Plant Essential Oils as Active Antimicrobial Agents

Essential oils derived from plants have been recognized for decades to exhibit biological activities, including antioxidant, anticancer, and antimicrobial attributes. Antimicrobial activities of these natural plant materials have been intensively explored in recent years, mainly in response to the overwhelming concern of consumers over the safety of synthetic food additives. Gram-negative organisms are believed to be slightly less sensitive to essential oils than Gram-positive bacteria. Generally, a higher concentration is required to obtain the same efficacy in foods than in synthetic media. The combinations of different types of essential oils or with other food additives have been found to potentially exhibit synergistic if not additive effects. This suggests a cost-efficient and wholesome alternative to both food industry and consumers, at the same time adhering to the hurdle technology in inhibiting proliferation of foodborne pathogens. This review aims to examine the conventional methods commonly used for assessment of antimicrobial activities of essential oils and phytochemicals, the use of these substances as antimicrobials in food products, factors that affect their efficacy, synergism between components or with available food preservatives as well as the challenges and future directions of using essential oils and phytochemicals as natural food preservatives.     

Recent food applications of microbial surfactants

Owing to their natural origin and environmental compatibility, interest in microbial surfactants or biosurfactants has gained attention during last few years. These characteristics fulfill the demand of regulatory agencies and society to use more sustained and green chemicals. Microbial-derived surfactants can replace synthetic surfactants in a great variety of industrial applications as detergents, foaming, emulsifiers, solubilizers, and wetting agents. Change in the trend of consumers toward natural from synthetic additives and the increasing health and environmental concerns have created demand for new “green” additives in foods. Apart from their inherent surface-active properties, biosurfactants have shown antimicrobial and anti-biofilm activities against food pathogens; therefore, biosurfactants can be versatile additives or ingredients of food processing. These interesting applications will be discussed in this review.     

Green Alternatives to Nitrates and Nitrites in Meat-based Products–A Review

Several food additives are added in food for their preservation to maintain the freshness of food (antioxidants) or to slow down or stop the growth of microorganisms (preservative agents). Nitrites and nitrates are used as preservative agents in meat. Nitrites give a smoked taste, a pinkish color in the meat and protect the consumers against the risk of bacterial deterioration. Their addition is however very limited as, in high dose, it can have risks on human health and the environment. Nitrites may also combine with secondary or tertiary amines to form N-nitroso derivatives. Certain N-nitroso compounds have been shown to produce cancers in a wide range of laboratory animals. Thus, alternatives of nitrates and nitrites are the object of numerous research studies. Alternatives, such as the addition of vitamins, fruits, chemicals products, natural products containing nitrite or spices, which have similar properties of nitrites, are in evaluation. In fact, spices are considered to have several organoleptic and anti-microbial properties which would be interesting to study. Several spices and combinations of spices are being progressively evaluated. This review discusses the sources of nitrites and nitrates, their use as additives in food products, their physicochemical properties, their negatives effects and the use of alternatives of nitrites and nitrates in preserving meat products.     

Plant extracts for the control of bacterial growth: efficacy, stability and safety issues for food application

The microbial safety of foods continues to be a major concern to consumers, regulatory agencies and food industries throughout the world. Many food preservation strategies have been used traditionally for the control of microbial spoilage in foods but the contamination of food and spoilage by microorganisms is a problem yet to be controlled adequately. Although synthetic antimicrobials are approved in many countries, the recent trend has been for use of natural preservatives, which necessitates the exploration of alternative sources of safe, effective and acceptable natural preservatives. Plants contain innumerable constituents and are valuable sources of new and biologically active molecules possessing antimicrobial properties. Plants extracts either as standardized extracts or as a source of pure compounds provide unlimited opportunities for control of microbial growth owing to their chemical diversity. Many plant extracts possess antimicrobial activity against a range of bacteria, yeast and molds, but the variations in quality and quantity of their bioactive constituents is the major detriments in their food use. Further, phytochemicals added to foods may be lost by various processing techniques. Several plant extracts or purified compounds intended for food use have been consumed by humans for thousands of years, but typical toxicological information is not available for them. Although international guidelines exist for the safety evaluation of food additives, owing to problems in standardization of plant extracts, typical toxicological values have not been assigned to them. Development of cost effective isolation procedures that yield standardized extracts as well as safety and toxicology evaluation of these antimicrobials requires a deeper investigation.     

Food colors: Existing and emerging food safety concerns

Food colors are added to different types of commodities to increase their visual attractiveness or to compensate for natural color variations. The use of these additives is strictly regulated in the European Union, the United States, and many other countries worldwide. There is a growing concern about the safety of some commonly used legal food colorants and there is a trend to replace the synthetic forms with natural products. Additionally, a number of dyes with known or suspected genotoxic or carcinogenic properties have been shown to be added illegally to foods. Robust monitoring programs based on reliable detection methods are required to assure the food is free from harmful colors. The aim of this review is to present an up to date status of the various concerns arising from use of color additives in food. The most important food safety concerns in the field of food colors are lack of uniform regulation concerning legal food colors worldwide, possible link of artificial colors to hyperactive behavior, replacement of synthetic colors with natural ones, and the presence of harmful illegal dyes—both known but also new, emerging ones in food. The legal status of food color additives in the EU, United States, and worldwide is summarized. The reported negative health effects of both legal and illegal colors are presented. The European Rapid Alert System for Food and Feed notifications and US import alerts concerning food colors are analyzed and trends in fraudulent use of color additives identified. The detection methods for synthetic colors are also reviewed.     

Recent trends in the use of food additives in the United Kingdom

The E number system for food additives was introduced in the 1960s and the E was intended to reassure consumers that permitted additives were safe. In the 1980s full ingredient declarations had to be provided on food products for the first time and manufacturers were permitted to use either the name or the number of the additive on the ingredient list. This paper outlines some of the trends in the sourcing, use and labelling of additives since the introduction of full ingredient listing. Generally, sourcing has become more global with a large number of suppliers being based in China. From an initial use of E numbers in ingredient lists, manufacturers are increasingly using the names of additives. This trend is being extended to avoid the use of anything the consumer might consider an additive, particularly in connection with colours and preservatives. Specifically, the colours used in the Southampton study on the impact of food colours on hyperactivity in children have largely been replaced by colouring foodstuffs, and the preservative used in the study, sodium benzoate, has been replaced by potassium sorbate in the majority of soft drinks. © 2014 Society of Chemical Industry     

Phenolic Compounds and Plant Phenolic Extracts as Natural Antioxidants in Prevention of Lipid Oxidation in Seafood: A Detailed Review

Lipid oxidation is the principal cause of quality loss in seafood, which is known to contain high amounts of polyunsaturated fatty acids. Such quality deterioration, associated with the development of off‐flavor as well as lowering of nutritive value, can be retarded by incorporation of additives having antioxidative properties. The use of synthetic antioxidants has long been practiced in retarding lipid oxidation. However, due to the potential health concerns of synthetic antioxidants, polyphenolic compounds, which are found in different plants and their manufactured by‐products, have been used as an alternative natural antioxidants to retard lipid oxidation in different seafood systems. Both pure phenolic compounds and crude plant phenolic extracts have been successfully used in delaying oxidation in fish muscle, fish oil, and fish oil‐in‐water emulsions. This article reviews in detail the phenolic antioxidants and their natural sources as well as focuses on the role of pure phenolic compounds and crude plant phenolic extracts on the prevention of lipid oxidation in different seafood systems.     

Colouring our foods in the last and next millennium

Summary Colour in one form or another, has been added to our foods for centuries. It is known that the Egyptians coloured candy, and wine was coloured as long ago as 400  bc . The developing food industry had available a vast array of synthetic colours in the late 1800s. This led to colours being added for decorative purposes and unfortunately to disguise low quality foods. There was no control over this use of colour and so inevitably legislation came into force. In particular this was as a result of health concerns over some of the toxic compounds used. An established list of permitted synthetic colours eventually came into force in most countries early in this century. In the last twenty years however, consumers have become increasingly aware of the ingredients in their foods and as such they require foods to be as 'natural' as possible. This combined with technological developments has fuelled the increase in the usage of naturally derived colours. Today the food industry has an extensive colour palette available, allowing selection of the most suitable colour for their application requirements. Legislation is also in place to protect the consumer. Colour suppliers are however constantly striving to improve the technical and physical properties of their colour portfolio, to make the use of colour easier, to improve the stability and to meet customer demands on the functional additives used within colour formulations. This paper will review all colours in terms of recent developments and regulations as well as addressing the question of the future of colours in the next millennium.     

Prevention of fungal spoilage in food products using natural compounds: A review

The kingdom Fungi is the most important group of microorganism contaminating food commodities, and chemical additives are commonly used in the food industry to prevent fungal spoilage. However, the increasing consumer concern about synthetic additives has led to their substitution by natural compounds in foods. The current review provides an overview of using natural agents isolated from different sources (plants, animals, and microorganisms) as promising antifungal compounds, including information about their mechanism of action and their use in foods to preserve and prolong shelf life. Compounds derived from plants, chitosan, lactoferrin, and biocontrol agents (lactic acid bacteria, antagonistic yeast, and their metabolites) are able to control the decay caused by fungi in a wide variety of foods. Several strategies are employed to reduce the drawbacks of some antifungal agents, like their incorporation into oil-in-water emulsions and nanoemulsions, edible films and active packaging, and their combination with other natural preservatives. These strategies facilitate the addition of volatile agents into food products and, improve their antifungal effectiveness. Moreover, biological agents have been investigated as one of the most promising options in the control of postharvest decay. Numerous mechanisms of action have been elucidated and different approaches have been studied to enhance their antifungal effectiveness.     

Encapsulation systems for lutein: A review

BackgroundThe increased demand by consumers for clean labels has encouraged industry to search for replacements of synthetic ingredients in food products, and in particular, colorants. Lutein, a xanthophyll found in marigolds and corn, can be used in food products as a natural colorant replacing yellow food dyes. Moreover, lutein is considered a nutraceutical due to its potentially beneficial health effects, such as prevention of macular degeneration, role in the development of the visual and nervous systems of fetuses, and its antioxidant properties. However, incorporation of lutein into foods is often limited because of its low-water solubility, chemical instability, and poor oral bioavailability. For this reason, colloidal encapsulation systems have been developed to facilitate the incorporation of lutein into aqueous food and beverage products.Scope and approachThis review focuses on exploring encapsulation options for lutein using various emulsion-based, nanoparticle- and microparticle-based and molecular inclusion encapsulation systems, as well as additives that can be used to increase its chemical stability in these systems. This review covers all aspects of lutein encapsulation, including both food-grade and pharmaceutical-grade encapsulation systems.Key findings and conclusionsThough lutein-loaded encapsulation systems are extensively explored in this review, emulsions are of the most interest in industry as they are cost efficient and can be designed to increase the stability of lutein by selecting the proper emulsifiers and emulsification techniques. Despite the extensive amount of research carried out on the encapsulation of hydrophobic bioactive molecules such as lutein, there are still opportunities to develop encapsulation systems that further protect these molecules during storage and also increase their bioavailability after ingestion.     

Oregano Essential Oil as an Antimicrobial and Antioxidant Additive in Food Products

Food consumers and industries urged the need of natural alternatives to assure food safety and quality. As a response, the use of natural compounds from herbs and spices is an alternative to synthetic additives associated with toxic problems. This review discusses the antimicrobial and antioxidant activity of oregano essential oil (OEO) and its potential as a food additive. Oregano is a plant that has been used as a food seasoning since ancient times. The common name of oregano is given to several species: Origanum (family: Lamiaceae) and Lippia (family: Verbenaceae), amongst others. The main compounds identified in the different OEOs are carvacrol and thymol, which are responsible for the characteristic odor, antimicrobial, and antioxidant activity; however, their content may vary according to the species, harvesting season, and geographical sources. These substances as antibacterial agents make the cell membrane permeable due to its impregnation in the hydrophobic domains, this effect is higher against gram positive bacteria. In addition, the OEO has antioxidant properties effective in retarding the process of lipid peroxidation in fatty foods, and scavenging free radicals. In this perspective, the present review analyzes and discusses the state of the art about the actual and potential uses of OEO as an antimicrobial and antioxidant food additives.     

Applications of chitosan for improvement of quality and shelf life of foods: a review

ABSTRACT:  Chitosan is a modified, natural biopolymer derived by deacetylation of chitin, a major component of the shells of crustacean. Recently, chitosan has received increased attention for its commercial applications in the biomedical, food, and chemical industries. Use of chitosan in food industry is readily seen due to its several distinctive biological activities and functional properties. The antimicrobial activity and film-forming property of chitosan make it a potential source of food preservative or coating material of natural origin. This review focuses on the applications of chitosan for improvement of quality and shelf life of various foods from agriculture, poultry, and seafood origin.     

Recent Developments in Minimal Processing: A Tool to Retain Nutritional Quality of Food

The modernization during the last century resulted in urbanization coupled with modifications in lifestyles and dietary habits. In the same era, industrial developments made it easier to meet the requirements for processed foods. However, consumers are now interested in minimally processed foods owing to increase in their awareness to have fruits and vegetables with superior quality, and natural integrity with fewer additives. The food products deteriorate as a consequence of physiological aging, biochemical changes, high respiration rat,e and high ethylene production. These factors contribute substantially to discoloration, loss of firmness, development of off-flavors, acidification, and microbial spoilage. Simultaneously, food processors are using emerging approaches to process perishable commodities, along with enhanced nutritional and sensorial quality. The present review article is an effort to utilize the modern approaches to minimize the processing and deterioration. The techniques discussed in this paper include chlorination, ozonation, irradiation, photosensitization, edible coating, natural preservative use, high-pressure processing, microwave heating, ohmic heating, and hurdle technology. The consequences of these techniques on shelf-life stability, microbial safety, preservation of organoleptic and nutritional quality, and residue avoidance are the limelight of the paper. Moreover, the discussion has been made on the feasibility and operability of these techniques in modern-day processing.     

乳酸菌在食品防腐中的应用

近年来,随着人们健康意识的逐渐增强,对于食品的营养和安全性要求更高,食品在贮存期间的保藏方法也逐渐受到关注,天然防腐剂和生物防腐受到了消费者的青睐。应用乳酸菌或其代谢产物除具备一些益生功能外,也可以实现延长食品货架期的目的,并在一些食品加工领域中得到了一些应用。本文就乳酸菌及其代谢产物在食品防腐中的应用进行了综述。     

The Issue of Undeclared Ingredients in Halal and Kosher Food Production: A Focus on Processing Aids

Since the early 1900s the food industry has undergone major advances that have led to more than half of the shelves in a modern supermarket being stocked with packaged and processed foods. These boxed, canned, and frozen foods achieve their convenience by using a number of food ingredients and processing aids. The original sources and the details of their processing prior to inclusion in the final food product are not provided to consumers but will determine their acceptability for both halal and kosher food production. While additives are generally declared on a product label, processing aids are not shown on the ingredient statement and thus the consumer is not even aware of their presence. Some additives can be legally grouped into generic categories (such as spices) that also make it difficult for consumers to determine what exactly is in the products they buy and how these products have been processed. Thus, consumers need to put more pressure on the kosher and halal marketing system to use trademarked symbols that represent an organization that the consumer can hold accountable and which provides both the companies and the consumer with confidence in the kosher and/or halal status of the products being offered in the marketplace.     

Marine food-derived functional ingredients as potential antioxidants in the food industry: An overview

Recently, a great deal of interest has been developed by the consumers towards natural bioactive compounds as functional ingredients in the food products due to their various health beneficial effects. Hence, it can be suggested that antioxidative functional ingredients from marine foods and their by-products are alternative sources for synthetic ingredients that can contribute to a consumer's well-being, as a part of nutraceuticals and functional foods. This contribution presents an overview of the marine food-derived antioxidants such as bioactive peptides, chitooligosaccharide derivatives, sulfated polysaccharides, phlorotannins and carotenoids with the potential utilization in the food industry.     

Nanoemulsions: Synthesis,Characterization, and Application in Bio‐Based Active Food Packaging

The increasing demands for foods with fresh‐like characteristics, lower synthetic additive and preservative contents, and low environmental footprint, but still safe to consume, have guided researchers and industries toward the development of milder processing technologies and more eco‐friendly packaging solutions. As sustainability acquires an increasingly critical relevance in food packaging, bio‐based and/or biodegradable materials stand out as suitable alternatives to their synthetic counterparts. In this context, the use of nanoemulsions has represented a step forward for improving the performance of sustainable food packaging devices, especially for the successful incorporation of new compounds and functionalities into conventional films and coatings. This class of emulsions, featuring unique optical stability and rheological properties, has been developed to protect, encapsulate, and deliver hydrophobic bioactive and functional compounds, including natural preservatives (such as essential oils from plants), nutraceuticals, vitamins, colors, and flavors. This article presents the surfactants (including naturally occurring proteins and carbohydrates), dispersants, and oil‐soluble functional compounds used for designing food‐grade nanoemulsions intended for packaging applications. The improved kinetic stability, bioavailability, and optical transparency of nanoemulsions over conventional emulsions are discussed considering theoretical concepts and real experiments. Bottom‐up and top‐down approaches of nanoemulsion fabrication are described, including high‐energy (such as high‐pressure homogenizers, microfluidics, ultrasound, and high‐speed devices) and low‐energy methods (for instance, phase inversion and spontaneous emulsification). Finally, incorporation of nanoemulsions in biopolymer matrixes intended for food packaging applications is also addressed, considering current characterization techniques as well as their potential antimicrobial activity against foodborne pathogens.     

Gas Chromatography‐Combustion‐Isotope Ratio Mass Spectrometry for Traceability and Authenticity in Foods and Beverages

As consumers demand more certainty over where their food and beverages originate from and the genuineness of ingredients, there is a need for analytical techniques that are able to provide data on issues such as traceability, authenticity, and origin of foods and beverages. One such technique that shows enormous promise in this area is gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS). As will be demonstrated in this review, GC‐C‐IRMS is able to be applied to a wide array of foods and beverages generating data on key food components such as aroma compounds, sugars, amino acids, and carbon dioxide (in carbonated beverages). Such data can be used to determine synthetic and natural ingredients; substitution of 1 ingredient for another (such as apple for pear); the use of synthetic or organic fertilizers; and origin of foods and food ingredients, including carbon dioxide. Therefore, GC‐C‐IRMS is one of the most powerful techniques available to detect fraudulent, illegal, or unsafe practices in the food and beverages industries and its increasing use will ensure that consumers may have confidence in buying authentic products of known origin.     

Methods used for extraction of plant volatiles have potential to preserve truffle aroma: A review

Truffles are considered one of the world's most highly prized foods mainly due to their desirable organoleptic properties and rarity. However, truffles are seasonal (harvested mostly in winter from June to August in the Southern Hemisphere and from December to February in the Northern Hemisphere) and extremely perishable. Truffles deteriorate rapidly showing undesirable changes within 10 days from harvest in aroma and visual appearance after harvest. The very short postharvest shelf life (about 7–10 days) limits the potential for export and domestic consumption all year round. Several preservation methods have been studied to prolong their shelf life without the loss of aroma. However, all traditional preservation techniques have their own shortcomings and remain challenging. The extraction of natural truffle aroma volatiles for food applications could be a potential alternative to replace the existing synthetic flavoring used for processed truffle products. Four commonly used extraction methods for recovering volatile compounds from plants, namely, supercritical carbon dioxide extraction, Soxhlet extraction, distillation, and cold pressing, are critically analyzed. Up to date, existing research about the extraction of aroma volatiles from truffles is limited in the literature but based on the volatility of the key truffle volatile compounds, supercritical carbon dioxide extraction may offer the best possibility so that a natural truffle-based product that can be used in food applications throughout the year can be made available.     

食品中着色剂的检测方法研究进展

着色剂是食品添加剂中的一大类分支,在食品加工和生产中有着广泛的应用。由于食品的基质类型复杂多样,着色剂的种类也非常多、性质差异大,给分析检测工作带来挑战。本文对近年来的食品中着色剂的检测方法进行综述,包括样品前处理和分析检测技术,并根据应用方法和适用的食品基质及检测目标物进行分类总结,为进一步开展食品中着色剂的检测方法的研究工作提供参考。