Structural and Functional Characterization of New Lipid Transfer Proteins with Chitin-Binding Properties: Insights from Protein Structure Prediction, Molecular Docking, and Antifungal Activity.

Faced with the emergence of multiresistant microorganisms that affect human health, microbial agents have become a serious global threat, affecting human health and plant crops. Antimicrobial peptides have attracted significant attention in research for the development of new microbial control agents. This work's goal was the structural characterization and analysis of antifungal activity of chitin-binding peptides from Capsicum baccatum and Capsicum frutescens seeds on the growth of Candida and Fusarium species. Proteins were initially submitted to extraction in phosphate buffer pH 5.4 and subjected to chitin column chromatography. Posteriorly, two fractions were obtained for each species, Cb-F1 and Cf-F1 and Cb-F2 and Cf-F2, respectively. The Cb-F1 (C. baccatum) and Cf-F1 (C. frutescens) fractions did not bind to the chitin column. The electrophoresis results obtained after chromatography showed two major protein bands between 3.4 and 14.2 kDa for Cb-F2. For Cf-F2, three major bands were identified between 6.5 and 14.2 kDa. One band from each species was subjected to mass spectrometry, and both bands showed similarity to nonspecific lipid transfer protein. Candida albicans and Candida tropicalis had their growth inhibited by Cb-F2. Cf-F2 inhibited the development of C. albicans but did not inhibit the growth of C. tropicalis. Both fractions were unable to inhibit the growth of Fusarium species. The toxicity of the fractions was tested in vivo on Galleria mellonella larvae, and both showed a low toxicity rate at high concentrations. As a result, the fractions have enormous promise for the creation of novel antifungal compounds.

Identification and Characterization of CC-AMP1-like and CC-AMP2-like Peptides in Capsicum spp.

Antimicrobial peptides (AMPs) are compounds with a variety of bioactive properties. Especially promising are their antibacterial activities, often toward drug-resistant pathogens. Across different AMP sources, AMPs expressed within plants are relatively underexplored with a limited number of plant AMP families identified. Recently, we identified the novel AMPs CC-AMP1 and CC-AMP2 in ghost pepper plants (Capsicum chinense x frutescens), exerting promising antibacterial activity and not classifying into any known plant AMP family. Herein, AMPs related to CC-AMP1 and CC-AMP2 were identified within both Capsicum annuum and Capsicum baccatum. In silico predictions throughout plants were utilized to illustrate that CC-AMP1-like and CC-AMP2-like peptides belong to two broader AMP families, with three-dimensional structural predictions indicating that CC-AMP1-like peptides comprise a novel subfamily of α-hairpinins. The antibacterial activities of several closely related CC-AMP1-like peptides were compared with a truncated version of CC-AMP1 possessing significantly more activity than the full peptide. This truncated peptide was further characterized to possess broad-spectrum antibacterial activity against clinically relevant ESKAPE pathogens. These findings illustrate the value in continued study of plant AMPs toward characterization of novel AMP families, with CC-AMP1-like peptides possessing promising bioactivity.

High performance liquid chromatography (HPLC) based genetic diversity profiling of chilli germplasm for fruit pungency and phytochemical contents.

Chilli peppers are widely consumed for their pungency, as used in flavoring the food and has many pharmaceutical and medicinal properties. Based on these properties an experiment was held using 83 varieties of chilli (Hot pepper and sweet pepper) were grown in suitable environment using Augment Block design and evaluated for fruit pungency and phytochemical contents using high proficiency liquid chromatography. Analysis of variance (ANOVA) of traits showed highly significant for all traits except for fruit length and capsaicin contents. The value of Least significant increase (LSI)was ranged 0.27-1289.9 for all traits showed high variation among varieties. Highly significant correlation was found among fruit diameter to fruit weight 0.98, while moderate to high correlation was present among all traits. The most pungent genotype 24,634 was 4.8 g in weight, while the least pungent genotypes i.e. PPE-311 (32.8 g), green wonder (40.67) had higher in weight. The genotypes 24,627, 32,344, 32,368 and 1108 marked as higher number of seeds in their placental region. It was observed that chilli genotype 24,621 had maximum length with considerable high amount of pungency act as novel cultivar. Principal component analysis (PCA) showed the high variability of 46.97 for two PCs with the eigen value 2.6 and 1.63 was recorded. Biplot analysis showed a considerable variability for fruit pungency, while huge variability was found for all traits among given varieties. PPE-311, T5 and T3 are found as highly divergent for all traits. The findings of this study are instrumental for selecting parents to improve desirable traits in future chilli pepper breeding programs. It will help plant/vegetable breeders for development of highly nutrient and pungent varieties and attractive for the consumer of food sector.

Vegetable and fruit wastes: Valuable source for organic fertilizer for effective growth of short-term crops: Solanum lycopersicum and Capsicum annum.

Agriculture plays a vital role in the food security and economies of Asian countries. Annually, numerous metric tons of vegetable and fruit wastes are disposed of. This research aimed to convert the food wastes encompassing the vegetable and fruit wastes into solid and liquid organic fertilizer and to evaluate their influence on the growth (germination, phytochemicals, and biomolecules) of Solanum lycopersicum and Capsicum annum. Solanum lycopersicum, known as tomato, and Capsicum annum, known as bell pepper or chili pepper, are globally significant crops valued for their medicinal properties and economic importance. The pot experiment was performed with organic fertilizers (solid and liquid organic fertilizer) and compared with the influence of chemical fertilizer and control soil without fertilizers. Interestingly, the liquid organic fertilizer effectively enhanced the biometric profile and chlorophyll content of S. lycopersicum and C. annum Viz., 1.23 mg g-1 and 0.89 mg g-1, respectively. The results of a 30-days pot experiment with various fertilizer treatments showed significant influence of liquid organic fertilizer on the fresh and dry weight biomass of both S. lycopersicum and C. annum. Subsequently, the solid organic fertilizer showed considerable influence on test crops, and the influence of these organic fertilizers was more significant than the chemical fertilizer on crop growth in 30-days experiment. These results suggest that the sustainable approach can effectively convert vegetables and fruit waste into valuable organic fertilizer enriched with plant growth supporting essential nutritional elements.

Unveiling the Biomedical Applications of Novel Coumarins Isolated From Capsicum Annuum L. Seeds by a Multivariate Extraction Technique.

For the first time, kinetic thermomagnetic extraction is a novel approach presented in this work. It required the application of four distinct variables: rotation speed (50, 75, and 100 rpm), magnetic field (0.8, 1.2, and 1.6 T), time interval (30, 60, and 90 min), and temperature (45, 55, and 65 °C). Numerous phytochemical categories were detected in the 81 crude chloroform extracts of green sweet bell pepper seeds that were collected, according to phytochemical analysis. Nine extracts were discovered to be linked to the coumarin chemical class and to have the same two extraction parameters: a 90-minute extraction duration and a 55 °C extraction temperature. To enable their coumarin contents to be chemically separated and chromatographically purified, two of these extracts containing coumarin were chosen. Four new phytocoumarins have been identified and their molecular structures distinguished using FTIR spectra, 1H-NMR, 13C-NMR, and mass analysis. By using MTT probing, it was discovered that these phytocoumarins exhibited anticancer activities against eight malignant populations and reduced oxidative stress in human SH-SY5Y populations. Similarly, the anti-inflammatory and antidiabetic properties were determined using three and two associated enzymes, respectively. The results demonstrated that the extracted phytocoumarins have exceptional oxidative stress-mitigating characteristics, ranging from 71.51 to 81.48 %, when compared to a positive control. Furthermore, they showed excellent cytotoxicity against the test malignant populations (IC50 values of 46.76-81.45 µg/ml). The isolates need to be taken into account as dual COX-2/5-LOX antagonists because they also showed a fascinating selective anti-inflammatory effect. The phytocoumarins under investigation have selectivity indices that are higher than those of the standards used, suggesting that they may have the ability to selectively block the COX2 enzyme that induces harmful inflammation. Compared to the standards, the phytocoumarins have a higher ability to block the catalytic activity of 5-LOX. This observation suggests that the phytocoumarins are powerful 5-LOX agents. Finally, they had a modest antidiabetic impact when tested against two blood-controlling enzymes. The authors came to the conclusion that the technique adopted is flexible and successful for extraction after modifying its components. Moreover, isolated phytocoumarins in general and natural-B1 in particular provide naturally derived solutions for oxidative stress and its associated diseases.

Effect mechanism of capsaicin and dihydrocapsaicin in chili on the oxidative stability of myoglobin in duck meat.

BACKGROUND: Myoglobin (Mb) in duck meat is commonly over-oxidized when heated at high temperatures, which may worsen the color of the meat. Enhancing the oxidative stability of Mb is essential for improving the color of duck meat. Capsaicin and dihydrocapsaicin (CA-DI) in chili exhibit antioxidant properties. This study investigated the effects of CA-DI on the structure and oxidative damage of Mb by fluorescence spectroscopy, differential scanning calorimetry analysis and particle size in duck meat during heat treatment. RESULTS: When the ratio of CA-DI to Mb was 10:1 g kg-1 and heat-treated for 36 min, oxymyoglobin significantly increased, and metmyoglobin significantly decreased compared with the control group (P < 0.05). In parallel, the carbonyl content of Mb in the CA-DI group decreased by 43.40 ± 0.10%, the sulfhydryl content increased by 188 ± 0.21%, and the free radical scavenging activity of Mb was significantly enhanced (P < 0.05). Moreover, the addition of CA-DI resulted in a significant decrease in the particle size of the Mb surface (P < 0.05). When the ratio of CA-DI to Mb was 10:1 g kg-1, CA-DI enhanced the thermal stability and significantly increased the thermal denaturation temperature of Mb. The molecular docking results indicated that hydrophobic interactions and hydrogen bonds were involved in the binding of CA-DI to Mb. CONCLUSION: CA-DI could combine with Mb and improve the oxidation stability of Mb in duck meat. This suggested that CA-DI could be a potential natural antioxidant that improves the color of meat products. © 2024 Society of Chemical Industry.

Dissipation kinetics and the evaluation of dietary risks associated with deltamethrin, ethion, fenazaquin, and fenpropathrin on bell pepper (Solanum annuum L.).

Bell peppers, a globally significant crop, face infestations from various pests. In a study, bell peppers were treated with deltamethrin, ethion, fenazaquin, and fenpropathrin at recommended and double the doses, repeated twice with a 10-day interval. The QuEChERS method underwent validation for linearity, matrix match, accuracy, and precision in bell pepper matrices for residue analysis. The limit of detection for the tested pesticides on bell peppers was 0.01 mg/L, with a quantification limit of 0.05 mg/L. Recovery studies showed a range of 94.80% to 102.80%. Initial deposits of deltamethrin, ethion, fenazaquin, and fenpropathrin on bell peppers at recommended doses were 0.371, 1.237, 0.617, and 0.640 mg/L, respectively, and at double doses were 0.712, 1.945, 1.221, and 1.189 mg/L, respectively. Safe waiting periods of 10, 11, 10, and 8 days were suggested for deltamethrin, ethion, fenazaquin, and fenpropathrin, respectively. The corresponding half-lives for the pesticides were 1.96, 1.79, 2.06, and 1.69 days, all following first-order dissipation kinetics. Dietary risk assessment indicated Hazard Quotients (HQ) below 1 and Theoretical Maximum Daily Intake (TMDI) below Acceptable Daily Intake (ADI) and Maximum Permissible Intake (MPI) levels. Therefore, at their recommended doses, the pesticides were deemed safe for bell pepper cultivation.

Dissipation pattern of tetraniliprole in/on green chilies.

Field and lab experiments explored tetraniliprole dissipation in chili plants. A supervised trial in Devarayapuram village, Coimbatore, assessed the CO2 chili variety (December-March 2018-2019). Using the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method and ultra-high-performance liquid chromatography (UHPLC), samples were collected up to 15 d post-application. Initial tetraniliprole deposits on chili fruits, 1-h post-spray, were 0.898 and 1.271 µg g-1 at single and double doses. Over 80% dissipated within 5 d, reaching below detection limits by day 7 and 10 for single and double doses, respectively. Transformation analysis favored first-order kinetics. Tetraniliprole half-life on chili fruit was 1.49 and 1.53 d at recommended and double doses. The safe waiting period was 4.16 and 5.04 d for 60 and 120 g a.i ha-1. This study provides insights into tetraniliprole dynamics in chili plants, crucial for effective pesticide management.

The impact of time and storage conditions on samples containing OC pepper sprays on the quantitative ratios of capsaicinoids.

Pepper sprays of the OC type constitute the majority of self-defense sprays available on the market. The active ingredient in these preparations is pepper extract: Oleoresin Capsicum, which contains capsaicinoids - natural compounds with irritant properties. Preparations from OC pepper sprays can be distinguished based on differences in the quantitative ratios of four main capsaicinoids: capsaicin, dihydrocapsaicin, nordihydrocapsaicin, and nonivamide. This raises the question whether information on the quantitative ratios of capsaicinoids can also provide answers to questions regarding comparisons of traces of OC preparations, such as whether traces revealed on the clothing of the victim could originate from an OC spray secured from the suspect, or whether traces on the clothing of the suspect and the victim could come from the same pepper spray. Such comparisons would be viable only if the capsaicinoid profile remained unchanged during evidence storage and as a result of solvent extraction from the tested material. The aim of the presented research was to determine if this is indeed the case. Model aging experiments were conducted to examine whether the capsaicinoid profile in traces of OC preparations changed over time and whether solvent extraction affected this profile. Samples of five different OC preparations were applied to cotton swabs, which, after the evaporation of volatile solvents, were placed in three types of packaging with varying levels of tightness and transparency (tight amber vials, polyethylene bags, paper envelopes). These prepared samples underwent solvent extraction with methanol and analysis using gas chromatography - mass spectrometry, after 28, 84, 147, 196, 252, and 301 days from preparation. The likelihood ratio (LR) was applied as a statistical tool to investigate the data obtained. The LR model was computed using the three variables based on the relative content of nordihydrocapsaicin, nonivamide, and dihydrocapsaicin. The cotton swabs used in the experiments served as a model for both the swabs used by the police for securing liquid evidence and the cotton clothing of individuals sprayed with OC pepper sprays. The findings of the conducted studies suggest that the quantitative relationships of capsaicinoids indeed change over time, both in preparations stored in original containers and in traces of these preparations present on clothing. For traces of OC preparations secured on swabs or present on clothing, these changes are more significant the longer the sample is stored and the less airtight the packaging used.

Residue estimation and dietary risk assessment of fenvalerate, novaluron, and profenofos in bell pepper grown under protected and open field conditions.

Residue studies were conducted in bell pepper crops (green and yellow bell pepper) to ensure the safe use of fenvalerate, profenofos, and novaluron (under open field and protected conditions) in randomized block design (RBD) following three applications at a 10-day interval over two consecutive years, 2021 and 2022. A robust analytical method was developed using quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and gas chromatography-tandem mass spectrometry (GC-MS/MS) for the determination of pesticide residues in bell pepper samples. The half-lives for fenvalerate were 2.47-2.87 and 2.50-3.03 days on bell pepper under open field conditions, whereas the corresponding values for bell pepper under protected conditions were 3.84-4.58 and 4.17-4.71 days, during 2021 and 2022, respectively. Profenofos displayed half-lives of 2.03-2.65 and 2.15-2.77 days in open field conditions and 3.05-3.89 and 3.16-3.78 days in protected conditions during 2021 and 2022, respectively. Similarly, novaluron had half-lives of 2.87-3.49 and 3.24-3.75 days under protected conditions in 2021 and 2022, respectively. The maximum residue limits (MRLs) were calculated to be 0.6 mg/kg for fenvalerate, while for profenofos it was 0.7 mg/kg on bell pepper under open field conditions at double doses, at the proposed pre-harvest interval (PHI) of 3 days. Likewise, for bell peppers grown under protected conditions, MRLs at the PHI of 3 days were determined to be 0.8 mg/kg for fenvalerate, 0.3 mg/kg for novaluron, and 1.5 mg/kg for profenofos. A dietary risk assessment study indicated that the percentage of acute hazard index (% aHI) was significantly lower than 100, and hazard quotient (HQ) values were below 1, signifying no acute or chronic risk to consumers. These findings underscore the safety of consuming bell peppers treated with fenvalerate, profenofos, and novaluron under the protected and open field conditions.

Exploring the chemical diversity of Capsicum chinense cultivars using NMR-based metabolomics and machine learning methods.

The habanero pepper (Capsicum chinense) is a prominent spicy fruit integral to the historical, social, cultural, and economic fabric of the Yucatan peninsula in Mexico. This study leverages the power of 1H NMR spectroscopy coupled with machine learning algorithms to dissect the metabolomic profile of eleven C. chinense cultivars, including those grown by INIFAP (Habanero-Jaguar, Antillano-HRA 1-1, Antillano-HRA 7-1, Habanero-HAm-18A, Habanero-HC-23C, and Jolokia-NJolokia-22) and commercial hybrids (Habanero-Rey Votán, Habanero-Kabal, Balam, USAPR10117, and Rey Pakal). A total of fifty metabolites, encompassing sugars, amino acids, short-chain organic acids, and nucleosides, were identified from the 1H NMR spectra. The optimized machine learning model proficiently predicted the similarity percentage between the INIFAP-grown cultivars and commercial hybrids, thereby facilitating a comprehensive comparison. Biomarkers unique to each cultivar were delineated, revealing that the Habanero-Rey Votán cultivar is characterized by the highest concentration of sugars. In contrast, the Balam cultivar is rich in amino acids and short-chain organic acids, sharing a similar metabolomic profile with the Jolokia-NJolokia-22 cultivar. The findings of this study underscore the efficacy and reliability of NMR-based metabolomics as a robust tool for differentiating C. chinense cultivars based on their intricate chemical profiles. This approach not only contributes to the scientific understanding of the metabolomic diversity among habanero peppers but also holds potential implications for food science, agriculture, and the culinary arts.

Effects of capsaicin loads on the properties of capsicum leaf protein-based nanocellulose composite films.

This study aims to enhance the functionality of conventional protein-based nanocellulose composite films (PNCF) to meet the high demand for natural antimicrobial packaging films. Capsicum leaf protein (CLP) and cellulose nanocrystals (CNCs) extracted from capsicum leaves were used as raw materials. Capsaicin, an essential antibacterial active ingredient in the capsicum plant, was used as an additive. The influence of different capsaicin loads on PNCF physicochemical and material properties was investigated under alkaline conditions. The results show that all film-forming liquids (FFLs) are non-Newtonian fluids with shear thinning behavior. When the capsaicin loading exceeds 20 %, the surface microstructure of PNCF changes from dense lamellar to rod-like. Capsaicin did not alter the PNCF crystal structure, thermal stability or chemical bonding. Capsaicin can be loaded onto the PNCF surface by intermolecular hydrogen bonding reactions with CLP and CNC, preserving capsaicin's biological activity. With increasing capsaicin loads from 0 % to 50 %, the mechanical and hydrophobic properties of PNCF decreased, whereas the diameter of the inhibition zone increased. All PNCFs have UV-blocking properties with potential applications in developing biodegradable food packaging materials. The results of this study provide a theoretical basis for the high-value utilization of capsicum cultivation waste and the preparation of novel PNCF.

Smartphone-based digital image colorimetry for the determination of total capsaicinoid content in chili pepper extracts.

A simple smartphone-based digital image colorimetry was proposed for the determination of total capsaicinoid content and the assessment of chili pepper pungency. The biobased solvent D-limonene was used for the first time to isolate analytes. Capsaicinoids were efficiently separated from chili pepper by solid-liquid extraction with D-limonene followed by partitioning of the analytes into the ammonium hydroxide solution to eliminate the matrix interference effect. For colorimetric detection of total capsaicinoid content, a selective chromogenic reaction was performed using Gibbs reagent (2,6-dichloroquinone-4-chloroimide). Measurements were performed using a smartphone-based setup and included image analysis with the program ImageJ. The limit of detection of the proposed procedure was 0.15 mg g-1. The intra-day repeatability did not exceed 10.0 %. The inter-day repeatability was less than 16.5 %. The comparison of the smartphone-based procedure with high-performance liquid chromatography showed satisfactory results.

Characterization of carboxylated cellulose nanofibrils and oligosaccharides from Kraft pulp fibers and their potential elicitor effect on the gene expression of Capsicum annuum.

Biomass-derived oligo- and polysaccharides may act as elicitors, i.e., bioactive molecules that trigger plant immune responses. This is particularly important to increase the resistance of plants to abiotic and biotic stresses. In this study, cellulose nanofibrils (CNF) gels were obtained by TEMPO-mediated oxidation of unbleached and bleached kraft pulps. The molecular structures were characterized with ESI and MALDI MS. Analysis of the fine sequences was achieved by MS and MS/MS of the water-soluble oligosaccharides obtained by acid hydrolysis of the CNF gels. The analysis revealed the presence of two families: one corresponding to homoglucuronic acid sequences and the other composed by alternating glucose and glucuronic acid units. The CNF gels, alone or with the addition of the water-soluble oligosaccharides, were tested on Chili pepper (Capsicum annuum). Based on the characterization of the gene expression with Next Generation Sequencing (NGS) of the C. annuum's total messenger RNA, the differences in growth of the C. annuum seeds correlated well with the downregulation of the pathways regulating photosynthesis. A downregulation of the response to abiotic factors was detected, suggesting that these gels would improve the resistance of the C. annuum plants to abiotic stress due to, e.g., water deprivation and cold temperatures.

Detection of aflatoxin B1 in chili powder using attenuated total reflectance-Fourier transform infrared spectroscopy.

Aflatoxin B1, a major global food safety concern, is produced by toxigenic fungi during crop growing, drying, and storage, and shows increasing annual prevalence. This study aimed to detect aflatoxin B1 in chili samples using ATR-FTIR coupled with machine learning algorithms. We found that 83.6% of the chili powder samples were contaminated with Aspergillus and Penicillium species, with aflatoxin B1 levels ranging from 7.63 to 44.32 µg/kg. ATR-FTIR spectroscopy in the fingerprint region (1800-400 cm-1) showed peak intensity variation in the bands at 1587, 1393, and 1038 cm-1, which are mostly related to aflatoxin B1 structure. The PCA plots from samples with different trace amounts of aflatoxin B1 could not be separated. Vibrational spectroscopy combined with machine learning was applied to address this issue. The logistic regression model had the best F1 score with the highest %accuracy (73%), %sensitivity (73%), and %specificity (71%), followed by random forest and support vector machine models. Although the logistic regression model contributed significant findings, this study represents a laboratory research project. Because of the peculiarities of the ATR-FTIR spectral measurements, the spectra measured for several batches may differ, necessitating running the model on multiple spectral ranges and using increased sample sizes in subsequent applications. This proposed method has the potential to provide rapid and accurate results and may be valuable in future applications regarding toxin detection in foods when simple onsite testing is required.

The difference analysis of physicochemical indexes and volatile flavor compounds of chili oil prepared from different varieties of chili pepper.

Because of its peculiar flavor, chili oil is widely used in all kinds of food and is welcomed by people. Chili pepper is an important raw material affecting its quality, and commercial chili oil needs to meet various production needs, so it needs to be made with different chili peppers. However, the current compounding method mainly relies on the experience of professionals and lacks the basis of objective numerical analysis. In this study, the chroma and capsaicinoids of different chili oils were analyzed, and then the volatile components were determined by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion migration spectrometer (GC-IMS) and electronic nose (E-nose). The results showed that Zidantou chili oil had the highest L*, b*, and color intensity (ΔE) (52.76 ± 0.52, 88.72 ± 0.89, and 118.84 ± 1.14), but the color was tended to be greenyellow. Xinyidai chili oil had the highest a* (65.04 ± 0.2). But its b* and L* were relatively low (76.17 ± 0.29 and 45.41 ± 0.16), and the oil was dark red. For capsaicinoids, Xiaomila chili oil had the highest content of capsaicinoids was 2.68 ± 0.07 g/kg, Tianjiao chili oil had the lowest content of capsaicinoids was 0.0044 ± 0.0044 g/kg. Besides, 96 and 54 volatile flavor substances were identified by GC-MS and GC-IMS respectively. And the main volatile flavor substances of chili oil were aldehydes, alcohols, ketones, and esters. A total of 11 key flavor compounds were screened by the relative odor activity value (ROAV). Moguijiao chili oil and Zidantou chili oil had a prominent grass aroma because of hexanal, while Shizhuhong chili oil, Denglongjiao chili oil, Erjingtiao chili oil, and Zhoujiao chili oil had a prominent floral aroma because of 2, 3-butanediol. Chili oils could be well divided into 3 groups by the partial least squares discriminant analysis (PLS-DA). According to the above results, the 10 kinds of chili oil had their own characteristics in color, capsaicinoids and flavor. Based on quantitative physicochemical indicators and flavor substances, the theoretical basis for the compounding of chili oil could be provided to meet the production demand more scientifically and accurately.

Investigation of the formation mechanism of the pepper starch-piperine complex.

In this study, a new carrier for loading piperine was prepared using pepper starch, and its interaction mechanism was investigated. The porous pepper starch-piperine complex (PPS-PIP) showed higher loading efficiency (76.15 %) compared to the porous corn starch-piperine complex (PCS-PIP (52.34 %)). This may be ascribed to the hemispherical shell structure of porous pepper starch (PPS) compared to the porous structure of porous corn starch (PCS) based on the SEM result. PPS-PIP had smaller particle size (10.53 µm), higher relative crystallinity (38.95 %), and better thermal stability (87.45 °C) than PCS-PIP (17.37 µm, 32.17 %, 74.35 °C). Fourier transform infrared spectroscopy (FTIR) results implied that piperine not only forms a complex with amylose but may also be physically present in porous starch. This was demonstrated by the short-range order and X-ray type. Molecular dynamics simulations confirmed that hydrogen bonding is the primary interaction between amylose and piperine. Besides the formation of the amylose-piperine complex, some of the piperine is also present in physical form.

Ready-to-use ratiometric bioluminescence immunosensor for detection of ochratoxin a in pepper.

Rapid, portable, and accurate detection tools for monitoring ochratoxin A (OTA) in food are essential for the guarantee of food safety and human health. Herein, as a proof-of-concept, this study proposed a ratiometric bioluminescence immunosensor (RBL-immunosensor) for homogeneous detection of OTA in pepper. The construct of the RBL-immunosensor consists of three components, including the large fragment of the split nanoluciferase (NanoLuc)-tagged nanobody (NLg), the small fragment of the split NanoLuc-tagged mimotope peptide heptamer (MPSm), and the calibrator luciferase (GeNL). The specific nanobody-mimotope peptide interaction between NLg and MPSm induces the reconstitution of the NanoLuc, which catalyzes the Nano-Glo substrate and produces a blue emission peak at 458 nm. Meanwhile, GeNL can produce a green emission peak at 518 nm upon substrate conversion via bioluminescent resonance energy transfer (BRET). Therefore, the concentration of OTA can be linked to the variation of the bioluminescence signal (λ458/λ518) measured by microplate reader and the variation of the blue/green ratio measured by smartphone via the competitive immunoreaction where OTA competes with MPSm to bind NLg. The immunosensor is ready-to-use and works by simply mixing the components in a one-step incubation of 10 min for readout. It has a limit of detection (LOD) of 0.98 ng/mL by a microplate reader and an LOD of 1.89 ng/mL by a smartphone. Good selectivity and accuracy were confirmed for the immunosensor by cross-reaction analysis and recovery experiments. The contents of OTA in 10 commercial pepper powder samples were tested by the RBL-immunosensor and validated by high-performance liquid chromatography. Hence, the ready-to-use RBL-immunosensor was demonstrated as a highly reliable tool for detection of OTA in food.

Determination of twelve neonicotinoid pesticides in chili using an improved QuEChERS method with UPLC-Q-TOF/MS.

In this study, a QuEChERS method based on citrate was developed and utilized for the analysis of twelve neonicotinoid pesticides in fresh red chilies, fresh green chilies, and dried chilies, coupled with ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS). In the sample preparation, acetonitrile containing 1% formic acid was used as the extraction solvent. Anhydrous sodium sulfate replaced the traditional anhydrous magnesium sulfate for water removal, effectively eliminating the issues of salt caking. Graphitized carbon black, octadecyl silica, and primary secondary amine were used as cleaning agents. The method showed good sensitivity, with the limits of quantification below 0.03 mg/kg for fresh chilies and below 0.15 mg/kg for dried chilies. Values of matrix effects ranged from -19.5% to 8.4%, and the recovery was 86.9% - 105.2%. The analytical method provided an effective tool for the high throughput detection of neonicotinoid pesticide residues in multiple chili matrices.

Capsicum leaf protein-based bionanocomposite films for packaging application: Effect of corn starch content on film properties.

The addition of corn starch (CS) enhances the interfacial adhesion of the film-forming liquids (FFLs), weakening the internal relative molecular motion. As a result, the rheological properties and zeta potential values of the FFLs were affected. A tight spatial network structure between capsicum leaf protein (CLP), lignocellulose nanocrystals (LNCs) and CS can be formed through intermolecular entanglement and hydrogen bonding interactions. The crystallinity, thermal degradation temperature, tensile strength and water contact angle of the protein-based bionanocomposite films (PBBFs) increased with increasing CS addition. This is due to the transformation of the secondary space structure of the CLP inside the PBBFs and the increase in cohesion. However, the excessive addition of CS forms aggregated clusters on the surface of PBBFs, which increases the surface roughness of PBBFs and causes more light scattering. Therefore, the brightness and yellowness values of the PBBFs increase, and the transmittance decreases.