Otimização de pectina e farinha de acerola em leite fermentado simbiótico e sobrevivência probiótica frente simulação de condições gastrointestinais in vitro
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Data
2017-06-30
Autores
Sgarbosa, Letícia [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivo: desenvolver um leite fermentado com Lactobacillus acidophilus- LA-5, Bifidobacterium lactis- BB-12 e Streptococcus thermophilus com concentrações otimizadas de farinha de acerola e pectina. Verificar as características físico-químicas, sensoriais e microbiológicas da formulação otimizada. Avaliar a viabilidade dos microrganismos e a sobrevivência dos microrganismos probióticos frente à simulação das condições gastrointestinais in vitro. Métodos: a farinha de acerola foi avaliada com relação ao conteúdo fenólico, atividade antioxidante e teor de fibras totais. Foi utilizada a Metodologia de Superfície de Resposta (MSR) para obtenção das concentrações otimizadas de farinha de acerola e pectina no leite fermentado. O leite fermentado otimizado foi avaliado durante 28 dias de armazenamento refrigerado (5 ± 1 °C) quanto às características físico-químicas: composição centesimal, pH, acidez Dornic, atividade antioxidante, sinérese, perfil de textura; às características sensoriais: sabor, impressão global e textura e às características microbiológicas: viabilidade dos microrganismos e sobrevivência gastrointestinal a partir de simulação de condições gastrointestinais in vitro dos microrganismos probióticos. Resultados: a farinha de acerola apresentou 52,50 mg EAG g-1 de compostos fenólicos totais, 226,86 mmols ET g-1 de atividade antioxidante segundo método de DPPH e 51mmol ET g-1 por FRAP com 56,28 ± 0,19 % de fibras totais. Somente a farinha de acerola influenciou significativamente (p < 0,05) os atributos sensoriais do leite fermentado simbiótico. O modelo matemático desenvolvido foi eficaz para determinar a região otimizada das variáveis independentes. A formulação otimizada apresentou 18,42 ± 0,75 g 100 g -1 de fibras dietéticas. Durante todo o período de estocagem não houve diferença estatística (p < 0,05) nos valores de pH comparando as formulações tratamento e controle. Em relação à acidez Dornic, verifica-se diferença estatística (p < 0,05) entre as formulações controle e tratamento. Embora declínio na atividade antioxidante do leite fermentado, observa-se expressiva atividade antioxidante mesmo ao final do período de armazenamento (1325,34 ± 39,95 mM eq. Trolox/g). Verifica-se aumento crescente nos valores de sinérese durante o tempo de estocagem dos leites fermentados. Somente para os parâmetros adesividade e gomosidade houve diferença estatística entre as formulações. O atributo sabor não apresentou diferença significativa ao longo dos 28 dias de armazenamento, diferentemente dos atributos impressão global e textura. A adição dos prebióticos reduziu significativamente (p < 0,05) a viabilidade dos microrganismos e a sobrevivência dos microrganismos probióticos após a simulação das condições gastrointestinais in vitro, com concentrações finais inferiores as da formulação controle (p < 0,05). Conclusão: a farinha de acerola apresentou elevada concentração de compostos fenólicos, atividade antioxidante e fibras, sendo a única variável que influenciou a aceitação sensorial do produto fermentado. O leite fermentado simbiótico apresentou alto conteúdo de fibras, elevada atividade antioxidante e boa aceitação sensorial durante 28 dias de armazenamento. A adição da farinha de acerola e da pectina não contribuiu com a viabilidade dos microrganismos e a sobrevivência probiótica frente ao processo de digestão gastrointestinal in vitro. A utilização de um subproduto agroindustrial é uma alternativa de aproveitamento e contribuição positiva ao meio ambiente.
Objective: to develop fermented milk with Lactobacillus acidophilus LA-5, Bifidobacterium lactis Bb-12 and Streptococcus thermophilus with optimized concentrations of acerola flour and pectin. The physical-chemical, sensorial and microbiological characteristics of the optimized formulation was verified. To assess the viability of microorganisms and the survival of probiotic microorganisms against the simulation of gastrointestinal conditions in vitro. Methods: acerola flour was evaluated for phenolic content, antioxidant activity and total fiber content. The Response Surface Methodology was used to obtain optimum concentrations of acerola flour and pectin in fermented milk. The optimized fermented milk was evaluated during 28 days of refrigerated storage (5 ± 1 °C) for the physico-chemical characteristics: centesimal composition, pH, Dornic acidity, antioxidant activity, syneresis, texture profile; sensory: taste, overall impression and texture and microbiological: viability of microorganisms and gastrointestinal survival from simulation of in vitro gastrointestinal conditions of probiotic microorganisms. Results: acerola flour presented 52.50 mg GAE g-1 of total phenolic compounds, 226.86 mmols TE g-1 of antioxidant activity according to DPPH method and 51 mmol TE g-1 by FRAP with 56.28 ± 0.19% of total fibers. Only acerola flour significantly influenced (p < 0.05) the sensorial attributes of symbiotic fermented milk. The developed mathematical model was effective in determining the optimized region of the independent variables. The optimized formulation showed 18.42 ± 0.75 g 100 g-1 dietary fiber. During the storage period there was no statistical difference (p <0.05) in the pH values comparing the treatment and control formulations. In relation to Dornic acidity, there was a statistical difference (p <0.05) between control and treatment formulations. Although a decline in the antioxidant activity of fermented milk, significant antioxidant activity is observed even at the end of the storage period (1325.34 ± 39.95 mM Trolox/g eq.).There is an increasing in syneresis values during the storage time of the fermented milks. Only for the adhesiveness and gum parameters, there was a statistical difference between the formulations. The flavor attribute did not present significant difference during the 28 days of storage, unlike the attributes global impression and texture. The addition of prebiotics significantly reduced (p < 0.05) the viability of microorganisms and the survival of probiotic microorganisms after simulation of gastrointestinal conditions in vitro, with final concentrations lower than those of the control formulation (p < 0.05). Conclusion: The acerola flour presented high concentration of phenolic compounds, antioxidant activity and fibers, being the only variable that influenced the sensorial acceptance of the fermented product. Symbiotic fermented milk presented high fiber content, high antioxidant activity and good sensory acceptance during 28 days of storage. The addition of acerola flour and pectin did not contribute to the viability of microorganisms and to the probiotic survival in the gastrointestinal digestion process in vitro. The use of an agroindustrial by-product is an alternative to the use and positive contribution to the environment.
Objective: to develop fermented milk with Lactobacillus acidophilus LA-5, Bifidobacterium lactis Bb-12 and Streptococcus thermophilus with optimized concentrations of acerola flour and pectin. The physical-chemical, sensorial and microbiological characteristics of the optimized formulation was verified. To assess the viability of microorganisms and the survival of probiotic microorganisms against the simulation of gastrointestinal conditions in vitro. Methods: acerola flour was evaluated for phenolic content, antioxidant activity and total fiber content. The Response Surface Methodology was used to obtain optimum concentrations of acerola flour and pectin in fermented milk. The optimized fermented milk was evaluated during 28 days of refrigerated storage (5 ± 1 °C) for the physico-chemical characteristics: centesimal composition, pH, Dornic acidity, antioxidant activity, syneresis, texture profile; sensory: taste, overall impression and texture and microbiological: viability of microorganisms and gastrointestinal survival from simulation of in vitro gastrointestinal conditions of probiotic microorganisms. Results: acerola flour presented 52.50 mg GAE g-1 of total phenolic compounds, 226.86 mmols TE g-1 of antioxidant activity according to DPPH method and 51 mmol TE g-1 by FRAP with 56.28 ± 0.19% of total fibers. Only acerola flour significantly influenced (p < 0.05) the sensorial attributes of symbiotic fermented milk. The developed mathematical model was effective in determining the optimized region of the independent variables. The optimized formulation showed 18.42 ± 0.75 g 100 g-1 dietary fiber. During the storage period there was no statistical difference (p <0.05) in the pH values comparing the treatment and control formulations. In relation to Dornic acidity, there was a statistical difference (p <0.05) between control and treatment formulations. Although a decline in the antioxidant activity of fermented milk, significant antioxidant activity is observed even at the end of the storage period (1325.34 ± 39.95 mM Trolox/g eq.).There is an increasing in syneresis values during the storage time of the fermented milks. Only for the adhesiveness and gum parameters, there was a statistical difference between the formulations. The flavor attribute did not present significant difference during the 28 days of storage, unlike the attributes global impression and texture. The addition of prebiotics significantly reduced (p < 0.05) the viability of microorganisms and the survival of probiotic microorganisms after simulation of gastrointestinal conditions in vitro, with final concentrations lower than those of the control formulation (p < 0.05). Conclusion: The acerola flour presented high concentration of phenolic compounds, antioxidant activity and fibers, being the only variable that influenced the sensorial acceptance of the fermented product. Symbiotic fermented milk presented high fiber content, high antioxidant activity and good sensory acceptance during 28 days of storage. The addition of acerola flour and pectin did not contribute to the viability of microorganisms and to the probiotic survival in the gastrointestinal digestion process in vitro. The use of an agroindustrial by-product is an alternative to the use and positive contribution to the environment.
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Palavras-chave
Alimento funcional, Lácteos, Viabilidade gastrointestinal, Functional food, Dairy, Gastrointestinal viability