Solid-state fermentation with orange waste: optimization of Laccase production from Pleurotus pulmonarius CCB-20 and decolorization of synthetic dyes

Laccases are oxidoreductase enzymes that have the ability to oxidize phenolic substrates. Its biotechnological potential has been greatly explored in many areas as biotechnology industry, bioremediation of dyes, food industry and environmental microbiology. The aim of this study was maximize the laccase production by Pleurotus pulmonarius (Fr.) Quélet in solid-state fermentation (SSF) using orange waste as substrate. After optimization the capability of the crude laccase to decolorize dyes was analyzed. The fermentation medium in the solid-state was optimized by applying a factorial design. After statistics optimization, laccase activity increased two times. The laccase activity appears to be correlated with the ability of crude extract to decolorize some industrial dyes. The optimized laccase was characterized with respect to optimum pH, influence of temperature and salts. Our results demonstrate that P. pulmonarius was an efficient producer of an important industrial enzyme, laccase, in a cheap solid-state system using orange waste as substrate.

Influence of osmotic dehydration on ascorbic acid loss in pickled dry peppers (Capsicum chinense)

The objective of this work was (1) to develop a dehydrated pepper with 45% humidity, determining the drying curves for pepper, with and without osmotic pre-treatment and (2) to evaluate the influence of both drying and osmotic treatment on the content ascorbic acid (vitamin C) in fresh pepper and pepper with 45% humidity. The experiments were carried out using the peppers cut in half, with and without osmotic pre-treatment, followed by drying in an oven at 70 ºC. The results showed that the osmotic pretreatment did not influence the retention of ascorbic acid during the drying of pepper. The sensory analysis regarding the color, flavor, and texture attributes revealed that there was no difference in the acceptability.

Avaliação físico-química, colorimétrica e aceitação sensorial de emulsão estabilizada com polpa de banana verde / Physical-chemical, colorimetric and sensorial characteristics of the emulsion formulation stabilized with green (unripe) banana pulp

Com o propósito de introduzir melhor aproveitamento da banana verde, em escala industrial, e também pelo seu alto teor de amido, foram preparadas formulações de emulsões tipo maionese estabilizadas com polpa de banana verde (PBV). A análise das emulsões foi realizada por meio de Metodologia de Superfície de Resposta. As formulações apresentaram alto teor de carboidratos, baixos teores de lipídios e baixos valores energéticos, além de elevados teores de sais minerais como potássio, ferro, magnésio, cálcio, fósforo e sódio. Esses constituintes conferem enriquecimento nutricional e, ainda, valorizam o produto. As amostras com menores teores de polpa (PBV) apresentaram maiores valores de luminosidade (L*) e com menores tendências a demonstrar cromas vermelho e amarelo (a* e b*). A demais, as amostras com maior teor de PBV apresentaram coloração similar àquela observada na maionese comercial. Em relação à aceitação das emulsões pelos consumidores, as médias de avaliação foram superiores a 6,95, em escala hedônica de nove pontos, o que significa alta aceitabilidade global. Outrossim, as formulações com maior teor de polpa de banana verde foram as preferidas entre os membros avaliadores. A aceitação das emulsões foi confirmada também pela atitude de compra, em que 75% dos consumidores opinaram que comprariam o produto.

Granules morphology and rheological behavior of green banana (Musa cavendishii) and corn (Zea mays) starch gels

In this work, it was used starch obtained from green banana (Musa cavendishii) and commercial corn (Zea mays) starch in order to compare the granule morphology and the rheological behavior of these gel-starches. Images of starch granules morphology were obtained from scanning electron microscope (SEM). The banana starch granules presented an oval and ellipsoidal shape with irregular diameters. Neverthless, the granules of corn starch showed a poliedric shape, with different sizes. The rheological behavior of gel starch solutions showed a non-newtonian character with a pseudoplastic behavior. Herschel-Bulkley model gave a good description on the rheological behavior of the gel starch. Banana gel-starch solutions showed higher values of shear stress and apparent viscosity when compared with corn gel-starch solutions. A progressive decrease in shear stress and viscosity occurred with the addition of sodium chloride and sucrose.

No presente trabalho foi utilizado amido obtido de banana verde (Musa cavendishii) e amido de milho (Zea mays) comercial, com o objetivo de comparar a morfologia dos grânulos e o comportamento reológico dos géis. As imagens da morfologia dos grânulos foram obtidas por microscopia eletrônica de varredura. Os grânulos de amido da banana apresentaram forma oval e elipsoidal com diâmetros irregulares, todavia, os grânulos do amido de milho mostraram forma poliédrica e diferentes tamanhos. As análises reológicas dos géis das soluções de amido mostraram caráter não-newtoniano, pseudoplástico. O modelo de Herschel-Bulkley foi o que melhor representou comportamento reológico dos géis. O gel de amido de banana verde obteve maiores valores de tensão de cisalhamento e viscosidade aparente quando comparada ao gel de amido de milho. Ocorreu um decréscimo progressivo na tensão de cisalhamento e na viscosidade com a adição de cloreto de sódio e sacarose aos géis.