Improved Light and In Vitro Digestive Stability of Lutein-Loaded Nanoparticles Based on Soy Protein Hydrolysates via Pepsin

Lutein-loaded lotus root starch nanoparticles: Preparation, release, and in vitro anti-inflammatory activity

The study aimed to construct an effective composite of lutein-loaded lotus root starch nanoparticles (LUT-LRSNPs) and evaluate its in vitro anti-inflammatory activity. LUT-LRSNPs were prepared via the antisolvent nanoprecipitation method and characterized by infrared spectroscopy, X-ray diffraction, and iodine complexation. The result confirmed that lutein was successfully encapsulated in LRSNPs with an encapsulation efficiency up to 84.6 %. Lutein combined with LRSNPs through hydrogen bonding and hydrophobic interaction to form a stable composite, which enhanced the photothermal stability of lutein and realized its controlled release. The cumulative release of lutein in simulated intestinal fluid reached 86.5 %. An inflammatory model was established by stimulating Caco-2 cells with lipopolysaccharide. LUT-LRSNPs significantly decreased the intensity of ROS, inhibited the secretion of TLR4 and the phosphorylation of p38, thus reducing the activation of the NF-κB pathway. It also reduced NO content, IL-1β, IL-6, and TNF-α secretion, as well as the corresponding mRNA expressions in a concentration-dependent manner, with the effect significantly superior to lutein. The prevention group generally exhibited better inhibitory effect than that of the treatment group. In conclusion, LUT-LRSNPs emphasized the enhanced anti-inflammatory effects of lutein and could constitute an alternative for preventing or alleviating related inflammations.

Improved encapsulation efficiency and storage stability of lutein by soy protein isolate nanocarriers with thermal and trypsin treatments

BACKGROUND

Encapsulation of bioactive compounds within protein-based nanoparticles has garnered considerable attention in the food and pharmaceutical industries because of its potential to enhance stability and delivery. Soy protein isolate (SPI) has emerged as a promising candidate, prompting the present study aiming to modify its properties through controlled thermal and trypsin treatments for improved encapsulation efficiency (EE) of lutein and its storage stability.

RESULTS

The EE of lutein nanoparticles encapsulated using SPI trypsin hydrolysates (SPIT) with three varying degrees of hydrolysis (4.11%, 6.91% and 10.61% for SPIT1, SPIT2 and SPIT3, respectively) increased by 12.00%, 15.78% and 18.59%, respectively, compared to SPI. Additionally, the photostability of SPIT2 showed a remarkable increase of 38.21% compared to SPI. The superior encapsulation efficiency and photostability of SPIT2 was attributed to increased exposure of hydrophobic groups, excellent antioxidant activity and uniform particle stability, despite exhibiting lower binding affinity to lutein compared to SPI. Furthermore, in SPIT2, the protein structure unfolded, with minimal impact on overall secondary structure upon lutein addition.

CONCLUSION

The precise application of controlled thermal and trypsin treatments to SPI has been shown to effectively produce protein nanoparticles with substantially improved encapsulation efficiency for lutein and enhanced storage stability of the encapsulated lutein. These findings underscore the potential of controlled thermal and trypsin treatments to modify protein properties effectively and offer significant opportunities for expanding the applications of protein-based formulations across diverse fields. © 2024 Society of Chemical Industry.

Utilization of soybean protein isolate hydrolysates as carriers: Improved encapsulation efficiency and stability of curcumin

This study aimed to explore the potential of soybean protein isolate hydrolysates (SPIH) prepared via Alcalase as delivery carriers and develop novel SPIH-Cur nanoparticles. Hydrolysis caused the varying degrees degradation in the 7S and 11S subunits, significantly enhancing SPI's antioxidant activity. The reduction in particle size and the exposure of hydrophobic groups in SPIH contributed to the formation of stable SPIH-Cur nanoparticles, due to their well binding capacity to curcumin (Cur). The 30 min SPIH-Cur sample exhibited the highest encapsulation efficiency (83.09 %), owing to its high binding affinity (Ka = 9.56 × 103 M-1). Encapsulation by SPIH also significantly improved Cur's thermal and light stability. Moreover, FTIR, fluorescence spectra, and molecular docking analyses revealed that the formation of SPIH-Cur were primarily driven by hydrophobic forces and hydrogen bonds. Above results provide a foundation for fabricating nanoparticles that deliver lipophilic bioactive compounds with high encapsulation efficiency and stability derived from SPIH.

Starter molds and multi-enzyme catalysis in koji fermentation of soy sauce brewing: A review

Soy sauce is a traditional fermented food produced from soybean and wheat under the action of microorganisms. The soy sauce brewing process mainly involves two steps, namely koji fermentation and moromi fermentation. In the koji fermentation process, enzymes from starter molds, such as protease, aminopeptidase, carboxypeptidase, l-glutaminase, amylase, and cellulase, hydrolyze the protein and starch in the raw ingredients to produce short-chain substances. However, the enzymatic reactions may be diminished after being subjected to moromi fermentation due to its high NaCl concentration. These enzymatically hydrolyzed products are further metabolized by lactic acid bacteria and yeasts during the moromi fermentation process into organic acids and aromatic compounds, giving soy sauce a unique flavor. Thus, the starter molds, such as Aspergillus oryzae, Aspergillus sojae, and Aspergillus niger, and their secreted enzymes play crucial roles in soy sauce brewing. This review comprehensively covers the characteristics of the starter molds mainly used in soy sauce brewing, the enzymes produced by starter molds, and the roles of enzymes in the degradation of raw material. We also enumerate current problems in the production of soy sauce, aiming to offer some directions for the improvement of soy sauce taste.