Peptide Research Database

Limosilactobacillus reuteri normalizes gut microbiota dysfunction and social deficits of rat offspring associated with prenatal exposure to stress.

Zhang F, Xu W, Zeng R, Chen J, Huang J

Prenatal stress (PS) is a potential risk factor for social behavior impairment in offspring. Here, we demonstrate that PS induces gut microbiota alterations that are associated with impaired sociability and social novelty preference in rat offspring. In addition, we found that these behavioral deficits could be partially rescued through either cohousing with normal offspring or fecal microbiota transplantation from control donors. Metagenomic analysis identified Limosilactobacillus reuteri (L. reuteri) as a key species based on the considerable difference in its abundance between the PS and control offspring. Subsequent investigations revealed that supplementing L. reuteri during critical neurodevelopmental windows restored oxytocin levels in the paraventricular nucleus (PVN) and rescued dopamine reward pathway function, thereby ameliorating PS-induced social deficits. Notably, these beneficial effects were completely abolished by either treatment with an oxytocin receptor antagonist or subdiaphragmatic vagotomy. Thus, both oxytocin signaling and vagal afferent pathways play essential roles in the observed benefits of L. reuteri. Our findings indicate that social behavior impairments in offspring exposed to prenatal maternal stress can be explained by a novel mechanism involving the gut microbiota-brain axis: whereby PS-induced depletion of specific commensal bacteria (particularly L. reuteri) disrupts vagus nerve-mediated oxytocinergic modulation of PVN-to-VTA dopaminergic circuits, ultimately leading to social behavior impairments in offspring.

Enhancing the oral processing and swallowing performance of cod soft gels

Yu X, Wang Y, Han L, Liu S, Yoo MJY, Dong X.

The decline in body functions caused by aging often leads to dysphagia in older adults, thereby making a comfortable and safe eating process particularly important. The study investigated the effects of oral processing, swallowing and in vitro digestive behavior of cod protein soft gels (CGs) with different amounts of HIPEs added (also with different textural properties). In oral environment (37 °C), the CGs gradually liquefied. The modulus and yield strain were significantly reduced; the viscosity was increased compared to the room temperature (25 °C). During chewing, the CGs with HIPEs required more force to chew, but the number of chewing cycles was reduced. The oil droplet in HIPEs significantly decreased the friction coefficient of CGs, which is beneficial for safety and comfort in swallowing. CGs with added HIPEs were preferred by sensory evaluators. Multivariate analysis successfully differentiated the samples and identified that sensory attributes like swallowing residue' and key lubrication parameters (VIP>1) were the primary drivers of sample classification. The addition of HIPEs significantly affected the digestibility of proteins in CGs, with a gradual decrease in the particle size and number of peptides in the digests. The results of this study can be used as a reference for the development of food products for older people with different levels of dysphagia.

Enhancing the oral processing and swallowing performance of cod soft gels

Yu X, Wang Y, Han L, Liu S, Yoo MJY, Dong X.

The decline in body functions caused by aging often leads to dysphagia in older adults, thereby making a comfortable and safe eating process particularly important. The study investigated the effects of oral processing, swallowing and in vitro digestive behavior of cod protein soft gels (CGs) with different amounts of HIPEs added (also with different textural properties). In oral environment (37 °C), the CGs gradually liquefied. The modulus and yield strain were significantly reduced; the viscosity was increased compared to the room temperature (25 °C). During chewing, the CGs with HIPEs required more force to chew, but the number of chewing cycles was reduced. The oil droplet in HIPEs significantly decreased the friction coefficient of CGs, which is beneficial for safety and comfort in swallowing. CGs with added HIPEs were preferred by sensory evaluators. Multivariate analysis successfully differentiated the samples and identified that sensory attributes like swallowing residue' and key lubrication parameters (VIP>1) were the primary drivers of sample classification. The addition of HIPEs significantly affected the digestibility of proteins in CGs, with a gradual decrease in the particle size and number of peptides in the digests. The results of this study can be used as a reference for the development of food products for older people with different levels of dysphagia.

Enhancing the oral processing and swallowing performance of cod soft gels

Yu X, Wang Y, Han L, Liu S, Yoo MJY, Dong X.

The decline in body functions caused by aging often leads to dysphagia in older adults, thereby making a comfortable and safe eating process particularly important. The study investigated the effects of oral processing, swallowing and in vitro digestive behavior of cod protein soft gels (CGs) with different amounts of HIPEs added (also with different textural properties). In oral environment (37 °C), the CGs gradually liquefied. The modulus and yield strain were significantly reduced; the viscosity was increased compared to the room temperature (25 °C). During chewing, the CGs with HIPEs required more force to chew, but the number of chewing cycles was reduced. The oil droplet in HIPEs significantly decreased the friction coefficient of CGs, which is beneficial for safety and comfort in swallowing. CGs with added HIPEs were preferred by sensory evaluators. Multivariate analysis successfully differentiated the samples and identified that sensory attributes like swallowing residue' and key lubrication parameters (VIP>1) were the primary drivers of sample classification. The addition of HIPEs significantly affected the digestibility of proteins in CGs, with a gradual decrease in the particle size and number of peptides in the digests. The results of this study can be used as a reference for the development of food products for older people with different levels of dysphagia.

Investigation of the stability profile of therapeutic α-MSH analogue: Insights from liquid chromatography-high resolution mass spectrometry analysis of afamelanotide.

In lab experiments, researchers studied the chemical stability of afamelanotide (melanotan-1), an approved drug for a rare light sensitivity disorder. By tracking how the peptide breaks down under various storage conditions, they identified the specific degradation pathways that could reduce its effectiveness. This work helps ensure the drug maintains its potency and safety throughout its shelf life.

Chawathe A, Sharma N

Afamelanotide, also known as melanotan-1, is a synthetic 13-amino acid peptidomimetic of α-melanocyte stimulating hormone (α-MSH), and is a critical peptide orphan drug used for the management of erythropoietic protoporphyria. It contains norleucine and D-phenylalanine at positions 4 and 7, in place of methionine and L-phenylalanine, respectively as found in endogenous peptide. Therapeutic peptide stability profiling is crucial in drug development because chemical and physical degradation during storage alters structural properties, potentially reducing efficacy and compromising safety by preventing target engagement. Stability testing for synthetic peptides is performed by following the International Council for Harmonisation (ICH) guidelines Q1A(R2) and Q5C. The current work endeavours to explore afamelanotide's degradation pathways under various chemical and physical stress conditions: acidic, basic, neutral, and oxidative stress, UV light exposure, and increased temperature at 60⁰C. The study demonstrated that afamelanotide undergoes degradation under all applied stress conditions with the generation of fourteen different degradation products (DPs) which were separated by gradient reversed-phase HPLC on a Zorbax SB C18 column (300 Å, 4.6*150 mm, 3.5 µm) and the method was validated according to the ICH Q2(R1) guideline. To enable comprehensive characterization, the analysis was coupled with ultra-high-performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS), where collision-induced dissociation yielded abundant and accurate fragmentation patterns, enabling the detailed structural elucidation of the products. While this work has identified several degradation pathways such as truncation, methylation, deacetylation, and oxidation, it also establishes complete stability profile of α-MSH analogue, thus offering key insights for the rational design of robust drug formulations.

Structural modulation of soy protein isolate and correlation with beany flavor: Effect of dry heating temperature

Liu Y, Wu S, Song H, Jiang L, Yan S, Qi B.

The beany flavor in soy protein isolate (SPI) limits its food applications. The effects of different dry heating treatment temperatures (80, 100, 120 and 140 °C) on the physicochemical properties and structure of SPI were investigated, as well as their relationship with beany flavor were investigated. Results showed that increasing temperature elevated particle size, zeta potential absolute value, and carbonyl content, while decreasing solubility. Spectroscopic analysis showed that with increase of dry heating temperature, the content of α-helix and β-sheet decreased while the content of β-turn and random coil increased, the structure became more disordered, the fluorescence quenching increased, and the degree of SPI oxidation intensified. When the dry heating temperature was 80 °C and 100 °C, the free sulfhydryl group content of SPI decreased, the disulfide bond content increased, the protein microstructure did not change significantly, and the essential amino acid content increased and beany flavor was suppressed. At 120 °C and 140 °C, the structure of SPI was severely damaged, and the levels of free sulfhydryl groups, disulfide bonds, essential amino acids, and beany flavor showed opposite trends. Therefore, dry heating treatment at 100 °C maximized amino acid retention and most effectively reduced the beany flavor. Hexanal, (E)-2-hexenal and 1-octen-3-ol were screened by VIP and OAV as the key beany flavor of SPI. In addition, a strong correlation was found between the three key beany flavor and the structure of the protein. This study provides an effective method and theoretical basis for mitigating beany flavor in vegetable proteins.

Structural modulation of soy protein isolate and correlation with beany flavor: Effect of dry heating temperature

Liu Y, Wu S, Song H, Jiang L, Yan S, Qi B.

The beany flavor in soy protein isolate (SPI) limits its food applications. The effects of different dry heating treatment temperatures (80, 100, 120 and 140 °C) on the physicochemical properties and structure of SPI were investigated, as well as their relationship with beany flavor were investigated. Results showed that increasing temperature elevated particle size, zeta potential absolute value, and carbonyl content, while decreasing solubility. Spectroscopic analysis showed that with increase of dry heating temperature, the content of α-helix and β-sheet decreased while the content of β-turn and random coil increased, the structure became more disordered, the fluorescence quenching increased, and the degree of SPI oxidation intensified. When the dry heating temperature was 80 °C and 100 °C, the free sulfhydryl group content of SPI decreased, the disulfide bond content increased, the protein microstructure did not change significantly, and the essential amino acid content increased and beany flavor was suppressed. At 120 °C and 140 °C, the structure of SPI was severely damaged, and the levels of free sulfhydryl groups, disulfide bonds, essential amino acids, and beany flavor showed opposite trends. Therefore, dry heating treatment at 100 °C maximized amino acid retention and most effectively reduced the beany flavor. Hexanal, (E)-2-hexenal and 1-octen-3-ol were screened by VIP and OAV as the key beany flavor of SPI. In addition, a strong correlation was found between the three key beany flavor and the structure of the protein. This study provides an effective method and theoretical basis for mitigating beany flavor in vegetable proteins.

Flavor enhancement of goat yogurt by black tea extract: volatile profile and sensory modulation during storage

Mao Y, Wei L, Pu M, Song S, Chen X, Sun Z, Mi Q, Zhang D, Zeng H, Liu Y, Pan Z, Wang B.

Black tea extract (BTE) was evaluated as a flavor modulator for goat yogurt stored for 28 days at 4 °C. Extracts prepared at 0, 2, 5 and 8 g leaves per 100 mL water (BTE0/2/5/8) were each dosed at 5% (v/v). BTE clearly lowered L∗ and moved a∗ and b∗ toward yellow–red in a dose–response. The panel preferred the mid-level (BTE5) as the most balanced sample. Combination analyses using electronic nose, electronic tongue, and GC–IMS revealed clear distinctions in taste and volatile profiles among all samples. GC–IMS identified 72 peaks corresponding to 62 volatile compounds. After BTE fortification, acetate and ethyl esters increased in abundance, while key ketones such as acetoin and 2-heptanone remained predominant. Heptanal, acetoin, 2-heptanone, and a few esters were some of the volatiles that met the VIP >1, ROAV ≥1, and significance criteria. These findings indicate that BTE5 effectively enhances fruity and floral characteristics while preserving creamy notes, providing practical guidance for developing black tea–flavored goat yogurts with improved sensory balance and consumer acceptability.

Structural modulation of soy protein isolate and correlation with beany flavor: Effect of dry heating temperature

Liu Y, Wu S, Song H, Jiang L, Yan S, Qi B.

The beany flavor in soy protein isolate (SPI) limits its food applications. The effects of different dry heating treatment temperatures (80, 100, 120 and 140 °C) on the physicochemical properties and structure of SPI were investigated, as well as their relationship with beany flavor were investigated. Results showed that increasing temperature elevated particle size, zeta potential absolute value, and carbonyl content, while decreasing solubility. Spectroscopic analysis showed that with increase of dry heating temperature, the content of α-helix and β-sheet decreased while the content of β-turn and random coil increased, the structure became more disordered, the fluorescence quenching increased, and the degree of SPI oxidation intensified. When the dry heating temperature was 80 °C and 100 °C, the free sulfhydryl group content of SPI decreased, the disulfide bond content increased, the protein microstructure did not change significantly, and the essential amino acid content increased and beany flavor was suppressed. At 120 °C and 140 °C, the structure of SPI was severely damaged, and the levels of free sulfhydryl groups, disulfide bonds, essential amino acids, and beany flavor showed opposite trends. Therefore, dry heating treatment at 100 °C maximized amino acid retention and most effectively reduced the beany flavor. Hexanal, (E)-2-hexenal and 1-octen-3-ol were screened by VIP and OAV as the key beany flavor of SPI. In addition, a strong correlation was found between the three key beany flavor and the structure of the protein. This study provides an effective method and theoretical basis for mitigating beany flavor in vegetable proteins.

Flavor enhancement of goat yogurt by black tea extract: volatile profile and sensory modulation during storage

Mao Y, Wei L, Pu M, Song S, Chen X, Sun Z, Mi Q, Zhang D, Zeng H, Liu Y, Pan Z, Wang B.

Black tea extract (BTE) was evaluated as a flavor modulator for goat yogurt stored for 28 days at 4 °C. Extracts prepared at 0, 2, 5 and 8 g leaves per 100 mL water (BTE0/2/5/8) were each dosed at 5% (v/v). BTE clearly lowered L∗ and moved a∗ and b∗ toward yellow–red in a dose–response. The panel preferred the mid-level (BTE5) as the most balanced sample. Combination analyses using electronic nose, electronic tongue, and GC–IMS revealed clear distinctions in taste and volatile profiles among all samples. GC–IMS identified 72 peaks corresponding to 62 volatile compounds. After BTE fortification, acetate and ethyl esters increased in abundance, while key ketones such as acetoin and 2-heptanone remained predominant. Heptanal, acetoin, 2-heptanone, and a few esters were some of the volatiles that met the VIP >1, ROAV ≥1, and significance criteria. These findings indicate that BTE5 effectively enhances fruity and floral characteristics while preserving creamy notes, providing practical guidance for developing black tea–flavored goat yogurts with improved sensory balance and consumer acceptability.