Water sorption isotherms on lyophilized jabuticaba (Myrciaria cauliflora) peel: potential byproduct for the production of dehydrated foods.

In this work, water sorption profiles on lyophilized jabuticaba peel were evaluated using the BET, GAB, Halsey, Henderson, Oswin and Smith isotherm models. All water sorption studies were conducted using the static gravimetric method and saturated CH3COOK, K2CO3, NaBr, SnCl2, KCl and BaCl2 solutions at 20, 30 and 35 °C. The best water sorption isotherm fits were determined with the GAB model at 20 °C, Oswin model at 30 °C and Halsey model at 35 °C. The curve profiles of the isotherm models employed were classified as type III. The results revealed that lyophilized jabuticaba peel can be safely stored at 20, 30 or 35 °C with the monitoring and control of relative humidity, equilibrium humidity and water activity. However, microbial action and undesirable enzymatic reactions may occur at 35 °C when the relative humidity is above 22%. The present results are useful for defining suitable storage and production conditions of a novel jabuticaba peel-based process for the production of dehydrated foods.

Phytotoxicity Increase Induced by Zinc Accumulation in Cichorium intybus.

The accumulation of zinc (Zn) in Cichorium intybus and effects of phytotoxicity during 90 days of growth on (natural) non-contaminated and Zn-contaminated soils were studied. The phytotoxicity effects were monitored by evaluating the leaf area, leaf biomass, leaf length and root length of the vegetable. The Zn concentrations ranged from 5.35 ± 1.05 to 37.5 ± 3.89 mg kg-1 in leaves of plants grown on natural soil, and from 334.0 ± 25.6 to 2232 ± 16.7 mg kg-1 when grown on Zn-contaminated soils. Zn accumulation caused a decrease in growth on contaminated soils and an increase in phytotoxicity. These effects were associated to high metal concentration, mobility and bioavailability in the soil as well as changes in the translocation mechanism from the roots to the leaves. Then, it must be avoided the organic fertilization of soils with either animal manure or other agricultural inputs containing high zinc concentrations.

Ecotoxicological effects of fipronil, neem cake and neem extract in edaphic organisms from tropical soil.

Veterinary medicines are widely applied for the treatment and prevention of animal diseases. Consequently, animal manure contains significant amounts of environmental pollutants that are potential sources of environmental pollution when inappropriately applied in soils. This work aimed to evaluate ecotoxicological effects of doses of commercial fipronil, neem cake and neem extract in the survival and reproduction of earthworms (Eisenia andrei), enchytraeidae (Enchytraeus crypticus) and springtails (Folsomia candida) in Oxisol and tropical artificial soil (TAS). Applications of fipronil, neem cake and extract in soil were carried out according to standardized ISO methodologies by using a random experimental design with five replicates. Toxic effects of fipronil for springtails in Oxisol and TAS were observed with LC50 of 0.26 mg kg-1 (0.18-0.35 mg kg-1) and 0.29 mg kg-1 (0.22-0.37 mg kg-1), respectively. It was not observed significant toxic effects of fipronil for earthworms and enchytraeidae in both soils. However, significant amounts of juvenile earthworm and adult enchytraeidae decreased in fipronil doses higher than 10 mg kg-1. Neem cake and extract were not toxic for earthworms and enchytraeidae but, significant amounts of juvenile springtails decreased in neem cake doses from 500 to 1000 mg kg-1. It can be concluded that the use of veterinary medicines containing synthetic compounds for preventing diseases in animals needs to be controlled to avoid environmental pollution after applying manure in soil. Veterinary medicines containing natural compounds as neem cake and extract are eco-friendly and could be efficiently applied in soil in a sustainable way.

Stabilization of ß-D-galactosidase in solution containing chitosan-based membrane: Central composite rotatable design.

ß-D-galactosidase is a hydrolase enzyme capable of hydrolyzing lactose in milk-based foods. Its free form can be inactivated in solution during the production of low-dosage lactose foods. Then, it is important to study strategies for avoiding the free enzyme inactivation with the aim of circumventing this problem. The stabilization of ß-D-galactosidase in aqueous solution after interactions with chitosan/eucalyptus sawdust composite membrane proved to be a potential strategy when optimized by central composite rotatable (CCR) design. In this case, the best experimental conditions for ß-D-galactosidase partitioning and stability in an aqueous medium containing the chitosan-based composite membrane reinforced with eucalyptus sawdust were i) enzyme/buffer solution ratio of 0.0057, ii) pH 5.6, iii) membrane mass of 50 mg, and iv) temperature lower than 37 °C. Significance was found for the linear enzyme/buffer solution ratio, linear temperature, and quadratic pH (p < 0.05) in the interval between 0 and 60 min of study. In the interval between 60 and 120 min, there was significance (p < 0.12) for linear temperature, the temperature-enzyme/buffer solution ratio interaction and the interaction between linear pH and linear enzyme/buffer solution ratio. The Pareto charts and response surfaces clearly showed all the effects of the experimental variables on the stabilization of ß-D-galactosidase in solution after interactions with the chitosan composite membrane. In this case, industrial food reactors covered with chitosan/eucalyptus sawdust composite membrane could be a strategy for the hydrolysis of lactose during milk-producing processes.

Pinus residue/pectin-based composite hydrogels for the immobilization of ß-D-galactosidase.

The aim of this work was to synthesize pinus residue/pectin-based composite hydrogels for the immobilization of ß-D-galactosidase. These hydrogels were synthesized via chemical crosslinking, and characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal analysis, mechanical assays, X-ray diffraction, and swelling kinetics. The water absorption mechanism in the hydrogel networks occurs by non-Fickian transport. The ß-D-galactosidase immobilization capacities of the hydrogels containing 0, 5 and 10% of pinus residue were respectively 242.08 ± 0.36, 181.27 ± 0.50 and 182.71 ± 0.36 mg enzyme per g dried hydrogel, at pH 4.0 and after 600 min. These values were 182.99 ± 0.41, 219.99 ± 0.47 and 218.56 ± 0.39 mg g-1, respectively, at pH 5.6. Pectin-based hydrogels demonstrated to be excellent solid supports for the immobilization of enzymes. ß-D-Galactosidase immobilized in pectin-based hydrogels could be applied in the hydrolysis of lactose contained in either dairy foods or lactose-intolerant individuals.

Full-factorial central composite rotational design for the immobilization of lactase in natural polysaccharide-based hydrogels and hydrolysis of lactose.

A full-factorial central composite rotational design (FFCCRD) was applied for studying the immobilization of lactase in Arabic gum-based and chitosan-based hydrogels, and hydrolysis of lactose. The optimal immobilization capacities of both hydrogels aiming to obtain high immobilized enzyme activity and low released fraction were determined at 25.0 °C, 39.88 mg mL-1 initial enzyme concentration and pH 6.5. The immobilized enzyme activity and released fraction from the Arabic gum-based hydrogel were 0.322 U mg-1 and 0.193, respectively, during the hydrolysis of lactose contained in UHT milk. These values were 0.289 U mg-1 and 0.136, respectively, using a chitosan-based hydrogel. The immobilized enzyme activity and released fraction from these hydrogels during the hydrolysis of standard lactose were 0.246 U mg-1 and 0.407, and 0.211 U mg-1 and 0.245, respectively. The best conditions for the immobilization of lactase and hydrolysis of lactose were achieved by applying FFCCRD, which were compared with experimental results.

Correction to: Adsorption and removal of chromium (VI) contained in aqueous solutions using a chitosan-based hydrogel.

The original publication of this paper contains an error. The correct 4th heading in Table 1 should be "Non-linear sips isotherm". The original article has been corrected.

Adsorption and removal of chromium (VI) contained in aqueous solutions using a chitosan-based hydrogel.

The aim of this work was to study the adsorption and removal of chromium (VI) ions contained in aqueous solutions using a chitosan-based hydrogel synthesized via chemical crosslinking of radical chitosan, polyacrylic acid, and N,N'-methylenebisacrylamide. Fourier-transform infrared spectroscopy confirmed the hydrogel synthesis and presence of reactive functional groups for the adsorption of chromium (VI) ions. The chromium (VI) adsorption mechanism was evaluated using non-linear Langmuir, Freundlich, Redlich-Peterson, and Sips isotherms, with the best fit found by the non-linear Redlich-Peterson isotherm. The maximum chromium (VI) adsorption capacities of the chitosan-based hydrogel were 73.14 and 93.03 mg metal per g dried hydrogel, according to the non-linear Langmuir and Sips isotherm models, respectively. The best kinetic fit was found with the pseudo-nth order kinetic model. The chromium (VI) removal percentage at pH 4.5 and 100 mg L-1 initial metal concentration was 94.72%. The results obtained in this contribution can be useful for future works involving scale-up of a water and wastewater treatment method from a pilot plant to full-scale plant.

Hydrolysis of lactose using ß-d-galactosidase immobilized in a modified Arabic gum-based hydrogel for the production of lactose-free/low-lactose milk.

ß-d-galactosidase was immobilized in a modified Arabic gum-based hydrogel for the hydrolysis of standard lactose and lactose contained in UHT milk with the aim of producing lactose-free/low-lactose milk. The hydrogel was synthesized by cross-linking the modified Arabic gum with acrylamide, using potassium persulfate as initiator. Fourier-transform infrared spectroscopy and scanning electron microscopy confirmed the formation of the hydrogel and its three-dimensional porous network. Swelling degrees in distilled water, drinking water, phosphate buffer solution at pH7.0 and acetate buffer solution at pH4.0 were 12.56 and 17.72, 10.65 and 12.58, 8.58 and 10.71, and 6.49 and 8.16g water per g dried hydrogel at room temperature and 37.0±1.0°C, respectively. The immobilization capacities of ß-d-galactosidase in acetate and phosphate buffer solutions at room temperature were 242.52±0.13 and 118.42±0.23mg enzyme per g dried hydrogel, respectively, after 1440min of contact. Higher enzymatic activities were found after immobilization in phosphate buffer solution due to the isoelectric point of ß-d-galactosidase. Hydrolysis of standard lactose and lactose contained in UHT milk was more efficient using immobilized ß-d-galactosidase than free ß-d-galactosidase. Immobilized ß-d-galactosidase was applied for three cycles of hydrolysis of lactose without significantly losing enzymatic activity.

Evaluation of soil contamination by heavy metals at public cemeteries in the municipality of Lages, southern Brazil / Avaliação da contaminação de solos por metais tóxicos em cemitérios públicos do município de Lages, Sul do Brasil

ABSTRACT The burial of bodies is a potentially polluting activity. Taking this into consideration, the aim of the present study was to verify the compliance of two cemeteries with environmental legislation and to quantify the concentrations of heavy metals in soils affected by burial activities. Physicochemical characterization of the soil was performed by analyzing control samples from areas near the cemeteries. Concentrations of cadmium, lead, chromium, nickel, zinc and copper were determined using high-resolution continuum source atomic absorption spectrometry. The two cemeteries had unsatisfactory properties for the retention of metal cations, with clay percentages ranging from 15.40 to 41.40% and sand percentages ranging from 28.75 to 66.85%. The control samples presented low cation exchange capacity (12.27 to 22.73 cmolc/dm³) and high aluminum (Al3+) saturation (66.74 to 90.16%). Although neither of the two cemeteries had concentrations above the limits established for the metals analyzed by Resolution No. 420/2009 of the National Environment Council, the contaminants may be leaching to groundwater due to inadequate soil characteristics.

RESUMO O sepultamento de corpos é uma atividade potencialmente poluidora. Este trabalho teve como objetivo verificar a adequação das áreas de dois cemitérios públicos à legislação ambiental e à atividade cemiterial e quantificar a concentração de metais pesados nos solos que estão sob influência desses empreendimentos. Realizou-se a caracterização físico-química do solo, com a análise de amostras testemunha de solo de cada cemitério. Também foram determinadas as concentrações dos metais pesados: cádmio, chumbo, cromo, níquel, zinco e cobre, por meio de espectrometria de absorção atômica de alta resolução com fonte contínua. As áreas dos cemitérios apresentam condições insatisfatórias para a retenção de íons catiônicos metálicos, com percentuais de argila variando entre 15,40 e 41,40% e de areia entre 28,75 e 66,85%. Os solos testemunha apresentaram reduzida capacidade de troca de cátions entre 12,27 e 22,73 cmolc/dm³) e elevada saturação por alumínio entre 66,74 e 90,16%. Apesar de nenhum dos cemitérios apresentar concentrações dos metais analisados acima dos limites de prevenção estabelecidos pela Resolução nº 420/2009 do Conselho Nacional do Meio Ambiente, em função das características dos solos, os contaminantes podem estar sendo lixiviados para os recursos hídricos subjacentes.

Morphological diversity of springtails (Hexapoda: Collembola) as soil quality bioindicators in land use systems / Diversidade morfológica de colêmbolos (Hexapoda: Collembola) como bioindicadora de qualidade do solo em sistemas de uso

Abstract: The aim of this work was to evaluate the soil quality of native forest, eucalyptus plantations, pasture, integrated crop-livestock, and no-tillage systems, correlating the morphological diversity of springtails with physical and chemical soil properties. Springtail samples were captured from soils of the southern plateau of the State of Santa Catarina in Brazil, during winter and summer, by using Pitfall traps, using a 3 × 3 point grid. The morphotyping of springtails consisted of the observation of five traits and for each one a partial value of the eco-morphological index was assigned to obtain the modified Soil Quality Index. A correlation of the morphotype abundance and diversity with physical (soil moisture, bulk density, biopores, microporosity, and macroporosity) and chemical (pH in water, calcium/magnesium ratio and total organic carbon content) soil properties was studied, describing all results by variance and multivariate analyses. The springtail abundance and diversity were influenced by the different land use systems. Higher soil quality index was determined in native forest followed by eucalyptus plantations, pasture, no-tillage system and integrated crop-livestock, in the winter. Moreover, higher soil quality index was found in native forest followed by integrated crop-livestock, eucalyptus plantations, no-tillage system and pasture, in the summer. Therefore, the quality index of a soil can be evaluated by the springtail morphological traits in correlation with the physical and chemical properties such as calcium/magnesium ratio, total organic carbon contents, biopores, macroporosity, microporosity, soil moisture, bulky density and pH.

Resumo: O objetivo deste trabalho foi avaliar a qualidade do solo de florestas nativas, reflorestamento de eucalipto, pastagem, sistemas de integração lavoura-pecuária e plantio direto, correlacionando a diversidade morfológica de colêmbolos com propriedades físicas e químicas do solo. Amostras de colêmbolos foram coletadas de solos do planalto sul do Estado de Santa Catarina no Brasil, durante o inverno e o verão, usando armadilhas de queda, em grade amostral de 3 × 3. A morfotipagem dos colêmbolos consistiu na observação de cinco características e para cada uma foi atribuído um valor parcial do índice eco-morfológico para a obtenção do Índice de Qualidade do Solo modificado. As avaliações foram da abundância e diversidade de morfotipos e de atributos físicos (umidade do solo, densidade do solo, bioporos, microporosidade e macroporosidade) e químicos do solo (pH em água, relação cálcio/magnésio e carbono orgânico total), descrevendo os resultados por análises de variância e multivariada. A abundância e a diversidade de colêmbolos foram influenciadas pelos diferentes sistemas de uso do solo. Maior índice de qualidade do solo foi determinado em floresta nativa seguida de reflorestamento de eucalipto, pastagem, plantio direto e integração lavoura-pecuária, no inverno. Além disso, encontrou-se maior índice de qualidade do solo em floresta nativa seguida de integração lavoura-pecuária, reflorestamento de eucalipto, plantio direto e pastagem, no verão. Portanto, o índice de qualidade do solo pode ser avaliado pelas características morfológicas de colêmbolos em correlação com as propriedades físicas e químicas, como razão cálcio/magnésio, teores de carbono orgânico total, bioporos, macroporosidade, microporosidade, umidade do solo, densidade do solo e pH.