Diana Fayad * ⁽¹⁾ and Nariman Nema ⁽¹⁾

(1). Faculty of Agricultural Engineering, Homs University, Homs, Syria.

(*Corresponding author: Diana Fayad. E-Mail: dianafayad685@gmail.com). 

Received:29/9/2024                      Accepted: 21/2/2025

Abstract: 

The aim of the research was to isolate bread yeast from several food sources (sweet wine, grape molasses, apple jam, artificial sweet orange juice, tamarind syrup, jallab syrup, dates) and classified into seven isolates as Saccharomyces cerevisiae based on their cultural, microscopic and biochemical properties. The yeast isolated from industrial sweet orange juice (YOJ) showed the highest fermentation power in a dough leavening test. The isolated sample was propagated in two media. The first medium (bm₁) is molasses obtained from Homs Sugar Factory after adding different concentrations of apple pomace extract (40-50-60)% using the submerged fermentation method. Physical, chemical and microbial properties of the resulting biomass were estimated. It was found that when adding 60% apple pomace extract to the molasses fermentation liquid, the dry matter value reached 29%, ash 0.132, fermentation strength 2800 cm³, and the protein value was 52%. Yeast (YOJ) was also propagated using a second medium (bm₂), which is a nutrient compound medium supplemented with many salts added to the molasses fermentation liquid. It was found that the protein value was 37% and its fermentation strength was 2000 cm³. When comparing the results of the first medium with the results of the Homs Sugar Factory medium, the 60% concentration of apple pomace extract outperformed the rest of the concentrations and the laboratory medium in terms of fermentation strength and protein value. When comparing the results of the second medium (nutrient-rich medium) with the results of the Homs Sugar Factory medium and the results of the best percentage of apple pomace extract (60%), significant differences appeared in terms of fermentation strength and protein value, and the 60% concentration of apple pomace extract was superior to both the synthetic medium and the sugar factory medium.

Keywords: fermentation strength, submerged fermentation, dough leavening, molasses, apple pomace.

 Full paper in Arabic: PDF