No abstract

The effect of a dry heat treatment on trypsin inhibitors, protein quality and molecular weight of products obtained from enzymatic hydrolysis of chickpea flours was analysed in order to use chickpeas as food protein hydrolysates. Chickpea flour obtained from dehusked seeds was processed under different conditions, either by heating or enzymatic treatment. Heat treatment at 140 °C for varying times (1–24 h) inactivated trypsin inhibitors and facilitated enzymatic treatment but showed an unacceptable loss in the nutritional quality of the protein for heating times longer than 6 h. Enzymatic treatment with a commercial protease, Alcalase 0.6L, at pH 8 and 50 °C, increased the protein nutritional value of the chickpea by breaking the protein chains into shorter peptide chains more suitable to human nutrition.

Chalcopyrite bioleaching process using Acidithiobacillus ferrooxidans and a mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans like bacterium was carried out. Two mineral particle sizes were evaluated, 200 and 325 Tyler mesh. The strains were adapted by gradually decreasing of the main energy sources and increasing in the mineral content. The experiments were performed in absence of ferrous sulphate and elemental sulfur. When the mixed culture was used, pH values were always over 2,1, indicating a probable passivation of Acidithiobacillus thiooxidans in the consortium. For both cultures, the Cu2+ dissolution occurred at relatively low redox potential values, around 400mV–450mV, while at high redox potential values, 550mV, chalcopyrite dissolution was inhibited. Copper lixiviation was around 40% for both tests. The Fourier Transform-Infrared spectra showed that the main oxidation phase is jarosite. The results showed that chalcopyrite oxidation is more dependent on the redox potential than particle size or type of culture used.

Advertisement calls of males from two Spanish populations of parsley frogs (Pelodytes punctatus) were recorded. Body size (SVL, mass) and calling temperature were measured, and age was determined through skeletochronolog y of phalanges . Calling males were 2-7 years old in Valencia. In Burgos, males were 1-6 years old and the age structure was highly skewed with more than 50% of the sample of males being 1 year old. The range of body temperatures of calling males was similar in both sites (10-15.1 ± C in Valencia, and 10-17.5 ± C in Burgos). Males called with the typical two-note advertisement call A-B, although in Burgos it was common to hear A-only calls. In both populations repetition of the second note was rare. Calls of both populations showed a negative correlation between temporal parameters (note duration, inter-note interval, pulse rate) and body temperature. On the other hand, spectral parameters (dominant frequencies and dominant frequency ranges) were not correlated to temperature and correlation with body size (SVL, mass) was non-signi cant. Age was not signi cantly correlated with dominant frequency or with any other measured call parameter. Call frequency in Pelodytes is a poor predictor of male body size and does not convey information on age. Thus, any size-related mating trends could result from non-static calling parameters such as call intensity, or from mechanisms of malemale competition (e.g. chorus attendance).

The sphalerite-pyrite oxidation by Acidithiobacillus ferrooxidans was studied to analyze how the formation of the elemental sulfur layers occurs around sphalerite grains. Two possible mechanisms of formation have been raised. One mechanism corresponds to the formation of sulfur pseudomorphs where, both, iron and zinc have been leached of the sphalerite, whereas compound sulfur is oxidized, in situ, to elemental sulfur, leaving an unreacted core of sphalerite that remains in the center. Another mechanism consists in the dissolution of iron, zinc and sulfur presents. When the attack by Fe3+ as by H+ broken the S-metal bonds, sulfur is then oxidized to a series of sulfur intermediate compounds. These compounds in solution then are oxidized to elemental sulfur, which precipitates on sphalerite grains.