Validation of in-vitro antifungal activity of thyme essential oil on Aspergillus niger and Penicillium paneum through application in par-baked wheat and sourdough bread

Waste to wealth: Polyhydroxyalkanoates (PHA) production from food waste for a sustainable packaging paradigm

The growing demand for sustainable food packaging and the increasing concerns regarding environmental pollution have driven interest in biodegradable materials. This paper presents an in-depth review of the production of Polyhydroxyalkanoates (PHA), a biodegradable polymer, from food waste. PHA-based bioplastics, particularly when derived from low-cost carbon sources such as volatile fatty acids (VFAs) and waste oils, offer a promising solution for reducing plastic waste and enhancing food packaging sustainability. Through optimization of microbial fermentation processes, PHA production can achieve significant efficiency improvements, with yields reaching up to 87 % PHA content under ideal conditions. This review highlights the technical advancements in using PHA for food packaging, emphasizing its biodegradability, biocompatibility, and potential to serve as a biodegradable alternative to petroleum-based plastics. However, challenges such as high production costs, mechanical limitations, and the need for scalability remain barriers to industrial adoption. The future of PHA in food packaging hinges on overcoming these challenges through further research and innovation in production techniques, material properties, and cost reduction strategies, along with necessary legislative support to promote widespread use.

Technological and microbiological characterization of an industrial soft-sliced bread enriched with chitosan and its prebiotic activity

Several studies have described the effects of chitosan as an ingredient in bread, particularly from a technological and functional point of view. However, these studies mainly focus on breads produced at lab scale with a short shelf life, which may not reflect the changes occurring in industrial production. Our study investigated the potential of using chitosan at an industrial scale to produce soft white bread, evaluating its impact on the final product's shelf life and providing deeper insights into the practical possibilities and limitations of its scalability. In particular, the rheological properties of the dough and the overall qualitative characteristics of the breads were evaluated when chitosan was used at 0.75 and 1.5%. The use of chitosan in bread dough increased its viscoelasticity, firmness and extensibility, making the dough more elastic but harder to mold and process industrially (extension resistance: 41.70 for 1.5% chitosan vs 22.55 for the control). Chitosan breads exhibited higher pH, aw (1.5%: 0.955 vs control: 0.934), firmness and a larger pore size, with a lower cut height and a more pronounced colour due to increased Maillard reactions. Microbiologically, the chitosan breads were within acceptable limits (<4 and 3 log CFU/g for aerobic mesophilic bacteria and yeasts, respectively) but showed no effect on spoilage microbiota. However, the addition of chitosan increased the prebiotic activity of the bread, as assessed by its ability to promote the growth of selected probiotics in simulated intestinal fluid, which has the potential to positively impact consumers' gut health.

Essential oils: An eco-friendly alternative for controlling toxigenic fungi in cereal grains

Fungi are widely disseminated in the environment and are major food contaminants, colonizing plant tissues throughout the production chain, from preharvest to postharvest, causing diseases. As a result, grain development and seed germination are affected, reducing grain quality and nutritional value. Some fungal species can also produce mycotoxins, toxic secondary metabolites for vertebrate animals. Natural compounds, such as essential oils, have been used to control fungal diseases in cereal grains due to their antimicrobial activity that may inhibit fungal growth. These compounds have been associated with reduced mycotoxin contamination, primarily related to reducing toxin production by toxigenic fungi. However, little is known about the mechanisms of action of these compounds against mycotoxigenic fungi. In this review, we address important information on the mechanisms of action of essential oils and their antifungal and antimycotoxigenic properties, recent technological strategies for food industry applications, and the potential toxicity of essential oils.

In vitro and Quantitative and Structure Activity Relationship (QSAR) evaluation of the antifungal activity of terpenoid constituents of essential oils against Alternaria alternata and Fusarium oxysporum

INTRODUCTION

Fungal genera Alternaria and Fusarium include human and plant pathogenic species. Several antifungals have been used for their control, but excessive use has contributed to resistance development in pathogens. An alternative to searching for and developing new antifungal agents is using essential oils and their main components, which have biological activities of interest in medicine and food production.

OBJECTIVE

To evaluate in vitro and in silico the antifungal activities of terpenoids against Alternaria alternata and Fusarium oxysporum.

MATERIALS AND METHODS

The minimum inhibitory concentration and minimum fungicidal concentration values of 27 constituents of essential oils used against Alternaria alternata and Fusarium oxysporum were evaluated in vitro. In addition, using genetic algorithms, quantitative models of the structure-activity relationship were used to identify the structural and physicochemical properties related to antifungal activity.

RESULTS

The evaluated compounds proved to be effective antifungals. Thymol was the most active with a minimum inhibitory concentration of 91.6 ± 28.8 μg/ml for A. alternata and F. oxysporum. Quantitative structure-activity relationship models revealed the octanolwater cleavage ratio as the molecular property, and the phenols as the main functional group contributing to antifungal activity.

CONCLUSION

Terpenoids exhibit relevant antifungal activities that should be incorporated into the study of medicinal chemistry. Inclusion of in silico assays in the in vitro evaluation is a valuable tool in the search for and rational design of terpene derivatives as new potential antifungal agents.

Novel Microemulsions with Essential Oils for Environmentally Friendly Cleaning of Copper Cultural Heritage Artifacts

Cleaning represents an important and challenging operation in the conservation of cultural heritage, and at present, a key issue consists in the development of more sustainable, "green" materials and methods to perform it. In the present work, a novel xylene-in-water microemulsion based on nonionic surfactants with low toxicity was obtained, designed as low-impact cleaning agent for metallic historic objects. Phase diagram of the mixtures containing polyoxyethylene-polyoxypropilene triblock copolymer Pluronic P84 and D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) as surfactants, water, ethanol and xylene was studied, and a microemulsion with low surfactant content was selected as suitable cleaning nanosystem. Essential oils (EOs) from thyme and cinnamon leaf were added to the selected microemulsion in order to include other beneficial properties such as anticorrosive and antifungal protection. The microemulsions with or without EOs were characterized by size, size distribution and zeta potential. The cleaning efficacy of the tested microemulsions was assessed based on their ability to remove two types of artificial dirt by using X-ray energy dispersion spectrometry (EDX), scanning electron microscopy (SEM), contact angle measurements and color analysis. Microemulsions exhibit high capacity to remove artificial dirt from model copper coupons in spite of very low content of the organic solvent. Both thyme and cinnamon oil loading microemulsions prove to significantly reduce the corrosion rate of treated metallic plates compared to those of bare copper. The antifungal activity of the novel type of microemulsion was evaluated against Aspergillus niger, reported as main treat in biocorrosion of historic copper artifacts. Application of microemulsion with small amounts of EOs on Cu plates inhibits the growth of fungi, providing a good fungicidal effect.

In vitro phytochemical analysis and antibacterial and antifungal efficacy assessment of ethanolic and aqueous extracts of Rumex nervosus leaves against selected bacteria and fungi

Background and Aim

Scientists are interested in identifying natural antibiotic substitutes that are effective against drug-resistant pathogenic microbes and spoilage fungi to counter pathogens and reduce the major public health problem of antibiotic residues in animal products. This study aimed to evaluate the antimicrobial activity of Rumex nervosus leaves (RNLs) as a medicinal herb against four bacterial and two fungal strains using absolute ethanol, 50% ethanol, and aqueous extracts.

Materials and Methods

The antimicrobial activities of various RNL extracts against selected microbes were evaluated using the disk diffusion antibiotic susceptibility test, minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum fungicidal concentrations, and the poisoned food technique.

Results

The absolute ethanol RNL extract showed the best bacteriostatic/bactericidal activity against Salmonella Typhimurium, Escherichia coli, and Staphylococcus aureus (MIC/MBC: 0.20/0.40, 0.20/0.40, and 0.32/0.65 mg/mL, respectively). The diameter of the zone of inhibition was larger (p < 0.05) for the 100% ethanol RNL extract (8.17 mm) against Salmonella Typhimurium, the 50% ethanol-RNL extract (11.5 mm) against E. coli, and the aqueous RNL extract (14.0 mm) against S. aureus than for any other bacterial isolate. The aqueous RNL extract strongly (p < 0.0001) inhibited the mycelial growth of Aspergillus fumigatus (100%) and Aspergillus niger (81.4%) compared with the control.

Conclusion

The results of this study suggest that RNL is a promising new natural antimicrobial agent for food preservation. To date, most research on the antimicrobial properties of natural herbs has been conducted in vitro, with few exceptions in vivo and intervention-based research.

Chitosan nanocomposite incorporated Satureja kermanica essential oil and extract: Synthesis, characterization and antifungal assay

The present study reports the design, synthesis, and characterization of nanoencapsulated Satureja kermanica essential oil/extract by chitosan biopolymer (SKEO-CSN)/(SKEX-CSN) for the antifungal efficacy against Fusarium oxysporum, Alternaria alternata, Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani, and Pythium aphanidermatum. The prepared SKEO-CSN and SKEX-CSN were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD). GC-Mass analysis was done to identify Satureja kermanica essential oil chemical compounds (SKEO). Thirty-five different components were detected from GC-MS analysis. Thymol (46.54 %), and Carvacrol (30.54 %) were demonstrated as major compounds. Antifungal studies showed that the SKEO-CSN and SKEX-CSN formulation effectively inhibit fungal growth more than free SKEO and SKEX. According to the results, SKEO-CSN and SKEX-CSN provide a wide range of promising antifungal effects and can be applied as an efficient green strategy to protect plants from fungus infections.

Antimicrobial mechanisms of spice essential oils and application in food industry

Spice essential oils (SEOs) are commonly used in food flavoring and are considered an effective food preservative. It has a broad range of applications and promising development prospects. As a natural food additive, SEOs' antimicrobial effects have been widely studied and utilized towards food preservation. Many SEOs have exhibited significant antimicrobial activities against food-borne pathogenic and food spoilage microorganisms. We reviewed the antibacterial and antifungal properties of SEOs, the active components, their corresponding mechanisms of actions, as well as their application in the food industry, providing a theoretical basis for SEOs' further development and application as natural preservatives.

Exploration of Lamiaceae in Cardio Vascular Diseases and Functional Foods: Medicine as Food and Food as Medicine

In the current scenario, cardiovascular disease (CVD) is one of the most life-threatening diseases that has caused high mortality worldwide. Several scientists, researchers, and doctors are now resorting to medicinal plants and their metabolites for the treatment of different diseases, including CVD. The present review focuses on one such family of medicinal plants, called Lamiaceae, which has relieving and preventive action on CVD. Lamiaceae has a cosmopolitan distribution and has great importance in the traditional system of medicine. Lamiaceae members exhibit a wide range of activities like antioxidant, antihyperlipidemic, vasorelaxant, and thrombolytic effect, both in vitro and in vivo–these are mechanisms that contribute to different aspects of CVD including stroke, heart attack, and others. These plants harbour an array of bioactive compounds like phenolic acids, flavonoids, alkaloids, and other phytochemicals responsible for these actions. The review also highlights that these plants are a rich source of essential nutrients and minerals like omega-3 and hence, can serve as essential sources of functional foods—this can have an additional role in the prevention of CVDs. However, limitations still exist, and extensive research needs to be conducted on the Lamiaceae family in the quest to develop new and effective plant-based drugs and functional foods that can be used to treat and prevent cardiovascular diseases worldwide.

Biological properties of Thymus zygis essential oil with emphasis on antimicrobial activity and food application

The Thymus plants have been used for centuries in traditional medicine and as a food spice, among this genus, Thymus zygis (red thyme) is a widespread plant, vastly used as a culinary flavouring agent. Its essential oil has demonstrated diverse bioactive properties, such as antimicrobial, insecticidal, larvicidal and antiparasitic activities. Numerous studies have characterized this essential oil showing that it possesses a broad antimicrobial spectrum and may even enhance the effect of certain antimicrobial agents. Its potential application as a food preservative has been analysed on different matrixes pointing to its antimicrobial activity against spoilage and pathogenic microorganisms in food. This review provides an insight in the chemical composition, antimicrobial, insecticidal, larvicidal and antiparasitic activities and toxicity of T. zygis essential oil, as well as its potential application in food as a preservative.

A Comprehensive Review on Bio-Preservation of Bread: An Approach to Adopt Wholesome Strategies

Bread is a food that is commonly recognized as a very convenient type of food, but it is also easily prone to microbial attack. As a result of bread spoilage, a significant economic loss occurs to both consumers and producers. For years, the bakery industry has sought to identify treatments that make bread safe and with an extended shelf-life to address this economic and safety concern, including replacing harmful chemical preservatives. New frontiers, on the other hand, have recently been explored. Alternative methods of bread preservation, such as microbial fermentation, utilization of plant and animal derivatives, nanofibers, and other innovative technologies, have yielded promising results. This review summarizes numerous research findings regarding the bio-preservation of bread and suggests potential applications of these techniques. Among these techniques, microbial fermentation using lactic acid bacteria strains and yeast has drawn significant interest nowadays because of their outstanding antifungal activity and shelf-life extending capacity. For example, bread slices with Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5 inhibited fungal development for up to 21 days with the lowest contamination score. Moreover, various essential oils and plant extracts, such as lemongrass oil and garlic extracts, demonstrated promising results in reducing fungal growth on bread and other bakery products. In addition, different emerging bio-preservation strategies such as the utilization of whey, nanofibers, active packaging, and modified atmospheric packaging have gained considerable interest in recent days.

Biocontrol Potential of Essential Oils in Organic Horticulture Systems: From Farm to Fork

In recent decades, increasing attention has been paid to food safety and organic horticulture. Thus, people are looking for natural products to manage plant diseases, pests, and weeds. Essential oils (EOs) or EO-based products are potentially promising candidates for biocontrol agents due to their safe, bioactive, biodegradable, ecologically, and economically viable properties. Born of necessity or commercial interest to satisfy market demand for natural products, this emerging technology is highly anticipated, but its application has been limited without the benefit of a thorough analysis of the scientific evidence on efficacy, scope, and mechanism of action. This review covers the uses of EOs as broad-spectrum biocontrol agents in both preharvest and postharvest systems. The known functions of EOs in suppressing fungi, bacteria, viruses, pests, and weeds are briefly summarized. Related results and possible modes of action from recent research are listed. The weaknesses of applying EOs are also discussed, such as high volatility and low stability, low water solubility, strong influence on organoleptic properties, and phytotoxic effects. Therefore, EO formulations and methods of incorporation to enhance the strengths and compensate for the shortages are outlined. This review also concludes with research directions needed to better understand and fully evaluate EOs and provides an outlook on the prospects for future applications of EOs in organic horticulture production.

Comparison of antifungal activity of essential oils of clove, lemongrass and thyme for natural preservation of dried apricots

Currently, the majority of fresh apricots destined for the production of dried apricots undergo sulphur oxide fumigation before drying to protect the fruit against fungal spoilage. To eliminate the use of sulphite, packaging assisted with essential oil is a promising strategy to increase shelf-life of dried apricots since it does not impact its flavor characteristics. In this study, three essential oils were selected: clove, lemongrass and thyme. They were screened for antifungal activity against Eurotium spp. with different methods: micro- and macro-dilution and agar-diffusion. Growth/no-growth data were used to develop models for all three methods. Clove exerted the strongest antifungal activity with an inhibitory concentration of 0.075%, 0.035% and 0.05% through respectively micro-dilution, macro-dilution and agar diffusion. For thyme the following values were obtained: 0.775%, 0.070% and 0.100%. This means that the antifungal activity of thyme is 10 times lower in micro-dilution and 2 times lower in macro-dilution and agar diffusion compared to clove. Through micro-dilution, lemongrass was found to have the second highest antifungal activity (0.25%). When used in the volatile atmosphere of dried apricots and in macro-dilution, the antifungal activity of lemongrass was the lowest, with respective values of > 0.200% and 0.105% for G/NG prediction.

Impact of encapsulated orange essential oil with β-cyclodextrin on technological, digestibility, sensory properties of wheat cakes as well as Aspergillus flavus spoilage

BACKGROUND

The majority of studies with essential oils in foods focus mainly on improving the shelf life of products; however, the present study goes further and demonstrates not only the effect of essential oil on conservation properties, but also the effect of free and encapsulated orange essential oil (OEO) on the technological, sensorial and digestibility properties of bakery products.

RESULTS

OEO was encapsulated into β-cyclodextrin (β-CD) by inclusion complex formation (β-CD/OEO 97.4% of encapsulation efficiency). OEO demonstrated in vitro antifungal activity against Aspergillus flavus (inhibition zone of 11.33 mm on mycelial growth). In situ antifungal activity against A. flavus confirmed that free OEO can effectively delay the fungal growth, unlike encapsulated OEO. Regarding texture profile and starch digestibility: cake with β-CD/OEO showed lower hardness (31.64 N) and lower starch digestibility (69.10%) than cake with free OEO (44.30 N; 82.10%, respectively) and the addition of OEO (both free and encapsulated) decreased the adhesiveness of the cakes. Cake with free OEO showed a higher intensity of orange aroma, being preferred by 60% of panelists, whereas cake with β-CD/OEO presented a very slight orange taste and aroma.

CONCLUSION

The encapsulation of OEO into β-CD improved the crumb texture of cakes and promoted a lower starch digestibility in the cakes. On the other hand, the encapsulation process was not effective under the conditions tested (OEO concentration and baking temperatures), compromising the action of the OEO as a natural flavoring and preservative agent. © 2021 Society of Chemical Industry.

Essential Oils and Their Application in Food Safety

Food industries are facing a great challenge due to contamination of food products with different microbes such as bacteria, fungi, viruses, parasites, etc. These microbes deteriorate food items by producing different toxins during pre- and postharvest processing. Mycotoxins are one of the most potent and well-studied toxic food contaminants of fungal origin, causing a severe health hazard to humans. The application of synthetic chemicals as food preservatives poses a real scourge in the present scenario due to their bio-incompatibility, non-biodegradability, and environmental non-sustainability. Therefore, plant-based antimicrobials, including essential oils, have developed cumulative interest as a potential alternative to synthetic preservatives because of their ecofriendly nature and generally recognized as safe status. However, the practical utilization of essential oils as an efficient antimicrobial in the food industry is challenging due to their volatile nature, less solubility, and high instability. The recent application of different delivery strategies viz. nanoencapsulation, active packaging, and polymer-based coating effectively addressed these challenges and improved the bioefficacy and controlled release of essential oils. This article provides an overview of essential oils for the preservation of stored foods against bacteria, fungi, and mycotoxins, along with the specialized mechanism of action and technological advancement by using different delivery systems for their effective application in food and agricultural industries smart green preservative.

Identification of saprophytic microorganisms and analysis of changes in sensory, physicochemical, and nutritional characteristics of potato and wheat steamed bread during different storage periods

Due to its nutritional value and no gluten, potato flour has recently been used as a new type of material to make steamed bread. However, compared to traditional wheat steamed bread, its shelf life is considerably shorter, the dominant microorganisms and storage properties also differ. High-throughput sequencing combined with molecular biology assay revealed that Bacillus methylotrophic and Bacillus subtilis were the dominant bacteria in the crumb of potato and wheat steamed bread, respectively. Moreover, Meyerozyma, Penicillium chrysogenum, Penicillium citrinum, and Aspergillus parasiticus were the main fungi in the crusts. Ethanol was the most volatile compound in fresh potato and wheat steamed bread. Following storage for 48 h, 2,3-butanediol and 3-hydroxy-2-butanone were established as the most volatile compounds. Although decreased sourness was observed, the specific volume, brightness, and nutritional composition remained nearly unchanged. These findings provide a valuable theoretical basis for the development of potato and wheat steamed bread preservation technologies.

Antifungal Activity of Aromatic Plants of the Lamiaceae Family in Bread

The antifungal effect of aromatic plants (oregano, thyme, and Satureja) in dry form and as essential oils was evaluated in vitro (in potato dextrose agar (PDA)) and in bread against two phytopathogenic fungi found in food (Aspergillusniger and Penicillium). Gas and liquid chromatography were used to analyze essential oils attained by hydrodistillation of the aerial parts of the aromatic plants and of the dried plant aqueous solutions that were autoclaved for 20 min at 121 °C before analysis. Carvacrol, α-pinene, p-cymene, and γ-terpinene were the main components of the essential oils, whereas carvacrol, rosmarinic and caffeic acids were the main components of the water extracts. In vitro antifungal test results showed that the addition of plants in dry form had great antifungal potential against both fungal strains studied. Penicillium was more sensitive to the presence of aromatic plants than Aspergillus. Among the three plant species tested, thyme was the most potent antifungal against both fungi. For the bread product, all three aromatic plants studied showed inhibitory effects against both fungi. Results presented here suggest that oregano, thyme and Satureja incorporated in a bread recipe possess antimicrobial properties and are a potential source of antimicrobial ingredients for the food industry.

The Inhibitory Effect of Wheat Husks Addition on Aflatoxins Production by Aspergillus flavus in Liquid Culture With Various Wheat Compositions as Carbon Sources

Wheat may be infected by the aflatoxigenic mold Aspergillus flavus during pre- and post-harvest activities. Control strategies reported to manage aflatoxin contamination of wheat are expensive and require extensive testing to verify the absence of toxic secondary metabolites or newly formed compounds. The objective of this study was to develop an in vitro new control strategy based on assessing the influence of wheat husks on aflatoxin production by A. flavus in liquid culture. The results showed that aflatoxin production is significantly influenced by the existence of husks in the wheat forms used as carbon substrates according to the following order: full wheat grains < half-crushed wheat grains < wheat flour 82% < wheat flour 72%. By applying a fractional factorial design and a response surface methodology, maximum aflatoxin production (2.567 ng/mg) was predicted when wheat flour 72% (39 g/l) as a carbon source, yeast extract (5 g/l), and a 75-ml medium volume/250 ml flask were utilized. At this optimized condition, after addition of wheat husk extract, the growth and synthesis of aflatoxins of A. flavus were repressed by 74.85 and 98.72%, respectively. This finding paves the way to examine the antifungal potential of wheat husk constituents and to compare their efficacy with thyme, cinnamon, sweet basil, and coriander essential oils, which possess antimycotic activities. Accordingly, the wheat husk component SiO₂ showed the highest growth inhibition (67.04%) and reduction of A. flavus aflatoxins (82.67%). These results are comparable to those obtained from various examined antimycotic essential oils.

Use of by-products of millet, amaranth and sorghum grains in bakery production

The use of additional gluten-free grain raw materials in the form of flour or secondary raw materials of cereal industry in the recipes of bakery products allows regulating the biotechnological processes of dough maturing and proofing, obtaining a finished product with new functional properties and high nutritional value. The purpose of the research is to justify experimentally the use of processed products of amaranth grain and sorghum for the production of bread of high quality and functionality. The methodological basis of the study is presented by a systematic analysis of the technology for the production of bakery products enriched with promising phyto-fortifiers. In accordance with the chosen methodology, the chemical composition is analyzed and the positive effect of the use of flour from millet grain, sorghum and amaranth seeds in the mixture with premium wheat flour on the quality of bread is experimentally justified. It was found that the introduction of these types of additional raw materials had a positive effect on the activation of baking yeast and the maturation of dough. In the production of bread from wheat flour of the highest grade, it is optimal to use these phyto-fortifiers in the amount of 3% by weight of the composite mixture.

Modelling and validation of the antifungal activity of DL-3-phenyllactic acid and acetic acid on bread spoilage moulds

Most interesting antifungal compounds from sourdough fermentation are acetic acid (AA) and DL-3-phenyllactic acid (PLA). Although the role of pH on the activity of organic acids has been established long time ago, no information is available on the importance of undissociated acid (HA) expressed on the aqueous phase of bread (C_HA, mmole/L). Mostly, concentrations (mmole/kg dough or bread, C_TOT) and pH are given side by side. The aim of this study was to show the importance of C_HA for adequate comparison of in-vitro growth data with bread shelf-life. Growth of Penicillium paneum and Aspergillus niger was recorded using a micro-dilution assay with optical density measurements. Parameters such as a_w (0.94-0.98), pH (4.6-6.0), temperature (10-30 °C), time (0-8 days) and C_TOT (0-300 mM) were varied. Growth/no-growth models were developed and shelf-life tests of par-baked breads of 45 days at 20 °C were conducted. The modelled inhibitory concentrations of undissociated acid were comparable with the shelf-life test of bread: (PLA) 50 versus 39-84 mmol/L; (AA) 110 versus 110-169 mmol/L. This study showed the applicability of G/NG models for bread shelf-life prediction and highlighted the importance of CHA. Moreover, it was found that naturally present PLA in sourdough bread is insufficient to increase bread shelf-life.

Comparison of antifungal activity of essential oils from different plants against three fungi

The antifungal activity of plant essential oils (EOs) extracted by steam distillation from seven different species (Cinnamon, Anise, Clove, Citronella, Peppermint, Pepper, and Camphor) was investigated. Three common fungi were isolated from moldy wheat bread, which were identified as Aspergillus niger, A. oryzae, and A. ochraceus. The antifungal activity of anise, peppermint, clove, cinnamon, pepper, citronella, and camphor EOs from seven different spices was confirmed by agar diffusion assay against three fungi. Among all the EOs, the cinnamon EO showed the highest antifungal activity for all the fungi strains with the largest inhibition zone at the concentration of 800 mg/mL and lowest MIC ranging from 0.0625 to 0.125 mg/mL, followed by clove EO. The remaining EOs exerted moderate inhibitory effects. Further research indicated the substantial inhibitory activities of cinnamon and clove EOs on mycelial growth and spore germination in a dose-dependent manner. Further, the in vivo inhibitory activity of selected EOs on naturally infected bread demonstrated that cinnamon and clove EOs can as be used as natural antifungal agents.

Antifungal properties of phosphatidylcholine-oleic acid liposomes encapsulating garlic against environmental fungal in wheat bread

Liposomes have gained great interest in the food and pharmaceutical industry as colloidal carriers of bioactive compounds. In this work, liposomes of phosphatidylcholine (PC) and oleic acid (OA) encapsulating garlic extract (GE) were developed to determine its aptitude as antifungal agent in wheat bread. The influence of GE on the properties of liposomes were followed by determination of size, Zeta potential, Fourier transform infrared patterns (FTIR), morphology, differential scanning calorimetry (DSC) and thermogravimetric (TGA) techniques. The produced PC-OA-GE liposomes showed spherical morphology with narrow size distribution, entrapment efficiency of 79.7% and zeta potential of -27.9 mV. In vitro antifungal test showed noticeable inhibitory activities for free and encapsulated GE against selected fungal strains. TGA analysis revealed that the presence of OA and GE in the formulation retards the liposomal thermal decomposition, as compared with the pure PC liposomes and the DSC enthalpy and main transition temperature variation in PC-OA-GE liposomes suggested a strong heat-induced rigidifying effect that could be attributed to the presence of garlic polysaccharides in the liposome surface, observed by FTIR. In the in situ test, the bread formulations with free or liposome-encapsulated GE (0.65 mL/100 g of dough) were microbiologically more stable as compared with the controls, showing mold inhibition for five days. Therefore, liposomes formulated with OA and GE showed potential as natural antifungal agent in bakery products.

Essential oils as natural preservatives for bakery products: Understanding the mechanisms of action, recent findings, and applications

Bakery products, as an important part of a healthy diet, are characterized by their limited shelf-life. Microbiological spoilage of these products not only affects the quality characteristics and result in the economic loss but also threatens consumer's health. Incorporation of chemical preservatives, as one of the most conventional preserving techniques, lost its popularity due to the increasing consumer's health awareness. Therefore, the bakery industry is seeking alternatives to harmful antimicrobial agents that can be accepted by health-conscious customers. In this regard, essential oils have been previously used as either a part of product ingredient or a part of the packaging system. Therefore, the antimicrobial aspect of essential oils and their ability in delaying the microbiological spoilage of bakery products have been reviewed. Several types of essential oils, including thyme, cinnamon, oregano, and lemongrass, can inhibit the growth of harmful microorganisms in bakery products, resulting in a product with extended shelf-life and enhanced safety. Research revealed that several bioactive compounds are involved in the antimicrobial activity of essential oils. However, some limitations, such as the possible negative effects of essential oils on sensory parameters, may limit their applications, especially in high concentrations. In this case, they can be used in combination with other preservation techniques such as using appropriate packaging materials. Further research regarding the commercial production of the bakery products formulated with essential oils is required in this area.

Effect of thyme essential oil against Bacillus cereus planktonic growth and biofilm formation

The objective of this study was to determine the effect of thyme essential oil (TEO) on the planktonic growth and biofilm formation of Bacillus cereus (B. cereus). GC-MS analysis of TEO allowed the detection of 13 compounds, and the major constituents were p-cymene (29.7%), thymol (23.73%), γ-terpinene (16.21%), and 1,8-cineole (9.74%). TEO exhibited a minimum inhibitory concentration (MIC) value against planktonic B. cereus of 0.25 mg/mL. The potent effect of TEO to inhibit the growth of planktonic B. cereus was due to cell membrane damage, as evidenced by reduced cell viability, protein changes, decreased intracellular ATP concentration, increased extracellular ATP concentration and cell membrane depolarization, and cellular morphological changes. In addition, TEO exerted a significant inhibitory effect on B. cereus biofilm formation, as confirmed by environmental scanning electron microscopic images. These findings suggested that TEO has the potential to be developed as a natural food additive to control foodborne contamination associated with B. cereus and its biofilm.