Alginate–pectin microcapsules as a potential for folic acid delivery in foods

Abstract

Most naturally occurring folate derivatives in foods are highly sensitive to temperature, oxygen, light and their stability is affected by processing conditions. Folic acid incorporated microcapsules using alginate and combinations of alginate and pectin polymers were prepared to improve stability. Folic acid stability was evaluated with reference to encapsulation efficiency, gelling and hardening of capsules, capsular retention during drying and storage. Use of alginate in combination with pectin produced more robust capsules and contributed to greater encapsulation efficiency. The capsules lost their spherical shape as a consequence of increased pectin. The high alginate capsules, A100:P0 (100% alginate: 0% pectin) and A80:P20 (80% alginate: 20% pectin) were of regular spherical shape, while those with more pectin, A70:P30 (70% alginate: 30% pectin) and A60:P40 (60% alginate: 40% pectin) formed irregular spheres. The loading efficiency, expressed as a percentage of the actual loading to theoretical loading, varied from 55–89% with the composition of the mixed polymers. After 11 weeks of storage at 4°C, folic acid retention in freeze-dried capsules was 100% (A70:P30 and A60:P40), 80% (A80:P20) and 30% (A100:P0). The blended alginate and pectin polymer matrix increased folic acid encapsulation efficiency and reduced the leakage from the capsules compared to those made with alginate alone and showed higher folic acid retention after freeze drying and storage.