Efeito da adição de revestimentos comestíveis sobre a qualidade de mamão desidratado após a secagem e durante o armazenamento
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Data
2013-03-11
Autores
Canizares, Diego [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os objetivos deste trabalho foram avaliar a cinética de secagem, retenção de vitamina C e retenção de cor no mamão fresco e pré-tratada (Carica papaya L.), após secagem convectiva e durante o armazenamento. Foram, também, determinadas as propriedades termodinâmicas e novas metodologias para estudos de encolhimento em mamão fresco sem cobertura. A vitamina C é um antioxidante natural com importantes propriedades nutricionais para a saúde humana. Clara de ovo é uma importante fonte de proteína. Coberturas comestíveis à base de hidrocolóides possuem propriedades de barreira a gases, são solúveis em água e tem capacidade de incorporar aditivos. Fatias de papaia foram imersas em solução de pectina a 2% (p/p) ou em solução de pectina (2 % p/p) com vitamina C (1 % p/p) ou em solução de pectina a 2 % (p/p) com clara de ovo comercial (2 % p/p). O revestimento de pectina foi gelificado por imersão em solução de lactato de cálcio em 2,8 % (p/p). As fatias de pectina com e sem cobertura foram desidratadas em secador convectivo a 60 °C e 70 °C. Análises de vitamina C, cor e água foram feitas em mamão fresco com e sem cobertura, antes e após a secagem e durante a armazenagem. Todos os ensaios de secagem foram realizados quatro vezes. As isotermas de desorção e adsorção de mamão sem cobertura foram desenvolvidas a 30 ° C, 50 ° C e 70 ° C, e esses dados foram utilizados para determinar as propriedades termodinâmicas. Duas metodologias para determinação do encolhimento foram estudadas em secagem a 60 ° C e 70 ° C de mamão sem cobertura. A análise da variância foi aplicada aos dados experimentais para identificar diferenças significativas ao nível de confiança de 95% (p <0,05). Coberturas comestíveis aumentaram a retenção de vitamina C, em especial as coberturas comestíveis de pectina e pectina...
The aims of this work were evaluate the drying kinetic, retention of vitamin C and retention of color in fresh and pre-treated papaya (Carica papaya L.), after air-drying and during storage. Moreover were studied thermodynamics properties and determinate new methodologies for shrinkage studies in fresh papaya. Edible coatings applying on surface of the foods can prevent oxidative reactions. Vitamin C is a natural antioxidant and nutritionally important for the human health. Egg white is an important protein source. Hydrocolloids edible coatings possess good barrier properties to gases, are soluble in water and can incorporate additives. Papaya slices were immersed in pectin solution at 2 % (w/w) or in pectin solution (2 %) with vitamin C (1 %) or even in pectin solution at 2 % (w/w) with commercial egg white (2 % w/w). The pectin coating was jellified by immersion in calcium lactate solution at 2.8 % (w/w). The pectin-coated and non-coated slices were air-dried at 60 °C and 70 °C temperatures. Vitamin C, color and water content was analyzed in fresh papaya and in coated papaya before and after drying and during storage. All drying experiments were done four times. Isotherms analysis of non-coated papaya were developed at 30°C, 50°C and 70°C and with those data were determinate the thermodynamic properties. Two methodologies of shrinkage were studied in drying of non-coated papaya at 60°C and 70°C. Analysis of variance was applied to experimental data to identify significant differences at 95% confidence level (p<0.05). Retention of vitamin C was not affected by temperature. We obtained considerable vitamin C content in the samples with vitamin C incorporated in pectin coating, after drying and storage. Drying kinetic of coated and non-coated was very similar, changing just with the temperature. Thermodynamics properties... (Complete abstract click electronic access below)
The aims of this work were evaluate the drying kinetic, retention of vitamin C and retention of color in fresh and pre-treated papaya (Carica papaya L.), after air-drying and during storage. Moreover were studied thermodynamics properties and determinate new methodologies for shrinkage studies in fresh papaya. Edible coatings applying on surface of the foods can prevent oxidative reactions. Vitamin C is a natural antioxidant and nutritionally important for the human health. Egg white is an important protein source. Hydrocolloids edible coatings possess good barrier properties to gases, are soluble in water and can incorporate additives. Papaya slices were immersed in pectin solution at 2 % (w/w) or in pectin solution (2 %) with vitamin C (1 %) or even in pectin solution at 2 % (w/w) with commercial egg white (2 % w/w). The pectin coating was jellified by immersion in calcium lactate solution at 2.8 % (w/w). The pectin-coated and non-coated slices were air-dried at 60 °C and 70 °C temperatures. Vitamin C, color and water content was analyzed in fresh papaya and in coated papaya before and after drying and during storage. All drying experiments were done four times. Isotherms analysis of non-coated papaya were developed at 30°C, 50°C and 70°C and with those data were determinate the thermodynamic properties. Two methodologies of shrinkage were studied in drying of non-coated papaya at 60°C and 70°C. Analysis of variance was applied to experimental data to identify significant differences at 95% confidence level (p<0.05). Retention of vitamin C was not affected by temperature. We obtained considerable vitamin C content in the samples with vitamin C incorporated in pectin coating, after drying and storage. Drying kinetic of coated and non-coated was very similar, changing just with the temperature. Thermodynamics properties... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Alimentos - Desidratação, Tecnologia de alimentos, Mamão - Secagem, Secagem, Frutas desidratadas, Vitamina C, Food - Drying
Como citar
CANIZARES, Diego. Efeito da adição de revestimentos comestíveis sobre a qualidade de mamão desidratado após a secagem e durante o armazenamento. 2013. 77 f. Dissertação (mestrado) - Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Biociências, Letras e Ciências Exatas, 2013.