Rodrigo Rodrigues Petrus

CARACTERIZAÇÃO FÍSICO-QUÍMICA, MICROBIOLÓGICA E SENSORIAL DE POLPA DE CUPUAÇU CONGELADA (Theobroma gradiflorum, Schum)

O presente trabalho visou a caracterização microbiológica, físico-química e a aceitação sensorial de polpa de cupuaçu congelada (Theobroma grandiflorum Schum). Analisaram-se 3 marcas do produto, denominadas A, B e C, fornecidas em saquinhos de polietileno de 100 g. A caracterização microbiológica foi fundamentada na quantificação de mesófilos aeróbios, bolores e leveduras, coliformes e na verificação da presença de Salmonella. Os testes físico-químicos basearam-se na determinação de extrato seco, atividade de água (Aa), cinzas totais, proteínas, lipídios, sólidos solúveis (°Brix), acidez titulável, ácido ascórbico, pH e cálculo do ratio. Os testes sensoriais da polpa foram conduzidos com o suco preparado a partir das amostras comerciais. Atributos de aparência, aroma, sabor e impressão global do suco foram avaliados por meio de testes de escala hedônica e de ordenação-preferência. As contagens médias de mesófilos aeróbios foram equivalentes a 1,6 x 102, 1,3 x 102 e 7,9 x 101 UFC.g–1 de polpa, nas marcas A, B e C, respectivamente. Para bolores e leveduras, obtiveram-se 4,9 x 101, <10 e 1,6 x 101 UFC.g–1. As contagens de coliformes a 30 e 45 °C foram inferiores a 0,3 NMP.g–1 nas três marcas. Constatou-se a ausência de Salmonella em 25 g de polpa, para todas as amostras testadas, em conformidade com a legislação vigente. Os resultados obtidos na caracterização físico-química revelaram desacordo de algumas amostras com a legislação para os parâmetros sólidos solúveis totais, acidez titulável e ácido ascórbico. Os resultados da análise sensorial não evidenciaram diferença entre as três marcas de polpa a 5% de significância para os testes de escala hedônica e ordenação-preferência. Concluiu-se que as três marcas de polpa congelada de cupuaçu apresentaram qualidades microbiológica e sensorial satisfatórias. No entanto, notou-se falta de uniformidade em relação aos padrões de identidade e qualidade, conforme determinado pela legislação nacional vigente.

Processamento e avaliação de estabilidade de bebida isotônica em garrafa plástica

The objective of this work was to obtain an isotonic drink by using pasteurization and packing into aseptic bottles, stable at room temperature, without the addition of chemical preservatives. For the sanitation of the plastic bottles some sanitizers were tested, based on their efficiency to destroy microorganism, maintaining minimum residual hydrogen peroxide, and keeping the drink sensory quality. The isotonic drink (pH 3,40) was thermaly processed in a plate pasteurizer at 85oC/5s and packed into PET bottles sanitized by spraying peracetic acid at 0.3%/5s at 30oC. The processed drink contained three different concentrations of potassium sorbate (control, 50 and 100mg/L). The stability of the products were evaluated at 25oC for 26 weeks by measuring the pH, soluble solids, titrable acidity, ascorbic acid, microbial count, and sensory tests. The sensory evaluation and the count of the total mesophilic aerobic bacteria, moulds and yeast were measured during storage. There was no difference (p<0,05) for the pH, soluble solids and acidity of the processed drinks during the storage period except for the ascorbic acid which reduced to about 30% of the initial value. At 26 weeks the total bacteria and mould and yeast count were <5.7CFU/mL and <10CFU/mL, respectively. There was no sensory evaluation diference (p<0,05) during the storage test. Such results indicated that the formulated isotonic drink can be processed at the above conditions, without the addition of chemical preservatives, and stored at room temperature for at least 6 months in good commercial quality.

Crossflow microfiltration of sugarcane juice - effects of processing conditions and juice quality

Sugarcane juice with passion fruit pulp was clarified using microfiltration under different T (temperature), P (pressure), and V (tangential velocity). The effects of these processing parameters were evaluated applying a rotational central composite experimental design (RCCD) and response surface methodology (RSM). The tests were performed at a filtration pilot plant using a polyamide hollow-fiber membrane with an average pore diameter of 0.4 μm and filtration area of 0.723 m 2 . In addition, the resistances to the permeate flux during the microfiltration were investigated according to the series resistance. The final permeate flux ranged from 7.05 to 17.84 L·h –1 ·m –2 . There was a rapid decline in flux (50%) in the initial stages of microfiltration. T and V were the major variables responsible for the flux increase. The concentration polarization showed the greatest influence on the flux decline, and highest values for the flux decline rate ( λ) were found when low pressures were used. In the clarified juice there was a reduction in the contents of total solids, proteins, vitamin C, and acidity, while the soluble solids, pH, and ash contents did not change. Finally, membrane process could produce high quality filtered sugarcane juice with substantial flux and increased luminosity improving organoleptical properties.

EFEITO DA TEMPERATURA DE PASTEURIZAÇÃO NA ESTABILIDADE DE CALDO DE CANA ACIDIFICADO

O tempo de vida util do caldo de cana in natura e bastante limitado em virtude das elevadas taxas de reacoes microbiologicas e enzimaticas que ocorrem na bebida apos a sua extracao. Visando a avaliacao do impacto da temperatura de pasteurizacao na qualidade e na estabilidade de caldo de cana acidificado, processaram-se nove lotes de caldo adicionados de polpa de maracuja. Os lotes foram pasteurizados a 85, 90 e 95 °C por 30 s, em triplicata, envasados assepticamente em garrafas de polietileno tereftalato (PET) e estocados a 7 °C, na ausencia de luz. Testes fisico-quimicos foram realizados para caracterizar a bebida. Determinaram-se as atividades de polifenoloxidase (PPO) e peroxidase (POD) antes e apos o processamento. Contagens de coliformes e analise de Salmonella foram realizadas para garantir a seguranca microbiologica da bebida. Parâmetros de cor foram medidos durante o periodo de estocagem. Cinquenta provadores avaliaram a aparencia, o aroma, o sabor e a aceitacao global da bebida por meio de testes de escala hedonica de sete pontos. A estabilidade sensorial foi estimada considerando-se medias de notas acima de quatro e porcentagens de aceitacao superiores a 60%. As medias dos valores de pH, de solidos soluveis e de acidez titulavel do produto final variaram entre 3,96 e 4,19;19,7 e 20,1 oBrix, e 0,163 e 0,175 g/100g de acido citrico, respectivamente. Os binomios empregados no processamento foram efetivos na inativacao da PPO; entretanto, a completa inativacao da POD foi alcancada apenas pelo tratamento a 95 °C/30 s. A estabilidade sensorial da bebida processada a 85, 90 e 95 °C/30 s foi estimada em 30, 40 e 50 dias, respectivamente. O aumento da temperatura de pasteurizacao impactou positivamente na estabilidade da bebida.

Sugarcane Juice Processing: Microbiological Monitoring

This study was undertaken to evaluate a pilot plant designed for sugarcane juice processing. The juice was extracted in an electric mill and acidified with citric acid until the pH of 4.3. Next, it was pasteurized in a plate heat exchanger at 95°C/30 sec, cooled to 10°C before being filled into a plastic bottle and induction sealed. Product filling was performed in an ISO class 5 unidirectional air-flow cabins. Three batches of acidified sugarcane juice were produced. The qualities of the raw material, rinse water of the processing and filling line, packaging and end product were all microbiologically evaluated. Hedonic scale tests were used to evaluate the sensory acceptance of the product. The total mean counts in mesophilic culture of molds and yeasts from the natural, fresh sugarcane juice were (6.26 and 5.20) log CFU/mL, respectively. These mean counts, in both rinse water samples of the processing line and the bottles, were lower than 1 log CFU/mL. The mean counts of molds and yeasts in acidified and pasteurized sugarcane juice were (2.63 and lower than 1) log CFU/mL, respectively. The findings indicated that the procedures that were evaluated met standards for acidified sugarcane juice to be produced then stored under refrigeration.

Effect of Pasteurization Temperature on Sensory Stability of an Acidified Sugarcane Juice Beverage

To evaluate the impact of pasteurization temperature on sensory stability of sugarcane juice with passion fruit pulp, nine batches of sugarcane juice with 4 g/100 g passion fruit pulp were processed at (85, 90 and 95)°C for 30s, in triplicate). The pasteurized beverage was aseptically packaged in Polyethylene Terephthalate (PET) bottles and stored at 7°C in the dark. The beverage was characterized by physicochemical tests. Enzymatic activities of Polyphenol Oxidase (PPO) and Peroxidase (POD) were determined before and after processing. Coliforms and Salmonella counts were performed to ensure safety of the beverage safety. Psychrotrophic bacteria and yeasts and molds counts were carried out to assess the microbiological stability. Color parameters were measured in the processed juice throughout the storage period. A team of fifty panelists evaluated the appearance, aroma, flavor, and overall impression of the beverage using seven-point hedonic scale tests. Sensory stability was estimated by considering score averages above four and percentages of acceptance above 60%. The pH, soluble solids and titratable acidity of end product ranged from (3.96 to 4.19), (19.7 to 20.1) oBrix, and (0.163 to 0.175) g/100 g citric acid, respectively. The three processing binomials were effective for PPO inactivation; however, complete POD inactivation was reached at 95 °C/30 s only. Coliforms and Salmonella counts were in compliance with Brazilian Regulations. The estimated sensory shelf-lives for sugarcane juice with passion fruit pulp processed at (85, 90 and 95)°C/30 s were (30, 40 and 50) days, respectively. Thus, the increase of temperature pasteurization had a positive effect on product’s stability.

INTERAÇÃO EMBALAGEM-ALIMENTO SOBRE A ESTABILIDADE DE DOCE DE CUPUAÇU (Theobroma grandiflorum Schum.)

Cupuaçu (Theobroma grandiflorum Schum.) is an exotic fruit with a promising economic potential, particularly due to its strong aroma and creamy texture. This study aimed to produce sweetened cupuaçu puree and evaluate the effects of packaging corrosion on its sensory properties and shelf-life in tinplated cans. After 240 days of storage, the commercially sterile product had average sensory analysis scores of 5.89 ± 0.21, 5.39 ± 0.30, 5.45 ± 0.21 and 5.49 ± 0.25, for appearance, aroma, flavor and overall appreciation, respectively. Sensory acceptance scores did not change during storage (p>0.05). Corrosion potential and low tin and iron levels in the product, which are parameters used to evaluate food-packaging interaction, demonstrated the product remained food-safe throughout its shelf-life. Tinplate is a promising packaging material for sweetened cupuaçu puree due to its mechanical and protective properties. Furthermore, tin plating is an economically viable food technology to extend the shelf-life of cupuaçu products and expand its domestic and international markets.