Fermentation of chicken carcass hydrolysate by yeast: Effects on composition and opportunities for value-added products

Poultry processing generates a substantial amount of chicken carcasses that is still underutilized. To address this issue, this study was conducted to investigate the effects of yeast fermentation on the chemical components in salt-free chicken carcass hydrolysate in order to valorize chicken carcasses with an intent to develop a novel fermented chicken sauce. Six types of yeasts were employed including typical soya sauce yeast, oleaginous dairy yeast, dry-fermented meat and wine yeasts. The yeasts were singly inoculated into the glucose-supplemented chicken hydrolysate and increased by approximately 2.0 log of CFU/mL within 24 h. Compared to other yeasts, Geotrichum candidum 3A showed lower glucose consumption after two days but the highest total organic acid and the lowest bitter amino acid production. The off-odorants (hexanal, octanal and some carboxylic acids) in the hydrolysate were depleted by all six yeasts, with Debaryomyces hasenii LAF 3 and Candida versatilis NCYC1433 producing more pleasant alcohols such as 2-phenylethanol and 2-methyl-1-propanol, while Pichia kluyveri Frootzen and Saccharomyces cerevisiae EC-1118 produced more fruity esters such as isoamyl acetate and 2-phenethyl acetate. This study provided a way to generate value-added sauce-like condiments with favorable flavour from chicken by-products. • G. candidum 3A reduced bitter amino acids more than other yeasts. • All the off-odorants were depleted by all six yeasts. • G. candidum 3A produced sulfur-containing compounds such as dimethyl disulfide. • D. hasenii LAF 3 and C. versatilis NCYC1433 produced more pleasant alcohols. • Two wine yeast strains produced more fruity esters such as isoamyl acetate.