Geraldo Arraes Maia

Physical-chemical changes during extraction and clarification of guava juice

Pink guavas from Ibiapaba plateau (Serra Grande) in Ubajara country, CE, Brazil, were mashed and the pulp treated with 600 ppm of a pectic enzyme at 45°C for 120 min. The pulp so-treated was pressed to give an average juice yield of 84.70%. The pressed juice was cloudy and pink in colour but, after addition of fining agents and filtration, a clear juice with a light yellow colour was obtained. This clear juice was preserved by the Hot-pack method. During the extraction and clarification of the juice, some of the important physical and chemical changes were followed by measuring changes in total soluble solids (“Brix), acidity, viscosity, total phenolics content, colour, turbidity and ascorbic acid retention.

Análise físico-química, microbiológica e sensorial de frutos de manga submetidos à desidratação osmótico-solar

Mango pulps were submitted to solar drying processing after osmotic pre-treatment in order to obtain intermediate moisture products. Four osmotic pre-treatments were tested, which were: immersion in sucrose solutions at 45o Brix, 55o Brix, 65o Brix and immersion in sequenced solutions of 45o, 55o and 65o Brix. The processing involved the following steps: osmotic dehydration in sucrose solutions additioned with conserving substances and solar drying. After drying, the 55o and 65o Brix treatments were selected through sensorial analysis for evaluation of the stability during 180 days of storage at room temperature (28o C). During all the processing and/or after obtaining the final product, it was done three kinds of evaluation, which were: analytic determinations (water activity, pH, total acid, vitamin C, soluble solids, moisture, total sugar, reducing sugars), microbiological analysis and sensorial tests. According to the results obtained, these products have shown good stability regarding to microbiological and sensorial features.

Estudo da estabilidade físico-química e química do suco de caju com alto teor de polpa

Obteve-se o suco de caju com alto teor de polpa utilizando-se o processo combinado de tratamento termico e conservantes quimicos. Utilizaram-se varios teores de metabissulfito de sodio e nitrogenio, estudando-se em seguida, a estabilidade dos produtos obtidos. Verificou-se que o suco tratado com nitrogenio e 300ppm de SO2 apresentou melhor qualidade no que se refere principalmente a cor, quando comparado aquele tratado somente com nitrogenio.

Efeito do processamento sobre componentes do suco de acerola

Acerola is a fruit which is much appreciated due to its high vitamin C content. It also has a good source of carotenoids and anthocyanins and is industrialised as frozen pulp and processed as juice. Research on the effects of processing on the nutritional constituent of tropical juices is scarce. Often, only the loss of vitamin C is evaluated. The aim of this work is to determine the effect of some processing operations (formulation/ homogenization and heat treatment) on physical and physical-chemical characteristics of acerola juice. The results of this research indicate small changes in the physical and physical-chemical characteristics, and a significant change in the pH, a decrease in the vitamin C and anthocyanins content and an increase in the carotenoids of the processed juice were observed.

Qualidade pós-colheita de frutos de diferentes clones de mangabeira (Hancornia speciosa Gomes)

Com o objetivo de avaliar a qualidade pos-colheita de frutos de diferentes clones de mangabeira (Hancornia speciosa Gomes) para consumo como fruto fresco e/ou industrializado, foram avaliados 10 clones: Ipojuca 3, 4 e 5 (IPJ 3, 4 e 5); Nizia Floresta 1, 6 e 8 (NIF 1, 6 e 8); Parnamirim 11 (PAR 11); Rio Tinto 7 (RIT 7); Extremoz 1 (EXT 1) e Touros 48 (TOU 48), oriundos de um Jardim Clonal instalado em 1996 do Banco Ativo de Germoplasma da Estacao Experimental de Mangabeira, pertencente a EMEPA - Empresa Estadual de Pesquisa Agropecuaria da Paraiba, situada em Joao Pessoa, PB. As mangabas foram colhidas manualmente em estadio de maturidade fisiologica, acondicionadas em caixas plasticas de transporte forradas no fundo com espuma de poliestireno e transportadas ao Laboratorio de Fisiologia e Tecnologia Pos-colheita da Embrapa Agroindustria Tropical, onde foram caracterizadas fisica, fisico-quimica e quimicamente. As caracteristicas de qualidade analisadas foram: massa total do fruto; comprimento, diâmetro, firmeza, numero de sementes; rendimento de polpa + casca; percentagem de sementes; pH; acidez total titulavel (ATT); solidos soluveis totais (SST); relacao SST/ATT; vitamina C total; acucares soluveis totais; acucares redutores, fenolicos polimericos, oligomericos e dimeros. A analise de variância revelou diferencas estatisticas para todas as caracteristicas pelo Teste F. De um modo geral os frutos de mangabeira dos clones avaliados apresentaram caracteristicas superiores as observadas na literatura, especialmente quanto aos padroes estabelecidos pela I.N. no 1 de 07/01/2000 do MAPA. Dentre os materiais geneticos avaliados pode-se destacar os clones RIT 8 e TOU 48 como os mais promissores para o mercado de frutas in natura, e os clones IPJ 3 e NIF 6 para o processamento agroindustrial.

Avaliação da qualidade microbiológica de frutos minimamente processados comercializados em supermercados de Fortaleza

O processamento minimo tem sido descrito como a manipulacao, o preparo, embalagem e a distribuicao de produtos agricolas, atraves de procedimentos como selecao, limpeza, lavagem, descascamento e corte, que nao afetem suas caracteristicas organolepticas, agregando valor aos mesmos. Varios fatores limitam o consumo destes produtos, os quais estao envolvidos na sua vida util, tais como: aumento da respiracao e da producao de etileno, escurecimento enzimatico, descoloracao da superficie, perda de agua e, sobretudo, alteracoes microbiologicas. No presente trabalho, o enfoque foi dado a este ultimo fator. Foram analisadas 20 amostras de goiaba, manga, melao japones, mamao formosa e abacaxi minimamente processados e comercializados em supermercados da cidade de Fortaleza-CE, considerando-se a quantificacao de coliformes totais, fecais, bolores e leveduras, e deteccao de bacterias potencialmente patogenicas, tais como Salmonella sp e Staphylococcus coagulase positivo. Atraves dos resultados deste trabalho, permitiu-se sugerir a necessidade de controle de qualidade, observando as boas praticas de fabricacao, para posterior implementacao de um sistema preventivo de APPCC, analise de perigos e pontos criticos de controle, para se assegurar um produto saudavel e seguro para o consumidor.

Estudo das variáveis de processo sobre a cinética de desidratação osmótica de melão

Osmotic dehydration represents a technological alternative to reduce post-harvest losses of fruits. The purpose of this work was to evaluate the influence of the osmotic solution concentration, fruit to osmotic solution ratio and system pressure on kinetics of the osmotic dehydration of melon. It was used 45o, 55o and 65oBrix sucrose solutions at 65oC, and 1:2 and 1:4 fruit to osmotic solution ratios. The osmotic treatments were carried out under atmospheric pressure and vacuum, for five hours. The use of vacuum in the osmotic dehydration of melon intensified the mass transport flows in the system when compared with the ones under atmospheric pressure, in the same conditions of concentration and fruit to osmotic solution ratio. The osmotic treatment under vacuum, which used 65oBrix sucrose solution and 1:4 fruit to osmotic solution ratio, showed be efficient for speeding up the water loss of the product, making possible to reach high degree of dehydration with a relatively small solids gain, in a shorter period of time when compared with the others treatments studied. The kinetics of the osmotic dehydration of melon is influenced by the process conditions, specially by the system pressure and osmotic solution concentration.

Storage stability of cashew apple juice preserved by hot fill and aseptic processes

Cashew (Anacardium occidentale L.) apples from Pacajus, Ceara State, Brazil, were processed into high pulp content juice. The juice was packed either by hot fill or an aseptic process and evaluated for physical, physical-chemical, and sensorial changes during a 12-month storage period at room temperature. The results indicated that pH, soluble solids, total acidity, total sugar content and color did not change significantly during storage nor were affected by the type of filling. The sensorial analysis showed that juice acceptance remained high throughout the storage period regardless of the filling system. Differences in juice viscosity persisted between both processes.

DESIDRATAÇÃO DA POLPA DE ACEROLA (Malpighia emarginata D.C.) PELO PROCESSO "FOAM-MAT"

A food supplement from dehydrated pulp using a non-conventional method of FOAM-MAT was produced. Several tests have been accomplished using different chemical agents to facilitate the foam formation, and an experiment has been chosen that most adjusted to the recommended density parameter (0.1 to 0.6). After the definition of the experimental conditions, the pulp was formulated and dehydrated in a drying hot-house with air circulation at a temperature of 60 to 70°C for 90 minutes. The product obtained was a powder with final humidity of 7.2%. Concomitant to the experiment the chemical analysis of the pulp had been accomplished. The obtained powder was immediately afterwards analysed with the purpose of identifying the new characteristics of the product and packed in 25g metalized bags and submitted to stability studies for a period of 3 months. Analysis of the results obtained showed that there was an increase in the basic nutrients mainly regarding to the content of vitamin C that showed an increase 10 times higher than natural pulp.

Processamento e conservação de manga por métodos combinados

A tecnologia de metodos combinados foi empregada na conservacao da manga (Mangifera indica, L.) em pedacos. A estabilidade fisico-quimica, microbiologica e sensorial da manga em pedacos foi obtida atraves do branqueamento com vapor saturado por 2 min, ajuste da atividade de agua (Aw) para 0,97, do pH para 3,6, adicao de 600 ppm de acido ascorbico, 1000 ppm de benzoato de sodio e 600 ou 900 ppm de dioxido de enxofre. Os produtos da manga processados nas condicoes descritas apresentaram, ao longo de 120 dias de armazenamento, teores de umidade, atividades de agua e pH na faixa para produtos de fruta de alta umidade; aumento dos acucares redutores; acentuada perda de SO2 (cerca de 60%) e vitamina C; reducao da contagem microbiologica, demonstrando que a selecao de obstaculos e suas intensidades foram capazes de assegurar a estabilidade microbiologica do produto. O teste de aceitabilidade mostrou que a manga conservada por metodos combinados teve boa aceitacao e que as medias dos atributos se assemelham aos resultados de testes sensoriais mencionados na literatura.