Журнал микробиологии и патологии

Natural Fermentation of Pyrus communis (Pear) Mesocarp by Associated Consortium Fungal Species

Abstract

Oluwatosin Adewusi Adedeji, Temitope Mulikat Audu

This study was conducted to evaluate the effect of associated consortium fungal species on the natural fermentation of the mesocarp of Pyrus communis (Pear). The combined role played by the fungi (moulds and yeasts) involve in the natural fermentation of the Pear mesocarp were also investigated.
Fresh and ripe pears were washed and surface sterilized with ethanol. The mesocarp was then scraped into a bowl and covered with a net to allow the action of aerobic fermentation for 50 days. Fungi were isolated from the samples at interval of 5 days. The morphological, microscopic and biochemical characteristics as well as the fungal count were also carried out according to standard methods. The physicochemical parameters of the pear’s mesocarp such as pH, total titrable acidity (TTA), moisture contents and total reducing sugar were also determined at every 5 days according to standard methods.
The results showed that there were eight strains of mould namely: Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Aspergillus fumigatus, Mucor mucedo, Penicillum frequentas, Penicillum chrysogemun and Fusarium solani; and three strains of yeasts namely Saccharomyces cerivisae, Schizoaccharomyces pombe and Saccharomyces ludwigii were identified to be involved in the fermentation process for the fifty days. The physico-chemical parameters results indicated progressive increase in pH from 3.73-6.73 with all values within the acidic range permitting the growth of microbial species; the TTA exhibited a rise and fall trend with range from 1.3-2.75 cm, the moisture content was found to be highest at 73.4% while the total reducing sugar exhibited a rise and fall in its values. The results of the microbial counts showed that the growth of mould species had prevalence as fermentation increases. The frequency of occurrence of mould present showed Aspergillus flavus to have the highest occurrence at 63.63% and for the yeast Schizosaccharomyces pombe at 72.27%.
The study concluded that a consortium of fungal species which are naturally associated with pear mesocarp can be effectively used in its fermentation.