Ανάπτυξη μοντέλου πρόβλεψης του ορίου ανάπτυξης/μη ανάπτυξης των Zygosaccharomyces bailii και Zygosaccharomyces rouxii σε προσομοιωμένα μη αεριούχα αναψυκτικά ως συνάρτηση εμπορικά διαθέσιμων συντηρητικών ενώσεων

Abstract

The main goal of this study was the development of two “Growth-No Growth” predictive models for the microorganisms Zygosaccharomyces bailii and Zygosaccharomyces rouxii based on simulated non-carbonated soft drinks. Specifically, data for modeling were produced in two different substrates (sucrose and fructose solutions) with a constant pH value of 3.0, three different inoculum levels (10, 100, and 1000 cfu/100 μL), and two different temperatures (12°C and 24°C) for each substrate, in the presence and absence of all possible combinations of the preservative compounds potassium sorbate (0, 100, 200, 300 ppm) and natural glycolipids (0, 12, 25, 50 ppm) and sodium benzoate (0, 50, 100, 150 ppm) and natural glycolipids (0, 12, 25, 50 ppm). The total incubation time was 15 days, and the cultures were monitored by measuring optical density in ELISA-type microplates at 600 nm. Each experimental trial was repeated three times (n=3). Two models were created with performance indices above 92% for the sucrose substrate and above 95% for the fructose substrate, with the predictive factors potassium sorbate, sodium benzoate, and natural glycolipids showing statistical significance in both cases. On their own, benzoate and sorbate were not sufficient to inhibit the growth of the microorganisms, highlighting their well-known resistance to weak organic acids. The use of natural glycolipids in all tested systems proved particularly effective, both alone at concentrations greater than 12 ppm and in combination with 100 ppm of sodium benzoate, even at low levels (12 ppm). In combination with potassium sorbate, growth was observed even when 12 ppm natural glycolipids and 200 ppm potassium sorbate were used in a sucrose substrate. Noteworthy was the growth of the microorganisms regardless of substrate, temperature, inoculum level and glycolipid levels (0, 12, 25, 50 ppm) when combined with 50 ppm sodium benzoate and 100 ppm potassium sorbate.