Chickpea-Derived Modified Antimicrobial Peptides KTA and KTR Inactivate Staphylococcus aureus via Disrupting Cell Membrane and Interfering with Peptidoglycan Synthesis.

The widespread bacterial contamination caused by foodborne pathogens has continuously driven the development of advanced and potent food antimicrobial agents. In this study, two novel antimicrobial peptides (AMPs) named KTA and KTR were obtained by modifying a natural AMP, Leg2, from chickpea storage protein legumin hydrolysates. They were further predicted to be stable hydrophobic cationic AMPs of α-helical structure with no hemolytic toxicity by several online servers. Moreover, the AMPs exerted superior antibacterial activity against two representative Staphylococcus aureus strains thanks to the increased hydrophobicity and positive charge, with minimum inhibition concentration value (4.74-7.41 µM) significantly lower than that of Leg2 (>1158.70 µM). Further, this study sought to elucidate the specific antimicrobial mechanism against Gram-positive bacteria. It was found that the electrostatic interactions of the AMPs with peptidoglycan were vital for peptide activity in combating Gram-positive bacteria. Subsequently, the cell membrane of S. aureus cells was irreversibly disrupted by increasing permeability and impairing membrane components, which led to the massive release of intracellular substances and eventual cell death. Overall, this work demonstrated that KTA and KTR were active against Gram-positive bacteria via peptidoglycan targeting and membrane-disruptive mechanisms and paved the way for expanding their application potential to alleviate food contamination.

Ultrasonically functionalized chitosan-gallic acid films inactivate Staphylococcus aureus through envelope-disruption under UVA light exposure.

The significant threat of foodborne pathogens contamination has continuously promoted the development of efficient antimicrobial food packaging materials. Here, an antimicrobial film was prepared with gallic acid-grafted-chitosan (CS/GA) that obtained by a two-step ultrasound method. The resultant films exhibited good transparency, improved UV barrier performance, and enhanced mechanical strength. Specifically, with the grafting of 1.2 % GA, the UV blocking ability of CS/GA film at 400 nm was significantly increased by 19.7 % and the tensile strength was nearly two times higher than that of CS film. Moreover, the CS/GA films exhibited an inspiring photoactivated bactericidal ability under 400 nm UVA light irradiation that eradicated almost 99.9 % of Staphylococcus aureus (S. aureus) cells within 60 min. To gain more insights into the antibacterial mechanism, the treated S. aureus cells were further investigated by visualizing bacterial ultrastructure and analyzing membrane properties. The results pointed to the peptidoglycan layer as the primary action target when bacteria come into contact with CS/GA films. Afterward, the intracellular oxidative lesions, disrupted bacterial integrity, and disordered membrane functional properties collectively resulted in eventual cell death. The findings revealed the unique peptidoglycan targeting and membrane disruptive mechanisms of CS/GA films, confirming the application values in controlling foodborne pathogens.

Super Antibacterial Capacity and Cell Envelope-Disruptive Mechanism of Ultrasonically Grafted N-Halamine PBAT/PBF Films against Escherichia coli.

Antibacterial materials are urgently needed to combat bacterial contamination, growth, or attachment on contact surfaces, as bacterial infections remain a public health crisis worldwide. Here, a novel ultrasound-assisted method is utilized for the first time to fabricate oxidative chlorine-loaded AH@PBAT/PBF-Cl films with more superior grafting efficiency and rechargeable antibacterial effect than those from conventional techniques. The films remarkably inactivate 99.9999% Escherichia coli and Staphylococcus aureus cells, inducing noticeable cell deformations and mechanical instability. The specific antibacterial mechanism against E. coli used as a model organism is unveiled using several cell envelope structural and functional analyses combined with proteomics, peptidoglycomics, and fluorescence probe techniques. Film treatment partially neutralizes the bacterial surface charge, induces oxidative stress and cytoskeleton deformity, alters membrane properties, and disrupts the expression of key proteins involved in the synthesis and transport of the lipopolysaccharide and peptidoglycan, indicating the cell envelope as the primary target. The films specifically target lipopolysaccharides, resulting in structural impairment of the polysaccharide and lipid A components, and inhibit peptidoglycan precursor synthesis. Together, these lead to metabolic disorders, membrane dysfunction, structural collapse, and eventual death. Given the films' antibacterial effects via the disruption of key cell envelope components, they can potentially combat a wide range of bacteria. These findings lay a theoretical basis for developing efficient antibacterial materials for food safety or biomedical applications.

Inhibitory mechanisms of promising antimicrobials from plant byproducts: A review.

Plant byproducts and waste present enormous environmental challenges and an opportunity for valorization and industrial application. Due to consumer demands for natural compounds, the evident paucity of novel antimicrobial agents against foodborne pathogens, and the urgent need to improve the arsenal against infectious diseases and antimicrobial resistance (AMR), plant byproduct compounds have attracted significant research interest. Emerging research highlighted their promising antimicrobial activity, yet the inhibitory mechanisms remain largely unexplored. Therefore, this review summarizes the overall research on the antimicrobial activity and inhibitory mechanisms of plant byproduct compounds. A total of 315 natural antimicrobials from plant byproducts, totaling 1338 minimum inhibitory concentrations (MIC) (in µg/mL) against a broad spectrum of bacteria, were identified, and a particular emphasis was given to compounds with high or good antimicrobial activity (typically <100 µg/mL MIC). Moreover, the antimicrobial mechanisms, particularly against bacterial pathogens, were discussed in-depth, summarizing the latest research on using natural compounds to combat pathogenic microorganisms and AMR. Furthermore, safety concerns, relevant legislation, consumer perspective, and current gaps in the valorization of plant byproducts-derived compounds were comprehensively discussed. This comprehensive review covering up-to-date information on antimicrobial activity and mechanisms represents a powerful tool for screening and selecting the most promising plant byproduct compounds and sources for developing novel antimicrobial agents.

Ultrasonic-assisted nanoencapsulation of kiwi leaves proanthocyanidins in liposome delivery system for enhanced biostability and bioavailability.

The poor biostability and bioavailability of proanthocyanidins limit their application. In this study, it was hypothesized that encapsulation in lecithin-based nanoliposomes using ultrasonic technology improves the above properties. Based on preliminary experiments, the effects of lecithin mass ratio (1-9%, wt.), pH (3.2-6.8), ultrasonic power (0-540 W), and time (0-10 min) on biostability and bioavailability of purified kiwi leaves proanthocyanidins (PKLPs) were determined. Nanoliposomes prepared optimally with lecithin (5%, wt.), pH = 3.2, ultrasonic power (270 W), and time (5 min) demonstrated a significantly (p < 0.05) improved physicochemical stability, homogeneity, and high encapsulation efficiency (73.84%) relative to control. The PKLPs bioaccessibility during in vitro digestion increased by 2.28-3.07-fold, with a remarkable sustained release and delivery to the small intestine. Similar results were obtained by in vivo analyses, showing over 200% increase in PKLPs bioaccessibility compared to the control. Thus, PKLPs-loaded nanoliposomes are promising candidates for foods and supplements for novel applications.

LC-MS/MS Based Volatile Organic Compound Biomarkers Analysis for Early Detection of Lung Cancer.

(1) Background: lung cancer is the world's deadliest cancer, but early diagnosis helps to improve the cure rate and thus reduce the mortality rate. Annual low-dose computed tomography (LD-CT) screening is an efficient lung cancer-screening program for a high-risk population. However, LD-CT has often been characterized by a higher degree of false-positive results. To meet these challenges, a volatolomic approach, in particular, the breath volatile organic compounds (VOCs) fingerprint analysis, has recently received increased attention for its application in early lung cancer screening thanks to its convenience, non-invasiveness, and being well tolerated by patients. (2) Methods: a LC-MS/MS-based volatolomics analysis was carried out according to P/N 5046800 standard based breath analysis of VOC as novel cancer biomarkers for distinguishing early-stage lung cancer from the healthy control group. The discriminatory accuracy of identified VOCs was assessed using subject work characterization and a random forest risk prediction model. (3) Results: the proposed technique has good performance compared with existing approaches, the differences between the exhaled VOCs of the early lung cancer patients before operation, three to seven days after the operation, as well as four to six weeks after operation under fasting and 1 h after the meal were compared with the healthy controls. The results showed that only 1 h after a meal, the concentration of seven VOCs, including 3-hydroxy-2-butanone (TG-4), glycolaldehyde (TG-7), 2-pentanone (TG-8), acrolein (TG-11), nonaldehyde (TG-19), decanal (TG-20), and crotonaldehyde (TG-22), differ significantly between lung cancer patients and control, with the invasive adenocarcinoma of the lung (IAC) having the most significant difference. (4) Conclusions: this novel, non-invasive approach can improve the detection rate of early lung cancer, and LC-MS/MS-based breath analysis could be a promising method for clinical application.

Effects of ethephon and low-temperature treatments on blood oranges (Citrus sinensis L. Osbeck): Anthocyanin accumulation and volatile profile changes during storage.

Health-promoting anthocyanins in blood oranges can be enriched via appropriate postharvest storage conditions. Here, we explored the changes of anthocyanin accumulation and volatile profiles of Tarocco blood oranges (Citrus sinensis L. Osbeck) treated by the low temperature alone and combined with ethephon (2 mg/mL) during 50 days of storage. The combination treatment of ethephon and low temperature (8 oC) significantly enhanced the levels of total anthocyanins (10.91 ± 0.25 mg/100 g) and individual cyanidin derivatives relative to low-temperature treatment alone. The increases of six cyanidin derivatives and three delphinidin derivatives identified by LC-MS/Q-TOF were consistent with the variation in total anthocyanins. Ethyl butanoate, ethyl 2-methylbutyrate, ethyl hexanoate, ethyl undecanoate, linalool, and d-limonene were identified as main contributors to overall aroma of fresh blood oranges. Volatile compositions and concentrations were decreased under different treatments of ethephon and temperatures, while ethephon could alleviate the loss of activity volatiles during cold storage.

Potential valorisation of baobab (Adansonia digitata) seeds as a coffee substitute: Insights and comparisons on the effect of roasting on quality, sensory profiles, and characterisation of volatile aroma compounds by HS-SPME/GC-MS.

The seeds of Africa's majestic baobab are often discarded or poorly utilized. Few studies explored its potential as a coffee substitute, while the key volatile compounds are still unknown. These compounds were hypothesized to be responsible for baobab's sensory acceptance. In this study, the physicochemical, sensory, and key volatile composition of brews from coffee beans and baobab seeds subjected to different roasting conditions were reported. Roasting increases pH while reducing acidity, total soluble solids, lightness (L*), redness/greenness (a*), and yellowness/blueness (b*) in coffee and baobab brews. Phenolic contents increased significantly (p < 0.05) with increased roasting intensity in baobab while degrading in coffee. Significant variability of volatile composition existed among coffee and baobab matrices and the roasting conditions. Nevertheless, the presence of several key coffee odorants in baobab from pyrazines, phenols, and furans chemical families, owing to their odour active value ≥ 1, likely contributed to its sensory acceptance.

Emerging chitosan-essential oil films and coatings for food preservation - A review of advances and applications.

With the rising demand for fresh and ready-to-eat foods, antimicrobial packaging has been developed to control or prevent microbial growth as well as maintain food quality and safety. Chitosan is an advanced biomaterial for antimicrobial packaging to meet the growing needs of safe and biodegradable packaging. The application of natural essential oils as antimicrobial agents effectively controls the growth of spoilage and pathogenic microbes. Thus, chitosan edible coatings and films incorporated with essential oils have expanded the general applications of antimicrobial packaging in food products. This review summarized the effect of essential oils on modifying the physicochemical characteristics of chitosan-based films. Notably, the antimicrobial efficacy of the developed composite films or coatings was highlighted. The advances in the preparation methods and application of chitosan films were also discussed. Broadly, this review will promote the potential applications of chitosan-essential oils composite films or coatings in antimicrobial packaging for food preservation.

Informative and corrective responsive packaging: Advances in farm-to-fork monitoring and remediation of food quality and safety.

Microbial growth and fluctuations in environmental conditions have been shown to cause microbial contamination and deterioration of food. Thus, it is paramount to develop reliable strategies to effectively prevent the sale and consumption of contaminated or spoiled food. Responsive packaging systems are designed to react to specific stimuli in the food or environment, such as microorganisms or temperature, then implement an informational or corrective response. Informative responsive packaging is aimed at continuously monitoring the changes in food or environmental conditions and conveys this information to the users in real time. Meanwhile, packaging systems with the capacity to control contamination or deterioration are also of great interest. Encouragingly, corrective responsive packaging attempting to mitigate the adverse effects of condition fluctuations on food has been investigated. This packaging exerts its effects through the triggered release of active agents by environmental stimuli. In this review, informative and corrective responsive packaging is conceptualized clearly and concisely. The mechanism and characteristics of each type of packaging are discussed in depth. This review also summarized the latest research progress of responsive packaging and objectively appraised their advantages. Evidently, the mechanism through which packaging systems respond to microbial contamination and associated environmental factors was also highlighted. Moreover, risk concerns, related legislation, and consumer perspective in the application of responsive packaging are discussed as well. Broadly, this comprehensive review covering the latest information on responsive packaging aims to provide a timely reference for scientific research and offer guidance for presenting their applications in food industry.

High-intensity ultrasound processing of baobab fruit pulp: Effect on quality, bioactive compounds, and inhibitory potential on the activity of α-amylase and α-glucosidase.

Effect of high-intensity ultrasound (HIU) compared with thermal treatments on baobab fruit pulp (BFP) quality and bioactive properties were investigated. HIU treatments, particularly at intensities of 687.5 W/cm2 for 5 min, and 344 W/cm2 for 15 min significantly (p < 0.05) increased the cloudiness index, ascorbic acid (AA) retention, total phenolic and flavonoid contents, and antioxidant capacity besides a more potent α-amylase and α-glucosidase inhibition relative to thermally treated samples. Moreover, the physicochemical parameters, colour index, and browning index were maintained with HIU besides lower 5-hydroxymethylfurfural values than thermal processing. HPLC analysis revealed that the content of most phenolic compounds was the highest in HIU treatments besides a 235-256% increase in procyanidin C1 compared with control samples. The AA retention following HIU treatments was 87.62-102.86% compared to 30.47-61.90% in thermally treated samples. Our analyses portrayed ultrasound as a feasible alternative to conventional thermal processing of BFP.

Ultrasound-assisted adsorption/desorption for the enrichment and purification of flavonoids from baobab (Adansonia digitata) fruit pulp.

This work described the purification and enrichment of flavonoids from baobab (Adansonia digitata) fruit pulp (BFP) by ultrasound-assisted adsorption/desorption procedure using macroporous resins. Four resins were tested and HPD-500 polar resin exhibited the best adsorption/desorption properties. Based on preliminary experiments and literature reports, the effects of various ultrasonic conditions including high power short time (HPST, 540 W for 5 min), medium power medium time (MPMT, 270 W for 15 min) and low power long time (LPLT, 45 W for 30 min) as well as different temperatures (T = 25-45 °C) on the adsorption of Total Flavonoids Content (TFC) were investigated in comparison with orbital shaking/no sonication (NS). Also, the effect of ultrasound on the desorption capacity and recovery of TFC was determined at different concentrations of ethanol (30-100%). Remarkably, ultrasonic treatment significantly increased the adsorption/desorption capacity and recovery and shortened the equilibrium time. The pseudo-second-order kinetic and Freundlich isotherm models better delineated the adsorption process under ultrasound. Moreover, the adsorption process was both spontaneous and thermodynamically favourable with physical adsorption and multilinear intraparticle diffusion being the predominant mechanisms of the whole process. HPST treatment at 25 °C with 80% ethanol as the desorption solvent most noticeably enhanced the adsorption/desorption of flavonoids and contributed to the highest recovery of TFC, Total Phenolic Content (TPC), and antioxidant capacity in addition to a 5-8-fold reduction in total sugar and acid contents when compared with NS treatment. Moreover, HPLC analysis revealed that the content of nine out of thirteen phenolic compounds from the HPST treatment was the highest, and the individual flavonoids content increased by 2-3-fold compared with the other treatments. Our analyses suggested that ultrasound can be employed as a practical approach to intensify the adsorption and desorption of functional compounds in BFP.

High-performance liquid chromatography (HPLC)-fluorescence method for determination of bisphenol A diglycidyl ether (BADGE) and its derivatives in canned foods.

Bisphenol A diglycidyl ether (BADGE) is used as a raw material for the production of epoxy resins and PVC organosols, which are commonly applied as inner coatings for food cans. BADGE and its derivatives can migrate from coatings to foodstuffs during processing and storage thereby creating adverse health issues. In this work, a method based on high-performance liquid chromatography (HPLC)-fluorescence detection (FLD) method was developed for the rapid determination of BADGE and its five derivatives in canned foods. Modeling software DryLab® was applied for the optimization of separation conditions. An adequate separation was achieved in 5 min including equilibration time, using a core-shell particle column; such application has not been reported so far. Also, the results showed that LOD varied from 0.01 to 0.20 ng/g, while LOQ varied from 0.03 to 0.66 ng/g, and RSD was found to be <8.64%. The analytical recoveries ranged from 70.46 to 103.44%. Excellent validation data revealed that this method is suitable for the investigation of can coating-to-food migration of BADGE and its derivatives. The HPLC-FLD method is rapid, inexpensive and highly efficient, which could be applicable for safety inspection of food contact materials involving BADGE and its derivatives.

Characterizing the phenolic constituents of baobab (Adansonia digitata) fruit shell by LC-MS/QTOF and their in vitro biological activities.

Baobab (Adansonia digitata) fruit is a part of the baobab tree, a revered multi-purpose tree native to Africa with a myriad of potentials in providing shelter, food, medicine, clothing and as a valuable source of natural antioxidants. A massive quantity of baobab fruit shells (BFS) is generated as a waste from the baobab fruit processing representing significant economic and environmental challenges at the same time an opportunity for its valorization and commercial utilization. The present study explored the potentials of BFS as a source of phenolic compounds. For this purpose, the phenolic constituents of BFS were identified by LC-MS/QTOF analysis. Also, the Total Phenolic Chromatographic Index (TPCI), TPC, TFC, and antioxidant capacity were compared with the baobab seeds and pulp. The antidiabetic potential through α-amylase and α-glucosidase inhibitory activities was also compared with that of acarbose. The LC-MS/QTOF analysis led to the identification of 45 compounds, including quercetin, kaempferol, proanthocyanidins, phenolic acids and their derivatives, several of which had never been reported in baobab fruit. Moreover, the BFS showed higher TPC, TFC, and antioxidant capacity than the baobab seeds and pulp and inhibited α-amylase and α-glucosidase enzymes activities with much higher potency than acarbose. This research demonstrated the promising potentials of BFS as a good source of phenolic compounds that can further be utilized for food and pharmaceutical applications.

Valorisation of baobab (Adansonia digitata) seeds by ultrasound assisted extraction of polyphenolics. Optimisation and comparison with conventional methods.

In this study, ultrasound-assisted extraction (UAE) of phenolic compounds in baobab (Adansonia digitata) seeds was optimised using RSM. Based on the single factor experiment results, the effect of four parameters, extraction time (10-20 min), temperature (40-60 °C), % amplitude (30-50) and solvent to solid ratio (20-30, mL/g) on Total Flavonoids Content (TFC) were investigated and optimised using a central composite design (CCD). The predicted optimal conditions with the highest desirably (0.874) were: 20 min, 30% amplitude, 60 °C temperature and 30 mL/g solvent to solid ratio. Under these conditions, the experimental TFC value (1633.84 ±â€¯10.75 mg RE/100 g DW) was highly correlated with the predicted value (1631.77 mg RE/100 g DW). Moreover, a comparative study confirmed that the recovery of TFC, TPC and antioxidant activity (DPPH and FRAP) was significantly higher in UAE than maceration and Heat Assisted Extraction (HAE) extraction methods in addition to a shorter extraction time. HPLC analysis of the UAE optimised sample extract revealed the presence of 10 phenolic compounds with the highest concentration of D-(+) catechin (87.18 ±â€¯14.57 µg/g). This study is the first attempt to optimise UAE parameters for the extraction of phenolic compounds in baobab seeds.

LC-MS/QTOF identification of phytochemicals and the effects of solvents on phenolic constituents and antioxidant activity of baobab (Adansonia digitata) fruit pulp.

Baobab fruit (Adansonia digitata) pulp has received a growing attention globally for its numerous nutritional and medicinal values. However, only limited information is available about its phytochemical composition. The purpose of this study was to identify the phytochemicals in baobab fruit pulp using LC-MS/QTOF and evaluate the effects of solvents on phenolic compounds content and antioxidant activity. The LC-MS analysis led to the identification of 46 compounds, based on standards and comparison with literature reports. Proanthocyanidins, phenolic acids, flavonols, and saponins were the most common compounds. The best solvent for Total Phenolic Compounds Content (TPCC), TPC, TFC and antioxidant activity was also defined: 80% acetone was the best for TPCC, TFC and FRAP, 30% acetone for TPC and 50% methanol for DPPH. Considering all the results, 80% acetone was determined as the best solvent for sample extraction. A high correlation was observed between phenolic compounds content and antioxidant activity.