Influence of dairy Penicillium spp. on nutrient content of citrus fruit peel

The aim of this study is to improve the nutritional value of bergamot fruit peel by solid-state fermentation with three strains of Penicillium camembe rti and seven strains of Penicillium roqueforti. To assess the effect of th eir growth on the chemical composition of the substrate, the following anal ytical determinations were carried out before and after microbial colonizat ion: crude protein, pure protein, non-proteic nitrogen, dry matter, ether e xtract, ash, neutral detergent fiber, acid detergent fiber, hemicellulose, cellulose, organic matter, and gross energy. The colonization with the moul ds produces substantial changes in the chemical composition of the bergamot fruit peel, notably significant increases in crude protein, ether extract, gross energy, and structural carbohydrates. The solid-state fermentation a ctivity of these moulds could prove a cost-effective way of recycling citru s fruit peel in animal feed, thus increasing its nutritional value by singl e cell protein. Nevertheless further research on the matter must be carried our, especially on the estimation of the biomass digestibility - in vitro, in sacco or in vivo - and on the check for eventual mycotoxins (roqueforti n, cyclopiazoic acid) produced by the moulds in the cellulose waste. (C) 19 99 Elsevier Science B.V. All rights reserved.