Bioactive compounds have drawn much attention according to their various health benefits. However, poor dissolvability, low stability and limited bioavailability largely narrow their applications. Although a variety of nontoxic ingredients have been rapidly developed as vehicles to deliver bioactive compounds in the last few years, most of them are non-bioactive. Pentacyclic triterpenoids, owing to their unique self-assembly and co-assembly behaviors and different physiological functions, can construct bioactive carriers due to their higher biodegradability, biocompatibility and lower toxicity. In this paper, the basic classification, biological activities and physicochemical properties of pentacyclic triterpenoids were summarized. Additionally, applications of self-assembled and co-assembled pentacyclic triterpenoids as bioactive delivery systems to load bioactive components and future research directions were discussed. This study emphasizes the potential of pentacyclic triterpenoids as bioactive delivery systems, offering a new perspective for constructing self- or co-assemblies for further synergetic biological applications.

Cereulide is a heat-stable cyclic depsipeptide toxin produced by Bacillus cereus and is responsible for foodborne emetic syndrome. Recent reports of Bacillus cereus contamination and cereulide occurrence in infant formula have raised increasing food safety concerns. Due to the immature immune and metabolic systems of infants, exposure to cereulide through contaminated formula may lead to potential health risks. However, direct application of existing cereulide analytical methods to infant formula remains challenging because of the unique processing technologies, encapsulated nutrients, and variable matrix composition of this product category, which may hinder toxin release and cause significant matrix interference. In practical analysis, inter-laboratory comparisons revealed that existing methods exhibited relatively large deviations and insufficient sensitivity, making them not specifically optimized for infant formula matrices. The present study was motivated by the need for a matrix-specific, sensitive, and reliable analytical method for cereulide determination in infant formula. In this study, a method based on solid-phase extraction coupled with ultra-performance liquid chromatography–tandem mass spectrometry (SPE–UPLC–MS/MS) was developed and validated. To improve the applicability of cereulide analysis to infant formula, this method incorporates a hydration-assisted extraction step tailored to infant formula, which increased the detected cereulide response by approximately fourfold, together with optimized SPE clean-up and improved chromatographic conditions to reduce matrix effects and enhance quantitative reproducibility. The method showed good linearity (0.1–10 μg·L⁻¹, R² > 0.999), low values for limit of detection (LOD) (0.03 μg·kg⁻¹) and limit of quantification (LOQ) (0.1 μg·kg⁻¹), and acceptable recoveries (94.4–110.3%) with RSDs below 3.7%. The developed method was successfully applied to commercial infant formula samples, and cereulide-positive samples were identified. This method provides a reliable analytical tool for the monitoring of cereulide in infant formula and contributes to improved food safety surveillance and exposure risk assessment.

Arachidonic acid (ARA) is an essential long-chain polyunsaturated fatty acid for infant growth and development, commonly added to infant formula and supplementary foods as ARA oil or ARA powder. Since December 2025, infant formula products have been recalled in several countries due to cereulide contamination in ARA ingredients. Cereulide, a heat-resistant emetic toxin produced by Bacillus cereus, presents a serious threat to infant health. However, specific analytical methods for cereulide detection in ARA raw materials remain scarce, hindering effective quality control and source prevention of food safety hazards. This study developed and validated a rapid ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method for the quantitative determination of cereulide in ARA oil and powder. Sample pretreatment was optimized according to matrix characteristics: for microencapsulated ARA powder, water dissolution was performed to release cereulide before acetonitrile extraction, whereas direct extraction was applied to ARA oil. Subsequent HLB-P pass-through solid-phase extraction effectively eliminated matrix interference in both matrices. The method exhibited excellent linearity (R² > 0.999) from 0.1 to 20 μg·L⁻¹, with an LOD of 0.03 μg·kg⁻¹ and an LOQ of 0.1 μg·kg⁻¹, respectively. Spike recoveries reached 90.7–107.0% for ARA oil (RSDs ≤ 6.5%) and 88.5–107.9% for ARA powder (RSDs ≤ 7.0%). This rapid and reliable method provides a critical analytical tool to monitor cereulide in ARA raw materials and mitigate infant safety hazards at the source.