ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00856.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Bioluminescence and fluorimetric fluorescein isothiocyanate‐casein based assays were compared for their ability to detect bacterial proteases in buffer and milk. Both assays gave linear relationships with protease concentration. The fluorimetric assay was overall 1000 times more sensitive than the bioluminescence assay. Only the fluorescent assay was capable of detecting protease activity produced in raw milk inoculated with Pseudomonas fluorescens and stored at 6°C. The protease activity was detectable in raw milk before physical changes occurred and was also detectable after a laboratory ultra high temperature treatment. Use of the fluorimetric assay is a promising means of detecting protease activity in raw materials before manufact

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00857.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Two surveys of freezing point depression (FPD) of milk from farms in England and Wales have been undertaken. Both bulk vat samples (non‐authenticated Central Testing samples) and authenticated herd samples were tested and the results compared with those from the survey of authenticated milks carried out in 1977, which has been used as the basis of interpretations of FPD results in BS3095. The results suggested that milk from herds in England and Wales may have a true FPD lower than that recorded in the British Standard and that the action taken for bulk samples with FPD below current thresholds (eg, 530, 525 m°C) may need to be reconsider

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00858.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00859.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

This paper reviews the different types of fermented milks and their microflora and includes recent work on yogurt, soft cheese and buttermilks, kefir and koumiss. There is considerable interest in the ‘new’ health promoting products which are now available. These are also discussed in the light of some recent findings on the ability to lower the blood cholesterol concentration and stimulate the immune response. Biotechnology techniques are being developed for many of the lactic acid bacteria involved in dairy fermentations, and in the final section some potential improvements are briefly revie

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00860.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Vanilla ice cream (10% fat) was prepared by substituting two corn sweeteners (high fructose corn sweetener‐90: HFCS‐90, and high maltose corn sweetener: HMCS) for sucrose on a 50:50 basis at 25, 50, 75 and 100% substitution levels. Physical tests were conducted on the firmness and melting rate of the ice cream, and no significant differences (p>0.5) were found among the variations. Sensory evaluation showed that an increase in the use of corn sweetener blend caused a decline in sweetness as well as vanilla intensity with some flavour masking. The corn sweetener blend did produce a smooth texture in the ice cream when used as a 100% replacement for sucr

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00861.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Bovine and caprine yogurt gels made using ‘ropy’ (extracellular polysaccharide‐producing starters) and ‘non‐ropy’ starter cultures were examined using dynamic (oscillatory) testing. The storage (G¸) and loss (G˝) moduli of the ropy gels were found to be lower than those of the equivalent non‐ropy ones. Both moduli of the ropy gels declined on storage (at 4°C). On the other hand, the loss tangents of the gels made using the ropy starters were higher than those of the non‐ropy gel systems. Caprine yogurt gels were some eight times weaker than the equivalent bovine systems, the ropy gels again being weaker that the non‐ropy systems. These data suggest that the secreted polysaccharide may well interfere with the gel struc

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00862.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1993.tb00863.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY