Study of undesirable flavor compounds in soy milk cheese curdled with liquid chickpea yeast and flavor improvement by adding natural substances (nutmeg - thyme) and probiotic compounds

Abstract

This research was conducted in the laboratories of the College of Engineering Technology - Department of Food Technology Engineering during the year 2024. The aim of the research was to study the improvement of some sensory properties (flavor) of soy milk cheese by using enhancers such as probiotic compounds and natural flavorings such as ground nutmeg and ground thyme to reduce undesirable flavor compounds responsible for the bitter, legume-like taste associated with soy products.

Liquid chickpea yeast (fermented chickpea infusion) was prepared using a reference method; soy milk and cheese were also prepared using a reference method, where different cheese samples were prepared and improved materials were added to them, and they were prepared for analysis on the gas chromatography device to detect undesirable flavor compounds, mainly ketones, aldehydes, and alcohols. The results showed that adding additives (nutmeg, thyme, probiotics) had a good effect on reducing the bitter taste of some volatile organic compounds responsible for the undesirable legume flavor in soy milk cheese. This was achieved by decreasing the concentration of some of the substances responsible for this undesirable taste and flavor. The two most important compounds are (9,12-Octadecadienoic acid (Z,Z)) and (Stearic acid), as measured by the peak area ratio (PAR). The PAR value in the control sample for the compound (linoleic, C18:2) 9,12-Octadecadienoic acid decreased from (48.44) to (26.62) in the thyme cheese sample, (10.84) in the nutmeg cheese sample, and (7.42) in the probiotic cheese sample. As for the compound stearic acid (C18:0), the PAR value decreased from (4.40) in the control sample to (2.42). In the probiotic cheese sample, (2.80) in the nutmeg cheese sample and (1.60) in the thyme cheese sample.