Enhanced β-carotene encapsulation and protection in self-assembled lyotropic liquid crystal structures

The aim of this study was to form liquid crystalline structures for retaining and protecting β-carotene (β-c). Tween 40-Span 20 (TxSy) were blended for obtaining target hydrophilic-lipophilic balance (HLB) values ranging from 9 to 15. TxSy were mixed with canola oil (O) as carrier and water (W) as solvent and incubated for 10 days at 37 °C. The formation of lyotropic liquid crystals (LLC) was visually monitored. Pseudo-ternary phase diagrams were constructed to identify the region of LLC formation, which occurred only at HLB values of 11 and 12, the formation region being significantly larger in the former case. The experiments at HLB = 11 were repeated but substituting 0.7% of O by β-carotene (β-c) to produce LLC loaded with β-c (LLC β-c). Finally, LLC β-c were stored in darkness at 25 °C during five weeks. Best LLC β-c yield occurred for an O+β-c:TxSy:W ratio of 40:40:20 (p < 0.05), but the lowest degradation of β-c (17.26%) happened for an O+β-c:TxSy:W ratio of 36:54:10 (p < 0.05). This work provides a procedure for obtaining LLC systems for efficient protection, retention and/or release of nutraceuticals or bioactive compounds such as vitamins, antioxidants and smell substances, which may be used for developing novel food products with desired properties.