Influence of pH on viscoelastic properties of heat-induced gels obtained with a β-Lactoglobulin fraction isolated from bovine milk whey hydrolysates

Food Chemistry, 219, 2017, 169–178

http://dx.doi.org/10.1016/j.foodchem.2016.09.137

A β-Lactoglobulin fraction (r-βLg) was isolated from whey hydrolysates produced with cardosins from Cynara cardunculus. The impact of the hydrolysis process on the r-βLg structure and the rheological properties of heat-induced gels obtained thereafter were studied at different pH values. Differences were observed between r-βLg and commercial β-Lg used as control. Higher values for the fluorescence emission intensity and red shifts of the emission wavelength of r-βLg suggested changes in its tertiary structure and more solvent-exposed tryptophan residues. Circular dichroism spectra also supported these evidences indicating that hydrolysis yielded an intermediate (non-native) β-Lg state.

The thermal history of r-βLg through the new adopted conformation improved the microstructure of the gels at acidic pH. So, a new microstructure with better rheological characteristics (higher conformational flexibility and lower rigidity) and greater water holding ability was founded for r-βLg gel. These results were reflected in the microstructural analysis by scanning electron microscopy.

Contributions of a compost-biochar mixture to the metal sorption capacity of a mine tailing

Environmental Science and Pollution Research

February 2016, Volume 23, Issue 3, pp 2595–2602

DOI: 10.1007/s11356-015-5489-0

One technique applied to restore degraded or contaminated soils is to use amendments made of different types of waste materials, which in turn may contain metals such as Cu, Pb and Zn. For this reason, it is important to determine the capacity of the soil to retain these materials, and to compare the sorption capacity between an amended soil and another unamended soil. The aim of this study was to determine the mobility and availability of these metals in the soil after applying the amendment, and how it affected the soil’s sorption capacity. Sorption isotherms were compared with the empirical models of Langmuir and Freundlich to estimate the sorption capacity. The overall capacity of the soils to sorb Cu, Pb or Zn was evaluated as the slope Kr. The amendments used in this study were a mixture made of compost and biochar in different proportions (20, 40, 60, 100 %), which were applied to the mine tailing from a settling pond from a copper mine. The mine tailing that were amended with the mixture of compost and biochar had a higher sorption capacity than the mine tailing from the unamended pond, and their sorption isotherms had a greater affinity towards Cu, Pb and Zn than the mine tailing that was studied. Therefore, the results obtained show that adding a mixture of compost and biochar favours the retention of Cu, Pb and Zn in mine tailing.

Assessing the influence of technosol and biochar amendments combined with Brassica juncea L. on the fractionation of Cu, Ni, Pb and Zn in a polluted mine soil

Journal of Soils and Sediments

February 2016, Volume 16, Issue 2, pp 339–348

DOI: 10.1007/s11368-015-1222-3

Soil metal pollution is a widespread problem around the world and remediation of these soils is difficult. The objective of this study was to investigate the effect of two different strategies on the chemical fractions of metals in a soil of a depleted copper mine: (1) amending with a mixture of a technosol made of wastes and biochar and (2) amending combined with planting vegetation (Brassica juncea).

A 3-month greenhouse experiment was carried out to evaluate the effects of organic amendments and vegetation on the metal fractionation of Cu, Ni, Pb and Zn in a mine soil of the depleted copper mine at Touro (Spain). We compared the influence of organic amendments alone (technosol + biochar) and combined with mustard plants (Brassica juncea L.).

The results showed that amending with a technosol made of wastes promoted plant growth (from 0.7 to 2.9 g of biomass produced) and reduced the CaCl2-extractable metal concentration in soil, reduced the mobility factor of Cu from 18.3 to 1.6, Ni from 47.5 to 2.3 and Pb from 17.9 to 2.1, and also reduced the concentration of metals in the mobile soil fractions. It was not possible to grow up Brassica juncea plants in the untreated settling pond soil due to the extremely degraded conditions of that soil. However, the application of the used technosol increased the Pb and Zn pseudototal concentrations in the amended soils.

We conclude that the combination of amending with wastes and planting B. juncea provides little additional benefit for remediating a metal-polluted soil compared with incorporation of wastes alone.

Contribution of waste and biochar amendment to the sorption of metals in a copper mine tailing

CATENA
Volume 137, February 2016, Pages 120–125
http://dx.doi.org/10.1016/j.catena.2015.09.010

One technique applied to restore degraded or contaminated soils is to use amendments made of different types of waste materials, which in turn may contain metals such as Cu, Pb and Zn. For this reason it is important to determine the capacity of the soil to retain these materials, and to compare the sorption capacity between an amended soil and another unamended soil. The aim of this study was to determine the chemical behaviour of these metals in the soil after applying the amendment, and how it affected the soil's sorption capacity. Another aim was to study the contribution of contaminating elements from the amendment itself. The amendments used in this study were a mixture made of waste material (sewage sludges, sludges from an aluminium plant, ash, food industry wastes, and sands from a wastewater treatment plant) and biochar (biomass of Acacia dealbata) (97%:3%) in different soil/amendment proportions. The soil was from a mine tailing. The mine tailings were amended with the mixture of waste and biochar which had a higher sorption capacity than the soil from the pond. The samples with amendment had a greater affinity for Cu, Pb and Zn than the mine soil. The results obtained show that adding a mixture made of waste and biochar favours the retention of Cu, Pb and Zn in mine tailing from metal mines.

Histolocalization of aldehyde accumulation in citral-treated Arabidopsis thaliana roots

Allelopathy Journal 37:71-76 · 2016

http://www.allelopathyjournal.org

Growth and development of Arabidopsis thaliana seedlings treated with the essential oil component citral have been severely affected. We analyzed whether citral can enter and accumulate into the roots and we found that it interferes with the plant metabolism accumulating mainly in the differentiation zone. Besides, the distribution of stained zones varied with the experimental time.

Nickel, Lead and Zinc Sorption in a Reclaimed Settling Pond Soil

Pedosphere

Volume 26, Issue 1, February 2016, Pages 39-48

doi:10.1016/S1002-0160(15)60020-0

The wastes used to amend soils sometimes have high concentrations of metals such as nickel (Ni), lead (Pb) and zinc (Zn). To determine the capacity of soils to retain these metals, the sorption capacities of different mine soils with and without reclamation treatments (tree vegetation and waste amendment) for Ni, Pb and Zn in individual and competitive situations were evaluated using the batch sorption technique. The untreated settling pond soil had low capacity for Ni, Pb and Zn retention. The site amended with wastes (sewage sludges and paper mill residues) increased the sorption capacity most, probably because of the higher concentrations of soil components with high retention capacity such as carbon and clay fraction. No significant competition was observed between metals in the competitive sorption experiment, indicating that the maximum of sorption was not achieved by adding 0.5 mmol L−1 of metal. We can conclude that, despite the possible additions of Ni, Pb and Zn from wastes to degraded soils, sewage sludges and paper mill residues have a high sorption capacity that would prevent the metals from being in a mobile form.