturas starters de frozen yogurts à base de soro líquido de queijo suplementados com inulina

The study aimed to analyze the physicochemical properties and starter culture viability of frozen yogurts produced with liquid cheese whey (LCW) and inulin at different proportions (F0: 66% LCW and 0% inulin; F1: 65% LCW and 1% inulin; F2: 64% LCW and 2% inulin; F3: 62% LCW and 4% inulin). Results demonstrated that the frozen yogurt F3 presented higher total solids and carbohydrates levels. LCW and inulin contributed to the overrun increase (11.8-18.2%) but did not interfere significantly in the retardation of the melting rate and range in the samples’ hardness. Over the storage time, formulation F3 showed lower pH and higher titratable acidity. However, from the sixtieth day of storage, the formulations of frozen yogurts varied in the pH and titratable acidity profile associated with the decline in the viability of starter cultures. Even so, the inulin supplementation positively affected the strains’ viability during storage. Based on our data, the formulation F3 presented better nutritional value, physicochemical characteristics, and stability over the storage period.

O estudo teve como objetivo analisar as propriedades físico-químicas e a viabilidade das culturas starters de frozen yogurts produzidos com soro líquido de queijo (SLQ) e inulina em diferentes proporções (F0: 66% SLQ e 0% inulina; F1: 65% SLQ e 1 % inulina; F2: 64% SLQ e 2% inulina; F3: 62% SLQ e 4% inulina). Os resultados demonstraram que o frozen yogurt F3 apresentou maiores teores de sólidos totais e carboidratos. SLQ e inulina contribuíram para o aumento do overrun (11.8-18.2%), mas não interferiram significativamente no retardo da taxa de derretimento e na variação da dureza das amostras. Ao longo do tempo de armazenamento, a formulação F3 apresentou menor pH e maior acidez titulável. Porém, a partir do sexagésimo dia de armazenamento, as formulações de frozen yogurts variaram o perfil de pH e acidez titulável associado ao declínio da viabilidade das culturas starter. Mesmo assim, a suplementação de inulina afetou positivamente a viabilidade das cepas durante o armazenamento. Com base em nossos dados, a formulação F3 apresentou melhor valor nutricional, características físico-químicas e estabilidade ao longo do período de armazenamento.

Evaluation of physicochemical properties and viability of starter culture of liquid cheese whey-based frozen yogurts supplemented with inulin / Avaliação de propriedades físico-químicas e viabilidade de culturas starters de frozen yogurts à base de soro líquido de queijo suplementados com inulina

ABSTRACT: The study aimed to analyze the physicochemical properties and starter culture viability of frozen yogurts produced with liquid cheese whey (LCW) and inulin at different proportions (F0: 66% LCW and 0% inulin; F1: 65% LCW and 1% inulin; F2: 64% LCW and 2% inulin; F3: 62% LCW and 4% inulin). Results demonstrated that the frozen yogurt F3 presented higher total solids and carbohydrates levels. LCW and inulin contributed to the overrun increase (11.8-18.2%) but did not interfere significantly in the retardation of the melting rate and range in the samples' hardness. Over the storage time, formulation F3 showed lower pH and higher titratable acidity. However, from the sixtieth day of storage, the formulations of frozen yogurts varied in the pH and titratable acidity profile associated with the decline in the viability of starter cultures. Even so, the inulin supplementation positively affected the strains' viability during storage. Based on our data, the formulation F3 presented better nutritional value, physicochemical characteristics, and stability over the storage period.

RESUMO: O estudo teve como objetivo analisar as propriedades físico-químicas e a viabilidade das culturas starters de frozen yogurts produzidos com soro líquido de queijo (SLQ) e inulina em diferentes proporções (F0: 66% SLQ e 0% inulina; F1: 65% SLQ e 1 % inulina; F2: 64% SLQ e 2% inulina; F3: 62% SLQ e 4% inulina). Os resultados demonstraram que o frozen yogurt F3 apresentou maiores teores de sólidos totais e carboidratos. SLQ e inulina contribuíram para o aumento do overrun (11.8-18.2%), mas não interferiram significativamente no retardo da taxa de derretimento e na variação da dureza das amostras. Ao longo do tempo de armazenamento, a formulação F3 apresentou menor pH e maior acidez titulável. Porém, a partir do sexagésimo dia de armazenamento, as formulações de frozen yogurts variaram o perfil de pH e acidez titulável associado ao declínio da viabilidade das culturas starter. Mesmo assim, a suplementação de inulina afetou positivamente a viabilidade das cepas durante o armazenamento. Com base em nossos dados, a formulação F3 apresentou melhor valor nutricional, características físico-químicas e estabilidade ao longo do período de armazenamento.

Evaluation of physicochemical properties and viability of starter culture of liquid cheese whey-based frozen yogurts supplemented with inulin / Avaliação de propriedades físico-químicas e viabilidade de culturas starters de frozen yogurts à base de soro líquido de queijo suplementados com inulina

The study aimed to analyze the physicochemical properties and starter culture viability of frozen yogurts produced with liquid cheese whey (LCW) and inulin at different proportions (F0: 66% LCW and 0% inulin; F1: 65% LCW and 1% inulin; F2: 64% LCW and 2% inulin; F3: 62% LCW and 4% inulin). Results demonstrated that the frozen yogurt F3 presented higher total solids and carbohydrates levels. LCW and inulin contributed to the overrun increase (11.8-18.2%) but did not interfere significantly in the retardation of the melting rate and range in the samples hardness. Over the storage time, formulation F3 showed lower pH and higher titratable acidity. However, from the sixtieth day of storage, the formulations of frozen yogurts varied in the pH and titratable acidity profile associated with the decline in the viability of starter cultures. Even so, the inulin supplementation positively affected the strains viability during storage. Based on our data, the formulation F3 presented better nutritional value, physicochemical characteristics, and stability over the storage period.(AU)

O estudo teve como objetivo analisar as propriedades físico-químicas e a viabilidade das culturas starters de frozen yogurts produzidos com soro líquido de queijo (SLQ) e inulina em diferentes proporções (F0: 66% SLQ e 0% inulina; F1: 65% SLQ e 1 % inulina; F2: 64% SLQ e 2% inulina; F3: 62% SLQ e 4% inulina). Os resultados demonstraram que o frozen yogurt F3 apresentou maiores teores de sólidos totais e carboidratos. SLQ e inulina contribuíram para o aumento do overrun (11.8-18.2%), mas não interferiram significativamente no retardo da taxa de derretimento e na variação da dureza das amostras. Ao longo do tempo de armazenamento, a formulação F3 apresentou menor pH e maior acidez titulável. Porém, a partir do sexagésimo dia de armazenamento, as formulações de frozen yogurts variaram o perfil de pH e acidez titulável associado ao declínio da viabilidade das culturas starter. Mesmo assim, a suplementação de inulina afetou positivamente a viabilidade das cepas durante o armazenamento. Com base em nossos dados, a formulação F3 apresentou melhor valor nutricional, características físico-químicas e estabilidade ao longo do período de armazenamento.(AU)

Increase of stress resistance in Lactococcus lactis via a novel food-grade vector expressing a shsp gene from Streptococcus thermophilus

The effects of the expression of a small heat shock protein (shsp) gene from Streptococcus thermophilus on stress resistance in Lactococcus lactis under different environmental stresses were investigated in this study. pMG36e-shsp, an expression vector, was first constructed by inserting a shsp open reading frame (ORF) cloned from S. thermophilus strain St-QC into pMG36e. Then, a food-grade expression vector, pMG-shsp, was generated by deleting the erythromycin resistance gene from pMG36e-shsp. The transformation rate of pMG-shsp was comparable to that of pMG36e-shsp when each of these two vectors was introduced into L. lactis. These results demonstrated that the shsp ORF could successfully used as a food-grade selection marker in both pMG-shsp and pMG36e-shsp. Furthermore, the growth characteristics were almost the same between L. lactis ML23 transformants harboring pMG36e or pMG-shsp. The survival rate of L. lactis ML23 expressing the shsp ORF were increased to 0.032%, 0.006%, 0.0027%, 0.03%, and 0.16% under the following environmental stresses: heat, acid, ethanol, bile salt and H2O2, respectively. These results indicated that the expression of the shsp gene in the food-grade vector pMG-shsp conferred resistance to environmental stresses without affecting the growth characteristics of L. lactis ML23.

Growth and exopolysaccharide production by Streptococcus thermophilus ST1 in skim milk

To analyze the exopolysaccharide (EPS) production by Streptococcus thermophilus ST1, cultures were cultivated in 10% (w/v) reconstituted skim milk under different growth conditions including various temperatures and pHs of growth medium, supplementation of the medium with various carbon sources (glucose, lactose, sucrose, galactose and fructose) and nitrogen source (whey protein concentrate, or WPC). The results showed that most EPS production by strain ST1 was obtained at a temperature (42°C) and pH (6.5) optimal for its growth. Supplementation of the skim milk medium with either carbohydrates or WPC increased both growth and polymer formation by different extents, with sucrose being most effective among the carbon sources tested. Under the optimal cultural conditions, i.e. pH 6.5, 42°C with 2% (w/v) sucrose and 0.5% (w/v) WPC, 135.80 mg l-1 of EPS was produced by strain ST1. The monosaccharide composition of the EPS was determined to be glucose and galactose (2:1), and the molecular mass of the EPS was 3.97 × 10(6) Da. The aqueous solution of the EPS at 1% (w/v) showed relatively high viscosity, indicating the potential of this EPS-producing S. thermophilus strain for applications in the improvement of physical properties of fermented milk products.

Effect of freeze drying process on some properties of Streptococcus thermophilus isolated from dairy products

The present investigation represents the effect of freeze drying on some properties as acid and bile tolerance of Streptococcus thermophilus MTCC 1938 culture isolated from dairy products. The cell paste obtained from milk based medium was freeze dried with a pressure of 50-100 mtorr for 24h at -40ºC. Acid and bile tolerance test exhibited 3.8-4.9 and 3.2-3.8 log counts reduction after freeze drying respectively.

ELABORAÇÃO E ESTOCAGEM DE IOGURTE COM TEORES REDUZIDOS DE LACTOSE POR MEIO DE HIDRÓLISE ENZIMÁTICA

Os derivados lácteos, bastante consumidos no Brasil e no mundo, oferecem aos consumidores uma variedade de produtos com alto valor nutritivo e de grande importância para a dieta dos indivíduos. Os leites fermentados apresentam características físicas, químicas e microbiológicas que, além do valor nutricional, oferecem benefícios à saúde dos consumidores. No entanto uma parcela considerável da população mundial apresenta algum grau de intolerância à lactose, ou má absorção da lactose, principal carboidrato do leite e derivados. Objetivou-se com o presente estudo, através da hidrólise enzimática da lactose, verificar a influência da enzima -galactosidase na elaboração de iogurte com baixo teor de lactose, frente ao comportamento dos microrganismos Streptococcus thermophilus e Lactobacillus delbrueckii subespécie bulgaricus, utilizados no processamento e às condições de fermentação e armazenamento. Os resultados do primeiro experimento (Artigo 1) indicam que houve diferenças significativas nos valores de pH e acidez titulável entre o tratamento sem pré-aquecido (temperatura inicial de leite igual a C 25) e o tratamento com pré-aquecimento (temperatura do leite inicial igual a C 40). O tratamento com pré-aquecimento atingiu valor mais elevados de acidez enquanto que o pH diminiu mais rapidamente do que o tratamento sem pré-aquecimento, o que dificulta o crescimento de microrganismos patogênicos. Em ambos os tratamentos, sem diferença significativa, as porcentagens de hidrólise da lactose foram suficientes para consumo da maioria das pessoas com má absorção de lactose. Foi demonstrado que a enzima contribuiu para reduzir a lactose, sem influenciar no processo de fermentação. No segundo experimento (Artigo 2), os resultados sugeriram que, durante a pré-hidrólise da lactose não ocorreram alterações no pH. Durante a fermentação, o pH foi considerado significativamente diferente, entre os tratamentos. No dia após a fermentação foram encontrados valores de pH sem diferença significativa entre o iogurte tradicional e o hidrolisado, porem diferente em comparação com iogurte pré-hidrolisado. Além disso, a cultura de iogurte foi enumerada e observou-se uma queda durante o armazenamento, porém, todos os tratamentos permaneceram acima da contagem mínima exigida. O comportamento dos carboidratos e ácido lático foram obtidos po HPLC e demostraram principalmente uma queda de 93,66% na concentração de lactose do produto pré-hidrolisado. Iogurte tradicional e hidrolisado atingiram 59,87% e 85,42% de lactose hidrolisada, respectivamente. Assim, a redução de lactose, por alguns tratamentos, foram suficiente para favorecer o consumo do produto para seres humanos portadores da sindrome de má absorção da lactose, sem , portanto, influenciar de na tecnologia de fabricação do Iogurte.

The dairy products, widely consumed worldwide and particularly in Brazil, offer to consumers a comprehensive range of products with high nutritional value, and are of great importance to the dietary requirements of individuals. For instance, fermented milk has physical, chemical and microbiological particularities that offer health benefits to consumers in addition to its nutritional value. However, a considerable amount of the world's population has some intolerance to lactose, or lactose malabsobation, the main carbohydrate in milk and dairy products. The aim of the study, through the lactose enzymatic hydrolysis, was to verify the influence of the -galactosidase enzyme in the low-lactose yogurt process, compared to the behaviour of the microorganisms Streptococcus thermophilus and Lactobacillus delbrueckii subspecies bulgaricus used during processing stages and the conditions of fermentation and storage. The results of the first experiment (Article 1) indicates that there were significant differences on pH and titratable acidity values among the non-preheated treatment (initial milk temperature equal 25 C) and preheated treatment (initial milk temperature equal 40 C). The preheat treatment reached higher acidity values and the pH dropped faster than non-preheat treatment, which discourages the growth of pathogenic microorganisms. In both treatments, with no significant difference, the percentages of lactose hydrolysis were sufficient for consumption of most human with lactose malabsorption. It has been shown that the enzyme has contributed to reduce the lactose concentration without influencing the fermentation process. In the second work (Article 2), results suggest that, during lactose pre-hydrolyze there were not changes at pH or titratable acidity values measured. Fermentation achieved pH values considered significantly different, between treatments. One day after fermentation was found lowers pH values and there was no significant difference between traditional a hydrolyzed yogurt, but different compared with pre-hydrolyzed yogurt. In addition, the yogurt culture was enumerated and it decreased during storage, however remained above the required minimum count during storage days. Also Carbohydrates and lactic acid behavior were observed in whole process in which lactose content had 73% less lactose and one day after fermentation 93.66 % less lactose. Traditional and hydrolyzed yogurt reached one day after fermentation 59.87% and 85.42% of lactose hydrolyzed, respectively. Hence, sufficient lactose reduction without fermentation influence was achieved, which favors the consumption for the most human, who has lactose malabsorption.

Impact of engineered Streptococcus thermophilus trains overexpressing glyA gene on folic acid and acetaldehyde production in fermented milk

The typical yogurt flavor is caused by acetaldehyde produced through many different pathways by the yogurt starter bacteria L. bulgaricus and S. thermophilus. The attention was focused on one specific reaction for acetaldehyde and folic acid formation catalyzed by serine hydroxymethyltransferase (SHMT), encoded by the glyA gene. In S. thermophilus, this enzyme SHMT also plays the typical role of the enzyme threonine aldolase (TA) that is the interconvertion of threonine into glycine and acetaldehyde. The behavior of engineered S. thermophilus strains in milk fermentation is described, folic acid and acetaldehyde production were measured and pH and counts were followed. The engineered S. thermophilus strains StA2305 and StB2305, have the glyA gene (encoding the enzyme serine hydroxymethyltransferase) overexpressed. These engineered strains showed normal growth in milk when it was supplemented with Casitione. When they were used in milk fermentation it was observed an increase in folic acid and in acetaldehyde production by StA2305 and for StB2305 it was noticed a significative increase in folic acid formation.

O acetaldeído, responsável pelo sabor e aroma característicos de iogurte, é produzido por diferentes vias metabólicas pelas bactérias lácticas: Streptococcus thermophilus (S. thermophilus) e Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). Neste trabalho, a atenção foi focada especificamente na reação para a formação de acetaldeído e de ácido fólico, catalisada pela enzima serina hidroximetil transferase (SHMT), codificada pelo gene glyA. A enzima SHMT catalisa diversas reações e, no caso da bactéria S. thermophilus, ela exerce também a atividade característica da enzima treonina aldolase (TA), definida como a interconversão do aminoácido treonina em glicina e acetaldeído. Foram construídas linhagens de S. thermophilus (StA2305 e StB2305) com super expressão do gene glyA. Estas linhagens modificadas apresentaram crescimento normal quando o leite foi suplementado com hidrolisado de caseína (Casitione). Quando foram usadas para fermentação de leite, observou-se: aumento na produção de ácido fólico e acetaldeído por StA2305 e aumento significativo na formação de ácido fólico por StB2305.

Impact of engineered Streptococcus thermophilus trains overexpressing glyA gene on folic acid and acetaldehyde production in fermented milk

The typical yogurt flavor is caused by acetaldehyde produced through many different pathways by the yogurt starter bacteria L. bulgaricus and S. thermophilus. The attention was focused on one specific reaction for acetaldehyde and folic acid formation catalyzed by serine hydroxymethyltransferase (SHMT), encoded by the glyA gene. In S. thermophilus, this enzyme SHMT also plays the typical role of the enzyme threonine aldolase (TA) that is the interconvertion of threonine into glycine and acetaldehyde. The behavior of engineered S. thermophilus strains in milk fermentation is described, folic acid and acetaldehyde production were measured and pH and counts were followed. The engineered S. thermophilus strains StA2305 and StB2305, have the glyA gene (encoding the enzyme serine hydroxymethyltransferase) overexpressed. These engineered strains showed normal growth in milk when it was supplemented with Casitione. When they were used in milk fermentation it was observed an increase in folic acid and in acetaldehyde production by StA2305 and for StB2305 it was noticed a significative increase in folic acid formation.

O acetaldeído, responsável pelo sabor e aroma característicos de iogurte, é produzido por diferentes vias metabólicas pelas bactérias lácticas: Streptococcus thermophilus (S. thermophilus) e Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). Neste trabalho, a atenção foi focada especificamente na reação para a formação de acetaldeído e de ácido fólico, catalisada pela enzima serina hidroximetil transferase (SHMT), codificada pelo gene glyA. A enzima SHMT catalisa diversas reações e, no caso da bactéria S. thermophilus, ela exerce também a atividade característica da enzima treonina aldolase (TA), definida como a interconversão do aminoácido treonina em glicina e acetaldeído. Foram construídas linhagens de S. thermophilus (StA2305 e StB2305) com super expressão do gene glyA. Estas linhagens modificadas apresentaram crescimento normal quando o leite foi suplementado com hidrolisado de caseína (Casitione). Quando foram usadas para fermentação de leite, observou-se: aumento na produção de ácido fólico e acetaldeído por StA2305 e aumento significativo na formação de ácido fólico por StB2305.

Effect of the addition of Streptococcus thermophilus as adjunct culture on ripening and physicochemical and sensory characterization of Prato cheese / Efeito da adição de Streptococcus thermophilus como cultura adjunta na maturação e caracterização físico-química e sensorial de queijo Prato

Lactic acid bacteria are responsible for performing fundamental functions for cheese manufacturing, such as production of lactic acid and volatile flavoring compounds. The aim of this investigation was to evaluate the Streptococcus thermophilus activity, as an adjunct culture, on proteolysis during ripening and, on the development of physicochemical characteristics and sensory properties of Prato type cheese. For this study, cheeses were manufactured in a pilot-scale, according to two treatment processes: (1) use of mesophilic culture - Lactococcus lactis ssp lactis and Lactococcus lactis ssp cremoris (treatment 1), and (2) mesophilic culture added with Streptococcus thermophilus (treatment 2). At 30 and 48 days of ripening, the physicochemical characteristics (dry matter, titratable acidity, fat, fat in dry matter, ashes, protein contents, ripening extension and depth indexes, tyrosine and tryptophan content, and water activity) were analyzed. Sensory properties (smell, aroma, sweetness, sourness, saltiness, bitterness, astringency, pungency, elasticity, firmness, friability, adhesiveness, solubility and humidity) were evaluated at 30 days of ripening. In cheeses under treatment 1, casein was most extensively hydrolyzed during ripening, thus they exhibited higher levels of acidity, bitterness, piquant taste, elasticity, and solubility when compared to those prepared with the a

As culturas lácteas desempenham funções fundamentais na maturação de queijos, tais como produção de ácido lático e de compostos aromatizantes voláteis. Neste trabalho, o objetivo foi avaliar a ação de Streptococcus thermophilus como cultura adjunta, nos índices de proteólise e nas características físico-químicas e sensoriais do queijo Prato. As amostras de queijo foram preparadas conforme dois tratamentos: (1) utilização de cultura mesofílica - Lactococcus lactis ssp lactis e Lactococcus lactis ssp cremoris (tratamento 1) e (2) cultura mesofílica acrescida de Streptococcus thermophilus (tratamento 2). Durante a maturação dos queijos, foram realizadas análises físico-químicas (extrato seco total, gordura, gordura no extrato seco - GES, cinzas, nitrogênio, proteína total, índice de extensão da maturação - IEM, índice de profundidade da maturação - IPM, tirosina, triptofano e atividade de água) e sensoriais (odor, aroma, doce, ácido, salgado, amargo, adstringente, picante, elasticidade, firmeza, friabilidade, adesividade, solubilidade e umidade). O queijo fabricado conforme o tratamento 1 foi o mais proteolítico, resultando em características sensoriais mais acentuadas de acidez, amargor, sabor picante, elasticidade e solubilidade, comparado ao produto preparado com adição de Streptococcus thermophilus.

Impact of engineered Streptococcus thermophilus trains overexpressing glyA gene on folic acid and acetaldehyde production in fermented milk

The typical yogurt flavor is caused by acetaldehyde produced through many different pathways by the yogurt starter bacteria L. bulgaricus and S. thermophilus. The attention was focused on one specific reaction for acetaldehyde and folic acid formation catalyzed by serine hydroxymethyltransferase (SHMT), encoded by the glyA gene. In S. thermophilus, this enzyme SHMT also plays the typical role of the enzyme threonine aldolase (TA) that is the interconvertion of threonine into glycine and acetaldehyde. The behavior of engineered S. thermophilus strains in milk fermentation is described, folic acid and acetaldehyde production were measured and pH and counts were followed. The engineered S. thermophilus strains StA2305 and StB2305, have the glyA gene (encoding the enzyme serine hydroxymethyltransferase) overexpressed. These engineered strains showed normal growth in milk when it was supplemented with Casitione. When they were used in milk fermentation it was observed an increase in folic acid and in acetaldehyde production by StA2305 and for StB2305 it was noticed a significative increase in folic acid formation.

O acetaldeído, responsável pelo sabor e aroma característicos de iogurte, é produzido por diferentes vias metabólicas pelas bactérias lácticas: Streptococcus thermophilus (S. thermophilus) e Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). Neste trabalho, a atenção foi focada especificamente na reação para a formação de acetaldeído e de ácido fólico, catalisada pela enzima serina hidroximetil transferase (SHMT), codificada pelo gene glyA. A enzima SHMT catalisa diversas reações e, no caso da bactéria S. thermophilus, ela exerce também a atividade característica da enzima treonina aldolase (TA), definida como a interconversão do aminoácido treonina em glicina e acetaldeído. Foram construídas linhagens de S. thermophilus (StA2305 e StB2305) com super expressão do gene glyA. Estas linhagens modificadas apresentaram crescimento normal quando o leite foi suplementado com hidrolisado de caseína (Casitione). Quando foram usadas para fermentação de leite, observou-se: aumento na produção de ácido fólico e acetaldeído por StA2305 e aumento significativo na formação de ácido fólico por StB2305.

Elaboration of fermented dairy beverages: acceptability and viability of probiotic cultures / Elaboração de bebidas lácteas fermentadas: aceitabilidade e viabilidade de culturas probióticas

This work aims to develop formulations of fermented dairy beverages with probiotic cultures (Lactobacillus acidophilus, Streptococcus thermophilus e Bifidobacterium bifidum) yellow monbin flavored, to characterize the chemical composition and to evaluate the stability during refrigerated storage for 28 days.The dairy beverages were developed from an experimental design 3x3, with two factors and three levels each: yellow monbin pulp (15, 20 and 25%) and whey (20, 30 and 40%). Nine formulations were produced and submitted to a sensory acceptability test. Thereafter three selected formulations were evaluated based on their microbiological characteristics, proximate composition, pH and titratable acidity. As the acceptance was higher than 70% in all the formulations, were selected that had a higher proportion of whey. Thus, the formulations F3, F6 e F9 were selected. Considering the proximate composition, the selected formulations not differed regarding for carbohydrates. The dairy beverages showed stability with respect to pH and acidity during the shelf life of 28 days and satisfactory results as the investigation of pathogenic microorganisms within the standards established. Quantification of lactic acid bacteria evidenced high numbers to Lactobacillus acidophilus and Streptococcus thermophilus, values between 11.6 to 10.2 CFU log/mL and 8.9 to 11 CFU log/mL, respectively. The s

Este trabalho teve por finalidade desenvolver formulações de bebidas lácteas fermentadas com cultura probiótica (Lactobacillus acidophilus, Streptococcus thermophilus e Bifidobacterium bifidum) sabor cajá, caracterizando-as quanto à composição centesimal e estabilidade durante armazenamento refrigerado por 28 dias. As bebidas lácteas foram desenvolvidas através de um planejamento fatorial 3x3, com dois fatores e três níveis cada: Polpa de cajá (15, 20 e 25%) e Soro de leite (20, 30 e 40%), gerando nove formulações. Estas formulações foram submetidas ao teste sensorial de aceitabilidade. Posteriormente, três formulações foram selecionadas e avaliadas quanto as analises microbiológicas, composição centesimal, pH e acidez titulável. Como o Índice de Aceitabilidade foi superior a 70% em todas as formulações foram selecionadas as que apresentaram maior proporção de soro de leite, ou seja, F3, F6 e F9. Quanto à composição centesimal, as formulações não apresentaram diferença significativa (p>0,05) para carboidratos. As bebidas lácteas demonstraram estabilidade com relação ao pH e acidez durante a estocagem refrigerada por 28 dias e resultados satisfatórios quanto à investigação de microrganismos patogênicos de acordo com a legislação vigente. A quantificação de bactérias lácticas evidenciou contagens significativas para Lactobacillus acidophilus e Streptococcus thermophilus, valor

Elaboration of fermented dairy beverages: acceptability and viability of probiotic cultures / Elaboração de bebidas lácteas fermentadas: aceitabilidade e viabilidade de culturas probióticas

This work aims to develop formulations of fermented dairy beverages with probiotic cultures (Lactobacillus acidophilus, Streptococcus thermophilus e Bifidobacterium bifidum) yellow monbin flavored, to characterize the chemical composition and to evaluate the stability during refrigerated storage for 28 days.The dairy beverages were developed from an experimental design 3x3, with two factors and three levels each: yellow monbin pulp (15, 20 and 25%) and whey (20, 30 and 40%). Nine formulations were produced and submitted to a sensory acceptability test. Thereafter three selected formulations were evaluated based on their microbiological characteristics, proximate composition, pH and titratable acidity. As the acceptance was higher than 70% in all the formulations, were selected that had a higher proportion of whey. Thus, the formulations F3, F6 e F9 were selected. Considering the proximate composition, the selected formulations not differed regarding for carbohydrates. The dairy beverages showed stability with respect to pH and acidity during the shelf life of 28 days and satisfactory results as the investigation of pathogenic microorganisms within the standards established. Quantification of lactic acid bacteria evidenced high numbers to Lactobacillus acidophilus and Streptococcus thermophilus, values between 11.6 to 10.2 CFU log/mL and 8.9 to 11 CFU log/mL, respectively. The s

Este trabalho teve por finalidade desenvolver formulações de bebidas lácteas fermentadas com cultura probiótica (Lactobacillus acidophilus, Streptococcus thermophilus e Bifidobacterium bifidum) sabor cajá, caracterizando-as quanto à composição centesimal e estabilidade durante armazenamento refrigerado por 28 dias. As bebidas lácteas foram desenvolvidas através de um planejamento fatorial 3x3, com dois fatores e três níveis cada: Polpa de cajá (15, 20 e 25%) e Soro de leite (20, 30 e 40%), gerando nove formulações. Estas formulações foram submetidas ao teste sensorial de aceitabilidade. Posteriormente, três formulações foram selecionadas e avaliadas quanto as analises microbiológicas, composição centesimal, pH e acidez titulável. Como o Índice de Aceitabilidade foi superior a 70% em todas as formulações foram selecionadas as que apresentaram maior proporção de soro de leite, ou seja, F3, F6 e F9. Quanto à composição centesimal, as formulações não apresentaram diferença significativa (p>0,05) para carboidratos. As bebidas lácteas demonstraram estabilidade com relação ao pH e acidez durante a estocagem refrigerada por 28 dias e resultados satisfatórios quanto à investigação de microrganismos patogênicos de acordo com a legislação vigente. A quantificação de bactérias lácticas evidenciou contagens significativas para Lactobacillus acidophilus e Streptococcus thermophilus, valor