Hydrothermal Degradation of Fats, Carbohydrates and Proteins in Sunflower Seeds after Treatment with Subcritical Water

Subcritical water is an alternative and environmentally friendly processing medium with interesting applications in many fields of research1. Its ability to degrade natural biopolymers2 (cellulose, protein etc.) into smaller, usually water-soluble products (sugars, amino acids etc.) has been found to be quite useful, especially in waste and biomass processing technologies. Nevertheless, for food processing, these degradation reactions can have a negative effect on the foods structure itself, resulting in an altered structure with lower quality or even formation of toxic compounds3,4. It is therefore important, that these hydrothermally induced reactions be studied in more detail in order to know how and when they occur. In this study, the hydrothermal degradation of fats, carbohydrates and proteins in subcritical water was observed. For the raw material, sunflower seeds were chosen, which were subjected to subcritical water. The hexane soluble (oil) and water-soluble phases (proteins and carbohydrates) were collected and analysed for products of hydrothermal degradation. Oil stability was investigated by analysing the content of total free fatty acids. The water-soluble phase, on the other hand, was analysed for the presence of any formed amino acids. Furthermore, the total carbohydrates were analysed to evaluate any loss of carbohydrates during the treatment.