Paulo Henrique Machado de Sousa

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.

Avaliação de macro e microminerais em frutas tropicais cultivadas no nordeste brasileiro

Brazil has great importance in the fruits market; however, data on the composition of Brazilian tropical fruits, mainly of those produced in the Northeast region, is scarce. In the present study, it was determined the macro- and micro-minerals of 11 tropical fruits cultivated in the Northeast of Brazil: pineapple, sweetsop, soursop, jackfruit, papaya, mangaba, murici, sapodilla, ciruela, tamarind, and umbu. The samples were dehydrated and mineralized in HNO3/HClO4 (3:1) solution. The minerals Ca, Mg, Mn, Zn, Fe, Co, Se and Ni were analyzed by atomic absorption spectrophotometry; Na and K by flame photometry; and P by the colorimetric method. The results indicated that tamarind is a rich source of all minerals available, especially of Mg, Cu and K, in addition to being a good source of Ca, P, Fe, and Se. Among the minerals evaluated in this study, K presented the highest content, followed by Ca and Mg. Sweetsop, soursop, sapodilla, and murici are good sources of two or more minerals. High correlations were obtained between K and the minerals P, Co, and Fe and between Co and Fe. Therefore, the consumption of the studied tropical fruits is suggested as an assistant to the reposition of mineral nutrients.

Influência da concentração e da proporção fruto: xarope na desidratação osmótica de bananas processadas

Considering the technological limitations of the traditional processes for production of banana fig with standard quality, the osmotic dehydration appears as an option to the standardization of this process. In this work to determine parameters of the banana osmotic dehydration process and to evaluate the influence of osmotic solution concentration on the physical chemical caracteristics of the fruit and stablish drying curves of pre treatment bananas through osmotic dehydration with and without vacuum. It was concluded that is possible to obtain dehydrated banana as a product of intermediate moisture, through osmotic pre treatment followed by drying. The characteristics of the product were influenced by concentration and proportion fruit:xyrop of the used medium.

Perfil dos consumidores de hortaliças minimamente processadas de Belo Horizonte

Consumers food consciousness has increased, however, time for preparing healthy food has decreased. Therefore, the market of minimally processed vegetable has increased rapidly, giving rise to the appearance of fresh products that can be prepared and consumed faster than conventional foods. Thus, the objective of this work was to establish the behavior and profile of minimally processed vegetable consumers in supermarkets of Belo Horizonte, Minas Gerais State, Brazil. Based on the answers to a survey, the consumers profile was traced, highlighting preferences, habits, complaints and demands. The survey was conducted with consumers of five supermarkets which sell minimally processed vegetables (MPV). Consumers were chosen randomly when they were buying in November 2004. Of two hundred and forty six interviewed persons, 23% were consumers of MPV. The main reasons for consumption were: easiness and feasibility (46%); short preparation time (21%) of meals and hygiene (11%) of the products; and the main reasons against consumption were: the high price of the precuts (31,9%); easy to prepare and/or to choose (23%) and distrusting (17,8%) the offered products. The major consumers were those with a better education. Comparing the overrating of MPV with other vegetables, a variation of 2,4 (potato) to 39,5 times (carrots) was found. On average the overrating found in markets for eleven MPV was of 10 times.

NMR Spectroscopy and Chemometrics to Evaluate Different Processing of Coconut Water

NMR and chemometrics was applied to understand the variations in chemical composition of coconut water under different processing. Six processing treatments were applied to coconut water and analyzed: two control (with and without sulphite), and four samples thermally processed at 110°C and 136°C (with and without sulphite). Samples processed at lower temperature and without sulphite presented pink color under storage. According to chemometrics, samples processed at higher temperature exhibited lower levels of glucose and malic acid. Samples with sulphite processed at 136°C presented lower amount of sucrose, suggesting the degradation of the carbohydrates after harshest thermal treatment. Samples with sulphite and processed at lower temperature showed higher concentration of ethanol. However, no significant changes were verified in coconut water composition as a whole. Sulphite addition and the temperature processing to 136°C were effective to prevent the pinking and to maintain the levels of main organic compounds.

Carnauba wax p-methoxycinnamic diesters: Characterisation, antioxidant activity and simulated gastrointestinal digestion followed by in vitro bioaccessibility.

The beneficial biological effects of cinnamic acid derivatives and the lack of studies on the antioxidant activity and bioavailability of cinnamic esters from carnauba wax, diesters were extracted from carnauba wax powder. Their structural, physical and morphological characteristics, antioxidant activity and in vitro bioaccessibility were measured. p-Methoxycinnamic diester (PCO-C) was identified, which has a crystalline, apolar structure and exhibited significant antioxidant activity (107.27 ± 3.92 μM Trolox/g of dry weight) before and after simulated in vitro gastrointestinal digestion and 32.46% bioaccessibility. In human cells, PCO-C (250 μg/mL) inhibited the production of intracellular reactive oxygen species, with an effect similar to that of Trolox (80 μM). Thermogravimetric analysis showed that PCO-C had high thermal stability and high UV absorption between 250 and 350 nm. These results indicate that this compound is promising as an antioxidant for pharmaceutical and food industry applications, such as the development of active packaging and functional foods.

Estabilidade de componentes bioativos do suco tropical de goiaba não adoçado obtido pelos processos de enchimento a quente e asséptico

The guava is one of the tropical fruits with the highest nutritional value, rich in vitamins C and pro-vitamin A, possessing excellent acceptance of in natura consumption as well as great industrial applicability. Vitamin C, carotenoids, anthocyanins and phenolics are considered compounds with antioxidant activity and the consumption of these substances in the daily diet can produce an effective protective action against the oxidative processes that occur naturally in the organism. This work aimed to study the stability of the vitamin C, carotenoids, anthocyanins and total phenolics of unsweetened guava tropical juice obtained by hot fill and aseptic processes for 250 days of storage at room temperature (28 ± 2 oC). The results showed that the total carotenoids and total phenolics did not vary during the storage time, while the vitamin C decreased.

Avaliação da qualidade microbiológica de hortaliças minimamente processadas

A microbiota e um fator de grande importância na qualidade e conservacao de vegetais minimamente processados. Muitos microrganismos podem afetar adversamente a qualidade e a seguranca desses produtos, considerando que microrganismos patogenicos, que normalmente nao estariam presentes, passam a compor a microbiota contaminante decorrente do manuseio a que sao submetidos. Objetivou-se, neste trabalho, determinar a qualidade microbiologica de hortalicas, anterior e posteriormente ao processo de sanitizacao, como tambem o periodo final da vida-de-prateleira dos produtos sanitizados, avaliando-se a presenca de Listeria sp., Listeria monocytogenes e Salmonella sp. Foram analisadas amostras de agriao, alface, cenoura ralada, espinafre, repolho verde ralado e rucula minimamente processados. As amostras nao sanitizadas foram analisadas no dia da coleta, e as sanitizadas analisadas a 1, 5 e 8 dias apos o processamento, a fim de determinar a condicao microbiologica dos produtos. As hortalicas foram armazenadas sob temperatura de 5oC. Salmonella sp. foi detectada em 12,7% das amostras, enquanto L. monocytogenes nao foi encontrada em nenhuma delas, embora outras especies de Listeria tenham sido isoladas de alface e cenoura. A presenca de Salmonella sp. tornaram 16 amostras improprias para o consumo humano, de acordo com a RDC no 12.

Chemical and physicochemical characteristics changes during passion fruit juice processing

Passion fruit is widely consumed due to its pleasant flavour and aroma acidity, and it is considered very important a source of minerals and vitamins. It is used in many products such as ice-cream, mousses and, especially, juices. However, the processing of passion fruit juice may modify the composition and biodisponibility of the bioactive compounds. Investigations of the effects of processing on nutritional components in tropical juices are scarce. Frequently, only losses of vitamin C are evaluated. The objective of this paper is to investigate how some operations of passion fruit juice processing (formulation/homogeneization/thermal treatment) affect this product’s chemical and physicochemical characteristics. The results showed that the chemical and physicochemical characteristics are little affected by the processing although a reduction in vitamin C contents and anthocyanin, large quantities of carotenoids was verified even after the pasteurization stage.

Estabilidade da polpa do bacuri (Platonia insignis Mart.) congelada por 12 meses

Conduziu-se este trabalho, com o objetivo de realizar o processamento e avaliar a estabilidade da polpa de bacuri (Platonia insignis Mart.) submetida ao congelamento durante 12 meses. Durante o periodo de armazenamento nao ocorreram alteracoes significativas nas caracteristicas fisico-quimicas da polpa quanto aos teores de solidos soluveis, pH, atividade de agua, acucares totais e redutores, vitamina C, compostos fenolicos polimericos e oligomericos, pectina total e soluvel e cor L, a* , b*, enquanto que a acidez total e relacao SST/AT variaram com o tempo de armazenamento. Os compostos fenolicos dimeros apresentaram aumento em funcao do tempo. Pelos resultados obtidos, a polpa de bacuri nao pode ser considerada uma boa fonte de vitamina C. Por outro lado, apresenta baixos teores de compostos fenolicos caracterizando a polpa como, potencialmente pouco adstringente e com potencial para o processamento. A qualidade microbiologica nao foi alterada durante o periodo de armazenamento. Os resultados apontam a eficiencia do congelamento na manutencao das caracteristicas fisico-quimicas e microbiologicas da polpa de bacuri.