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Effect of moisture content of oil type sunflower seed on fungal growth and seed quality during storage
Author(s) -
Robertson J. A.,
Chapman G. W.,
Wilson R. L.
Publication year - 1984
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02672132
Subject(s) - alternaria alternata , germination , biology , sunflower seed , sunflower , horticulture , penicillium , alternaria , spore , aspergillus , botany , fungus , water content , zoology , food science , geotechnical engineering , engineering
Oil‐type hybrid sunflower seed exposed to relative humidities of 65%, 84% and 93% in environmental chambers at 10 C attained equilibrium moisture contents (mc) of 7.5±0.2%, 10.1±0.2% and 13.4±0.5% and were stored under these conditions for up to 60 weeks (wk). At 7.5% mc, germinability of seed changed very little during storage, but at 10.1% mc and 13.4% mc, germination significantly decreased during storage. At 7.5% mc, free fatty acid (FFA) levels in extracted oil did not change significantly during 60 wk of storage. However, at 10.1% mc, FFA increased significantly during 40 wk of storage and were significantly correlated with the invasion of seed by the storage fungus Aspergillus (r=0.81) At 13.4% mc, FFA increased significantly during storage and were positively correlated with the invasion of seed by Aspergillus and Penicillium and negatively correlated with germination percentage. Invasion of surface‐disinfected seed by fungi decreased from 83% to ca 66% of total seed during storage at 7.5% mc. The predominant fungus was Alternaria alternata (Fr.) Keissler. A previously unreported Alternaria sp., morphologically similar to A. ricini (Yoshii) Hansford and A. macrospora , was isolated from 9% of the seed. At 10.1% mc, fungal invasion also decreased for 24 wk and then began increasing again. At 24 wk of storage, Aspergillus began invading the seed. At 13.4% mc, 100% of the seed were invaded with fungi within 8 wk of storage. Total Alternaria rapidly decreased during storage: and after only 4 wk of storage, the seed were invaded by both Aspergillus and Penicillium . After 24 wk of storage, the predominant genus was Aspergillus , followed by Penicillim and Alternaria . Other fungi invading the seed were Cladosporium, Phoma, Mucor, Rhizopus and several unidentified fungi.