摘要:

AbstractWater systems formed by total protein of yeastSaccharomyces cerevisiaeand model systems on the basis of unfractionated casein were studied by viscosimetry and electron microscopy.Methodologically, both methods offered a possibility of distinguishing several quantitatively different concentration intervals in protein solutions under different conditions. Viscosimetry gave the most informative results at the concentration intervals where the solutions approached the true ones, while electron microscopy did so when supermolecular formations prevailed. In comparing the data obtained by these two methods the following conclusions were drawn:At low temperatures (4–10 °C) yeast protein was in molecular‐dissociated condition. Association in the system starts at 10 °C, and becomes enhanced with a rise in temperature. A temperature rise to 25–30 °C promotes a more compact packing of polypeptide chains; further heating leads to high‐temperature denaturation.Lipids induce covering of polypeptide chains and prevent associations. thus leading to an increase in the system's therm

ISSN:0027-769X    

DOI:10.1002/food.19880320402

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe traditional process for preparing agadagidi is described. Yeasts and bacteria were the associated microorganisms involved in various stages of fermentation. The frequently isolated genera areSaccharomyces, Leuconostoc.andStreptococcus. BacilliusandMicrococcusoccurred occasionally. Morphological and biochemical properties of the isolate were studied in pure cultures. There was variability of occurrence of the associated microorganism during isolations. Titratable acid and alcohol content increased gradually till the end of fermentation, while the total soluble solid and pH however decreased.

ISSN:0027-769X    

DOI:10.1002/food.19880320403

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractTemperature, mono‐ and disaccharides affected lipids, biomass production as well as odd‐chain and unsaturated fatty acids contents ofCandida tropicalis.With various sugars as carbon sources at 30 °C, the order for biomass production was, galactose>glucose>sucrose>fructose>lactose, while lipids production/g biomass decreased as follows: galactose, glucose, sucrose, fructose and lactose. On the other hand, the odd‐chain fatty acids contents decreased in the following order: fructose, sucrose, glucose and lactose. Lowering the temperature of cultivation to 15 °C, decreased biomass and lipids production. However, a notable decrease in odd‐chain fatty acids contents was

ISSN:0027-769X    

DOI:10.1002/food.19880320404

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19880320406

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe oxalic acid content of the fresh juice of some healthy citrus fruits in Nigeria is very low (0.012%). Whereas in the juice of fruits infected withAspergillus aculeatus, oxalic‐acid content increased to 0.028%, the oxalic‐acid content of the juice infected withA. tamariiwas lower (0.008%) than in healthy fruits. However, the oxalic‐acid content of citrus‐fruit pulp was much higher than in the juice and was much higher in the infected (0.68%) than in the pulps of healthy citrus fruits (0.11%). The oxalic‐acid content of fruits pulps infected withA. aculeatuswas consistently the highest. The oxalic‐acid content of the rind of healthy fruits (0.10%) was low (though higher than in the juice) but in the infected fruits, the oxalic‐acid content of the rind was much higher, being highest again in those infected withA. aculeatus(0.65%). The effects of oxalic acid on man, animals, plants and some of its uses in medicine and industry

ISSN:0027-769X    

DOI:10.1002/food.19880320407

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19880320409

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractDuring the reaction of oxidized ethyl linoleate with egg albumin in dry medium at 60 °C, hydroperoxides were rapidly decomposed almost completely, while carbonylic anisidine‐active and thiobarbituric‐acid‐active substances were decomposed rapidly in the beginning and only slowly afterwards. Both hydroperoxides and carbonylic oxidation products were substantially more stable in mixtures with cellulose than with albumin. Hydrogen‐bonded lipoproteins were rapidly formed, passed through a maximum, and remained nearly constant in the last reaction stage. Covalently bonded lipids in lipoproteins were mainly formed in the stage following the rapid decomposition of hydroperoxides and carbonylic compounds, and immediately following the decrease of hydrogen‐bonded lipoproteins. The binding of oxidized lipids into lipoproteins was accompanied by the formation of protein oligomers and by the loss of availa

ISSN:0027-769X    

DOI:10.1002/food.19880320410

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractPectolytic enzyme production byPenicillium oxalicumwas depressed when the medium of Bauer et al. plus 0.5 g polypectate (NaPP) per 1 was supplemented with 0.5 g yeast extract per 1. At peak production time (8 days after inoculation of medium), enzyme recovered from the medium containing yeast extract was about four times less than that recovered from the medium lacking yeast extract. Purification of the enzyme was only possible in the medium without yeast extract. Production of oxalic acid in the medium supplemented with yeast extract was also about five times less than in the medium not supplemented with yeast extract.

ISSN:0027-769X    

DOI:10.1002/food.19880320411

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19880320413

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractA simple quantitative TLC method for the determination of the residues of herbicide inhibiting photosynthesis was compared with capillary GLC for the analysis of atrazine, chloridazone, lenacil, phenmedipham and desmedipham in sugar beet and sugar. No significant differences in the determination limit and precision of the two methods were found.Monitoring of herbicide residue levels in commercial sugar revealed low levels of atrazine (0.003 mg kg−1on average) in all the samples. This contamination level does not present a health hazard for consumer

ISSN:0027-769X    

DOI:10.1002/food.19880320414

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY