CHEMICAL CHARACTERISATION OF UNFERMENTED AND MICROBIALLY FERMENTED CITRUS PEEL MEAL

Abstract

This study was carried out to chemically assess the nutritional value of unfermented and microbially fermented citrus peel meal with a view to suggesting their possible use in animal feeding. Fresh citrus peels (Citrus sinensis) were washed, sundried, ground and inoculated with three different microorganisms; namely Saccharomyces cerevisae, Lactobaccillus delbruckii and Lactobacillus coryneformis; at the rate of single, double and triple combination in a plastic container under aerobic condition. They were fermented for a period of 0, 3 and 7 days. The fermented samples thereafter, were sundried and chemically analyzed. The crude protein (CP) content increased with the mean value of 17.84% as the day of fermentation increased from 0 to 7 days while, the manner of inoculation led to 20.21% - 23.50% increment with a concomitant decrease in crude fibre (CF) by 13.75% and 20.67% as the fermentation days increased from 0 through 3 to 7 days. The manner of inoculation led to a decrease of CF by 8.42% to 45.65% with significant (p<0.01) interaction of the two main effects. The anti-nutritional factors typified by oxalate, phytate and flavanoid decreased as the fermentation days increased (p<.001) with the manner of inoculation. Except for the tannic acid equivalent, the value of the other anti-nutritional factors quantified significantly (p<0.05) depended on the two factors examined. All the fibre fractions (except Acid Detergent Lignin) decreased as the fermentation days increased and with the manner of inoculation (p<.001) with significant interaction (p<.001) of the two factors. The energy values of the fermented citrus peel meal varied (p<0.001). While Phy:Zn molar ratio and [Ca][Phy]:[Zn] decreased with increased in fermentation period and manner of inoculation (p<.001), the Ca:Phy molar ratio increased (p<.001) as the day of fermentation and manner of inoculation increased, suggesting that in the peel’s Ca and Zn are bio-available. In conclusion, fermenting sweet orange (Citrus sinensis) fruit peel, an agro waste, as done in this study, yielded a feeding stuff comparable in nutritive quality to maize, which could be used in animal nutrition