Effect of Alcalase Modification of Yellow Lupin (Lupinus luteus L.) Protein Isolate on Some Functional Properties and Antioxidant Activity.

Protein isolate obtained from sweet yellow lupin (Lupinus luteus L.) and its Alcalase hydrolysates were examined for their functional and antioxidant properties in relation to surface hydrophobicity of proteins and peptides and molecular weight distribution. Enzymatic hydrolysis improved the foaming characteristics of lupin proteins, while the emulsifying properties deteriorated. It means that good foaming properties of preparations are determined by the presence of low-molecular δ conglutin and small subunits of γ conglutins. In turn, larger proteins such as α and ß conglutin are responsible for maintaining good emulsifying properties. The measured surface hydrophobicity was consistent with the results of emulsifying properties. It has also been shown that the scope of changes in antioxidant properties due to hydrolysis, measured by DPPH method and as reducing power, is more pronounced than with the use of ABTS and FRAP methods.

Effect of adding essential oils of coriander (Coriandrum sativum L.) and hyssop (Hyssopus officinalis L.) on the shelf life of ground beef.

This study examined the effect of adding essential oils of hyssop and coriander at the highest concentration (0.02% v/w) sensorially acceptable to a panel of assessors on the microbiological and biochemical characteristics of stored ground beef. Vacuum-packed meat was stored at 0.5±0.5°C and 6±1°C for 15days. The greatest beneficial effect of both additives was in inhibiting the development of undesirable sensory changes (extending acceptability by up to 3days) and the growth of Enterobacteriaceae (by up to approximately 1-2 log cycles compared with the controls). The effect on lactic acid bacteria, total viable bacterial count and other groups of microorganisms investigated was minor (up to 1 log cycle) and similar for both oils. Neither did these additives significantly affect amino nitrogen levels, protease activity, the proportions of meat pigments, protein electropherograms and pH levels. This indicates the limited effect of these essential oils in the concentrations applied on preserving vacuum-packed minced beef.

Crystal and molecular structures of trichloro-cobalt(II) complexes of epiquinine, epiquinidine, and epidihydrocinchonine.

Cinchona alkaloids are very well known antimalarials but the mechanism of their biological action still remains to be elucidated. The structural studies of active erythro and inactive threo alkaloid complexes are an important step to this aim. In this paper results of crystal structure analysis of three cobalt complexes of threo alkaloids are presented: (epiquininium)trichlorocobalt(II) (EpiQnCoCl3), (epiquinidinium)trichlorocobalt(II) (EpiQdCoCl3) and (epidihydrocinchoninium)trichlorocobalt(II) (EpiCnCoCl3). The complexes are zwitterions in which trichlorocobalt substituents are coordinated to quinoline nitrogen atoms and quinuclidine nitrogen atoms are protonated. EpiQnCoCl3 adopts uncommon conformation with quinoline moiety oriented in the opposite direction in comparison to the analogous uncomplexed alkaloid. The packing in the crystal structures is determined mainly by the hydrogen bonds, in which the chlorine atoms of substituents and solvent molecules contribute. Atoms participating in hydrogen bonds in EpiQnCoCl3 and EpiQdCoCl3 form large rings, while in EpiCnCoCl3 only chains are present. Solvent molecules are very important for the packing mode. In contrast to most erythro alkaloids, the hydroxyl oxygen atom in the title complexes forms weak or not well defined hydrogen bonds. The contribution of very weak intramolecular interactions N1--H1...O12 cannot be excluded. Such "trace" interactions can be considered a relic of the unprotonated status of an epi alkaloid.