Nano-encapsulation improves thermal stability of bioactive compounds Omega fatty acids and silymarin in bread
This study aimed to develop functional bread enriched with omega-3 fatty acids or silymarin. Nano sized complexes prepared in suspension by means of high-pressure homogenization were spray dried to obtain micron sized aggregated particles of omega-3 fatty acids and silymarin encapsulated with high amylose corn starch (HACS). These particles were incorporated into bread formulation at different amounts. Addition of particles up to 2.5% had no adverse effect on bread quality parameters and sensory properties. The particles remained intact in crumb, but partially destroyed in the crust. Additional amylase activity in the dough caused an increase in the rate of lipid oxidation and silymarin degradation during baking. The results of present study revealed that nano-encapsulation helps improving the thermal stability of heat labile bioactive compounds in bread at elevated temperatures.
Addition of various bioactive compounds into food formulations is an increasing trend to develop functional foods. However this issue holds many technological challenges. Limited stability of certain bioactive compounds at extreme conditions limits also their use especially in bakery products. Polyunsaturated fatty acids (PUFA) like omega-3 fatty acids are desirably used in food enrichment because of their positive health benefits regarding to coronary heart disease, inflammatory and immune disorders, early childhood development, and psychiatric disorders (1). Unsaturation of these fatty acids makes them susceptible to oxidative deterioration; consequently undesirable taste and odor are developed in the food product. Thus, protecting lipids high in PUFA against oxidation is essential to make them more stable under processing and storage conditions. Silymarin, derived from the milk thistle plant, Silybum marianum, has been used for centuries as a natural remedy for diseases of the liver and biliary tract (2). Sonnenbichler et al. isolated a mixture named silymarin, and it was with flavonolignan mixture, which includes silibinin, isosilibinin, ...