Determination of 3'-Sialyllactose in Edible Bird's Nests and the Effect of Stewing Conditions on the 3'-Sialyllactose Content of Edible Bird's Nest Products

Abstract

Sialyllactose is an acidic oligosaccharide that has an immune-protective effect against pathogens and contributes to developing the immune system and intestinal microbes. In this study, a method for the determination of 3'-sialyllactose by high-performance liquid chromatography tandem mass spectrometry was established. The sample was treated with 0.1% formic acid methanol solution, and the gradient elution was performed with 0.05% formic acid water and 0.1% formic acid acetonitrile. The hydrophilic liquid chromatographic column was used for separation. The results showed that the linearity was good in the concentration range of 1~160 μg/L. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were 0.3 μg/kg and 1.0 μg/kg, the recovery range was 91.6%~98.4%, and the relative standard deviation (RSD) was 1.5%~2.2%. This method is fast and sensitive. In addition, the 3'-sialyllactose content in edible bird's nest products produced by different processes was studied. It was found that within the tested range, 3'-sialyllactose in edible bird's nest products increased with the intensity of stewing and increased with the addition of sugar. In short, the results provided a new method for detecting the nutritional value of edible bird's nests, as well as a new direction for improving the nutritional value of edible bird's nest products.

Keywords: 3′-sialyllactose; edible bird’s nest; high-performance liquid chromatography-tandem mass spectrometry.

Figure 1

The responses of [M + Na]⁺ and [M − H]⁻ molecular ion peaks and fragment ion peaks. (A): [M + H]⁺ molecular ion peaks; (B): [M + Na]⁺ molecular ion peak; (C): [M − H]⁻ molecular ion peak; (D): [M + Na]⁺ fragment ion peak; (E): [M − H]⁻ fragment ion peak.

Figure 2

Product-ion scan spectra of 3′-sialyllactose.

Figure 3

Effect of initial ratio of different mobile phases on chromatographic peak pattern. (A): C18 column; (B): C18-AQ column; (C–E): Chromatograms of HILIC columns with different initial mobile phase ratios of 75%, 83%, and 90%, respectively.

Figure 4

3′-sialyllactose concentration and peak area curve.

Figure 5

Relationship between 3′-sialyllactose content and heat treatment temperature (n = 2, p < 0.05). The same letter means no significant difference at the 0.05 level, while different letters mean significant difference at the 0.05 level. The average value of the largest group is labeled as (a), and the groups with significant differences increase alphabetically according to the average size, as below.

Figure 6

Relationship between 3′-sialyllactose content and heat treatment time (n = 2, p < 0.05).

Figure 7

Relationship between 3′-sialyllactose content and sugar content (n = 2, p < 0.05).