Determination of thiobarbituric acid reactive substances in microencapsulated products

Food samples are usually extracted or distillated before quantification of thiobarbituric acid reactive substances (TBARS) for evaluation of secondary lipid oxidation, which is a challenge for microencapsulation projects with limited sample quantities. Our approach was to use a ternary solvent mixture of 1-butanol, isopropanol, and 0.5 M HCl (in water) at a proportion of 2:2:1 (v/v/v) to completely dissolve microcapsules of fish oil. The solvent system allowed the construction of highly linear standard curves with good sensitivity: 0.4–13 μM 1,1,3,3,-tetramethoxypropane as a TBA reactive standard with a R2 value of 99.86%. For a sample of fish oil coated by corn zein, only 40 mg of the sample was needed to obtain reliable and repeatable TBARS values. Further, several common encapsulation materials gave low interferences to the assay. The proposed approach, with the above qualities along with good precision and accuracy, may be applicable to a variety of relevant bioactive compounds and encapsulation materials.