The chemical composition and the preservative, antimicrobial, and antioxidant effects of Thymus broussonetii Boiss. essential oil: an in vitro and in silico approach.

Introduction: The aim of this study was to evaluate the antioxidant, antimicrobial, and preservative efficacy of Thymus broussonetii Boiss. essential oil (EO) in a topically applied formulation using a challenge test. Methods: The essential oil was extracted from the aerial part of T. broussonetii using hydrodistillation, and the obtained EO was further analyzed by gas chromatography/mass spectrometry (GC/MS). The antioxidant effect of the EO was evaluated using three methods: the inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), ß-carotene-linoleic acid, and the ferric reducing antioxidant power (FRAP) methods. The antimicrobial activity and the minimum inhibitory concentration (MIC) of this EO were assayed by the disk-diffusion method and the broth microdilution method, respectively. The preservative efficacy of T. broussonetii EO was assayed at 1% and 2% (v/w) in a topical cream formulation using a challenge test against standard-specific microorganisms recommended by the European Pharmacopoeia. Furthermore, the identified phytochemical compounds were docked for their effect on nicotinamide adenine dinucleotide phosphate oxidase, human casein kinase 1 alpha 1 (CSNK1A1), glycogen synthase kinase 3, Staphylococcus aureus nucleoside diphosphate kinase, Escherichia coli beta-ketoacyl-[acyl-carrier protein] synthase, Pseudomonas aeruginosa LasR ligand-binding domain, and sterol 14-alpha demethylase (CYP51) from Candida albicans. The ADME/toxicity was predicted by analyzing the absorption, distribution, metabolism, and excretion parameters. Results and discussion: chemical composition of the EO revealed the presence of thymol (63.09%), p-cymene (11%), and γ-terpinene (8.99%) as the major components. The antioxidant assays revealed that the essential oil exhibited strong antioxidant activity, as indicated by the minimum inhibitory concentration IC50 (IC50 = 210 ± 0.3 µg/mL for the DPPH assay, IC50 = 145 ± 0.1 µg/mL for the ß-carotene assay, and IC50 = 84 ± 0.21 µg/mL for the FRAP assay) when compared to quercetin and butylated hydroxytoluene (BHT) as controls. The investigated essential oil exhibited important antimicrobial activity against all the tested microorganisms, and the MICs of the EO against bacteria and fungi were 0.02%-1%. Moreover, the EO of T. broussonetii evaluated at 2% (v/w) in a cream formulation succeeded in satisfying the A criteria for preservation efficacy against S. aureus, E. coli, and Aspergillus brasiliensis but exhibited less efficacy against P. aeruginosa (1.78 log reduction in the number of CFU/g after 7 days of evaluation) and C. albicans (1.09 log reduction in the number of CFU/g after 14 days of evaluation) when compared to the synthetic preservative phenoxyethanol 1% (v/w). In silico results showed that the antimicrobial activity of T. broussonetii EO is mostly attributed to thymol, terpinen-4-ol, and aromadendrene, while the antioxidant activity is attributed to thymol. These results indicate that the EO of T. broussonetii possesses important antimicrobial and antioxidant properties and can, therefore, be used as a natural preservative ingredient in the cosmetic industry.

Effect of Allium Jesdianum's extract on the physicochemical, antioxidant, antimicrobial and sensory properties of Sausage characteristics.

The study investigated the use of Allium Jesdianum plant extract as a natural preservative in sausage dough at varying concentrations. After preparation, chemical and microbial tests were conducted on the samples at zero, 14, 28, and 42 days. The study found no significant changes in pH, moisture, fat, or protein content, but the control samples consistently had the highest total volatile nitrogen (TVN) levels. The peroxide test revealed a significant difference between the control and extract samples. Sensory analysis indicated a significant difference between the control and the 200 and 300 ppm extracts (P < 0.05). Addition of Jesdianum extract significantly reduced the total viable count and psychrophilic bacteria compared to the control, subsequently extending the shelf-life of the product to over 42 days. Overall, Allium Jesdianum extract, with its antioxidant and antimicrobial properties, is beneficial in preserving sausage products and can be recommended as a nitrite substitute.

Comparative study on effect of pomegranate peel powder as natural preservative and chemical preservatives on quality and shelf life of muffins.

This research aims to investigate the potential of utilizing pomegranate peel powder (PPP) as a natural preservative in muffin preparation. Pomegranate peel is a rich source of bioactive compounds, including phenolics, flavonoids, and tannins, which possess high antioxidant and antimicrobial properties. The In-Vitro antifungal activity of pomegranate peel powder (8% PPP), potassium sorbate (0.1% PS) and calcium propionate (0.5% CP) was assessed against Penicillium sp. and Aspergillus sp. using poison food technique. The PPP showed the anti-fungal activity by delaying the growth of microorganism on media plate similar to the PS and CP. The effect of utilization of PPP on quality characteristics of muffins were compared with the muffins with chemical preservatives (0.1% PS and 0.5% CP). The viscosity and specific gravity of batter significantly increased from 7.98 to 11.87 Pa s and 1.089-1.398 respectively on addition of 8% PPP. The optical microscopic structure of PPP added batter revealed the decrease in the number of air cells from 24 to 12 with radius range of 6.42-72.72 µm and area range of 511.03-15,383.17 µm2. The functional properties of flour with PPP had higher water absorption capacity, foaming stability, emulsification activity and emulsion stability than others. The addition of PPP significantly increase the weight (32.83 g), and decrease the height (31.3 mm), volume (61.43 cm3), specific volume (1.67 cm3/g) and baking loss (10.19%). The 418.36% increase in fibre content, 14.46% and 18.46% decrease in carbohydrates and energy value was observed in muffin with 8% PPP as compared to control respectively. The total phenols was increased from 0.92 to 12.5 mg GAE/100 g, total tannin from 0.2 to 8.27 mg GAE/100 g, In-vitro antioxidant activity by DPPH from 6.97 to 29.34% and In-vitro antioxidant activity by FRAP from 0.497 to 2.934 mg AAE/100 g in muffins added with 8% PPP. The muffin with PPP was softer than control and muffin with 0.1% PS. The addition of PPP resulted to improve in muffin texture but taste slightly bitter. During the storage of muffins at room temperature (27-30 °C), the moisture content of muffin with PPP was reduced from 17.04 to 13.23% which was higher than the rest of the treatments. Similarly, the hardness of sample with PPP was higher than the sample with 0.5% CP, but lowers than control and sample with 0.1% PS throughout the storage period. The results suggest that pomegranate peel powder can be successfully used as a natural preservative in place of chemical preservatives in muffins, to extend the shelf life. This study provides the opportunity to use PPP as functional ingredient and natural preservative in different bakery products.

Controlling soft rot of green pepper by bacteriocin paracin wx3 and its effect on storage quality of green pepper.

A bacteriocin paracin wx3 was investigated as a candidate of natural preservative to control green pepper soft rot. Firstly, paracin wx3 was heterologously expressed in Pichia pastoris X33 with an improved yield of 0.537 g/L. Its size and amino acid sequence were confirmed by Tricine-SDS-PAGE and LC-MS/MS. Then, result of antibacterial activity showed that its MIC value against Pectobacterium carotovorum was 16 µg/mL. In vitro, paracin wx3 completely killed the pathogen at high concentrations ≥8 × MIC. In vivo, disease incidence of green pepper soft rot was decreased from 90% (control) to <2% (8 × MIC). Subsequently, results of action mode showed that paracin wx3 inhibited the growth of pathogen by pore-formation on cell membrane. Last, paracin wx3 treatment reduced losses of weight, firmness, total soluble solid, Vc of green pepper during storage. It also inhibited the production of soft rot volatile p-xylene, 1-butanol, 2-methyl-2-propanol, 3-hydroxybutan-2-one-D, 2-pentyl furan, butanal, etc.

Natural Extracts and Their Applications in Polymer-Based Active Packaging: A Review.

At a time when food safety awareness is increasing, attention is paid not only to food and additives but also to packaging materials. Most current food packaging is usually made of traditional petroleum-based polymeric materials, which are not biodegradable and have adverse effects on the environment and health. In this context, the development of new non-toxic and biodegradable materials for extending the best-before date of food is receiving increasing attention. In addition, additives in packaging materials may migrate outward, resulting in contact with food. For this reason, additives are also seen as a transition from synthetic additives to natural extracts. Active extracts from animals and plants having good antioxidant and antibacterial properties are also beneficial for human health. It is indisputable that active extracts are ideal substitutes for synthetic additives. Polymer packaging materials combined with active extracts not only maintain their original mechanical and optical properties and thermal stability but also endow polymers with new functions to extend the shelf life of food. This review paper provides an overview of this promising natural extract-containing polymer-based active packaging, with a focus on plant essential oils (containing phenolics, monoterpenes, terpene alcohols, terpene ketones, and aldehydes), pigments (procyanidins), vitamins (vitamin B), and peptides (nisin). In particular, this paper covers the research progress of such active extracts, in single or compound forms, combined with diverse polymers (mostly biopolymers) for food packaging applications with particular focus on the antioxidant and antibacterial properties of packaging materials.

Synergistic antimicrobial interaction of plant essential oils and extracts against foodborne pathogens.

Essential oils (EOs) and plant extracts have demonstrated inhibitory activity against a wide range of pathogenic bacteria. In this study, the chemical composition of manuka, kanuka, peppermint, thyme, lavender, and feijoa leaf and peel EOs and feijoa peel and leaf extracts were analyzed, and their antimicrobial activity against Escherichia coli, Salmonella enterica Typhimurium, Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes were determined. The results showed that the major compounds varied among different EOs and extracts, with menthol in peppermint EO, thymol and carvacrol in thyme EO, linalool in lavender EO, ß-caryophyllene in feijoa EO, and flavones in feijoa extract being the most prevalent. The study found that while EOs/extracts had antimicrobial activity alone, no individual EO/extract was highly effective against all tested species. Therefore, their combinations were tested to identify those that could broaden the spectrum of activity and act synergistically. The checkerboard method was applied to assess the possible synergism between the paired combinations of EOs/extract. The peppermint/thyme, peppermint/lavender, and peppermint/feijoa peel extract combinations exhibited a synergistic effect against E. coli and L. monocytogenes, with the peppermint/thyme and peppermint/feijoa peel extract combinations being the most effective against all five pathogens. Time-to-kill kinetics assays demonstrated that peppermint/thyme and peppermint/feijoa peel extract combinations achieved complete eradication of E. coli within 10-30 min and L. monocytogenes within 4-6 h. This study provides a promising approach to developing a natural alternative for food preservation using synergistic combinations of EOs/extracts, which could potentially reduce the required dosage and broaden their application in food products as natural preservatives.

Green active coating from chitosan incorporated with spontaneous cinnamon oil nanoemulsion: Effects on dried shrimp quality and shelf life.

Green active film from chitosan (C) incorporated with spontaneous emulsified cinnamon oil nanoemulsion (CONE; droplet size of 79.27 nm and polydispersity index of 0.27) was developed. The obtained chitosan film containing CONE (C + CONE) had tensile elongation and light protective effect higher than C film due to the incorporation of bioactive compounds from cinnamon oil as proven by Fourier Transform Infrared Spectroscopy. The effect of C + CONE as active edible coating on the physical, chemical, and microbiological properties of dried shrimp was then investigated. The quality of samples coated with C + CONE (DS + C + CONE) was compared to those coated with C (DS + C) and without coating (DS). In this study, C + CONE could enhance astaxanthin content and reduce lipid oxidation in dried shrimp. During 6 weeks of storage, C + CONE was found to be an effective antimicrobial coating that significantly inhibited growth of bacteria, delayed lipid oxidation and retarded the production of volatile amines in dried shrimp. DS + C + CONE had lower malonaldehyde equivalents (0.52 mg/kg oil), trimethylamine (11.74 mg/100 g), total volatile base nitrogen (84.33 mg/100 g) and total viable count (4.80 Log CFU/g), but had higher astaxanthin content (12.53 ± 0.12 µg/g) than DS and DS + C. The results suggested that the developed C + CONE coating has potential to be used as active coating for preserving food quality.

The effect of propolis extract as a valuable natural additive on the quality characteristics of toast bread.

This study aimed to evaluate the effect of ethanolic propolis extract (EPE) as a natural antimicrobial and antioxidant agent on the physicochemical, microbial, and sensory characteristics of toast bread, as well as phenol content and antioxidant activity. In this regard, 0.1, 0.3, and 0.5% of EPE were used in the bread doughs and the quality characteristics of the breads were assessed. The bread with 0.5% EPE showed the highest phenolic content (24.02 mgGAE/g.d.m) and antioxidant activity (59.03%). These amounts were 12.96 mgGAE/g and 16.45% higher than those of the control (without EPE), respectively (p < .05). The hardness, fracturability, and chewiness of the bread samples were influenced by the levels of EPE on the third and fifth days of storage. EPE decreased the L* and a* of bread samples, but an increasing trend was observed in the b*, chroma, and browning index by elevating the levels of propolis. Propolis extract showed an inhibitory effect on mold growth in samples. The bread with 0.5% of EPE had the lowest mold count after 5 days of storage which was not significant compared to the first day. There was no significant difference in sensory evaluation between the overall acceptance of bread samples. Therefore, EPE has the potential to be used as a natural additive with antimicrobial and antioxidant characteristics in toast bread.

Optimization of antioxidant and lycopene extraction from tomato pomace using Hansen solubility parameters and its application in chicken meat preservation.

Tomato pomace, composed of peels and seeds, is often discarded or used as animal feed. However, it contains valuable phytochemicals, including lycopene. Lycopene, a natural pigment, is an antioxidant known for reducing the risk of chronic diseases like cardiovascular ailments and cancer. In this study, we aimed to study the possibility of valorizing tomato pomace by quantifying phenolic compounds, evaluating the antioxidant activity of their extracts, as well as extracting and quantifying lycopene, and studying the effect of tomato peel extract on the oxidative stability of chicken patties during storage. The effectiveness of different solvent mixtures for the extraction of lycopene was evaluated using Hansen solubility parameters (HSPs). The obtained results showed that the best solvent mixture was hexane/acetone (50/50) with a Hansen theoretical distance of 7.2, indicating its favorable solvation power. It also achieved a notable extraction yield of 3.12% and the highest lycopene yield of 20.05 mg/100 g. This combination demonstrated the highest values in terms of total phenolic (24.06 mg equivalent gallic acid/100 g dry matter) and flavonoid content (30.55 mg equivalent catechin/100 g dry matter), indicating a significant presence of these compounds. However, its 1,1-diphenyl-2-picrylhydrazyl (13.51 µg/mL) and ABTS, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, (8.52 µg/mL) IC50 values were comparatively lower than the other mixes. The use of this fraction as a food additive and antioxidant showed significant competitiveness with the conventional preservative, 2,6-di-tert-butyl-4-methylphenol. Tomato extract can be considered a potential natural preservative in food preparations due to its high lycopene content. PRACTICAL APPLICATION: This research provides valuable insights into optimizing the extraction of antioxidants from tomato pomace, using HSPs. The findings have the potential to benefit the food industry by developing improved methods for preserving chicken meat through the application of these optimized antioxidant extracts. By enhancing the preservation process, this study may contribute to extending the shelf life and maintaining the quality of chicken meat, leading to reduced food waste and improved consumer satisfaction.

Development and Characterization of Antioxidant and Antibacterial Films Based on Potato Starch Incorporating Viola odorata Extract to Improve the Oxidative and Microbiological Quality of Chicken Fillets during Refrigerated Storage.

In this research, the antioxidant and antibacterial activities of active films based on potato starch containing Viola odorata extract (VOE) were investigated both in vitro and in chicken fillets. The VOE was added to the starch film formulation at 0, 1, 2, and 3% (w/v). The results showed that by increasing the extract level, the total phenol content and antioxidant and antibacterial activity of the films against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium improved remarkably. The results of the meat tests indicated the significant antioxidant and antimicrobial activity of active films containing different levels of VOE in chicken fillets, and a direct relationship was observed between the concentration of the extract and the functional activity of the films, so with the increase in the concentration of the extract in the films, the rate of lipid oxidation and growth of microorganisms in the chicken fillets decreased significantly during the storage period, and less volatile nitrogen bases, metmyoglobin, and oxidation products were produced in the fillets. In general, the results of this research demonstrated that an active film based on potato starch containing VOE (especially 2 and 3% levels) has the ability to extend the oxidative and microbiological shelf life of chicken fillets during cold storage for at least eight days.

Citrus sinensis Peel Oil Extraction and Evaluation as an Antibacterial and Antifungal Agent.

Throughout the tropical and subtropical climates, the genus Citrus can be found. The current study was conducted to extract the Citrus sinensis peel oil and evaluate its antibacterial, antifungal and antiparasitic potential. Petroleum ether was used to extract the C. sinensis peel oil through a Soxhlet apparatus. The antimicrobial and antifungal potential was determined via agar well diffusion method and minimum inhibitory concentrations (MIC) were calculated (test bacterial strains: Staphylococcus aureus, Escherichia coli and Streptococcus agalactiae; test fungal strains: Aspergillus flavus, Aspergillus niger, Altrnaria alternata). Antiparasitic activity against Leishmaniatropica was determined following standard protocol using amphotericin-B as positive and Dimethyl Sulfoxide (DMSO) as a negative control and the percentage inhibition was calculated. The oil extracted was brownish yellow with a tangy smell, water-insoluble, density (0.778 g/cm3) and specific gravity (0.843 g/cm). In antibacterial activity, the diameter of the zone of inhibition was maximum against E. coli (14 mm) and minimum for S. agalactiae (10 mm). While in antifungal activity diameter of the zone of inhibition was maximum against A. flavus (12.5 mm) and minimum for A. alternata (8.6 mm). S. agalactiae exhibited the minimum MIC value (6 mg/mL) and in fungal strains A. alternata exhibited the minimum value (2 mm). Citrus sinensis peel oil displayed antileishmanial efficiency of 60% at 50 µg/mL concentration after 48 h of incubation. C. sinensis peel oil demonstrated antimicrobial capabilities, implying that it could be used as a natural preservative in food or as an effective treatment against a variety of pathogenic organisms. Industries should extract oil from the waste of citrus fruits which will be beneficial from an economic point of view.

Characteristics of reduced-fat mayonnaise prepared by oleaster as a fat replacer and natural antioxidant.

Due to the disadvantages of consuming fat and synthetic preservatives, the demand to reduce them in lipid-based products like mayonnaise is increasing. In the current research, there were two goals, the first one was studying the effect of using oleaster flour in different concentrations (4%, 6%, and 8%) as a natural preservative, whereas the second one was studying the effect of oleaster as different fat replacement (FR) levels (10%, 20%, 30%, and 40%) on the physicochemical, antioxidant, and the rheological properties and stability of reduced-fat mayonnaise samples. Given results showed that with increasing the oleaster concentration, the antioxidant property increased significantly. The peroxide value after 60 days of storage for the 30% FR 8 was 2.01%, compared to the control sample without antioxidant and with TBHQ, which were 10% and 2.68%, respectively. The highest stability index (100%) was observed in the 30% FR and 40% FR samples. In terms of rheological characteristics, the 30% FR 8 oleaster showed the highest viscosity and the lowest frequency dependency. It can be concluded that oleaster has a high potential to be used in the formulation of low-fat mayonnaise as a fat replacer.

Potential of Syzygnium polyanthum as Natural Food Preservative: A Review.

Food preservation is one of the strategies taken to maintain the level of public health. Oxidation activity and microbial contamination are the primary causes of food spoilage. For health reasons, people prefer natural preservatives over synthetic ones. Syzygnium polyanthum is widely spread throughout Asia and is utilized as a spice by the community. S. polyanthum has been found to be rich in phenols, hydroquinones, tannins, and flavonoids, which are potential antioxidants and antimicrobial agents. Consequently, S. polyanthum presents a tremendous opportunity as a natural preservative. This paper reviews recent articles about S. polyanthum dating back to the year 2000. This review summarizes the findings of natural compounds presented in S. polyanthum and their functional properties as antioxidants, antimicrobial agents, and natural preservatives in various types of food.

Antimicrobial Activity against Foodborne Pathogens and Antioxidant Activity of Plant Leaves Traditionally Used as Food Packaging.

In accordance with Thai wisdom, indigenous plant leaves have been used as food packaging to preserve freshness. Many studies have demonstrated that both antioxidant and antimicrobial activities contribute to protecting food from spoilage. Hence, the ethanolic extracts of leaves from selected plants traditionally used as food packaging, including Nelumbo nucifera (1), Cocos nucifera (2), Nypa fruticans (3), Nepenthes mirabilis (4), Dendrocalamus asper (5), Cephalostachyum pergracile (6), Musa balbisiana (7), and Piper sarmentosum (8), were investigated to determine whether they have antioxidant and antimicrobial activities against spoilage microorganisms and foodborne pathogens that might be beneficial for food quality. Extracts 1-4 exhibited high phenolic content at 82.18-115.15 mg GAE/g and high antioxidant capacity on DPPH, FRAP and SRSA assay at 14.71-34.28 µg/mL, 342.92-551.38 µmol Fe2+/g, and 11.19-38.97 µg/mL, respectively, while leaf extracts 5-8 showed lower phenolic content at 34.43-50.08 mg GAE/g and lower antioxidant capacity on DPPH, FRAP, and SRSA at 46.70-142.16 µg/mL, 54.57-191.78 µmol Fe2+/g, and 69.05->120 µg/mL, respectively. Extracts 1-4 possessed antimicrobial activities against food-relevant bacteria, including Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, and Escherichia coli. Only N. mirabilis extract (4) showed antimicrobial activities against Salmonella enterica subsp. enterica serovar Abony and Candida albicans. Extracts 5-8 showed slight antimicrobial activities against B. cereus and E. coli. As the growth and activity of microorganisms are the main cause of food spoilage, N. fruticans (3) was selected for bioassay-guided isolation to obtain 3-O-caffeoyl shikimic acid (I), isoorientin (II) and isovitexin (III), which are responsible for its antimicrobial activity against foodborne pathogens. N. fruticans was identified as a new source of natural antimicrobial compounds I-III, among which 3-O-caffeoyl shikimic acid was proven to show antimicrobial activity for the first time. These findings support the use of leaves for wrapping food and protecting food against oxidation and foodborne pathogens through their antioxidant and antimicrobial activities, respectively. Thus, leaves could be used as a natural packaging material and natural preservative.

Nanoemulsion application in meat product and its functionality: review.

Nanotechnology in the food industry can increase the effectiveness of food ingredients. Nanotechnology can increase the bioavailability and absorption of bioactive compounds, enhance their stability, and improve the sensory quality of the product. Processed meat products are easily damaged due to bacterial activity. Advanced nanoemulsions as a meat preservative are nanoemulsions that can be used as preservative agents in meat products, particularly essential oil nanoemulsions, due to their antimicrobial and antioxidant properties. Its application is still limited to foods made from meat products. Therefore, this literature review examines nanoemulsion and its application in meat products and functionality improvement. Also, in the future, nanoemulsions in meat products must be made safe, and the government and businesses must work together to build consumer trust. It can be concluded that essential oil-based nanoemulsion has the potential to be used as an additive in meat products because it can kill bacteria, fight free radicals, improve flavor, and keep food fresh. Nanoemulsion is challenging in the meat industry because it can be toxic due to its tiny droplets (under 200 nm).

Inhibitory effect of natural extract mixtures on microbial growth and lipid oxidation of sausages during storage.

Large amounts of additives are used during meat product processing to maintain product quality and shelf life. With the growing interest in healthy foods, natural plant-based additives are being used as alternatives to synthetic additives. In this study, six types of natural extracts with excellent antibacterial activity were selected, and their antibacterial and antioxidant activities against four types of pathogens were evaluated in various combinations. In addition, the pH, color, amount of thiobarbituric acid reactive substances (TBARS), and growth of pathogenic microorganisms were analyzed during the storage of sausages treated with various combinations of these extracts. The natural extract mixtures exhibited different antibacterial activities, depending on the combination. Compared to grapefruit seed extract, a mixture of natural extracts extracted with ethanol (M4) reduced the Escherichia coli content by more than 99.9% after 8 days of storage and slowed the growth of Listeria monocytogenes and Salmonella spp. by more than 80% after 14 days. Compared to untreated (NC) and grapefruit extract (PC)-treated sausages, sausages treated with the natural extract mixtures showed a significant decrease in CIE L* and an increase in CIE a* and CIE b* (p < 0.05). The pH value was significantly lower in sausages containing natural extract mixtures than in the NC and PC sausages (p < 0.05). The natural plant extract mixtures significantly prevented lipid oxidation (p < 0.05). In summary, different types of natural extract mixtures have a synergistic effect when used together, suggesting that natural preservatives can generally inhibit the growth of microorganisms and oxidation of processed meat.

Emulsions containing composite (clove, oregano, and cinnamon) essential oils: Phase inversion preparation, physicochemical properties and antibacterial mechanism.

Natural essential oils (EOs), especially those combining different individual EOs (also termed composite EOs) with enhanced performance, are becoming healthy, market-sought food preservatives/additives. This study aims to provide insights into the challenge regarding EOs processing due to their low solubility and the elusive mechanism under the enhanced bio-reactivity of composite EOs. A unique oil/water interacting network was created by phase-inversion processing, which enhances EO solubilization and emulsification to form composite EO formulations (EOFs) containing ordinary cinnamon, oregano and clove EOs. These EOFs mainly contained cinnamaldehyde, carvacrol and eugenol and exhibited excellent post-storage stability. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability of EOFs (at 15.880 µL/mL) was > 88%, and the Ferric reducing antioxidant power (FRAP) was 1.8 mM FeSO4·7H2O. The minimum inhibitory concentration (MIC) of EOFs against E. coli and S. aureus was ∼7.940 µL/mL. The EOFs could cause quick deterioration of bacterial structures, demonstrating high efficacy in bacteria-killing and anti-biofilm formation.

Novel approach for the inhibition of Helicobacter pylori contamination in yogurt using selected probiotics combined with eugenol and cinnamaldehyde nanoemulsions.

Different strains of probiotics were screened in vitro to select the one with the highest anti-H. pylori activity. Three nanoemulsions of eugenol, cinnamaldehyde and their mixture were fabricated and tested also in vitro against the same pathogen. The selected probiotic strains, the nanoemulsion mixture and their combination were imbedded in a lab-manufactured yogurt which is deliberately contaminated with 6.0 log cfu/g H. pylori during manufacture. The inhibitory activity of all treatments on the growth of H. pylori and the other microorganisms in yogurt was evaluated during 21 days. Combining the selected probiotic strains with the nanoemulsion mixture in the contaminated yogurt reduced the count of H. pylori by 3.9 log cycle. The nanoemulsion showed lower inhibitory effect against the other microorganisms like probiotics, starter culture and total bacterial count in the tested yogurt, where their enumeration did not fall below 106 cfu/g at the end of yogurt storage period.

Antioxidant and Antibacterial Activity of Four Tannins Isolated from Different Sources and Their Effect on the Shelf-Life Extension of Vacuum-Packed Minced Meat.

Four tannin samples extracted from chestnut wood (tannin oenologique, TO), grape (tannin VR grape, TVG), oak gall (tannin galalcool, TG), and oak tree (tannin VR supra elegance, TE) were evaluated for antioxidant and antibacterial activity. The highest total phenolic content (TPC) values were observed in the order of TVG > TG > TE > TO (p < 0.05). The antioxidant activities of all samples were determined in terms of DPPH radical scavenging activity, reducing power, metal-chelating activity, and linoleic acid peroxidation assay. The antioxidant activities of all samples vary and no correlation was observed with the respective TPC values of each sample. Antibacterial activities indicate that all samples showed more or less inhibitory effects against selected Gram-positive and Gram-negative bacteria. Based on antioxidant and antibacterial activity, TO and TVG were selected for the beef mince quality preservation study during refrigerated storage. Both TO and TVG at two different concentrations, 0.25 and 0.5%, could cease the chemical and microbial changes as compared to the control sample. Although total viable count (TVC) did not show a significant difference, the H2S-producing bacteria count was lower in all samples treated with TO and TVG compared to sodium metabisulfite (SMS) and the control sample (p < 0.05). Therefore, TO and TVG could be promising natural food preservatives during refrigerated storage.

Lactoferrin's potential application in enhancing yoghurt's microbial and sensory qualities, with emphasis on the starter culture activity.

This research paper aimed to examine the antibacterial activity of lactoferrin (LF) as a potential natural alternative in the dairy sector, by measuring its minimum inhibitory concentration (MIC) against a number of common food-borne pathogens as well as Pseudomonas aeruginosa, one of the major dairy product spoiling microorganisms. Additionally, a viability experiment was applied to laboratory-manufactured set yoghurt to assess its impact on the activity of starter culture, sensory properties and STEC survivability. The findings demonstrated that LF exhibited significant antimicrobial activity, particularly against E. coli and S. typhimurium with MIC values of 0.0001 and 0.01 mg/ml, respectively. However, P. aeruginosa and B. cereus were quite resistant to LF requiring higher concentrations for MIC (2.5 mg/ml). By the third day of storage, LF at 0.0001 and 0.001 mg/ml significantly reduced the survivability of Shiga toxin-producing E. coli STEC by 70 and 91.6%, respectively, in the lab-manufactured yoghurt. Furthermore, LF enhanced the sensory properties of fortified yoghurt with a statistically significant difference in comparison to the control yoghurt group. There was no interference with the activity of the starter culture throughout the manufacturing process and the storage period. In conclusion, the potent antimicrobial effect of LF opens a new avenue for the dairy industry's potential applications of LF as a natural preservative without negatively influencing the sensory properties and starter culture activity of fermented products.