Application of Persimmon Pectin with Promising Emulsification Properties as an Acidified Milk Drinks Stabilizer.

The present study aimed to evaluate the capability of persimmon pectin (PP) as a stabilizer for acid milk drinks (AMDs) compared with commercial high-methoxyl pectin (HMP) and sugar beet pectin (SBP). The effectiveness of pectin stabilizers was assessed by analyzing particle size, micromorphology, zeta potential, sedimentation fraction, storage, and physical stability. Results of CLSM images and particle size measurements showed that PP-stabilized AMDs had smaller droplet sizes and more uniform distributions, indicating better stabilization potential compared with the HMP- and SBP-stabilized AMDs. Zeta potential measurements revealed that the addition of PP significantly increased the electrostatic repulsion between particles and prevented aggregation. Moreover, based on the results of Turbiscan and storage stability determination, PP exhibited better physical and storage stability compared with HMP and SBP. The combination of steric repulsion and electrostatic repulsion mechanisms exerted a stabilizing effect on the AMDs prepared from PP. Overall, these findings suggest that PP has promising potential as an AMD stabilizer in the food and beverage industry.

The Antifreeze and Cryoprotective Activities of a Novel Antifreeze Peptide from Ctenopharyngodon idella Scales.

The purpose of this study is to obtain new antifreeze peptides (AFPs) that are natural, safe, and high activity from Ctenopharyngodon idella scales. The optimal hydrolysis conditions were investigated, and chromatography-based isolation was conducted using thermal hysteresis activity (THA) as an index. Molecular dynamic simulation (MDs) was explored to reveal the antifreeze mechanism of the AFPs. The results showed that the optimal hydrolysis conditions were 4000 U/g papain enzyme for 60 °C at pH 5.0 and substrate concentration (1:10) for 3 h, as unveiled by single-factor experiment results. The AFPs documented a THA of 2.7 °C when the Th was 1.3 °C. Hydrophilic peptide, named GCFSC-AFPs, with a THA of 5.09 °C when the Th was 1.1 °C was obtained after a series isolation of gel filtration, ion exchange, and reversed-phase HPLC chromatography. The AFPs had a molecular weight of 1107.54~1554.72 Da with three main peptides in the amino acid sequence of VGPAGPSGPSGPQ, RGSPGERGESGPAGPSG, and VGPAGPSGPSGPQG, respectively. The survival rate of yeast with GCFSC-AFPs reached 84.4% following one week of exposure at -20 °C. MDs indicated that GCFSC-AFPs interfered with the ice-water interaction and thus inhibited the ice crystallization process. Our data suggested that the GCFSC-AFPs were a novel and potential antifreeze agent in the food industry.

Persimmon tannin unevenly changes the physical properties, morphology, subunits composition and cross-linking types of gliadin and glutenin.

To answer which is the key component caused the alterations of gluten in the presence of persimmon tannin (PT), the changes on physical properties, morphology, subunits coposition and cross-linking types of glutenin and gliadin were investigated. The results showed that compared with gliadin, glutenin was more sensitive to PT due to the greater changes in the thermal stability, network structure and aggregation behavior. This might be explained by the remarkable decreases in soluble subunits content, free sulfhydryl groups (SH), disulfide bonds (SS) and free amino groups (-NH2) cross-linking of glutenin after 8% of PT addition, as well as the varying degree in subunits composition. Therefore, glutenin played a more important role in the changes in the properties and network structure of gluten induced by PT than gliadin. Our work provided a guidance for the incorporation of phenolic compounds in wheat flour-based products.

Targeting Lipid Rafts as a Rapid Screening Strategy for Potential Antiadipogenic Polyphenols along with the Structure-Activity Relationship and Mechanism Elucidation.

Obesity is a global public health problem that endangers human health, and a rapid search for compounds with antiadipogenic activity could provide solutions to overcome this problem. Polyphenols are potential antiadipogenic compounds, but the screening strategy, structure-activity relationship (SAR), and elucidation of their mechanisms of action remain poorly understood because of the high diversity of polyphenols. Lipid rafts, enriched with sphingolipids and cholesterol, are considered a potential target of polyphenols for the regulation of cellular processes and diseases. Here, a novel rapid screening active polyphenol strategy that targets the lipid rafts using molecular dynamic simulation was developed and validated by 3T3-L1 preadipocyte assay. The screening strategy is high-throughput, inexpensive, reagent-free, and effort saving. In addition, the SAR and mechanisms of action mediating the differentiation-inhibition of the preadipocyte by polyphenols were well elucidated by utilizing multiple technologies, such as "raft-like liposomes" systems, giant plasma membrane vesicles, noninvasive lipid raft probes, and ultrahigh-resolution microscopy. High inhibitory-activity polyphenols could penetrate deeper into the hydrophobic lipid center, in an inverted V-shaped manner or by insertion of galloyl groups into rafts, thus disrupting the ordered domain of lipid rafts. In contrast, the medium and low inhibitory-activity polyphenols could only localize on the surface of lipid rafts, exerting slight and the weakest interference with a lipid raft structure, respectively. The combined use of reliable technologies could yield new knowledge on the SAR and the molecular mechanisms of polyphenols.

Interactions of chlorogenic acid and isochlorogenic acid A with model lipid bilayer membranes: Insights from molecular dynamics simulations.

Because of the negative side-effects of synthetic preservatives, the naturally-occurring polyphenols aroused intense interest of researchers. It has been suggested that chlorogenic acid (CA) and isochlorogenic acid A (iso-CAA) were good candidates to replace the synthetic preservatives. Moreover, the bactericidal activity of iso-CAA was stronger than CA, and the anti-bacterial activities of iso-CAA and CA were highly membrane-dependent. However, the mechanisms were still unclear. Therefore, in the present study, we investigated the mechanisms of the interactions between the two polyphenols and lipid bilayers through molecular dynamics simulations. The results revealed that iso-CAA could be inserted much deeper into POPG lipid bilayer than CA. We also found that hydrophobic interactions and hydrogen bonds both contributed to the insertion of iso-CAA into the POPG lipid bilayer, and the quinic acid moiety was the key structure in iso-CAA to form hydrogen bonds with POPG lipid bilayer. We believed that these findings would provide more useful information to explain the stronger bactericidal activity of iso-CAA than CA at the atomic level.

Influence of the gallate moiety on the interactions between green tea polyphenols and lipid membranes elucidated by molecular dynamics simulations.

Previous studies suggested that naturally occurring EGCG primarily acted on the bacterial cell membrane then damaged the membrane and the gallate moiety in EGCG was very important to its anti-bacterial activity. However, the detailed mechanisms were still poorly understood. In this paper, EGCG and EGC were selected to study the great contribution of gallate moiety on the anti-bacterial activities of polyphenols. The results indicated that EGCG could penetrate deeper into the POPG lipid bilayer and possess more potent structure-perturbing potency on the POPG lipid bilayer than EGC. We also found that EGCG had the ability to form hydrogen bonds with the deeper inside oxygen atoms in the POPG lipid bilayer and the gallate moiety was the key functional group for EGCG forming hydrogen bonds with the POPG lipid bilayer. Moreover, results from the binding free energy analysis demonstrated that the gallate moiety made great contribution to the high affinity between EGCG and the POPG lipid bilayer. We believed that these findings could yield useful insights into the influence mechanisms of gallate moiety on the anti-bacterial activities of polyphenols.

Galloyl Group in B-type Proanthocyanidin Dimers Was Responsible for Its Differential Inhibitory Activity on 3T3-L1 Preadipocytes due to the Strong Lipid Raft-Perturbing Potency.

The effects of three B-type proanthocyanidin (PA) dimers covering procyanidin B2 (B-0g), procyanidin B2 3'-O-gallate (B-1g), and procyanidin B2 3,3'-di-O-gallate (B-2g) on 3T3-L1 preadipocyte differentiation and the underlying mechanisms were investigated. The results showed that digalloylated B-type PA dimers (B-2g) strongly inhibited 3T3-L1 preadipocyte differentiation through disrupting the integrity of the lipid raft structure and inhibiting the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) and then downregulating the expression of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) factors, followed by B-1g, while B-0g had little effect. The different inhibitory effects were mainly due to the difference in the B-type PA dimer structure and the ability to interfere with lipid rafts. The greater the galloylation degree of B-type PA dimers, the stronger the ability to disrupt the lipid raft structure and oppose 3T3-L1 preadipocyte differentiation. In addition, galloylated B-type PA dimers had greater molecular hydrophobicity and topological polarity surface area and could penetrate into the lipid rafts to form multiple hydrogen bonds with the rafts by molecular dynamics simulation. These findings highlighted that the strong lipid raft-perturbing potency of galloylated B-type PA dimers was responsible for inhibition of 3T3-L1 preadipocyte differentiation.

Persimmon tannin changes the properties and the morphology of wheat gluten by altering the cross-linking, and the secondary structure in a dose-dependent manner.

The effects of persimmon tannin (PT) on the texture, viscoelasticity, thermal stability, and morphology of gluten were studied and the underlying mechanisms were also explored. The results showed that PT increased the hardness and viscoelasticity but lowered the cohesiveness and extensibility of gluten in a dose-dependent manner. Additionally, PT increased the denaturation temperature and enthalpy of gluten, and induced the formation of gluten with compact structure. High concentration of PT (8%) significantly increased the hardness and viscoelasticity of gluten, and induced the formation of compact structure of gluten by disturbing the conformation of gluten, and interfering gluten cross-linking through decreasing disulfide bonds, free sulfydryl groups, and free amino groups. In contrast, low concentration (0.25%) of PT slightly altered the gluten properties and morphology. Our work extended the study on the supplementation of phenolic compounds in wheat flour-based products.