Abstract Vinasse is the main liquid waste of the ethanol industry and its valorization by a bioprocess as a substrate for production of a value-added product contributes to the ethanol process. This work aimed to study the possibility to use vinasse for poly(3-hydroxybutyrate) (PHB) production by Cupriavidus necator. The growth of C. necator was evaluated using different vinasse concentrations and no inhibitory effect was observed. Cultivations in a bioreactor were carried out with pure vinasse, vinasse with nitrogen and vinasse with nitrogen and mineral salts. The best values of total biomass (5.1 g.L-1) and PHB (26% of total biomass) were obtained in the cultivation with nitrogen and salts added. The results indicated that vinasse could be used for PHB production. However, vinasse should be used in association with another substrate, aiming to improve the production. This is the first report on vinasse valorization for PHB production by C. necator.

ABSTRACT Mathematical models are widely used to predict the shelf life of foods. Lactic acid bacteria (LAB), particularly Lactobacillus plantarum, Weissella viridescens and Lactobacillus sakei, are the main spoilage bacteria of refrigerated, vacuum-packed meat products, stored in modified atmosphere, and their growth determines the shelf life length of these products. The objective of this study was to model the growth of L. plantarum, W. viridescens and L. sakei under different isothermal cultivation conditions and establish secondary models to describe the effect of temperature on the growth parameters of these bacteria. The LAB growth was evaluated in culture medium at temperatures of 4, 8, 12, 16, 20 and 30 ºC. The fit of Baranyi and Roberts (BAR) and Gompertz (GO) primary models to the growth curves of LAB was compared by statistical indices, in which the BAR model showed slightly better fits to the experimental data. The BAR growth parameters were used to establish the secondary models, µmax and Nmax were established for the three LAB. The power model described the influence of temperature on the parameter λ for L. plantarum, and other bacteria showed no lag phase. The growth of LAB was strongly influenced by storage temperature and the obtained models allow predicting the growth of these bacteria within the temperature range from 4 to 30 ºC.

Abstract Empirical sigmoidal models have been widely applied as primary models to describe microbial growth in foods. In predictive microbiology, the maximum specific growth rate (µ max ) and the lag phase (λ) are the parameters of some models and have been considered as biological parameters. The objective of the current study was to propose mathematical equations to obtain the parameters μ max and λ for any sigmoidal empirical growth model. In a case study, the performance was compared of two models based on empirical parameters and two models based on biological parameters. These models were fitted to experimental data for Lactobacillus plantarum in six isothermal conditions. Some advantages of the proposed approach were the practical and biological interpretation of these parameters, and the useful information of the secondary modeling describing the dependence of µ max and λ with the temperature.

Resumo A extração de poli(3-hidroxibutirato) (P(3HB)) com a utilização de solventes tóxicos e voláteis é contraditória à ideia do emprego destes biopolímeros para minimizar as agressões ambientais causadas pelos polímeros petroquímicos. O carbonato de propileno (CP) possui baixa toxicidade e alto ponto de ebulição, o que garante baixo risco de perdas por evaporação e alto rendimento de recuperação, podendo assim ser reutilizado. O objetivo deste trabalho foi verificar o efeito da reutilização do CP, recuperado do processo de extração de P(3HB) produzido por Cupriavidus necator, no rendimento e pureza do biopolímero e avaliar as perdas de solvente durante as etapas do processo de extração. Verificou-se a possibilidade de recuperar 80% do CP ao longo do processo. O solvente recuperado foi reutilizado onze vezes sem perder sua eficiência no rendimento e na pureza do produto. Desta forma, o presente estudo propõe a reutilização do CP, no processo de extração de P(3HB), contribuindo assim para a redução dos custos de produção deste biopolímero.

Abstract Poly(3-hydroxybutyrate) (P(3HB)) extraction using toxic volatile solvents is contradictory to the idea of using this biopolymer to minimize environmental aggressions caused by petrochemical polymers. Propylene carbonate (PC) has low toxicity and high boiling point, which ensure a low risk of losses due to evaporation and high recovery performance, allowing for reuse. The aim of this study was to investigate the effect of reusing PC recovered the process of extraction of P(3HB) produced by Cupriavidus necator on the performance and purity of the biopolymer and evaluate the amount of solvent loss during the stages of the extraction process. It was observed that 80% of PC could be recovered throughout the process. The recovered solvent was reused eleven times without losing its efficiency in terms of product performance and purity. Hence, the present study proposes to reuse PC in the process of P(3HB) extraction, thus contributing to reduce the costs for the production of this biopolymer.

Abstract Chopped mussel meat packaged in retort pouches was processed in a laboratory-scale water immersion retort, adapted for processing under overpressure conditions. Retort temperature effects on product yield and on cook value were evaluated by setting the F0 at 7 min. The effects of different pre-treatments (salting and marination) on the characteristics of mussels were evaluated after processing at retort temperature of 118 °C and during a whole year of storage at 25 °C. The salted samples showed better yield during storage, while no differences were found for the other physicochemical parameters.

The aim of this study was to establish primary and secondary models to describe the growth kinetics of Byssochlamys fulva on solidified apple juice at different temperatures. B. fulva was inoculated on solidified apple juice at 10, 15, 20, 25 and 30 °C. Linear-with-breakpoint, Baranyi and Roberts, and Huang primary models (without upper asymptote) were fitted to the data, and they showed good ability to describe the growth kinetics. B. fulva showed longer adaptation time on apple juice than on culture medium, but growth rates were similar as reported in the literature. The dependence of µmax and λ parameters on temperature was described with Square Root and Arrhenius-Davey secondary models, respectively. These models were important to establish process/storage conditions and apple juice shelf life.

Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the presence of molds (including heat resistant species) and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macroscopic and microscopic characteristics after cultivation on standard media at 5, 25 and 37ºC, during 7 days. Among the 19 isolated found, 63% were identified as Penicillium with 50% belonging to the P. expansum specie. With regards to heat resistant molds, the species Neosartorya fischeri, Byssochlamys fulva and also the genus Eupenicillium sp., Talaromyces sp. and Eurotium sp. were isolated. The thermoacidophilic spore-forming bacteria were identified as A. acidoterrestris by a further investigation based on 16S rRNA sequence similarity. The large contamination found indicates the need for methods to eliminate or prevent the presence of these microorganisms in the processing plants in order to avoid both spoilage of apple juice and toxin production.

Poly (3-hydroxybutyrate) (P(3HB)) is a biopolymer, completely biodegradable, which has similar properties to fuel-based polymers. However to make it economically competitive it is necessary the study of cheap sources of substrate. The influence of hydrolyzed rice starch supplemented with soybean oil at different temperatures (30, 35 and 40 °C) was studied in the production of P(3HB) by C. necator. The percentage of P(3HB) produced in the cultures at 30, 35 °C was 30, 39% and 35, 43% without and with supplementation of oil, respectively. The culture at 40 °C showed no production phase due to a possible oxygen limitation. These results demonstrate that hydrolyzed rice starch supplemented with soybean oil increases the yield of P(3HB) and temperature of 35 ºC is the most favorable for biopolymer production.

Nesta pesquisa, foram estudados fatores que influenciam a ativação de ascósporos do fungo termorresistente Neosartorya fischeri (meio de aquecimento, a temperatura de produção e idade dos ascósporos). Os meios de aquecimento utilizados foram sucos de abacaxi e de mamão, em diferentes ratios (ºBrix/acidez) e a temperatura de ativação foi 85ºC. Pôde-se observar que o fungo N. fischeri apresentou seus menores tempos de ativação quando presentes no suco de abacaxi e no mamão, nas condições de temperatura e de idade de produção de 25ºC por 1 mês e o ratio do meio de aquecimento de 10 para suco de abacaxi e de 26 para suco de mamão. Nestes ensaios, o tempo de ativação foi de 5 minutos para suco de abacaxi e 10 minutos para o suco de mamão a 85ºC. Ascósporos produzidos a 35ºC, durante 3 meses e aquecidos em suco de abacaxi com ratio 38 e em suco de mamão com ratio 66 apresentaram os maiores tempos de ativação sendo estes de 15 a 20 minutos, respectivamente. Através de uma análise estatística, verificou-se que os fatores que mais influenciaram no tempo de ativação dos ascósporos foram o ratio e a temperatura de produção dos ascósporos.

In this research factors that influence the activation of Neosartorya fischeri ascospores (heating medium, temperature of production and age of the ascospores) were studied. The heating medium used was pineapple and papaya nectars at different ratios (ºBrix/acidity). Lower activation times were observed for the N. fischeri ascospores in pineapple and papaya nectars under the conditions of temperature and production age of 25ºC for 1 month and using ratios of the heating medium of 10 for pineapple nectar and 26 for papaya nectar. In these cases, the activation time was 5 minutes for the pineapple nectar and 10 minutes for the papaya nectar at 85ºC. For the ascospores produced at 35ºC over three months, heated in pineapple nectar at a ratio of 38 and in papaya nectar at a ratio of 66, the longest activation times of 15 and 20 minutes, respectively, were observed. The statistical analysis showed that the factors which had the most influence in the activation time of the ascospores were the ratio and the production temperature of ascospores.

Polyhydroxyalkanoates (PHAs) are carbon and energy storage materials that are accumulated as intracellular granules in a variety of microorganisms during unbalanced growth. PHAs have drawn attention due to their properties similar to conventional plastics and complete biodegradability. They can be used for food and cosmetics packaging, and in medicine and agriculture. However, their applicability is reduced because of their high production cost compared to conventional plastics. An overview on production strategies of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) aiming at reducing the production costs is presented.