Peptides with Charged Amino Acids Mitigate nZnO-Induced Growth Inhibition of Lactobacillus rhamnosus LRa05.

Growing concern is about the potential side effects of nanomaterials from food packaging, notably zinc oxide nanoparticles (nZnO). Previous research revealed that walnut-derived peptides could mitigate this inhibitory effect, but the mechanism involved is unclear. Here, we found that not all peptides have such an effect. Based on the growth inhibition model of Lactobacillus rhamnosus LRa05 induced by nZnO, we assessed the protective effects of various peptides. Notably, four peptides containing charged amino acids (PPKNW, WPPKN, ADIYTE, and WEREEQE) were found to effectively alleviate the growth inhibition phenomenon. We hypothesize that the peptide-nZnO interaction modifies this effect, as confirmed through infrared, Raman, and fluorescence spectroscopy. Our results highlight amide bonds, amino groups, carboxyl groups, and benzene rings as key peptide binding sites on nZnO, with static quenching primarily due to hydrogen bonds and van der Waals forces. This study elucidates peptide characteristics in nZnO interactions, facilitating a deeper exploration of food matrix-nanocomposite interactions.

Effects of Ilisha elongata protein, soy protein and whey protein on growth characteristics and adhesion of probiotics.

The effects of different food source proteins on the growth characteristics and intestinal adhesion of Lactobacillus plantarum 45 (LP45) were investigated by adding Ilisha elongata protein, soy protein and whey protein to the probiotic bacteria in vitro and using a probiotic adhesion model based on mouse intestinal tissues. Ilisha elongata protein and soy protein significantly reduced the growth time of LP45 and increased the total number of colonies fermented by LP45; whey protein only reduced the growth time of LP45; the effect of the three food source proteins on the acid production capacity of LP45 was small. These showed that the three food-derived proteins promoted the proliferation and adhesion of probiotics in the intestine, which were beneficial to the active role of intestinal probiotics and improved the intestinal microenvironment.

Interaction mechanism between ZnO nanoparticles-whey protein and its effect on toxicity in GES-1 cells.

The interaction between zinc oxide nanoparticles (ZnO NPs) and whey protein (WP) was studied. The gastric epithelial cell line (GES-1) was used to evaluate the toxicity intensity of ZnO NPs. The interaction mechanism of ZnO NPs and WP was studied by spectroscopic techniques. The results showed that the inhibitory effect of ZnO NPs on cells activity could be reduced when added to ZnO NPs at a concentration of 50 µg/ml. The fluorescence quenching mechanism of ZnO NPs on WP is a combination of dynamic and static quenching. The interaction force between ZnO NPs and WP can be considered as H-bond and VdW force, and they have two binding sites. The interaction between WP and ZnO NPs leads to the loosening of the structural skeleton of WP and the extension of peptide chain, which exposes the tyrosine (Tyr) and tryptophan (Trp) hydrophobic groups in the hydrophobic region of protein molecules and reduces the hydrophobicity of the microenvironment. The ZnO NPs might form a complex with WP through H-bond, hydrophobic interactions, and so on, leading to peptide chain rearrangement, and finally causing changes in the secondary structure of α-helix. Practical Application This study provides a theoretical basis for future research on the interaction between food ingredients and nanomaterials, the evaluation of toxicity of nanomaterials and the application scope of nanomaterials in food field.

Effects of Ilisha elongata proteins on proliferation and adhesion of Lactobacillus plantarum.

The effects of aquatic proteins on the proliferation and adhesion of intestinal probiotic bacteria were investigated by in vitro fermentation and mouse in vitrointestinal tissue models. Compared with the control group, the Illisha elongata protein reduced the growth time of Lactobacillus plantarum (LP45) by 34.25% and increased the total number of colonies by 6.61%. The Ilisha elongata salt-solubale protein performed better than water-soluble protein in vitro proliferation of LP45. Ilisha elongata salt-soluble protein significantly increased the number of viable bacteria adhering to intestinal, and caused changes in the amount of polysaccharides, proteins and biofilms in the intestinal tissue model. These results indicate that the Ilisha elongata protein is beneficial to the proliferation and adhesion of probiotics in the intestinal, and can be used as an active protein beneficial to intestinal health.

Study on the interaction of Hericium erinaceus mycelium polysaccharides and its degradation products with food additive silica nanoparticles.

Gastric mucosal injury is a common gastrointestinal disorder. Hericium erinaceus polysaccharide, the major active ingredient in Hericium erinaceus, can reduce gastric mucosal damage to some extent. In this study, two different products HMP-Vc and HMP-Ce were obtained by Vitamin C and cellulase degradation of Hericium erinaceus mycelium polysaccharide (HMP). The gastroprotective activity of polysaccharides and its interaction products with food additives silica nanoparticles (nSiO2) were studied in GES-1 cells. It was found that gastroprotective activity of HMP was significantly higher than that of degradation products, and the addition of nSiO2 could enhance this activity of HMP. The greatest difference between the degradation products and HMP was the reduction of the triple helix structure, which might be the reason of the gastroprotective activity was less than that of HMP. Moreover, nSiO2 might interact with HMP through hydrogen bonding to enhance its activity.

Effect of Scomberomorus niphonius peptide on the characteristics of resveratrol.

Resveratrol has a variety of physiological activities, but its bioavailability in the body is low. In this study, the interaction between the peptide SH, prepared from Scomberomorus niphonius, and resveratrol was judged by fluorescence spectroscopy. Then, SHa1 was obtained by the purification of SH, and its effect on the characteristics of resveratrol was studied. SHa1 interacted with resveratrol at 37 °C for 30 min to obtain the complex SHa1-R, which then showed an obviously stronger inhibition on B16 cells than resveratrol using the MTT assay after in vitro gastrointestinal digestion. The solubility and digestive stability of SHa1-R were higher than that of free resveratrol. The intestinal absorption rate of SHa1-R was also increased compared with resveratrol according to the non-inverted rat intestinal sac model. The structure of SHa1 was analyzed by UPLC, auto amino acid analysis, and UPLC-MS/MS. The molecular weight of SHa1 was mainly concentrated under 1000 Da, and it was rich in glutamic acid, aspartic acid, lysine, and leucine. Eighteen possible peptides were identified from SHa1. The results suggested that the peptide SHa-1 may help to increase the bioavailability of resveratrol by increasing the solubility, digestive stability and intestinal absorption of resveratrol, thereby promoting its inhibitory effect on B16 cells.