Examen microscopique de grains de café riotés
Forty samples of commercial coffee - mainly supplied by the Illycaffe Company, Trieste - which were classified as check beans, beans with off flavours but no Rio taste, and beans with Rio taste proper, were examined under a light microscope and a scanning electron microscope. Sources: Arabica: Brazil (Minas Gerais, Espirito Santo, Santos, Rio); Puerto Rico, Honduras, México. Robusta: Madagascar, Central African Republic. The beans with off flavours but no Rio taste are highly fermented beans, with various bacteria and/or yeasts. The epidermis, cell-walls and cytoplasmic content may be heavily degraded. The beans with Rio taste are ripe beans (with serotonin in the cuticle and heavy losses of tryptophan) infected by one or several types of mould. These moulds attack either the pectic or cellulose compounds of the beans. Internally, the cell-walls of the cytoplasm and the central mucilage are severely damaged or completely destroyed. These moulds can easily go throught the epidermis of the beans but the favourite site for penetration is through the embryo. Of all the moulds recorded, only Aspergillus fumigatus is always found in the beans with Rio taste. The beans very often show signs of more or less extensive fermentation caused by bacteria or yeasts, or both. The check beans are not infected, except occasionally on the silver-skin, but may have signs of very slight fermentation on the epidermic cells
Main Authors: | , , |
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Format: | biblioteca |
Published: |
París (Francia)
1988
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Subjects: | COFFEA ARABICA, COFFEA CANEPHORA, CAFE RIO, COMPOSICION, PALATABILIDAD, MICROSCOPIA, MICROORGANISMOS, FLORA MICROBIANA, MOHO, CALIDAD, |
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Summary: | Forty samples of commercial coffee - mainly supplied by the Illycaffe Company, Trieste - which were classified as check beans, beans with off flavours but no Rio taste, and beans with Rio taste proper, were examined under a light microscope and a scanning electron microscope. Sources: Arabica: Brazil (Minas Gerais, Espirito Santo, Santos, Rio); Puerto Rico, Honduras, México. Robusta: Madagascar, Central African Republic. The beans with off flavours but no Rio taste are highly fermented beans, with various bacteria and/or yeasts. The epidermis, cell-walls and cytoplasmic content may be heavily degraded. The beans with Rio taste are ripe beans (with serotonin in the cuticle and heavy losses of tryptophan) infected by one or several types of mould. These moulds attack either the pectic or cellulose compounds of the beans. Internally, the cell-walls of the cytoplasm and the central mucilage are severely damaged or completely destroyed. These moulds can easily go throught the epidermis of the beans but the favourite site for penetration is through the embryo. Of all the moulds recorded, only Aspergillus fumigatus is always found in the beans with Rio taste. The beans very often show signs of more or less extensive fermentation caused by bacteria or yeasts, or both. The check beans are not infected, except occasionally on the silver-skin, but may have signs of very slight fermentation on the epidermic cells |
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