M J Robert Nout, Tri D Martoyuwono, Peter C J Bonné, George T Odamtten
Tempe is an Indonesian proteinaecous food produced from soya beans by fermentation mainly by Rhizopus spp. A common traditional inoculum for this fermentation is usar, consisting of heavily sporulated Rhizopus spp of which the mycelium, grown on added and inoculated soya beans, adheres to leaves of the waru tree (Hibiscus spp). A description of various waru trees is given together with their suitability for usar making. The epiphytic fungi on waru trees of various geographical origins (Indonesia, Africa, The Netherlands) were investigated. Cladosporium spp were present on all the leaves sampled. However, Rhizopus spp predominated over the other fungi encountered on the Indonesian leaves. Experimental incubation of leaves with and without added soya beans showed that the epiphytic fungi are less competitive than Rhizopus spp and will not interfere if normal usar‐making conditions are observed. Experiments with alternative attachment surfaces (paper, a textile) indicated that the waru leaves do not provide environmental selectivity through growth‐inhibiting substances, but that they serve mainly as a convenient attachment surface with moisture‐retaining capacity while providing adequate aeration for fungal development. Copyright © 1992 John Wiley & Sons, Ltd
Department of Food Science, Agricultural University, Wageningen, 6703 HD, Bomenweg 2, Netherlands; Central Laboratory, Brawijaya University, Malang, 163, Jl Mayjen Haryono, Indonesia; Department of Botany, University of Ghana, Legon, PO Box 55, Ghana
