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Factors affecting milk clotting activity of rennet substitute extracted from green bracts of artichoke (Cynara scolymus) flowers in different buffer solutions were evaluated. These factors include extraction pH, clotting temperature, extract concentrations, addition of CaClR 2 R, NaCl and glucono delta-lactone (GDL) at different concentrations. The proteolytic activity of different extract solutions and rheological properties of produced curd was studied as well. The obtained results indicated that the optimum clotting activity of artichoke crude extracts improved water holding capacity and susceptibility to syneresis obtained at pH value of 5.0-6.0, temperature of 65-70°C and 3%, 0.04-0.05, 3%, 0.5% of crude extract, CaClR 2 R, NaCl and GDL concentrations, respectively. The optimum clotting activity of artichoke crude extracts indicated that the sodium acetate buffer solution T4 (5% NaCl in sodium acetate buffer, pH 5.0) and sodium phosphate buffer, T5 (5% NaCl in sodium phosphate buffer, pH 5.5), T6 (5% NaCl in sodium phosphate buffer, pH 6.5), and T7 (5% NaCl in sodium phosphate buffer, pH 7). Results also indicated that artichoke crude extracted in sodium phosphate buffer solutions and sodium acetate buffer (T4) had higher proteolytic activity than other buffers. The best rheological properties of resultant curds were noticed in sodium phosphate buffers (T5, T6, T7) and sodium acetate buffer (T4).

This study was designed to evaluate some properties of fruit yoghurts made with adding carrot and guava pulp during storage. The obtained results revealed that, the pH was decreased by time of storage while acidity was increased in all types of drinking yoghurt. Adding of 10, 15 and 20% guava pulp in yoghurt increased significantly (p<0.05) the total phenolic compounds (TPC), antioxidant activity (AA), fiber content and ascorbic acid (Vitamin c). The rheological and sensory properties of yoghurt were improved comparing to the control samples, While the protein content, pH value and syneresis decreased significantly (p<0.05) than control samples. On the other hand, Addition of 10, 15 and 20% carrot pulp to yoghurt increased (TPC), (AA), ascorbic acid and fiber content, while the protein content, pH value decreased. Along the storage period of all treatments, the TS, acidity, synersis and viscosity increased significantly, while the pH value, ascorbic acid, acetaldehyde content, AA,TPC were decreased significantly.

In this study, functional yoghurt beverages were fortified with different sorts of carrot products including of 5% fresh carrot pulp (FCP), carrot treated with instant controlled pressure drop (CDIC), and carrot treated with conventional hot air drying (CHAD). The different treatments were analyzed for physicochemical, rheological, microbiological, and organoleptic properties when fresh and after 10 and 20 days of storage at 4±1 °C. Total solids, protein, fat, and ash contents were found to be higher in carrotyoghurt beverages as compared to the control. In addition, there was a gradual decrease in total phenolic contents and antioxidant activities during storage period. Furthermore, the treatments supplemented with CDIC and CHAD exhibited higher water holding capacity. The addition of carrot products had a positive impact on the starter culture bacteria. The viable probiotic cell count throughout the product shelf-life was above the minimum count required in a probiotic product (more than log 6 CFU/g) for treatments containing CDIC and CHAD. However, CDIC and FCP gained the highest scores for the overall sensory attributes.