Lactic acid fermentation of broiler processing waste: physical properties and chemical analyses

Broiler processing waste (offal), consisting of broiler heads, viscera, and feet, was collected from a commercial processing plant, ground, mixed with a fermentable substrate, and inoculated with actively growing organisms from a commercial silage culture. The offal mixture was fermented at 11, 19, and 37 C for up to 48 h and evaluated for pH, odor, and aqueous, solid, and oil fractions produced by centrifugation. Freshly ground offal, fermented offal, and aqueous and solids fractions were analyzed for moisture, fat, and protein content. The oil fraction produced by centrifugation of the fermented offal was analyzed for fatty acid composition. The optimum fermentation conditions, as determined by final pH, were obtained by the addition of 6% sucrose, inoculation with 10(6) cfu of silage culture organisms/kg of offal, and incubation at 37 C. The pH decreased from 6.2 to 3.9 in 24 h. Freshly ground offal and 48-h fermented offal were found to contain 63.2% moisture, 15.9% fat, and 14.9% protein, and 57.3% moisture, 19.1% fat, and 12.9% protein, respectively. The aqueous and solid fractions were 73.3% moisture, 1.1% fat, and 12.1% protein, and 57.7% moisture, 6.8% fat, and 21.8% protein, respectively. Fermentation was effective in decreasing pH, altering the odor and viscosity, and, upon centrifugation, increasing fat recovery and producing fractions that were easily separated.