Enrichment of Wheat Flour with Spirulina. Evaluation of Thermal Damage to Essential Amino Acids during Bread Preparation

Abstract

Microalgae and cyanobacteria represent a sustainable and valuable source of essential amino acids and bio-active molecules (e.g. poly-unsaturated fatty acids and antioxidants) which, if added to staple food, could enrich its nutritional profile and the human diet. In this study, two different composite mixtures were obtained by adding different percentages (1% and 2%) of Spirulina powder to "Italian type 1" semi-whole wheat flour (W = 300) after which the chemical, physical, alveographic, and rheological parameters were subsequently analyzed. Spirulina powder did not cause drastic changes at the rheological level when added up to 2%. Furthermore, the concentration of proteins significantly increased in the samples enriched with 1% Spirulina (3.17%) and 2% Spirulina (5.12%), while at the same time the gluten content decreased by 5.62% and 7.41%, respectively. The total amount of essential amino acids in the samples enriched with 1% and 2% Spirulina (48,209 and 55,286 mg aa/kg DW, respectively), was higher in comparison with 45,433 mg aa/kg DW of the control, and those concentrations were maintained after the baking process. Spirulina powder confirmed the hypothesis of being able to improve the supply of essential amino acids that is lacking in wheat flour. The next steps include an investigation into the sensory and liking characteristics of the product.