Plant based protein powder production from sesame processing waste using spray drying and freeze drying techniques and characterization of powders

The purpose of this thesis was to produce plant based protein powder from an agro-industrial waste source (sesame bran) using spray and freeze drying methods, to perform detailed physicochemical analyses, and to determine powder product properties. The effect of spray drying process parameters was investigated using response surface methodology by central composite rotatable design (CCRD). For the optimum spray drying process conditions, the effects of dependent variables (powder product yield, protein yield, water activity, process time) were determined by considering independent variables (inlet air temperature and outlet air temperature). Physicochemical analyses and powder product characterization of plant based protein powders produced using spray and freeze drying at optimum conditions were carried out. The optimum process conditions were determined as 165 °C inlet air temperature and 74 °C outlet air temperature. Under this condition, 69.0% powder product yield, 68.2% protein yield, 70 min. process time and 0.215 water activity values were obtained in the powder product. Freeze dried protein powders revealed significantly improved wettability (2.3 s) and dispersibility (98.6%) values with higher foaming capacity (35%). Protein powders produced by freeze drying had considerably lower bulk and tapped densities, which are important parameters for processing and transportation. On the other hand, spray drying provided higher water holding capacity (0.94 g water/g protein) and better color properties (L*: 71.4). The production of plant based protein powder from sesame bran has been successfully carried out using spray drying and freeze drying methods. Drying methods showed different effects on the physicochemical properties of protein powders such as the protein content, mineral and amino acid composition, bulk properties, foaming capacity, color and surface morphology. Protein powders derived from sesame bran were found to be high in methionine, which is a sulfur containing essential amino acid. The newly developed protein powder as a functional ingredient could offer sustainable options to food industry and could open up new opportunities to be used in various formulations.