Impacts of thermal treatment, xylose and cysteine addition on aroma compounds profile in lactic acid bacterium fermented pork hydrolysates

Abstract

To valorise meat by-products such as trimmings from the food industry, this study investigated the influence of thermal treatment, cysteine and xylose addition on the modification of volatile compounds in lactic acid bacterium fermented pork hydrolysates on the basis that xylose and cysteine are precursors to aroma compounds formation via the Maillard reaction. In this study, xylose (3.5% w/v) and cysteine (1.0% w/v) were added to Lactobacillus fermentum fermented pork hydrolysates and the mixture was adjusted to pH 5.5 before thermal treatment at 100 °C for 60 min. The addition of xylose and cysteine combination produced most of the desired sulfur-containing volatiles such as 2-furfurylthiol (5.21 ppb) and methionol (1.61 ppb) that would impart a savoury and roasted meat note. Lipid derived aldehydes (mainly hexanal) and alcohols (mainly 1-hexanol and 1-octen-3-ol) were significantly decreased after the Maillard reaction, while thermal degradation of amino acids increased the amount of some Strecker aldehydes such as benzaldehyde. In conclusion, the potent sulfur-containing volatiles were formed only when both cysteine and xylose were present, but the variety and amount of these volatile compounds were limited due to the moderate heating temperature and shorter time.