Polyphosphates as inhibitors of surface mould growth on hard cheese during ripening

A novel treatment using polyphosphates to protect cheeses against superficial mould growth was assayed. The treatments were: control commercial paint with natamycin (I), commercial paint based on polyvinyl–water (II), immersion in a saturated solution of polyphosphate (III), immersion and commercial paint (IV), commercial paint of polyphosphate solutions (V) and immersion and commercial paint of a saturated solution of polyphosphates (VI). The cheeses were ripened for 6 months. Superficial mould growth was inhibited in groups IV and VI when compared to cheeses from the control group (I). Statistical sensory analysis made between cheeses from groups IV and I (control) showed no significant differences.     

POTENTIAL TOXICITY OF PYOVERDIN FROM PSEUDOMONAS ON MOUSE LIVER

Pseudomonas fluorescens were isolated from food and water. Bacterial strains were grown on synthetic medium and pyoverdin was purified with Fe³⁺. Iron was removed from some samples with 8-hydroxyquinoline to obtain free-pyoverdin. Purification was performed by chloroform/phenol, diethylether/water extractions, column chromatography and silica gel slabs. Mice were given water with pigment for prolonged periods to study the chronic effect on liver. Alanine amino transferase (ALT) and Aspartate amino transferase (AST) increased significantly in animals treated with pyoverdin-Fe, free-pyoverdin and heated pyoverdin. Sex dependence was not observed. The effect on hepatic enzymes was also studied employing chromatographic peaks separately and mixed. Analyses of variance for statistical evaluation was applied. Controls treated withpyoverdin-negative culture extract did not show amino transferase's increase. It was found that prolonged ingestion of pyoverdin can affect hepatic enzymes in mice.     

ANTIOXIDANT PROPERTIES OF LENTINUS EDODES AND AGARICUS BLAZEI EXTRACTS

ABSTRACT

This work aimed to evaluate the antioxidant activity of Lentinus edodes and Agaricus blazei mushrooms, as well as to measure the content of total phenolic compounds of mushroom extracts and verify the oxidative stability of soybean oil added with mushroom extracts that showed higher antioxidant activity according to the methods of the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^•) free radical scavenging and the β‐carotene/linoleic acid system. According to the DPPH^• method, the maximum antioxidant activity for L. edodes and A. blazei methanol extracts was 92.84 and 95.10%, respectively. For the β‐carotene/linoleic acid system, the highest values of antioxidant activity were 93.06% for L. edodes and 78.96% for A. blazei. The content of total phenolic compounds ranged from 7.21 to 128.44 and 26.67 to 134.67 mg gallic acid equivalent/g for L. edodes and A. blazei, respectively. The oxidative stability values provided by the Rancimat method indicated that the two varieties presented similar induction period of 19.85 h.

PRACTICAL APPLICATIONS

Mushrooms present high content of antioxidant compounds that are capable of reducing the harmful effects of free radicals. Among the antioxidants present in mushrooms, phenolic compounds stand out as phenolic acids, flavonoids and tocopherols. To decrease or prevent lipid oxidation, synthetic antioxidants are used as food additives. Nevertheless, studies have revealed that these compounds are likely to pose risks to human health. The concern regarding the safety of synthetic antioxidants has motivated the search of natural antioxidants that can substitute them totally or partially.

     

The prediction of water activity in aqueous solutions in connection with intermediate moisture foods IV. aW Prediction in aqueous non electrolyte solutions

A systematic survey was made of water activity reduction in single non electrolyte aqueous solutions together with an examination of the theoretical aspects of a _W predictions. The prediction of a _W in multicomponent aqueous solutions of non electrolytes as well as of mixed strong electrolyte–non electrolyte solutions was also studied.