Deterioration of shelled oil palm kernels caused by seedborne fungi

Autoclaved oil palm kernels were inoculated with spores of seedborne isolates of either Aspergillus flavus, A. niger, Penicillium chrysogenum, P. janthinellum, Paecilomyces varioti, Syncephalastrum racemosum or Fusarium oxysporum. At 0, 2, 4 and 8 weeks after inoculation, determinations were made of the moisture content, oil, free fatty acids (FFA), sugars and protein nitrogen. The principal biochemical changes induced by these fungi were increases in moisture content and FFA, decreases in total oil and total sugars and a degradation of protein nitrogen. Aspergillus flavus caused the greatest changes, and P. varioti caused the least changes under the moisture conditions of this experiment. The main type of deterioration was hydrolytic rancidity of the oil, resulting in a dark reddish-orange-coloured oil and a discoloration of the kernel meal.