Preparation, Digestion, and Storage of Microencapsulated Nervonic Acid-Enriched Structured Phosphatidylcholine

Abstract

This study focuses on the encapsulation of nervonic acid-enriched structured phospholipid (NA-enriched SPL) by analysing its physical and chemical properties. Wall materials for encapsulation were initially screened, with whey protein isolate and maltodextrin exhibiting the most favourable characteristics. Optimisation of encapsulation parameters determined that a core-to-wall ratio of 1:3 provided the highest physical stability. Encapsulated samples underwent in vitro digestion, where MC-FD exhibited the highest digestibility (79.54%), followed by CV-E (72.1%) and NA-enriched SPL (29.82%). Storage stability was assessed over 90 days at 4 °C, 25 °C, and 45 °C by monitoring particle size, zeta potential, polydispersity index, microscopy, fatty acid composition, and primary and secondary lipid oxidation. MC-FD demonstrated superior stability, maintaining its physical and chemical properties, particularly at 4 °C. In contrast, CV-E showed the lowest physical stability, with significant changes in appearance and increased particle size at elevated temperatures (25 °C and 45 °C).

Keywords: conventional emulsion; digestion; encapsulation; microcapsule; nervonic acid; storage.

Figure 1

SEM images of optimised CV-E (A,B) and MC-FD (C–F).

Figure 2

DSC melting curves of MC-FD (A) and CV-E (B).

Figure 3

FTIR spectra of WPI, MD, SPC, and (MC-FD).

Figure 4

Average particle size D_3,2 (A) and zeta potential (B) of CV-E, MC-FD, and SPC. Error bars represent means (n = 3) ± standard deviations. Different letters indicate whether they are significantly different in the original form, gastric, and intestinal phases (Duncan, p < 0.05).

Figure 5

The particle size distribution of CV-E, MC-FD, and SPC after in vitro digestion in the original (A), gastric (B), and intestinal phases (C).

Figure 5

The particle size distribution of CV-E, MC-FD, and SPC after in vitro digestion in the original (A), gastric (B), and intestinal phases (C).

Figure 6

% of FFAs released in CV-E and MC-FD measured with a pH-stat in an in vitro digestion model. Data points and error bars represent means (n = 2).

Figure 7

Microstructure of CV-E, MC-FD, and SPC after exposure to simulated gastric and intestinal digestion.

Figure 8

Formation of lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS) in MC-FD (A,B) and CV-E (C,D) during storage up to 90 days at 4 °C, 25 °C, and 45 °C. Data points and error bars represent means (n = 2) ± standard deviations.

Figure 8

Formation of lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS) in MC-FD (A,B) and CV-E (C,D) during storage up to 90 days at 4 °C, 25 °C, and 45 °C. Data points and error bars represent means (n = 2) ± standard deviations.

Figure 9

MC-FD and CV-E average particle size (A,B), PDI (C,D), and zeta potential (E,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days, respectively. Data points and error bars represent means (n = 2) ± standard deviations.

Figure 9

MC-FD and CV-E average particle size (A,B), PDI (C,D), and zeta potential (E,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days, respectively. Data points and error bars represent means (n = 2) ± standard deviations.

Figure 9

MC-FD and CV-E average particle size (A,B), PDI (C,D), and zeta potential (E,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days, respectively. Data points and error bars represent means (n = 2) ± standard deviations.

Figure 9

MC-FD and CV-E average particle size (A,B), PDI (C,D), and zeta potential (E,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days, respectively. Data points and error bars represent means (n = 2) ± standard deviations.

Figure 10

% of Nervonic acid (A,B), saturated fatty acid (C,D), and polyunsaturated fatty acid (E,F) changes of MC-FD (A,C,E) and CV-E (B,D,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days. Large standard deviations reflect particle instability, caused by coalescence and/or aggregation.

Figure 10

% of Nervonic acid (A,B), saturated fatty acid (C,D), and polyunsaturated fatty acid (E,F) changes of MC-FD (A,C,E) and CV-E (B,D,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days. Large standard deviations reflect particle instability, caused by coalescence and/or aggregation.

Figure 10

% of Nervonic acid (A,B), saturated fatty acid (C,D), and polyunsaturated fatty acid (E,F) changes of MC-FD (A,C,E) and CV-E (B,D,F) during storage at 4 °C, 25 °C, and 45 °C for up to 90 days. Large standard deviations reflect particle instability, caused by coalescence and/or aggregation.