Patrícia Blumer Zacarchenco

Microbiological, sensory and post-acidification evaluation during shelf-life of fermented milks containing Streptococcus thermophilus, Bifidobacterium longum and Lactobacillus acidophilus

Taste and acidity sensorial attributes, pH, titratable acidity and microbial counts of milks fermented separately by Bifidobacterium longum, Lactobacillus acidophilus and Streptococcus thermophilus and a beverage prepared by mixing them were studied during 21 days at 4oC. The mixed beverage and Str. thermophilus fermented milk did not differ significantly (p < 0.05) for the sensorial attributes among them. Milk fermented by Str. thermophilus showed the highest titratable acidity and the lowest pH while milk fermented by Bif. longum showed the lowest titratable acidity and the highest pH. Str. thermophilus and Bif. longum counts remained constant in the beverage and in the separated fermented milks, during the 21 days of storage, while Lb. acidophilus counts were reduced by 1 log cycle.

Development and shelf-life determination of pasteurized, microfiltered, lactose hydrolyzed skim milk

The segment of the world population showing permanent or temporary lactose intolerance is quite significant. Because milk is a widely consumed food with an high nutritional value, technological alternatives have been sought to overcome this dilemma. Microfiltration combined with pasteurization can not only extend the shelf life of milk but can also maintain the sensory, functional, and nutritional properties of the product. This studied developed a pasteurized, microfiltered, lactose hydrolyzed (delactosed) skim milk (PMLHSM). Hydrolysis was performed using β-galactosidase at a concentration of 0.4mL/L and incubation for approximately 21h at 10±1°C. During these procedures, the degree of hydrolysis obtained (>90%) was accompanied by evaluation of freezing point depression, and the remaining quantity of lactose was confirmed by HPLC. Milk was processed using a microfiltration pilot unit equipped with uniform transmembrane pressure (UTP) ceramic membranes with a mean pore size of 1.4 μm and UTP of 60 kPa. The product was submitted to physicochemical, microbiological, and sensory evaluations, and its shelf life was estimated. Microfiltration reduced the aerobic mesophilic count by more than 4 log cycles. We were able to produce high-quality PMLHSM with a shelf life of 21 to 27d when stored at 5±1°C in terms of sensory analysis and proteolysis index and a shelf life of 50d in regard to total aerobic mesophile count and titratable acidity.

Properties of Streptococcus thermophilus fermented milk containing variable concentrations of Bifidobacterium longum and Lactobacillus acidophilus

Sensory evaluation and analysis of pH, titratable acidity and microbial counts after 1, 7, 14 and 21 days of storage of five combinations of lyophilized Bifidobacterium longum and/or Lactobacillus acidophilus added to milk fermented with Streptococcus thermophilus were studied during storage at 4oC. The taste and acidity sensory attributes were significantly (P<0.05) perceived as the storage time increased. Favourite combinations contained, initially, Bif. longum and L. acidophilus (108 and 107 cfu/mL, respectively) and Bif. longum only (108 cfu/mL). These combinations did not differ significantly among them and neither from the standard fermented milk. The lowest sensory scores and highest titratable acidity values were obtained for fermented milk added of L. acidophilus (108 cfu/mL initial concentration). During the 21 days of storage at 4oC the viable cell counts of: Str. thermophilus did not change. Bif. longum viable cells counts kept constant or reduced 1 logarithmic cycle and L. acidophilus reduced 1 or 2 logarithmic cycle. We did not observe inhibition of over-acidification caused by the presence of bifidobacteria or L. acidophilus.

Ocorrência de Bacillus sporothermodurans em leite UAT/UHT brasileiro e a influência do tratamento térmico

Bacillus sporothermodurans (BSP) has been isolated worldwide, but mainly in European contries as an usual contaminant of milk by the UHT system. Even being non pathogenic, generally its presence results in product rejection based on international microbiological standards limiting the counts to a maximum of 100 cfu/ml. In this research work, the occurrence of BSP was evaluated in UHT milk samples produced in different regions of Brazil (Central, South and Southeast) and processed by the indirect thermal treatment system (plate or tube exchangers) or by the direct system (steam infusion or steam injection). A total of 100 commercial samples were analysed both quantitatively by spread plate technique using Brain Heart Infusion Esculin Agar (BHI-E agar) and qualitatively after thermal shock treatment (115°C/7min), followed by incubation and plating in that medium. The results showed a total of 45% of the examined samples with counts above 100 cfu/ml, varying from 2 .104 and 9,5 .105 cfu/ml. However, 71.4% of the samples processed by indirect system were above limits, while none of the samples heat treated by the direct system, that allows a more drastic temperature condition, were rejected. A similar picture was observed in the qualitative evaluation, with contamination levels of 71,7 and 22,2% for the indirect and direct system, respectively. A total of 300 cultures were isolated from contaminated samples, showing cultural, morphological and biochemical patterns similar to BSP, except a late glucose fermentation capacity showed by most of the isolated strains. When 24 representative strains were submitted to PCR-RAPD evaluation and compared to the reference BSP strain (DSMZ 10599), they were confirmed as Bacillus sporothermodurans based on their DNA pattern.O Bacillus sporothermodurans (BSP) tem sido isolado em todo o mundo, principalmente nos paises europeus, como um contaminante usual do leite processado pelo sistema UAT/UHT. Embora o BSP nao seja patogenico, o leite contaminado fica fora dos padroes da legislacao, que fixa o limite de contagem de microrganismos aerobios mesofilos em 100ufc/ml. Tal bacilo foi pesquisado em amostras de leite UAT produzido nas regioes Sul, Sudeste e Centro-Oeste do Brasil, processado pelos sistemas de aquecimento indireto (trocadores a placas ou tubulares) e direto (injecao ou infusao de vapor). Foi analisado um total de 100 amostras, avaliadas quantitativamente pela tecnica de espalhamento superficial no meio diferencial agar infusao de cerebro e coracao - esculina (agar BHI-E). Na analise qualitativa as amostras foram submetidas a choque termico (115oC/7min), incubadas e plaqueadas no referido agar. Os resultados revelaram um total de 45% de amostras com contagens acima do limite toleravel (100ufc/ml), oscilando entre 2x104 e 9,5x105ufc/ml. No entanto, em funcao do tipo de sistema de aquecimento, as variacoes foram muito acentuadas, sendo que na avaliacao quantitativa os indices de rejeicao foram de 71,4% nas amostras aquecidas indiretamente e naquelas processadas diretamente. Isto se deve, provavelmente, as condicoes mais drasticas de tratamento termico utilizada pelos laticinios com sistema direto de aquecimento. Na analise qualitativa, os indices de rejeicao foram de 71,7 e 22,2%, respectivamente. Trezentas culturas foram isoladas das amostras contaminadas, revelando caracteristicas culturais, morfologicas e bioquimicas similares as de BSP, exceto pela capacidade de fermentacao lenta da glicose evidenciada pela maioria delas. Deste total, 24 cepas tiveram seu DNA cromossomico avaliado pelo metodo PCR-RAPD, sendo que os perfis obtidos foram muito similares ao de BSP referencia (DSMZ 10599) confirmando tratar-se de Bacillus sporothermodurans.

Efeito do fator de concentração do retentado na composição e proteólise de queijo minas frescal de baixo teor de gordura fabricado por ultrafiltração

The effect of milk concentration by ultrafiltration on the chemical composition and proteolysis of low fat Minas Frescal cheese during refrigerated storage was determined. Three batches of cheese were made in one day using milk concentrated by ultrafiltration at three different concentration factors (CF): 2:1, 3:1 and 4:1. Cheese making was replicated on a different day. Protein breakdown, as well as pH and titratable acidity changes, were monitored during cheese storage for 2, 10, 20 and 30 days. It was observed that pH decreased with time, while titratable acidity and protein breakdown increased. The different concentration factors tested did not significantly change cheese composition and proteolysis, which means that the inclusion of whey proteins did not inhibit rennet proteolytic activity as expected. This leads us to believe that potential advantages associated with the use of ultrafiltration retentates in cheesemaking were compensated by negative effects related to the high humidity level of low fat cheese made from ultrafiltration retentates. Consequently, the shelf-life of this typically Brazilian cheese was lower than that of cheese made by conventional procedures.

Characterization of Fresh Cheese with Addition of Probiotics and Prebiotics

Universidade Estadual Paulista, Departamento de Quimica e Bioquimica, Instituto de Biociencias de Botucatu

Ácido linoleico conjugado (CLA) - benefícios para saúde, sua presença e estabilidade em produtos lácteos

O Programa de Puericultura acompanha o crescimento e o desenvolvimento de criancas durante os primeiros anos de vida, estabelecendo condutas preventivas adequadas a idade da crianca, sendo fundamental na prevencao de doencas e no controle da mortalidade infantil. Este trabalho teve como objetivo avaliar o estado nutricional das criancas atendidas no Programa de Puericultura em uma Unidade de Saude do Municipio de Guarapuava-PR. Foram investigados 55 prontuarios de criancas inscritas no Programa para verificacao das variaveis de peso, altura, perimetro cefalico, numero de consultas realizadas, aleitamento materno exclusivo ate os seis meses de idade, alimentacao atual e uso de suplementacao. Os resultados mostraram que a maioria das criancas avaliadas estava eutroficas para os parâmetros nutricionais avaliados, sendo Peso/Idade (85,5%), Peso/Estatura (65,5%), Estatura/Idade (76,4%) e Indice de Massa Corporal/Idade (72,7%). A maioria das criancas fazia uso de suplementacao (67,3%), 38,2% de aleitamento materno complementar e 40% nao receberam leite materno de forma exclusiva ate os seis meses de idade. Destaca-se a importância do acompanhamento do crescimento e desenvolvimento como parte integral a saude da crianca em programas e acoes de promocao a saude e qualidade de vida.O comportamento alimentar dos adolescentes geralmente e vinculado ao consumo de alimentos com alto valor energetico e pobres em nutrientes, com omissao de refeicoes e tendencia as restricoes alimentares, contribuindo, dessa forma, para alteracoes no estado nutricional, o que pode desencadear futuras patologias como a anorexia e bulimia. O objetivo do presente trabalho foi avaliar o efeito da imagem corporal sobre o estado nutricional e comportamento alimentar de adolescentes do sexo feminino, com faixa etaria entre 14 e 17 anos (media de 15,41±1,11 anos), frequentadoras de um Centro Estadual de Educacao Profissional no municipio de Guarapuava-PR. Participaram do estudo 96 adolescentes, regularmente matriculados na Instituicao. Foram analisadas questoes relativas a percepcao da imagem corporal, comportamento alimentar e dados antropometricos. Apos a avaliacao dos resultados, observou-se uma media de altura de 1,62±0,06m, peso de 56,07±5,21kg e IMC de 21,41±2,24kg/m². A maioria das meninas apresentou IMC adequado (84,4%) e nao mostraram riscos para desenvolver transtornos alimentares (72,9%), sendo que a maioria demonstrou distorcao da imagem corporal (52,1%). Torna-se necessario maior atencao em relacao a alimentacao, pois a distorcao da imagem corporal pode levar a pratica de dietas restritivas e desenvolvimento de transtornos alimentares.O aumento da procura de produtos prontos para consumo e considerado uma tendencia atual, principalmente em grandes centros urbanos, refletindo na expansao de estabelecimentos como redes de “fast-food”, padarias, confeitarias e lanchonetes, e aumentado de forma direta a preocupacao pelos orgaos de vigilância na manutencao da qualidade higienico-sanitaria dos produtos comercializados. Este trabalho teve como objetivo avaliar a qualidade microbiologica de bolos cremosos comercializados no municipio de Curitiba-PR e analisar as condicoes higienico-sanitarias as quais os produtos foram expostos durante o processamento e armazenamento. Para a presente pesquisa foram coletadas 14 amostras diferentes de bolos cremosos. Avaliou-se a qualidade microbiologica de cada amostra seguindo recomendacoes contidas na RDC no12, de 02 de janeiro de 2001, ANVISA/MS. Neste estudo constatou-se o nao isolamento de Salmonella em nenhuma das amostras analisadas. Em 14,3% (n=2) das amostras o NMP de coliformes termotolerantes apresentou-se acima do padrao microbiologico vigente. Em 28,6% (n=4) das amostras, observou-se contagens de estafilococos coagulase-positiva acima do limite estabelecido, sendo que 02 amostras eram potencialmente capazes de causar intoxicacao alimentar. Observou-se a incidencia de 14,3% (n=2) de Listeria sp nas das amostras analisadas. O numero mais provavel de coliformes totais acima de 2,17 log/g foi quantificado em 05 amostras (35,7%). Os resultados mostram que ha necessidade de maior controle de qualidade desde a aquisicao da materia-prima ate ao produto acabado, atraves da adocao de Boas Praticas de Fabricacao e o Programa de Analise de Perigos e Pontos Criticos de Controle, de forma a garantir um produto saudavel e seguro para o consumidor.

Brazilian Yogurt-like Products

Fermented milk, yogurts, and whey beverages are products that are very appreciated in Brazil, ranging from infants to older people. They are dairy products with similar technological processes, but differ in chemical composition, ingredients used, and sensory characteristics. This chapter will focus on the production of fermented milk, yogurts, and whey beverages in Brazil, discussing the regulatory aspects, consumer market, processing steps, and products available on the market, including those containing functional ingredients (probiotic and prebiotic), or for particular nutritional uses (lactose-free and light and diet formulations).

EFEITO DOS SAIS FUNDENTES NAS CARACTERÍSTICAS DO REQUEIJÃO CREMOSO SEM ADIÇÃO DE GORDURA E COM TEOR REDUZIDO DE SÓDIO

Requeijao cremoso , a type of processed cheese widely consumed by the Brazilian population, may be considered a food source of fat and sodium, two nutrients the consumption of which - when present at high concentrations - may lead to the development of cardiovascular diseases. Considering the high and frequent consumption of this product in Brazil, it is highly important to develop alternative and healthier food products, such as a requeijao made without the addition of fat and with a reduced sodium content (NFARSR). For that reason, the objective of this study was to develop an optimized NFARSR formulation, by replacing fat by whey protein concentrate (WPC 34%) and reducing the sodium level by replacing 40% sodium chloride (NaCl) by potassium chloride (KCl) and part of the traditional emulsifying salt (Joha S9) - which contains 30.5% sodium - by an emulsifying salt with a sodium level of 8.2% (Joha SK75). The formulation was optimized using a factorial experimental design of the 22 type with two factors (Joha S9 and Joha SK75) and two levels (+1, -1), resulting in a total of 11 treatments. The 11 formulations were evaluated microbiologically and also as to physical-chemical, sensory and instrumental texture parameters using the response surface method. The NFARSR formulation with the best performance was R5, made with a blend of 1.0% JohaS9 and 1.2% Joha SK75.

Occurrence of Bacillus sporothermodurans and the influence of the thermal processing procedure on its presence in brazilian UHT milk

Bacillus sporothermodurans (BSP) has been isolated worldwide, but mainly in European contries as an usual contaminant of milk by the UHT system. Even being non pathogenic, generally its presence results in product rejection based on international microbiological standards limiting the counts to a maximum of 100 cfu/ml. In this research work, the occurrence of BSP was evaluated in UHT milk samples produced in different regions of Brazil (Central, South and Southeast) and processed by the indirect thermal treatment system (plate or tube exchangers) or by the direct system (steam infusion or steam injection). A total of 100 commercial samples were analysed both quantitatively by spread plate technique using Brain Heart Infusion Esculin Agar (BHI-E agar) and qualitatively after thermal shock treatment (115°C/7min), followed by incubation and plating in that medium. The results showed a total of 45% of the examined samples with counts above 100 cfu/ml, varying from 2 .104 and 9,5 .105 cfu/ml. However, 71.4% of the samples processed by indirect system were above limits, while none of the samples heat treated by the direct system, that allows a more drastic temperature condition, were rejected. A similar picture was observed in the qualitative evaluation, with contamination levels of 71,7 and 22,2% for the indirect and direct system, respectively. A total of 300 cultures were isolated from contaminated samples, showing cultural, morphological and biochemical patterns similar to BSP, except a late glucose fermentation capacity showed by most of the isolated strains. When 24 representative strains were submitted to PCR-RAPD evaluation and compared to the reference BSP strain (DSMZ 10599), they were confirmed as Bacillus sporothermodurans based on their DNA pattern.O Bacillus sporothermodurans (BSP) tem sido isolado em todo o mundo, principalmente nos paises europeus, como um contaminante usual do leite processado pelo sistema UAT/UHT. Embora o BSP nao seja patogenico, o leite contaminado fica fora dos padroes da legislacao, que fixa o limite de contagem de microrganismos aerobios mesofilos em 100ufc/ml. Tal bacilo foi pesquisado em amostras de leite UAT produzido nas regioes Sul, Sudeste e Centro-Oeste do Brasil, processado pelos sistemas de aquecimento indireto (trocadores a placas ou tubulares) e direto (injecao ou infusao de vapor). Foi analisado um total de 100 amostras, avaliadas quantitativamente pela tecnica de espalhamento superficial no meio diferencial agar infusao de cerebro e coracao - esculina (agar BHI-E). Na analise qualitativa as amostras foram submetidas a choque termico (115oC/7min), incubadas e plaqueadas no referido agar. Os resultados revelaram um total de 45% de amostras com contagens acima do limite toleravel (100ufc/ml), oscilando entre 2x104 e 9,5x105ufc/ml. No entanto, em funcao do tipo de sistema de aquecimento, as variacoes foram muito acentuadas, sendo que na avaliacao quantitativa os indices de rejeicao foram de 71,4% nas amostras aquecidas indiretamente e naquelas processadas diretamente. Isto se deve, provavelmente, as condicoes mais drasticas de tratamento termico utilizada pelos laticinios com sistema direto de aquecimento. Na analise qualitativa, os indices de rejeicao foram de 71,7 e 22,2%, respectivamente. Trezentas culturas foram isoladas das amostras contaminadas, revelando caracteristicas culturais, morfologicas e bioquimicas similares as de BSP, exceto pela capacidade de fermentacao lenta da glicose evidenciada pela maioria delas. Deste total, 24 cepas tiveram seu DNA cromossomico avaliado pelo metodo PCR-RAPD, sendo que os perfis obtidos foram muito similares ao de BSP referencia (DSMZ 10599) confirmando tratar-se de Bacillus sporothermodurans.