Expression of recombinant Streptokinase from local Egyptian Streptococcus sp. SalMarEg

Streptokinase (SK) is a therapeutically important thrombolytic agent. Cardiovascular disease is the first cause of adult death worldwide. In Egypt about 13% of the population die every year due to ischemic heart disease. In spite of this fact, there is no local production of cardiovascular therapeutics. We reported for the first time the expression of a recombinant SK from a local Streptococcus strain. When produced on industrial scale this r-SK may substantially contribute to reducing the costs of thrombolytic therapy in developing countries. In this study, a highly purified r-SK from Streptococcus sp. isolated from Egyptian pharyngitis patients was obtained. The isolated strain was partially identified using 16S rDNA sequencing and named Streptococcus sp. SalMarEg. It was found to be phylogenetically related to Streptococcus pyogenes. Analysis of the obtained sequence showed high similarity with other SK genes. The protein expression in a prokaryotic system obtained a 47-kDa SK protein that could be purified using a single-step his-tagged affinity purification chromatography, with nearly 80% recovery. The clot lytic activities of both recombinant and commercial SK were similar, thus giving the basis to scale up this SK product in order to evaluate the possibilities of its commercialization in local and/or regional markets.Key words: Streptokinase, Streptococcus SalMarEg, thrombolytic agent, heterologous expression

Chickpea protein isolation, characterization and application in muffin enrichment

The aim of this study was to enhance the nutritional value and the functional characteristics of muffins by enriching with chickpea protein isolate, while keeping their rheological characteristics. Chickpea Protein isolate (CPI) was prepared by alkaline solubilization (pH 11), followed by isoelectric precipitation at pH 4.5. SDS-PAGE revealed three subunits with molecular weights of 47, 30 and 85 kDa; representing the globulin fractions, legumin-like and vicilin-like proteins. Maximum protein solubility (83.32%) was obtained at pH 11. CPI exhibited an emulsifying activity index of 25.17 m² g¯¹, emulsion stability index of 14.09 min. The foaming capacity and stability were 62% and 94.49%, respectively. Water and oil absorption were 3.65 and 2.30 mL g¯¹, respectively. CPI was added to muffin batter at 0, 2.5, 5, 7.5 and 10%. CPI fortified muffins showed reduction in moisture content, which influenced texture profile analysis through increasing hardness, gumminess and chewiness values. Additionally, both protein content and protein digestibility of muffins increased to 22.2 and 94.08%, respectively. CPI-enriched muffins were darker (lower L) with yellowish crumbs (higher b). Finally, preliminary sensory evaluation showed high consumer acceptance for CPI-enriched muffins

Physicochemical, texture and sensorial evaluation of pasta enriched with chickpea flour and protein isolate

Pasta is healthy, cheap, versatile, and convenient as a carrier of bioactive components. The present work focused on increasing the nutritional quality of pasta via chickpea flour and protein isolate in addition to monitoring the influences of this fortification on the physicochemical, texture and sensory attributes of functional pasta. Eight fortified pasta products were prepared of durum semolina wheat with partial replacements of 2.5, 5, 7.5 and 10% of chickpea flour (CF)/or chickpea protein isolate (PI). Cooking quality, moisture content, swelling index, starch content, in-vitro protein digestibility, texture and sensory properties were evaluated. CF and PI fortifications decreased optimum cooking time (Min. 5 min) and starch content (Min. 62%) with overall increases in cooking losses (Max. 5.79%), swelling index (SI) (Max. 31.69%), hardness (Max. 22.13 g), cohesiveness (Max. 1.13), springiness (Max. 1.11 cm), gumminess (Max. 21.34 N) and doubled the chewiness (Max. 21.36 g cm¯¹). The impact of pasta enrichment on its in-vitro protein digestibility against control (91.89%) was varied where CF substitution resulted increased protein digestibility (Max. 95.57%), while counter results have been announced by PI that significantly decreased pasta protein digestibility to (48.55%). Absorbed water was increased along with CF or PI substitutions resulting in higher moisture cooked pasta (Max. 68.83%). Panelists’ opinion summed the upraised differences positively affecting chickpea fortified pasta sensory attributes to gain high acceptance scores. Enrichment the nutritional quality of pasta by fortification with chickpea flour and protein isolate can be recommended supported by enhancements in rheological and sensorial properties