Lipolytic activity and degradation of rapeseed oil and rapeseed by spoilage fungi
Aspergillus, Eurotium and Penicillium spp. from rapeseed were able to grow and produce lipases over a range of water activities ( a w) at both 15 and 25°C on tributyrin agar. The ability to produce lipases was not directly related to growth rate. The clearing zone: growth rate ratios gave lipase ind...
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Veröffentlicht in: | International journal of food microbiology 1993-08, Vol.19 (3), p.217-227 |
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Sprache: | eng |
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Zusammenfassung: | Aspergillus, Eurotium and
Penicillium spp. from rapeseed were able to grow and produce lipases over a range of water activities (
a
w) at both 15 and 25°C on tributyrin agar. The ability to produce lipases was not directly related to growth rate. The clearing zone: growth rate ratios gave lipase indices which varied markedly between test fungi and with
a
w. The fungi with the highest indices were
Aspergillus candidus and
Aspergillus versicolor and
Penicillium expansum and
Penicillium hordei. The
Aspergillus spp. generally grew faster on a 1% crude rapeseed oil at 25°C and 0.995 and 0.95
a
w than on the tributyrin agar.
P. hordei degraded the rapeseed oil more rapidly than
Eurotium amstelodami or
Penicillium aurantiogriseum, with optimum activity at 0.98
a
w.
E. amstelodami was the least effecitve at degrading the rapeseed oil under all
a
w conditions. The lipase indices were compared with the ability of the test fungi to degrade irradiated rapeseed. Dry matter loss over 4-week periods were greater at 25 than 15°C, regardless of
a
w. At 15°C,
Penicillium spp. caused significantly greater dry matter losses than
Aspergillus spp.
A. niger degraded rapeseed faster than other
Aspergillus spp. tested at 0.98
a
w, but at 0.95 and 0.90
a
w there was little difference between species. |
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ISSN: | 0168-1605 1879-3460 |
DOI: | 10.1016/0168-1605(93)90079-V |