FRESH STATE CHEMICAL CHARACTERIZATION OF AGROINDUSTRIAL BYPRODUCTS AND THE EFFECT OF PASTEURIZATION FOR ITS USE AS SUBSTRATES ON EDIBLE MUSHROOM CULTIVATION. PANAMA. 2002.

Abstract

Lignocellulosic biomass from as rice straw, coffee pulp and banana plant leaves, was chemically characterized to investigate on the following mushroom production quality indicators: nitrogen, cellulose, hemicellulose and lignin contents. The chemical characterization was performed on two substrate presentations: fresh and pasteurized. The data was analyzed by means of a hierarchic model and random sampling techniques. The pasteurization effect upon the quality indicators was estimated by means of a differential analysis and the application of the same hierarchic model. The results show a significant difference on chemical composition among the substrates (P<0.01). This difference was observed both in the fresh and the pasteurized substrates. The substrate with the highest nitrogen content was coffee pulp, both in its fresh and pasteurized states (3.01% ± 0.11 y 3.04%± 0.09, respectively). Ash content was higher in rice straw and banana leaves, with a similar trend in both substrate states (13.65% ± 0.75 in the fresh state and 11.72% ± 0.67 in the pasteurized state for rice straw; 14.20% ± 0.70 in the fresh state and 11.80%± 0.72 in the pasteurized state for banana leaves). Lignin content showed highly significant differences in the fresh state of the substrates, with the highest and lowest values found in coffee pulp (20.97% ± 0.73) and rice straw (5.74% ± 0.63), respectively. In the pasteurized state, the differences in lignin contents were significant with the same trend as in the fresh state (rice straw, 8.57% ± 0.88; coffee pulp, 26.02 ± 1.02; banana leaves, 18.35 ± 0.88). The highest cellulose content was found on rice straw and coffee pulp, both in the fresh and the pasteurized states (rice straw 33.92% ± 1.24 in the fresh state and 34.31% ± 1.03 in the pasteurized state; coffee pulp, 36.51% ± 1.44 in the fresh state and 33.16% ± 1.19 in the pasteurized state). Nevertheless, the significance level was higher for the fresh state trends. The pasteurization effect was not significant (P>0.05) for ash, nitrogen and hemicellulose contents. The same effect was as highly significant for cellulose only (P<0.01). For lignin, the effect was statistically significant (P<0.05). Differential analysis showed that banana leaves were the substrates with the highest response level to the pasteurization process, mainly for lignin and cellulose contents. The observed differences in the chemical composition among the three tested substrates, show that they provide a choice spectrum for the cultivation of different species of edible mushroom. It is advisable to use the pasteurized state values for the substrate as reference or control values for the edible mushroom cultivation processes.