Angela Silva

Optimisation of long-term activated-sludge treatment of winery wastewater

Abstract The results obtained in work carried out in order to verify the overall efficiency of full-scale, long-term, activated-sludge treatment of winery wastewater are presented. The analytical data showed the high removal of COD (average 98%; min. 97.6; max. 99.1) during the whole experimentation period and with various working parameters. The effluent had chemico-physical values in conformity with Table A of Italian Law No. 319 of 10 May 1976. Sludge production was lower than that produced by ordinary activated-sludge plants. Moreover, because of the low contents of heavy metals, organic matter and N, P, K content, this aerobic sludge is suitable for direct agricultural use or for compost production. The plant proved itself to be flexible enough to withstand large variations in the hydraulic and pollution loads and was found to have a low running cost.

Living immobilized Acetobacter in Ca-alginate in vinegar production: Preliminary study on optimum conditions for immobilization

SummaryThe optimum conditions forAcetobacter immobilization were investigated. The results show that: 1) the maximum oxygen uptake rate (OURm) and cell release are related to alginate and cell concentration in the gel; 2)different alginate concentration does not affect cell viability, but long storage in CaCl2 reduces the number of living cells; 3)the double alginate gel layers had no influence on cell viability and on the OURm and prevented cell leakage from the gel matrix.

Odor-active Compound Adsorption onto Bentonite in a Model White Wine Solution

This work extends the concepts proposed in a previous research paper about the interaction between the aroma of two white wines and bentonites. Such previous results led to hypothesized that some odor-active compounds were removed through direct adsorption mechanism on the clays. As a consequence, this paper examined the adsorption isotherms at 17±1°C of three bentonite samples added in three different amounts to a model white wine without the presence of wine macromolecule. The clays were analyzed for the elemental composition, the surface charge density, and the specific surface area (SSA) and differences were analyzed by Tukey’s test. The analysis of variance (ANOVA) was used to demonstrate the significance of the bentonite on the aroma reduction. The Langmuir and the Freundlich models were fitted to the adsorption data. The most experimental adsorption isotherms were robustly fitted by the Freundlich equation indicating that, under the condition of the study, the adsorption process more frequently occurred with a heterogeneous energy distribution of an infinite number of surface active sites. Overall, the modeling prediction ability tested by the error on r 2 in cross validation enhanced differences both among the odor-active compounds and among the clays. Samples having a lower SSA value and a greater charge density per surface unit seemed to interact with most of the odor-active compounds primarily through physical mechanisms. Differently, the clay with a large SSA value and a low charge density per surface unit promoted stronger adsorptions that were probably driven by chemical interactions especially for ethyl esters. For the tested odor-active compounds differences in the adsorption intensity and capacity depended mainly on the bentonite characteristics rather than on the properties of the substances.

Antibacterial activity of papain and bromelain on Alicyclobacillus spp.

Alicyclobacillus spp. are spore forming bacteria that are often related to the deterioration of acidic products such as beverages and citrus juices. After the process of industrial pasteurization, the spore produced by the bacteria can germinate and the microorganism can grow, causing sensory abnormalities in the product. Alternative biopreservatives, such as the antimicrobial compounds, are of considerable importance to the food industry. Papain and bromelain are proteolytic enzymes derived frompapaya and pineapple, respectively. These enzymes are widely used in medicine and in the pharmaceutical and food industries, but while some studies have described their antibacterial action, no studies of the Alicyclobacillus spp. exist. The aimof this studywas to analyze the antibacterial effect of papain and bromelain on Alicyclobacillus spp. through 1) determining minimum inhibitory and bactericidal concentration (MIC and MBC); 2) determining the death time curve of the micro-organism in the presence and absence of enzymes; and 3) investigating the enzymatic mechanism on the microorganism. The antibacterial activity of enzymes in combination with nisin was also evaluated. The results showed that for the Alicyclobacillus acidoterrestris strain, the MIC of papain was 0.98 μg/mL and the MBC was 3.91 μg/mL, while theMIC of bromelain was 62.5 μg/mL and the MBCwas 250 μg/mL. The concentration of 4 ×MIC for both the enzymes was sufficient to eliminate 4 logs of the micro-organism after 24 h of incubation. Through the use of enzyme inhibitors specific for cysteine proteases, it was found that the antibacterial activity of papain and bromelain is not related to its proteolytic activity, butmay be related to other activities, such as amidse and esterase. The synergistic activity of the enzymes revealed a fractional inhibitory concentration (FIC) level of 0.16. Combination with nisin revealed an FIC of 0.25 for papain and 0.19 for bromelain, indicating synergism between both compounds. The application of enzymes in reconstituted orange juice contaminated with A. acidoterrestris was found to be effective, as after 48 h of incubation, at three different temperatures, the initial microbial population was eliminated. This study showed that the enzymes papain and bromelain have an antibacterial effect on A. acidoterrestris.

Controlling Ochratoxin A in the Vineyard and Winery

Abstract: The chapter summarises the current availability of data on the toxicology of ochratoxin A (OTA) and public concern over human exposure to it, taking into account that the International Program on Chemical Safety/World Health Organisation has recently indicated a need for further study and evaluation with respect to human health potential. The fungi responsible for the presence of OTA in grapes and wine are defined, as are favourable meteorological conditions and cropping systems. A short description of efforts devoted to understanding the problem (i.e. research projects) is included. Grape processing has a significant impact on the fate of OTA during the main stages of winemaking (crushing, maceration, alcoholic fermentation, malo-lactic fermentation, bottling, ageing), and critical steps of the process have been identified. Post-harvest strategies for the control of OTA in wines are focused on developments in the field of biological decontamination of OTA through the use of yeasts and lactic acid bacteria. Worldwide surveys have determined the main risk factors. The approach of risk assessment is described and data on wine consumption and the related risk of OTA ingestion are reported with some comments on the effective related risk. The approach of a decision support system (DSS) is described, including the development of a predictive model, good agricultural practices and good manufacturing practices to minimise OTA in grapes and wine.

Model for prediction of immobilized Acetobacter cell number in calcium alginate gel droplets

The geometry of calcium alginate gel spheres is studied by fractal interpretation for prediction of number of cells to be immobilized. For alginate concentrations from 1 to 5% the simulated results are of 6.65×108, 1.44×108 and 5.27×107 N cell mL−1 for respectively 1.5, 2.5 and 3.5 mm gel sphere diameters. Simulated data are compared with those resulting from literature and particularly with experimental trials where from 107 to 108 N cell mL−1, in 2% alginate beads with a diameter of 1.5 mm, is able to fulfil mechanical and swelling characteristics of alginate gel beads besides to supply good oxygenation.

Valorisation of stalks from different grape cultivars for sugars recovery

This study has been realized under a national project Valorvitis focused on the valorisation of wine making by-products for the production of high added-value compounds. The aim of this work was to investigate the possibility of recovering sugars as hemicelluloses hydrolysates suitable for bioethanol production. The production of hemicelluloses hydrolysates from stalks of six different grape cultivars was studied to assess: the cultivar influence on the recovery of non-structural sugars in the washing pre-treatment step; the influence of the cultivar and of the liquid/solid ratio in the acid hydrolysis step on the recovery of structural sugars; and the cultivar influence on the content of sugars degradation products(5-HMF, furfural and 5_MF), total phenols (based on Folin index), phenolic acids (by HPLC) and minerals in the hydrolysates (since these compounds could positively or negatively influence fermentation processes). The applied process consisted in a washing pre-treatment, followed by a dilute acid hydrolysis step (2 % sulfuric acid with two different solvent-to-solid ratios (10:1 and 20:1). The pre-treatment allowed to recover from 4.7 to 6.8 g(Glucose+Fructose)/100 gdm depending on the cultivar, but in very diluted liquors (< 5 g/L as Glu+Fru). The 10:1 ratio was selected for the hydrolysis, since allowing for almost the same xylose yield as for the 20:1 ratio (from 4 to 7.4 g/100 gdm depending on the cultivar), the liquors contained lower amounts of phenolic compounds and sugar degradation products. The antioxidant activity (based on the radical ABTS test) of the hydrolysates (which could have an inhibitory effect in fermentation) was slightly influenced by the cultivar but not by the solvent to solid ratio. For all the cultivars, mineral analysis showed a certain content in micro and macronutrients that could positively influence a hypothetical fermentation process for bioethanol production. Therefore, the applied process could be optimized in order to recovery higher quantity of sugars with a reduced generation of inhibitory substances, to be used in fermentation processes.

Trapped Acetobacter in membrane bioreactor: fractal interpretation of a compatible population

Acetobacter localisation within membrane porosity and cell release in permeate stream were investigated. Predictions by a model based on the fractal nature of membranes were compared with the data obtained from pilot plant running tests. The results indicate possibilities for application in studies to help and control the process.

Avaliação da Atividade Antibacteriana de Enzima Natural em Alicyclobcillus Acidoterrestris

Marcia Maria dos Anjos, Angela Aparecida da Silva, Isabella Carolini Pascoli, Jane Graton-Mikcha, Jane GratonMikcha, Miguel Machinski-Junior, Celso Vataru Nakamura, Benicio Alves de Abreu-Filho. Avaliacao da Atividade Antibacteriana de Enzima Natural em Alicyclobcillus Acidoterrestris. In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-285 Avaliacao da Atividade Antibacteriana de Enzima Natural em Alicyclobcillus Acidoterrestris

Avaliação Quantitativa da Qualidade Microbiológica do Ar de Ambientes Climatizados de Manipulação de Alimentos da Universidade Estadual de Maringá.

Jessica Marchiori Bicalho, Marcia Maria dos Anjos, Angela Aparecida da Silva, Isabella Carolini Pascoli, Celso Vataru Nakamura, Benicio Alves de Abreu-Filho. Avaliacao Quantitativa da Qualidade Microbiologica do Ar de Ambientes Climatizados de Manipulacao de Alimentos da Universidade Estadual de Maringa.. In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-150 Avaliacao Quantitativa da Qualidade Microbiologica do Ar de Ambientes Climatizados de Manipulacao de Alimentos da Universidade Estadual de Maringa.