Evolution of Functional Compounds During Accelerated Storage
Figure 3 provides a comprehensive overview of the changes in various functional components during the accelerated storage period, shedding light on critical differences between emulsions prepared via HPH and MF.
Triglycerides (TAG) and Phospholipids (PL): The decrease rate of TAG and PL in HPH-prepared emulsions exhibited a rapid increase from the 5th day to the 30th day, indicative of substantial degradation. In contrast, the decrease rate in MF-prepared emulsions increased more gradually, with a notable change observed from the 15th day onwards. This disparity in the decrease rate of TAG and PL between HPH and MF emulsions was statistically significant.
The continuous and rapid increase in the decrease rate of EPA and DHA in HPH-prepared emulsions from the 5th day to the 30th day underscores their vulnerability to oxidation. In contrast, MF-prepared emulsions exhibited a slower increase in the decrease rate of these essential fatty acids, indicating better retention. This retention of EPA and DHA in MF emulsions corresponds with their lower POV and AV values compared to HPH emulsions, signifying a reduced rate of PUFA oxidation.
Astaxanthin: Astaxanthin, known for its strong antioxidant activity, displayed a stark contrast in behavior between HPH and MF emulsions. HPH emulsions experienced a consistently high decrease rate of astaxanthin throughout the storage period, while MF emulsions maintained a nearly constant decrease rate over 30 days. This variation in astaxanthin degradation aligns with the observations of POV and AV, where higher astaxanthin decrease rates correlated with elevated POV and AV due to the substantial loss of astaxanthin and a subsequent decrease in protective capacity.
Phosphatidylcholine (PC): The PC content in MF-prepared emulsions remained relatively higher throughout the storage period, and as time progressed, it decreased gradually. These results collectively indicate that MF emulsions exhibited better storage stability and were more effective in inhibiting chemical degradation compared to HPH emulsions.
The lower rates of functional component degradation in MF-prepared emulsions can be attributed to several key factors. MF emulsions possess superior stability characterized by smaller particle sizes, uniform distribution, and reduced aggregation or coalescence. These attributes collectively act as barriers that impede oxidative transfer processes, forming a protective shield against deteriorative oxidation reactions. Consequently, KO emulsions produced through MF not only serve as a protective barrier against oxidative processes but also retain essential nutrients to a greater extent. The results presented in this section underscore the marked contrast in the behavior of functional compounds in emulsions prepared by HPH and MF during accelerated storage. MF emulsions consistently exhibit lower degradation rates of TAG, PL, EPA, DHA, astaxanthin, and better retention of PC, highlighting their superior storage stability and their capacity to preserve valuable nutrients. These findings emphasize the potential of MF-prepared emulsions for various applications that demand extended shelf life and nutrient retention.