Bioactive amines and phenolic compounds in cocoa beans are affected by fermentation.

Cocoa is the target of increased scientific research as it is one of the richest source of bioactive compounds. The formation of bioactive amines and their changes in cocoa beans during seven days of traditional fermentation was investigated for the first time. In addition, total phenolic compounds, anthocyanins contents and the scavenging capacity against ABTS radical were determined to monitor the fermentation process. Only two biogenic amines (tryptamine and tyramine) and two polyamines (spermidine and spermine) were detected in cocoa beans during fermentation. Fermentation was characterized by three stages: i) high levels of tryptamine, phenolics, and scavenging capacity; ii) high contents of spermine, total biogenic amines and total polyamines; and iii) the highest spermidine levels and total acidity, but the lowest total phenolic compounds and anthocyanins contents. The scavenging capacity of cocoa beans during fermentation correlated with total phenolic compounds and anthocyanins contents.

Effects of packaging, mineral oil coating, and storage time on biogenic amine levels and internal quality of eggs.

This study was carried out with the aim of evaluating the effects of mineral oil application on eggshells and the use of plastic packages with lids on the physical-chemical and microbiological quality and biogenic amine contents of eggs stored under refrigeration for up to 125 d. A total of 1,920 eggs from 46-wk-old Hyline W36 laying hens were randomly distributed into 4 groups soon after classification: (i) 480 eggs were stored in pulp carton tray packages; (ii) 480 eggs were stored in plastic packages with lids; (iii) 480 eggs were stored in carton packages after the application of mineral oil; and (iv) 480 eggs were stored in plastic packages with lids after the application of mineral oil. The internal quality was measured by Haugh units, by the counts of mesophilic and psychrotrophic microorganisms, by the most probable number of total and thermal-tolerant coliforms, by the counts of molds and yeasts, by the analysis of Salmonella spp. and Staphylococcus spp., and by the levels of biogenic amines in the egg yolk and albumen. The application of mineral oil to the eggshell resulted in higher Haugh unit values throughout storage, and the use of plastic packages altered the internal quality. The application of mineral oil and the use of packaging had no effects on the microbiological and biogenic amine results. Microbiological analyses showed the absence of Salmonella spp., Staphylococcus aureus, thermal-tolerant coliforms, and fungi. However, the highest counts of mesophilic (1.1 × 10(7) cfu/g) and psychrotrophic (6.7 × 10(7) cfu/g) microorganisms were recorded. The highest values of biogenic amines detected and quantified were putrescine (2.38 mg/kg) and cadaverine (7.27 mg/kg) in the egg yolk and putrescine (1.95 mg/kg), cadaverine (2.83 mg/kg), and phenylethylamine (2.57 mg/kg) in the albumen. Despite these results, the biogenic amine levels recorded were considered low and would not be harmful to consumer health.

Comparison between phase-transfer and cloud-point methodologies for the micellar extraction of biogenic amines.

We compared the recently developed surfactant-based extraction with sodium bis-[2-ethylhexyl]-sulphosuccinate (AOT) in heptane (the phase-transfer method) and the well established methodology with poly(oxyethylene)-7,5-(p-tert-octylphenyl) ether (Triton X-114; the cloud-point technique) to extract and preconcentrate biogenic amines. Both procedures were optimized and applied to the extraction of biogenic amines from a beer sample. In order to improve the degree and monitoring of the extraction otherwise achieved with underivatized amines, the fluorescent reagent dansyl chloride was used. Since the different procedures described in the literature are not in agreement, we optimized the derivatization reaction. Accordingly a systematic investigation of the experimental variables, one by one, yielded the following optimum conditions: dansyl chloride, 5mg/mL; 27 degrees C; reaction time, 25min; pH, 10.35 at ionic strength, 0.7mol/L. Both surfactant-based extraction procedures are simple and sensitive, but the use of AOT instead of Triton X-114 offers certain advantages. Detection limits of between 0.03 and 0.8pmol injected were obtained when AOT was used, whose range is similar to or better than the other published techniques; while the corresponding values for Triton X-114 were between 0.2 and 1.2pmol injected. The phase-transfer extraction is faster than the cloud-point method, and no heating is required. For both approaches, the recovery was very high for all the amines studied and the reproducibility quite good for almost all. Upon comparison of calibration curves in pure water with those in the presence of samples, matrix effects were detected.

Ruthenium(II) bipyridyl complexes as photolabile caging groups for amines.

The synthesis and characterization of a series of ruthenium bis(bipyridine) complexes where the inorganic moiety acts as a photolabile protecting group is described. Complexes of the type [Ru(bpy)2L2]+ where bpy = 2,2'-bipyridine and L = butylamine, gamma-aminobutyric acid, tyramine, tryptamine, and serotonin were studied by nuclear magnetic resonance, cyclic voltammetry, and electronic absorption spectroscopy. In all cases, ligands are coordinated by the amine group. The complexes are stable in water for several days and deliver one molecule of ligand upon irradiation with visible light (450 nm). These properties make them suitable for their use as biological caged compounds.

Immobilized artificial membrane chromatography: quantitative structure-retention relationships of structurally diverse drugs.

The chromatographic capacity factors (log k') for 32 structurally diverse drugs were determined by high performance liquid chromatography (HPLC) on a stationary phase composed of phospholipids, the so-called immobilized artificial membrane (IAM). In addition, quantitative structure-retention relationships (QSRR) were developed in order to explain the dependence of retention on the chemical structure of the neutral, acidic, and basic drugs considered in this study. The obtained retention data were modeled by means of multiple regression analysis (MLR) and partial least squares (PLS) techniques. The structures of the compounds under study were characterized by means of calculated physicochemical properties and several nonempirical descriptors. For the carboxylic compounds included in the analysis, the obtained results suggest that the IAM-retention is governed by hydrophobicity factors followed by electronic effects due to polarizability in second place. Further, from the analysis of the results obtained of two developed quantitative structure-permeability studies for 20 miscellaneous carboxylic compounds, it may be concluded that the balance between polarizability and hydrophobic effects is not the same toward IAM phases and biological membranes. These results suggest that the IAM phases could not be a suitable model in assessing the acid-membrane interactions. However, it is not possible to generalize this observation, and further work in this area needs to be done to obtain a full understanding of the partitioning of carboxylic compounds in biological membranes. For the non-carboxylic compounds included in the analysis, this work shows that the hydrophobic factors are of prime importance for the IAM-retention of these compounds, while the specific polar interactions, such as electron pair donor-acceptor interactions and electrostatic interactions, are also involved, but they are not dominant.