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Role of blueberry peroxidase in anthocyanin degradation in blueberry juice is examined. It is revealed that chlorogenoquinone is the major component influencing degradation.

Background: Although allergy to sunflower seed and oil is a relatively rare occurrence, several cases of sunflower seed allergy have been observed, and we have already described one case of anaphylaxis after eating sunflower oil and margarine., Objective: The aim of our study was to determine and characterize the allergens from sunflower oil at the different steps of the refining process: crude pressed oil (step A), acidification and neutralization (step B), pregumming by centrifugation (step C), washing (step D), bleaching (step E), gumming by filtration (step F), and deodorization (step G)., Methods: A sample of oil from each step of the process (steps A to G) was heat extracted with PBS. The protein concentration of each extract was evaluated by using the micro-Bradford assay. Samples were run on SDS-PAGE. The immunoblot was performed with the serum of a patient sensitized to sunflower seed and oil., Results: The extracts obtained after each step reveal a decrease in total protein concentration from 13.6 microg/mL to 0. 22 microg/mL. The result of SDS-PAGE shows 5 bands, from 67 kd to 145 kd, with the most abundant being the 67-kd protein. The amount of this protein decreases after each step of the process. It is, however, still present in trace amounts in the refined oil. The 67-kd protein, which is mainly present in the crude oil and slightly in the refined oil, has been shown to be allergenic., Conclusion: Because of the presence of allergenic proteins, refined sunflower oil may pose a threat to people highly sensitized to sunflower seeds.

Caffeic acid o-quinone (CQ) was prepared by oxidation of caffeic acid with o-chloranil in organic media. The reaction between the purified CQ and cyanidin 3-glucoside (Cy 3-glc, o-diphenolic anthocyanin) was monitored by HPLC, and quantitative analyses were performed to establish the stoichiometry of the reaction. The results indicate that Cy 3-glc is degraded by a coupled oxidation mechanism with integration of CQ into the degradation products. The ratio of degraded Cy 3-glc to CQ incorporated into the condensation products was approximately 2.0. No brown products could be detected, only a slight orange color. Moreover, the addition of purified polyphenol oxidase to the slightly colored media resulted in the disappearance of the caffeic acid formed from the reaction of coupled oxidation (Cy 3-glc/CQ) and the formation of brown polymers. The degradation products were isolated by gel filtration on Sephadex G-25. The UV-vis spectra and chemical analysis (acidic hydrolysis) of the degradation products suggest that they resulted from the condensation of caffeic acid and Cy 3-glc. HPLC analysis showed that the partial purified fraction contained a mixture of complex condensation products.

Biomass of Aspergillus niger was obtained from a microbial culture and a copper (Cu) induction was performed after 72 h of fermentation. The crude induced metallothionein extract was obtained by cell disruption and partly purified by a heat treatment and ultrafiltration. The purification of metallothionein by affinity chromatography resulted in three major fractions: FIVa, FIVb and FIVc3. Cu analysis demonstrated that only fraction FIVc contained the Cu-metallothionein. Spectrophotometric analyses of FIVc demonstrated the presence of a peak at 259 nm and a ratio of 78 mol of Cu per mol of protein. Electrophoretic analyses of FIVc, performed under denaturing conditions, showed the presence of one band with molecular mass of 21 kDa; however, two isoforms were observed under native conditions with molecular masses of 9.5 and 10.5 kDa and isoelectric points of 6.2 and 6.5, suggesting a recombination process due to denaturation.

The mechanism of the massive extracellular production of citric and isocitric acids by Saccharomycopsis lipolytica grown on n-paraffins has been studied. When growth stops, because of nitrogen limitation, the intracellular concentration of ATP sharply rises whereas that of AMP and ADP decreases to a low level. At the same time production of acids begins. The activity of the NAD-dependent isocitrate dehydrogenase which requires AMP for activity becomes very low and prevents the oxidative function of the citric acid cycle whereas isocitrate lyase is not inhibited. As citrate synthase inhibition by ATP appears to be insufficient to stop n-paraffin degradation, citric and isocitric acids accumulation can take place. Massive excretion of these acids, however, probably still involves other physiological changes brought about by nitrogen limitation, possibly some permeabilization of the cell to these acids.