Cross-linking of gluten proteins applying transglutaminase from Streptomyces sp. CBMAI 1617 in wheat dough and other materials

Orientador: Hélia Harumi SatoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: As proteínas do glúten variam em tamanho de 30.000 a vários milhões de Daltons e formam um dos maiores e mais complexos polímeros presentes na natureza. A determinação das propriedades tecnológicas destas proteínas frente a diversos processos é um desafio que é intensificado quando novas ligações isopeptídicas são formadas com o auxílio de enzimas como a transglutaminase (TG). Esta é uma enzima que catalisa a formação de ligações cruzadas 'épsilon'-('gama'-glutamil)lisina intra e intermoleculares entre proteínas. A TG de Streptomyces sp. CBMAI 1617 (SB6) foi produzida em frascos de Erlenmeyer contendo meio de cultura composto de 2,5% de amido de batata; 0,5% de glicose; 2,45% de peptona de caseína e 0,8% de KH2PO4.7H2O; pH 7,0. O meio de cultivo foi fermentado a 30 ºC, sob agitação constante de 150 rpm durante 96 h, resultando em atividade enzimática de 3,5 U mL-1. A preparação enzimática de SB6 obtida por fracionamento com sulfato de amônio, diálise e liofilização apresentou 516,2 U g-1 de atividade. A TG comercial (BiobondTM TG-M) e a SB6 foram caracterizadas bioquimicamente e apresentaram temperatura ótima de atividade a 40 °C e entre 35-40°C, e pH ótimo de atividade entre 5,5-6,0 e 6,5, respectivamente. As massas de farinha de trigo às quais se adicionou 1,10 Ug-1 de TG comercial apresentou maior tempo e altura de desenvolvimento quando misturadas em mixógrafo, indicando a formação de uma massa mais forte quando comparada com uma massa controle. De forma similar a adição de TG comercial em massas de glúten resultou em massas mais fortes em todas as concentrações utilizadas (0,87 e 1,73 U g-1). Entretanto, a SB6 foi a preparação enzimática que teve maior impacto na polimerização das proteínas, promovendo a inclusão de gliadinas na rede proteica. O processo de extração severa ou branda do glúten também impactou significativamente a qualidade das massas. O tratamento das massas de glúten obtido pelo processo severo com SB6 favoreceu a formação de folhas-ß na estrutura secundária das proteínas. A gliadina apresentou excelente capacidade de formação de espuma que foi favorecida pela adição de SB6. A polimerização das gliadinas foi promovida, resultando na expansão do volume dos poros das espumas liofilizadas. Assim, os resultados evidenciam o potencial da SB6 em modificar as propriedades das proteínas do trigo com aplicabilidade em vários processos tecnológicos da indústria de alimentosAbstract: Gluten proteins range in size from 30,000 to several million Daltons and form one of the largest and most complex polymers available in nature. The determination of the technological properties of these proteins in different processes is a challenge that is intensified when new isopeptidic bonds are formed with the aid of enzymes such as transglutaminase (TG). This is an enzyme that catalyzes the formation of intra- and intermolecular 'épsilon'-('gama'-glutamyl)lysine cross-links between proteins. The TG from Streptomyces sp. CBMAI 1617 (SB6) was produced in Erlenmeyer flasks containing culture medium composed of 2.5% potato starch, 0.5% glucose, 2.45% casein peptone and 0.8% KH2PO4.7H2O, pH 7.0. The culture medium was fermented at 30 ºC, under constant agitation of 150 rpm for 96 h, resulting in enzyme activity of 3.5 UmL-1. The SB6 enzyme preparation obtained by fractionation with ammonium sulfate, dialysis and lyophilization presented an activity of 516.2 U g-1. Commercial TG (BiobondTM TG-M) and SB6 were biochemically characterized and presented an optimal activity temperature at 40 °C and between 35-40 °C; and optimum activity pH between 5.5-6.0 and of 6.5, respectively. The wheat flour doughs containing 1.10 U g-1 of commercial TG presented higher peak time and peak height when mixed in a mixograph, indicating the formation of a stronger dough when compared to a control. Similarly, the addition of commercial TG in gluten doughs resulted in stronger doughs for all concentrations used (0,87 and 1,73 U g-1). However, SB6 was the enzymatic preparation that had the greatest impact on the polymerization of proteins, promoting the inclusion of gliadins in the protein network. The harsh or mild gluten extraction also had a significant impact on the quality of gluten doughs. The treatment of gluten based doughs prepared with harshly separated gluten and SB6 favored the formation of ß-sheets in the secondary structure of the proteins. Gliadin presented excellent foaming ability which was favored by the addition of SB6. Polymerization of the gliadins was promoted, resulting in the expansion of the pore size of the lyophilized foams. Thus, the results show the potential of SB6 to modify the properties of wheat proteins with applicability in various technological processes of the food industryDoutoradoCiência de AlimentosDoutora em Ciência de Alimentos141871/2013-0CNP

EXPECTATIVAS GERADAS PELA MARCA SOBRE A ACEITABILIDADE DE CERVEJA: ESTUDO DA INTERAÇÃO ENTRE CARACTERÍSTICAS NÃO SENSORIAIS E O COMPORTAMENTO DO CONSUMIDOR

Due the important interaction between food extrinsic factors (brand name, packaging and other informations) and consumer behavior, the objective of this work was to evaluate the influence of brand name on beer samples acceptability. Data analysis was carried out by two techniques: descriptive statistics and paired comparison t test. Eight commercial brands of Pilsen beer were evaluated by 101 consumers in three sessions of acceptance tests: blind test, packaging test and informed test. Descriptive statistics allowed the conclusion that consumer’s acceptance varied among the three sensory sessions. Brands B, C and D positively influenced consumer’s acceptance, while the other brands had a negative impact on samples sensory acceptance, although in different proportions. Paired comparison t test allowed the conclusion that expectation generated by packaging was negatively disconfirmed for brands B, C and D, which indicates that sensory quality was inferior than expected. For brand H, a positive disconfirmation occurred and consumers liked the beer in a sensory way, although they disliked its packaging. For brand E, other packaging factors increased the acceptance. Brand name of samples A, F and G generated a negative impact on consumer’s evaluation. Therefore brand name influenced consumers’ response. It emphasizes the fact that extrinsic or non-sensory characteristics of food interferes over consumers‘ choice and may be, sometimes, more important than sensory characteristics.Tendo em vista a importante interação entre características extrínsecas ao alimento (marca, embalagem e outras informações) e o comportamento do consumidor, o objetivo deste trabalho foi avaliar a influência da marca na aceitação de amostras de cerveja. Para tanto, foram empregadas duas técnicas de análise de dados: a estatística descritiva e o teste t para amostras pareadas. Oito marcas comerciais de cerveja Pilsen foram avaliadas por 101 consumidores em três sessões de testes de aceitação: teste-cego, teste da embalagem e teste com informação da marca. Os resultados apresentados de maneira descritiva permitiram concluir que houve variação substancial da aceitação das amostras nas três sessões. As marcas B, C e D influenciaram de maneira positiva a aceitação do consumidor, enquanto as demais exerceram impacto negativo na aceitação das amostras, ainda que em diferentes proporções. Por meio do teste t verificou-se que para as cervejas B, C e D houve desconfirmação negativa da expectativa gerada pela embalagem, indicando que a qualidade sensorial foi inferior ao esperado. Para a marca H, a desconfirmação foi positiva, evidenciando que os consumidores gostaram sensorialmente da cerveja, apesar de terem desgostado da sua embalagem. Para a cerveja E houve indícios de que atributos adversos à marca causaram aumento da sua aceitação. A marca gerou impacto negativo na avaliação das amostras A, F e G. Houve, portanto, influência da marca sobre a resposta do consumidor. Isto evidencia que as características extrínsecas ou não sensoriais do alimento desempenham papel fundamental na sua escolha, podendo sobrepujar algumas vezes suas características sensoriais

Estudo de mercado de iogurte da cidade de Belo Horizonte/MG

O estudo do perfil dos consumidores e dos fatores envolvidos no processo de compra do iogurte é uma ferramenta importante na identificação dos diferentes segmentos desse mercado e de suas potencialidades. Assim, neste trabalho entrevistaram-se 387 consumidores de iogurte, residentes em Belo Horizonte - MG, que responderam os questionários estruturados. Os resultados foram analisados de forma descritiva, e para verificar a correlação entre características sociodemográficas com o perfil de consumo aplicou-se a análise de correlação de Pearson. Os resultados indicaram que o iogurte sabor morango apresenta maior aceitação pelos consumidores, que a categoria light/diet possui grande parte do seu público consumidor (54%). Segundo a pesquisa, 39,9% dos respondentes que não consomem iogurte light/diet disseram não consumi-lo por não gostar desse produto. Isto revela a importância de pesquisas para desenvolvimento de iogurte light/diet visando à melhoria da qualidade sensorial. O fato de não ver necessidade de consumir o produto foi apontado como um dos principais motivos por não consumir iogurte da categoria light/diet. A qualidade, a marca e o preço apresentaram grande importância na conquista de mercado, sendo os três principais atributos observados no momento da compra de iogurte na cidade estudada. Analisando a correlação entre consumo e fator sociodemográfico, observou-se que a renda e a idade influenciam tanto na frequência de consumo de iogurte quanto no consumo do produto na versão light/diet.The study of consumers´ profile and the factors involved in the moment of purchasing yogurt is an important tool for identifying different market segments and their potentialities. Therefore, the aim of this study was to interview 387 yogurt consumers residing in the city of Belo Horizonte MG, Brazil, using structured questionnaires. The results were analyzed in a descriptive way. Pearson´s correlation was applied in order to verify the correlation between sociodemographic characteristics and the consumers´ profile. The results indicated that strawberry flavored yogurt shows the greatest acceptance among consumers and the category of light/diet represents a great part of the consumers' preferences (54%). According to the survey, 39,9% of the respondents that do not consume light/diet yogurts stated that they do not appreciate these products. These results shows the importance of carrying out research to develop light/diet yogurt with improved sensorial quality. One of the main reasons pointed out for consumers not to eat light/ diet yogurt is that they do not see the need for consuming it. In the city the research took place, quality, brand and price had the greatest importance in the act of purchasing, since these were the three main attributes reported to have been observed in the moment of the purchase.The analysis of the correlation between consumption and socio-demographic factors showed that income and age influence both the frequency of yogurt consumption and the consumption of the light/diet version of the product

Araçaúna : a non-exploited source of pigments

Orientador: Adriana Zerlotti MercadanteDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Os pigmentos naturais, entre os quais se destacam antocianinas e carotenóides, proporcionam cor aos alimentos. A cor percebida é considerada um fator de qualidade e um atributo fundamental na aceitação e escolha de um alimento. Em paralelo, estes pigmentos também possuem importantes funções biológicas, sendo considerados promotores da saúde humana. A araçaúna (Psidium eugeniaefolia) é uma fruta de cor roxa, de sabor exótico e mede até 3 cm de diâmetro, encontrada na região da Mata Atlântica, desde o Estado do Espírito Santo até o Rio Grande do Sul. Por se tratar de uma fruta pouco pesquisada objetivo do presente trabalho foi caracterizar e quantificar as antocianinas e os carotenóides. A composição de carotenóides e de antocianinas foi determinada em três lotes de araçaúna coletados no município de Santa Maria de Jetibá, Estado do Espírito Santo. Os lotes apresentaram em média entre 3,0 e 3,2 mg/g de antocianinas, entre as quais se destaca cianidina 3- glucosídeo (74%). Em relação aos carotenóides, o conteúdo variou entre 30,0 e 35,4 µg/g, sendo os carotenóides majoritários a luteína (49-53%), seguido de ß-caroteno (13%). Esses pigmentos foram separados, identificados e quantificados por cromatografia líquida de alta eficiência acoplada a um detector de arranjo e diodos e espectrômetro de massas (HPLC-DAD-MS/MS)Abstract: The natural pigments, mainly anthocyanins and carotenoids, promote color to food. The perceived color is considered a factor of quality and a key attribute of acceptance and choice of this food. Additionally, these pigments also present remarkable biological functions and are considered promoters of the human health. Araçaúna (Psidium eugeniaefolia) is a purple fruit, presenting an exotic flavor and it is up to 3 cm in diameter. They are found in the Atlantic Forest region, from Espírito Santo State to Rio Grande do Sul State, Brazil. Taking in consideration that few reports are found in literature about this fruit, the aim of this work was to characterize and quantify anthocyanins and carotenoids. The composition of carotenoids and anthocyanins were determined in three batches of araçaúna collected from Santa Maria de Jetibá, Espirito Santo State. The batches presented concentration between of 3.0 and 3.2 mg/g (dry basis) of anthocyanins, where cyanidin 3 - glucoside was the major one (74%). Regarding the carotenoid content, it ranged between 30.0 and 35.4 mg/g (dry basis), where the main carotenoids were lutein (49-53%), followed by ß-carotene (13%). These pigments were separated, identified and quantified by high performance liquid chromatography coupled to a diode array detector and tandem mass spectrometer (HPLC-DAD-MS/MS)MestradoCiência de AlimentosMestre em Ciência de Alimento

Impact of gluten separation process and transglutaminase source on gluten based dough properties

This study evaluated the effect of the wheat gluten (WG) separation process and transglutaminase (TG) microbial source on WG dough quality, and opportunities to use these factors to tailor dough quality. Two types of gluten (harshly and mildly separated), two types of TG (commercial and novel SB6), and three TG concentrations were evaluated for effects on dough mixing properties, protein structure and solubility. Mildly separated gluten improved dough development parameters, resulting into higher values of most compared with harshly separated gluten. Despite more strongly cross-linked proteins being found in the harshly separated gluten, both gluten types showed similar levels of cross-linking at optimum mixing time, although differences in the secondary protein structure were indicated. Thus, disulfide-sulfhydryl exchange reactions were found to be promoted by mixing, although restrictions on establishment of new bonds because of prior cross-links in the material were clearly indicated. Degree of polymerization in doughs made from mildly separated gluten increased to varying extents with TG addition depending on TG source and concentration. Thus, for the first time, we show that an appropriate combination of WG separation procedure and TG source can be used to tailor gluten dough end-use properties87661669CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQnão te

Processing conditions and transglutaminase sources to “drive” the wheat gluten dough quality

Gluten proteins are highly impacting the quality of various gluten-based products, and transglutaminases (TGs) are used to influence the protein cross-linking. In this study we monitored the interplay of “harsh” and “mild” gluten processing for dough mixing and pasta-like sheet production and TGs from a commercial and newly sourced bacteria (SB6). Despite the harshly separated gluten presenting strongly cross-linked proteins in the beginning of the mixing, similar levels of polymerization were achieved at the optimum mixing time but with differences in the secondary protein structure. TG addition increased polymerization in wheat doughs, possibly as a result of increased glutenin polymerization, while gliadins become more soluble with SB6. This enzyme also dramatically increased polymerization in mild gluten. These results show that an adequate investigation when using TGs and gluten from various origins is necessary to adequately predict the quality in various gluten-based products, thus, of great relevance to the food industry65CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSem informaçã

Ranking descriptive analysis in the sensory characterization of strawberry flavored diet yogurt enriched with whey protein concentrate

Este estudo avaliou as características sensoriais de iogurte diet sabor morango enriquecidos com concentrado protéico de soro (CPS). Três formulações contendo 0,5%, 1% e 1,5% de CPS (F2, F3 e F4 em ordem crescente de concentração) e uma formulação controle sem adição de CPS (F1) foram desenvolvidas e avaliadas por meio da Análise Descritiva por Ordenação. Vinte provadores selecionados e treinados avaliaram as amostras caracterizadas pelos atributos: cor rosa, viscosidade, aroma característico de iogurte de morango, sabor característico de iogurte de morango, gosto doce, gosto ácido e consistência. As formulações diferiram significativamente (p < 0.05) nos atributos gosto doce e consistência. As amostras F3 e F4 apresentaram maior consistência confirmando a eficiência do CPS no aumento da consistência.This study evaluated the sensory characteristics of diet strawberry flavored yogurt enriched with whey protein concentrate (WPC). Three formulations containing 0,5%, 1% and 1.5% of WPC (F2, F3 and F4 in order of increasing concentration) and a controlled formulation without the addition of WCP (F1)  were developed and evaluated by Ranking Descriptive Analysis. Twenty selected and trained panelists evaluated the samples characterized by attributes: pink color, viscosity, characteristic aroma of strawberry yogurt, characteristic flavor of strawberry yogurt, sweet taste, sour taste and consistency. The formulations differed significantly (p < 0.05) in the attributes sweet taste and consistency. Samples F3 and F4 showed greater consistency confirming the efficiency of the WPC in increasing the consistency

Morphological and structural heterogeneity of solid gliadin food foams modified with transglutaminase and food grade dispersants

We show in this study the impact of transglutaminase (SB6), glycerol (Gly) and linoleic acid (LA) on the development of gliadin (Glia) solid edible foams. Two concentrations of SB6 were tested, 0.58 U/g and 1.17 U/g, and sufficiently high concentration of SB6 was found essential to crosslink the gliadins. Greater cross-linking in foam prepared with gliadin and 1.17 U/g of SB6 (2-TG-Glia) was followed by an increase of the size of the bubbles as well as improved bubble spatial homogeneity when compared to the non-treated gliadin foam (0-Glia). The inclusion of Gly had little effect on the periodic morphology of 2-TG-Glia, and the formed bubbles decreased in size. The 3D images of 2-TG-Glia revealed that the boundaries of the foams were less definied as observed by x-ray tomography. Nanomorphology studied by SAXS indicated that Gly impared the unfolding of gliadin in the foam. The addition of linoleic acid (LA) in the foams caused formation of the discontinous Glia network with large and sparce bubbles as revealed by x-ray tomograms. The synergistic interactions of Glia and LA led to the formation of lamellar phases in the foams as observed by SAXS. The results from this study show gliadin as a promising resource to create diverse new aerated foods and contribute to achieve the demand for plant proteins with great foaming functionality. The addition of food-grade dispersants such as, glycerol and linoleic acid, show a versatility and suitability of gliadin for new food applications such as breakfast cereals and snacks108CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSem informaçã