Dynamic Zanthoxylum pungency characteristics and their correlation with sanshool composition and chemical structure

Enzymatic synthesis of N-succinyl-L-phenylalanine and exploration of its potential as a novel taste enhancer

N-succinyl-L-phenylalanine (SP) has been identified as a taste-active contributor in an array of foods. Despite its recognized importance, the understanding of its synthesis and taste enhancement properties remains rudimentary. The study examined the enzymatic synthesis of SP with 45.58 ± 1.95% yield. This was achieved under optimized conditions: 0.3 mol/L L-phenylalanine, 0.9 mol/L succinic acid, 30,000 U/L of the AY 50C, pH 4 and 55 °C for 24 h. Sensory evaluation and electronic tongue revealed that the incorporation of a mere 1 mg/L SP substantially increased the kokumi, umami, and saltiness intensities, indicating the potential of SP as a potent taste enhancer. Moreover, time-intensity (TI) results demonstrated a significant increase of umami duration in samples containing 1 mg/L of SP (210.0 ± 0 s), a significant extension compared to the control group (150.0 ± 0 s). Notably, the intensity of umami and saltiness in the SP sample were consistently higher than that of control group. The sigmoid curve analysis further confirmed that SP exhibited a synergistic effect on umami and saltiness perceptions. Moreover, the study also illuminated interaction of SP with T1R1, T1R3, TMC4, TRPV1, and CaSR receptors, resulting in significant enhancement in umami, saltiness, and kokumi.

Degradation and transformation mechanisms of pungent substances in huajiao (Zanthoxylum bungeanum) oil during storage: Induced by ultraviolet irradiation

The pungency of huajiao (scientifically known as Zanthoxylum bungeanum) oil (ZBO), a crucial seasoning oil, is notably influenced by storage conditions, an aspect insufficiently explored in current research. Through the use of high-performance liquid chromatography and liquid chromatography-mass spectrometry, this study systematically investigated the stability of pungent compounds in ZBO under various storage conditions. It also elucidated the degradation and transformation mechanisms of these substances when exposed to ultraviolet (UV) irradiation. The results underscore elevated temperature, light exposure, oxygen, and storage duration as pivotal factors influencing compound degradation, with UV light emerging as the primary driving force. After 48 h of UV exposure, the primary pungent compound, hydroxy-α-sanshool, experienced a significant loss of 85.49%, indicating a pronounced inclination towards isomerization and oxidation. Notably, this study reveals, for the first time, the possible degradation-transformation pattern of hydroxy-γ-sanshool: a mutual conversion with hydroxy-γ-isosanshool and isomerization to (2E,4E,8Z,10E,12Z)-N-(2-hydroxy-2-methylpropyl) tetradeca-2,4,8,10,12-pentaenamide.

Molecular simulation screening and sensory evaluation unearth a novel kokumi compound with bitter-masking effect: N-lauroyl-L-tryptophan

N-lauroyl-L-tryptophan (LT), which has the strongest potential flavor-presenting activity, was skillfully screened from numerous N-Lau-AAs docked to different taste receptors by molecular simulation techniques. Subsequently, LT was synthesized employing food-grade commercial enzymes and structurally characterized, the optimized yields of LT could reach 69.08%, 76.16%, and 50.40%, respectively. Sensory and E-tongue evaluations showed that LT at 1 mg/L significantly benefited the performance of different taste sensations and exhibited different bitter taste masking effects: L-Ile (68.42%), L-Trp (68.18%), D-salicylic acid (48.48%) and quinine (35.00%). The molecular docking results illustrated that LT had a high affinity for various taste receptors, dominated by hydrogen bonding and hydrophobic interactions. This work provided a rare systematic elucidation of the potential and mechanism of enzymatically synthesized LT in enhancing taste properties. It provides novel insights into the directions and strategies for the excavation and innovation of flavor enhancers and food flavors.

Da-Jian-Zhong decoction alleviates diarrhea-predominant irritable bowel syndrome via modulation of gut microbiota and Th17/Treg balance

ETHNOPHARMACOLOGICAL RELEVANCE

Da-Jian-Zhong decoction (DJZD) is a herbal formula clinically used for abdominal pain and diarrhea induced by spleen-Yang deficiency syndrome. Recently, treatment of diarrhea-predominant irritable bowel syndrome (IBS-D) with DJZD has received increasing attention, but the underlying mechanism of action remains elusive.

AIM OF THE STUDY

We aimed to evaluate the therapeutic effect of DJZD on IBS-D rats and to elucidate the underlying mechanisms.

MATERIALS AND METHODS

An IBS-D rats model was constructed using a two-factor superposition method of neonatal maternal separation and Senna folium aqueous extract lavage. Moreover, the effect of DJZD was evaluated based on the body weight, rectal temperature, abdominal withdrawal reflex (AWR), and Bristol stool scale score (BSS). The factors that regulate the DJZD effects on IBS-D were estimated using whole microbial genome, transcriptome sequencing (RNA-Seq), flow cytometry, and quantitative reverse transcription polymerase chain reaction (RT-qPCR) analyses.

RESULTS

We found that DJZD alleviated the symptoms of IBS-D rats, with the low-dose (2.4 g/kg) as the better ones, as shown by the higher body weight and lower AWR score and BSS. At the phylum level, the relative abundance of Bacteroidetes was obviously increased, and at the genus level, Lactobacillus and Parabacteroides were increased, while that of Firmicutes_bacterium_424 and Ruminococcus gnavus was decreased in DJZD group. Furthermore, the significantly enriched GO terms after treatment with DJZD mainly included the immune response, positive regulation of activated T cell proliferation, and positive regulation of interleukin-17 (IL-17) production. Importantly, flow cytometry analysis further revealed that the T helper cell type 17/regulatory T cell (Th17/Treg) balance contributed to the DJZD-induced alleviation of IBS-D symptoms, as DJZD downregulated Th17/Treg ratio and Th17 cell-related cytokines IL-17 and IL-6 levels in the colon.

CONCLUSIONS

These results demonstrated that DJZD has a good therapeutic effect on IBS-D rats, probably by maintaining the homeostasis of gut microbiota and regulating Th17/Treg balance and its related inflammatory factors.

Multiple effects of spicy flavors on neurological diseases through the intervention of TRPV1: a critical review

The spicy properties of foods are contributed by various spicy flavor substances (SFs) such as capsaicin, piperine, and allicin. Beyond their distinctive sensory characteristics, SFs also influence health conditions and numerous studies have associated spicy flavors with disease treatment. In this review, we enumerate different types of SFs and describe their role in food processing, with a specific emphasis on critically examining their influence on human wellness. Particularly, detailed insights into the mechanisms through which SFs enhance physiological balance and alleviate neurological diseases are provided, and a systematic analysis of the significance of transient receptor potential vanilloid type-1 (TRPV1) in regulating metabolism and nervous system homeostasis is presented. Moreover, enhancing the accessibility and utilization of SFs can potentially amplify the physiological effects. This review aims to provide compelling evidence for the integration of food flavor and human health.

Rapid determination of geographical authenticity and pungency intensity of the red Sichuan pepper (Zanthoxylum bungeanum) using differential pulse voltammetry and machine learning algorithms

The development of an analytical method for assessing pungency intensity and determining geographical origins is crucial for evaluating the quality of visually similar Zanthoxylum bungeanum pericarp (PZB). This study analyzed 210 PZB samples from 14 origins across China, focusing on origin adulteration identification and pungency intensity using a combination of differential pulse voltammetry (DPV) and machine learning algorithms. The artificial neural network (ANN) and K-nearest neighbor (KNN) algorithms provided the highest accuracy in origin identification (100 %) and adulteration detection (97.9 %) respectively. Moreover, the ANN excelled in predicting pungency intensity (R2 = 0.918). Assessment via feature importance analysis of DPV features revealed that segments of polyphenols (0.34-0.52 V and 1.0-1.2 V) and alkylamides (1.0-1.2 V) contributed significantly to the PZB pungency intensity. These findings highlight the potential of DPV as a reliable method for assessing the quality of PZB, and offer a promising solution for ensuring the geographical authenticity of this important crop.

Mechanistic elucidation of the degradation and transformation of hydroxy-α-sanshool and its conformers as the pungent dietary components in Sichuan pepper: A DFT study

To better understand the structural changes of sanshool pungent dietary components during the process and preservation of Sichuan pepper and pungent foods, the mechanistic insights into the intrinsic degradation and transformation of 16 hydroxy-α-sanshool conformers have been explored computationally. Our results have revealed that increasing the cis-CC bond numbers in the most stable all-trans hydroxy-β-sanshool structure causes the maximum 34.21 kJ/mol conformational energetic difference, and the existent probability of C2nnn would be lower than that of C1nnn (n = 1,2). The isomerization between the conformers could be much easier when they are excited by light radiation, as the strength of the CC bonds and their connected CC bonds becomes significantly close, and the relative energies among conformers are largely reduced. Besides, the different combination of cis/trans-CC bonds changes the delocalization degree of molecular Frontier orbitals, which consequently causes the different photochemical stability. Finally, the possible molecular oxidation degradation mechanism is proposed.

The establishment of comprehensive quality evaluation model for flavor characteristics of green Sichuan pepper (Zanthoxylum armatum DC.) in Southwest China

In this study, the quality indexes and sensory evaluation of Zanthoxylum armatum DC. from the main production areas in Southwest China were analyzed. Further, correlation analysis (CRA), principal component analysis (PCA) and cluster analysis (CA) were used to comprehensively evaluate the quality characteristics of Z. armatum. The results showed that the sensory indexes and physicochemical indexes of Z. armatum were significantly correlated. Five principal component factors were extracted from 12 indexes by PCA, and a comprehensive evaluation model of quality was established with Y = 0.2943Y₁ + 0.2387Y₂ + 0.1896Y₃ + 0.1679Y₄ + 0.1094Y₅. On this basis, 21 producing areas were grouped into 4 groups and 3 groups by Q-type CA, respectively. R-type CA showed that the content of hydroxyl-sanshools, linalool content and b* value were the quality characteristic indexes of Z. armatum in Southwest China. This work provided an important theory and practice reference for Z. armatum quality evaluation and in-depth product development.