Publications Scientifiques

The exploitation of food industry wastes and their conversion into value-added products present a promising and continuously growing field, given the diversity of elaborated wastes. The current work aimed to utilize sweet cheese whey as a growth medium for acid protease production by a local fungus strain. The biochemical and physicochemical properties of the cheese whey, such as pH, conductivity, chemical oxygen demand, biological oxygen demand (BOD5), total nitrogen and protein contents, and mineral salts, were assessed using various analytical methods. The effect of certain parameters on acid protease production by Mucor circinelloides MG603064.1 through the SmF process was investigated using the conventional design method "One factor at a time". Subsequent to characterization, the crude extract was used in a trial to create fromage frais, compared to the commercial rennin CHY-MAX® Powder Extra. Cheese whey characterization revealed its richness in total nitrogen (1.044 ± 0.044 g/l), protein content (6.52 ± 0.04 g/l), and principal mineral salts: calcium (1.637 ± 0.037 g/l), phosphorus (1.173 ± 0.023 g/l), and chloride (1.66 ± 0.09 g/l). The optimal values of the SmF process for acid protease production, such as the inoculum size, beef extract, and KH2PO4 supplements, the initial pH of cheese whey, and incubation temperature were, respectively, 11% (v/v), 0.4% (w/v), 0.5% (w/v), 5.5, and 30°C. Under these conditions, the lowest milk-clotting time of 290 s was achieved, representing an 18.41-fold increase compared to the initial step using the unoptimized medium. The enzyme showed maximum milk-clotting activity at pH 5, a temperature of 60°C, and in the presence of 0.025 M of CaCl2. The enzyme activity also significantly improved with sonication (35 kHz) for 10 min. The crude extract of M. circinelloides ensured the production of fresh cheese samples with characteristics roughly similar to those obtained by the control (CHY-MAX® rennin). The acid protease of M. circinelloides could successfully substitute the conventional rennin in the manufacture of fresh cheese.

Extracellular protease from Mucor pusillus was purified 18-fold with 7.56% recovery by ion-exchange chromatography and gel filtration. The enzyme was found to be monomeric in nature, having a molecular mass of 49 kDa. The enzyme acted optimally at 50°C and was stable in the temperature range 30–50°C. It was completely inactivated by heating for 30 min at 65°C. The optimum of activity for the purified extract was observed at milk CaCl2 concentration of 0.02 m and at milk pH of 5. These properties, except for temperature, were similar to those of rennet

Publications Scientifiques

Browse

Filters

Settings

Sort By

Results per page

Search Results