Production of high quality functional proteins from legumes and plant based agroindustrial wastes and byproducts

Abstract

In this thesis, technological and bioactive properties of protein concentrates and isolates form Turkish lentil and chickpea cultivars and hazelnut meal has been characterized. This study aimed to increase industrially suitable alternatives to soy and animal origin proteins. The functional properties (solubility, gelation, water and oil absorption, emulsion and foaming capacity and stability) of globulin proteins from chickpeas are comparable or superior than those of soy proteins and most animal proteins (fish and bovine gelatin, egg white and whey proteins) with the exception of gelation capacity of bovine gelatin. The chickpea proteins got extremely high water (4.9-7.9 g/g) and oil (10.9-14.6 g/g) absorption capacity. The lentil globulins showed high protein solubility (0.56-0.69 g/g) and oil absorption capacities (6.9-10.4 g/g), but missed water absorption and gelation properties. The lentil proteins showed 2-3 fold higher antioxidant capacity than the chickpea proteins, and antioxidant lentil protein fractions could be separated or concentrated by isoelectric precipitation, ion exchange chromatography and ultrafiltration. The hazelnut meal globulins showed satisfactory oil absorption (7.4-9.4 g/g) and good foaming (7.1 to 18.9 ml foam with 10 mg/ml), but poor water absorption, gelation and emulsion properties. The hazelnut proteins also form water soluble yellowish to brownish and reddish colored transparent edible films with 10-12.5 % (w/w) solutions. However, the most outstanding properties of hazelnut meal proteins is their high bioactivity including free radical scavenging (158-461 μmol Trolox/g), iron chelation (60.7-126.7 μmol EDTA/g) and angiotensin-converting enzyme inhibition (IC50: 0.57-1.0 mg/mL) capacities. Thus, a functional beverage, hazelnut milk enriched with trypsin and pepsin hydrolyzed hazelnut globulins, was developed as an example functional food product. This work showed the good potential of selected Turkish plant resources as animal and soy protein alternatives.