Evaluation of α-tocopherol microencapsulation stability with either coconut oil or canola oil cores in Greek yogurt and butter

Abstract

Worldwide vitamin-E consumption is below the recommended daily allowance (RDA). Therefore, the present work developed functional yogurt/butter with α-tocopherol microencapsulated in canola (α-CAN) or coconut oil (α-COC), using ora-pro-nobis mucilage and whey protein isolate as natural wall material. The primary hypothesis is that α-tocopherol degrades faster than its microencapsulated counterpart in whole food systems. Physical characteristics, pH and color remained constant over 28 days. Color varied from the control, with the total color difference (ΔE) ranging from 0.29 (α-free) to 0.87 (α-CAN) for yogurt and 5.07 (α-CAN) to 6.14 (α-free) for butter. The antioxidant activity of yogurt significantly increased from 15.99 (control) to 34.84% (α-COC), and for butter, it increased from 28.94 (control) to 67.03% (α-COC). The α-tocopherol decreased from 16.60 to 12.70 mg/100 g for yogurt and from 15.40 to 12.83 mg/10 g for butter. No significant differences (p>0.05) presented for α-COC, α-CAN, or α-free; hence microencapsulation did not significantly improve α-tocopherol stability. α-tocopherol degradation was greater for yogurt than butter due to the dissolution of the wall material, as both the continuous phase and wall material are hydrophilic, causing the release and oxidation of α-tocopherol. In butter, the fortification was more effective when the core contained coconut oil.

Keywords

• Encapsulation
• High-performance liquid chromatography
• Quality
• Rheology
• Vitamin E