Investigation of rheological and bioactive properties of dough and bread enriched with protein extracts from Spirulina platensis

Spirulina platensis is a simbiotic, multicellular and filamentous blue-green microalgae. In context of this thesis, enrichment of wheat flour with Spirulina platensis powder (SP) and protein extracts from Spirulina platensis by ultrasound-assisted extraction (SPE) and investigation of rheological nad technofunctional properties of the flours were carried out. Moreover, texturel, sensory and colour properties of the enriched bread samples and changes in the total phenolic content, antioxidant activity and in vitro protein digestibility (%)during in vitro gastro-intestinal digestion were investigated. According to the results of exensograph and farinograph analysis of the enriched flours with SP and SPE, the best ratios for SP and SPE were determined as 0.125%, 0.25% and 0.5%. Total phenolic content and antioxidant activity by CUPRAC method of the samples were 26.06±1.29-31.69±0.09 mg GAE/100 g and 36.17±2.19-51.78±7.95 mg TE/100 g dry weight, before in vitro digestion, respectively (p≥0.05). Antioxidant activity of the samples (SP-%0.125, SP-%0.5 ve SPE-%0.25) increased after in vitro gastric digestion (p<0.05). The protein digestibility (%) of the breads ranged from 81.86±2.07% to 85.02±2.58% (p≥0.05). The firmness value of the control sample was the highest (919.4±34.7 g, p<0.05). The breads with SP and SPE were different from the others in terms of L*, a* and b* values (p<0.05). The L*, values ranged from 52.2 to 60.8 (p<0.05) and it decreased with addition of SP and SPE. According to the results of sensory analysis, the most preferable bread sample was SPE-0.50%.