Francisco Javier Casado

Chemical profile of industrially fermented green olives of different varieties

Over 160 fermented brines, from green olives of Manzanilla, Hojiblanca, and Gordal varieties processed in five companies in two consecutive seasons, were analysed for physicochemical characteristics, organic acids, sugars, and volatile components. The composition of the brine following fermentation was assumed to be identical to that of the aqueous phase of the olives. Olive variety and processor were found to have a greater influence than season on both physicochemical characteristics and chemical composition. Hojiblanca olives presented values of pH, combined acidity, and volatile acidity significantly (P<0.05) higher than those of Manzanilla and Gordal, reflecting different processing conditions. The volatile/total acidity ratio, which did not differ between varieties or seasons, appeared to correlate with development of the “fourth stage” of fermentation. The major compounds were lactic, acetic, succinic and formic acids, ethanol, and methanol, with the contents of ethanol and formic acid being significantly different in all three varieties. Residual fermentation substrates, such as mannitol, glucose, sucrose, and citric acid, in addition to propanol, propionic acid, 2-butanol, and acetaldehyde, were found in low concentrations.

Table Olives: Varieties and Variations

Publisher Summary Table olives are the products prepared from sound fruits of the cultivated olive tree. Table olive production was initially restricted to the producing regions, mainly around the Mediterranean Sea. Today, however, olive preparation has extended to both North and South America, and even Australia. A characteristic common to almost all olive varieties is their extreme bitterness when tasted fresh. The glucoside oleuropein is responsible for this, and the different processing methods are aimed at removing this compound in order to obtain fruits with more-palatable attributes. It could be said that there are as many processing methods as places where olives are consumed. In an attempt to normalize the different products, the International Olive Council has a Trade Standard Applying to Table Olives, in which the types, trade preparations, quality factors, and other properties are described. This chapter aims to describe in detail the different kinds or classifications applicable to table olives, explaining the distinctive traits for each case.

Influence of processing conditions on acrylamide content in black ripe olives.

The presence of acrylamide was investigated in different presentations of commercial black ripe olives, a well-known sterilized alkali-treated product. The analysis was performed by gas chromatography-mass spectrometry (GC-MS) after bromination of acrylamide, using (13C3)acrylamide as internal standard. In-house validation data for commercial ripe olives showed good precision and accuracy of the method, with repeatability below 3% and recoveries between 94 and 105%. Acrylamide was detected in all samples, but its concentration varied significantly from 176 to 1578 microg/kg of pulp. The effects of different processing conditions (two preservation methods and three darkening methods), cultivar (Hojiblanca or Manzanilla), and presentation form (pitted or sliced olives) on acrylamide content were evaluated in experiments performed in an olive-processing plant. All canned samples were sterilized at 121 degrees C for 30 min. Statistical analysis of the data indicated that the effects of darkening method and olive cultivar were the most pronounced. Acrylamide contents did not significantly differ after 6 months of storage. The small amounts of free amino acids and reducing sugars found in olives before sterilization did not significantly correlate with the acrylamide formed.

Luminescent lead(II) complexes: new three-dimensional mixed ligand MOFs

Two new lead(II) butyrate-based compounds with formulae [Pb2(but)4(4,4′-bipy)(H2O)]n (1) and [Pb2(but)4(bpe)(H2O)]n (2) [with but = butyrate; 4,4′-bipy = 4,4′-bipyridine and bpe = 1,2-bis(4-pyridyl)ethene] have been synthesized and characterized, with the aim of obtaining different three-dimensional (3D) structures from the typical two-dimensional (2D) lamellar one of most of metal alkanoates, and enhancing the properties of the products synthesized, using these two different N bridging ligands (4,4′-bipy and bpe). Both new complexes show a similar 3D (42638)-sra network in a monoclinic lattice (C2/c) and present interesting photophysical properties. The two compounds have been fully characterized by single crystal X-ray diffraction (synchrotron radiation), thermogravimetric analysis, differential scanning calorimetry, UV-Vis absorption spectroscopy, and steady-state fluorescence and lifetime measurements.

Fermented vegetables containing benzoic and ascorbic acids as additives: benzene formation during storage and impact of additives on quality parameters.

Chemical and sensorial changes related to the use of benzoates and ascorbic acid as additives in packed fermented vegetables were investigated. For this, three selected vegetables (green olives, cucumbers, and caperberries) stored under different conditions (glass or plastic containers, ambient or refrigerated storage) were used. In all cases, benzoic acid remained unchanged (glass bottle) or decreased slightly (plastic pouch) at prolonged storage. Ascorbic acid was partially or totally degraded during storage, the degradation rate depending on the storage conditions and the vegetable matrix. Benzene levels higher than 10 μg/L were found in cucumbers and caperberries containing both additives, but only when packed in plastic pouches and after prolonged storage at room temperature. In these conditions, an appreciable browning of brine, related to AA degradation, was also found. The use of benzoate alone had a significant influence on vegetable color, but flavor was not significantly affected at the benzoate levels tested. On the basis of the present study, benzoates should be removed from fermented vegetable formulations containing ascorbic acid to eliminate possible benzene formation during long-term storage.

Lithium–thallium(I) butyrates binary system: an intermediate salt and liquid crystal from non-mesogenic compounds.

The binary system between lithium and thallium(I) butyrates, [xLiC3H7CO2 + (1 − x) TlC3H7CO2], where x = mole fraction, has been carefully analyzed, solving the temperature and enthalpy vs. composition phase diagrams. The formation of an intermediate salt or complex with a composition (2 : 1), an ionic liquid crystal phase and a metastable solid solution has been detected. The complex melts incongruently at Tfus = 494.7 K, with ΔfusHm = 7.70 kJ per mol of mixture. Its low temperature crystal structure (monoclinic, P21/c) has been solved and refined using X-ray synchrotron radiation and has been found to be bilayered, as is typical from pure metal alkanoates and, as it happens, for other two analogous intermediate salts studied recently by our group. The liquid crystal phase detected is formed from two non-mesogenic pure compounds, appearing in the binary system between 394.1 and 436.6 K and for x = 0.10 up to x = 0.29. Binary phase diagrams are shown to be a powerful tool to detect and predict the formation of liquid crystal phases and mixed crystals.