Organic Acids and Meat Preservation: A Review

Despite the application of various preservation methods, many problems are still encountered as a result of food spoilage and food poisoning. There is increasing demand for foods produced with milder treatments, and the movement towards more natural and even certified organic foods has been the fastest growing sector of the food industry over the last decade. The interest in bio-preservation of food systems has necessitated the development of new natural antimicrobial compounds from different origins, and in response to modern consumer trends and food legislation, the food industry is faced with serious challenges. Both conventional and organic modes of production are at risk of contamination, but it is possible that organic food might present a bigger problem. Organic acids have been of considerable value as food preservatives since they are also food ingredients and often naturally produced by microorganisms. However, limited data on their effects in commercial practice are available, and despite regulatory approval, organic acids are not widely accepted in commercial practice, and in particular in meat decontamination.

Susceptibility of microorganisms to the most currently used preservatives has been decreasing, and there is concern that decontamination with organic acids could result in the emergence of acid-tolerant food-borne pathogens, evolving to overcome the protective barrier of the human gastric stomach. In the evaluation and integration of new processing/preservation treatments, research objectives would have to include the identification of specific targets of organic acids—understanding the molecular mechanisms that confer high level resistance and analysing pathogen response to antimicrobials. This article provides an overview of various studies done on organic acids as preservatives and highlights aspects such as application, antimicrobial action, and future prospects. Other important issues, such as the application of functional genomics in developing new preservation methods, resistance development, and conventional laboratory procedures are also discussed.     

Organic Acids and Meat Preservation: A Review

Despite the application of various preservation methods, many problems are still encountered as a result of food spoilage and food poisoning. There is increasing demand for foods produced with milder treatments, and the movement towards more natural and even certified organic foods has been the fastest growing sector of the food industry over the last decade. The interest in bio-preservation of food systems has necessitated the development of new natural antimicrobial compounds from different origins, and in response to modern consumer trends and food legislation, the food industry is faced with serious challenges. Both conventional and organic modes of production are at risk of contamination, but it is possible that organic food might present a bigger problem. Organic acids have been of considerable value as food preservatives since they are also food ingredients and often naturally produced by microorganisms. However, limited data on their effects in commercial practice are available, and despite regulatory approval, organic acids are not widely accepted in commercial practice, and in particular in meat decontamination.

Susceptibility of microorganisms to the most currently used preservatives has been decreasing, and there is concern that decontamination with organic acids could result in the emergence of acid-tolerant food-borne pathogens, evolving to overcome the protective barrier of the human gastric stomach. In the evaluation and integration of new processing/preservation treatments, research objectives would have to include the identification of specific targets of organic acids—understanding the molecular mechanisms that confer high level resistance and analysing pathogen response to antimicrobials. This article provides an overview of various studies done on organic acids as preservatives and highlights aspects such as application, antimicrobial action, and future prospects. Other important issues, such as the application of functional genomics in developing new preservation methods, resistance development, and conventional laboratory procedures are also discussed.     

姜黄素在食品保鲜中应用的研究进展

姜黄素是一种绿色天然的食品保鲜剂,无毒无害,而且具有抗菌、抗氧化等保鲜效果。但由于姜黄素的水溶性差,生物利用率不高等问题,限制了其应用领域,所以增加姜黄素的生物利用率是拓宽其应用领域的重要因素。文章介绍了姜黄素的结构和食品保鲜原理,还综述了近年来姜黄素在食品保鲜领域中利用微胶囊、静电纺丝、纳米络合和胶体等方式提高其生物利用率的研究进展,为了姜黄素在食品保鲜领域中进一步的开发和利用提供一定的参考。     

Encapsulation of curcumin in electrosprayed gelatin microspheres enhances its bioaccessibility and widens its uses in food applications

Curcumin has uses as a food colorant and functional ingredient, these uses being restrained owing to its low solubility in water, which limits its dispersion in food matrices and its bioaccessibility. Curcumin–gelatin microparticles produced by electrohydrodynamic atomization were developed to overcome these problems. Microparticles with a size up to 1.2 μm in diameter, in which curcumin was in the amorphous state, were obtained. Both curcumin water solubility and bioaccessibility were significantly improved by encapsulation (38.6 and 11.3-fold higher than commercial curcumin, respectively). A gellified fish product was used to evaluate the coloring capacity of microencapsulated curcumin, finding a better dispersion for microencapsulated curcumin than for commercial one. However, curcumin bioaccessibility was similar owing to curcumin solubilization into the protein matrix. In spite of this, a protective effect of curcumin was observed, as the antioxidant activity of the bioaccessible fraction of the gel supplemented with microencapsulated curcumin was higher.Industrial relevanceCurcumin is a potential natural food coloring and functional ingredient which impairs an attractive yellowish-orange color to food and possesses a wide range of biological activities. However its use in food is restrained owing to its low solubility in water. Curcumin encapsulation using a soluble polymer is a promising strategy to widen the use of curcumin as an ingredient in the food industry.     

Recent developments in cold plasma decontamination technology in the food industry

BackgroundThe advent of the 21^st century has witnessed a growing demand of safe and nutritious foods. The food industry is adopting novel non-thermal food processing technologies. Cold plasma is one such promising non-thermal food processing method which uses charged, highly reactive gaseous molecules and species to inactivate contaminating microorganisms on foods and packaging materials.Scope and approachThe paper gives the reader an overview of the cold plasma technology in food industry. It reviews principles of plasma generation, including mechanisms of action of the process on microorganisms. It also highlights different plasma generation systems, various published results of plasma application to inactivate microorganisms in vitro and in various food products, food packages and equipment surfaces. The challenges of the process, its effects on food quality and the future prospects are highlighted.Key findings and conclusionsThis article aims to review and apprise readers about the important fundamentals and latest trends in the Cold Plasma technology. The on-going studies on plasma technology prove that cold plasma is strongly effective for surface decontamination, with efforts in-progress for liquid processing. The short time of application causes no significant deterioration in food products. Thus, it is an apt alternative processing technology which could also help to counter food allergenicity, seed germination, packaging material printing, waste-water treatment, modify food functionality, extract bio-actives etc. Further research is needed for scaling-up of this process for future commercialization.     

Intervention Technologies for Ensuring Microbiological Safety of Meat: Current and Future Trends

Abstract: This article reviews current and future techniques that are applied in the meat industry to ensure product safety. Consumer demand for high‐quality food and raised economic standards have triggered the development of emergent technologies to replace traditional well‐established preservation processes. Some promising nonthermal and thermal technologies, such as chemical and biological interventions, high hydrostatic pressure (HHP), irradiation, active packaging, natural antimicrobials and microwave, radiofrequency, and steam pasteurization, are under consideration for the preservation of meat products. All these alternative technologies are designed to be mild, energy‐conserving, environmentally friendly, and maintaining natural appearance and flavor, while eliminating pathogens and spoilage microorganisms. Their combination, as in the hurdle theory, may improve their effectiveness for decontamination. The objective of this article is to reflect on the possibilities and especially the limitations of the previously mentioned technologies.     

Chemical Reactions and Stability of Riboflavin in Foods

ABSTRACT: Riboflavin is relatively stable during thermal and nonthermal food processing and storage but is very sensitive to light. It can accept or donate a pair of hydrogen atoms. It can act as a photosensitizer (through either Type I or Type II mechanism) or a prooxidant for food components under light. Photosensitization of riboflavin causes production of reactive oxygen species such as superoxide anion, singlet oxygen, hydroxy radical, and hydrogen peroxide. Radicals and reactive oxygen species accelerate the decomposition of proteins, lipids, carbohydrates, and vitamins, and could cause significant nutrient loss in foods. Carbohydrates are less sensitive to riboflavinphotosensitized oxidation than proteins, lipids, or vitamins. Riboflavin is an excellent photosensitizer for singlet oxygen formation and a superb reactant for singlet oxygen, with the reaction rate of 1.01 ± 10¹⁰/M/s.     

Antioxidants in bakery products: a review

Fats impart taste and texture to the product but it is susceptible to oxidation leading to the development of rancidity and off-flavor. Since ancient times it has been in practice to use antioxidants in foods. Discovery of synthetic antioxidants has revolutionized the use of antioxidants in food. The effect of these antioxidants in bakery products were reviewed and found to be effective in enhancing the shelf life. Animal experimental studies have shown that some of the synthetic antioxidants had toxigenic, mutagenic, and carcinogenic effects. Hence there is an increasing demand for the use of natural antioxidants in foods, especially in bakery products. Some of the natural antioxidants such as alpha-tocopherol, beta-carotene, and ascorbic acid were already used in bakery products. These natural antioxidants are found to be effective in enhancing the shelf life of bakery products but not to the extent of synthetic antioxidants. Baking processing steps may lower the antioxidative activity but techniques such as encapsulation of antioxidants can retain their activity. Antioxidative activity of the plant extracts such as garcinia, curcumin, vanillins, and mint were reviewed but studies on their role in bakery products were limited or very few. Hence there is a wide scope for study under this direction in depth.     

Human Milk Composition and Preservation: Evaluation of High-pressure Processing as a Nonthermal Pasteurization Technology

Human milk is seen not only as a food, but as a functional and dynamic biologic system. It provides nutrients, bioactive components, and immune factors, promoting adequate and healthy growth of newborn infants. When mothers cannot supply their children, donated breast milk is the nutrition recommended by the World Health Organization, as it is a better alternative than infant formula. However, because of the manner in which donor milk is handled in human milk banks (HMB) many of the properties ascribed to mother's own milk are diminished or destroyed. The major process responsible for these losses is Holder pasteurization. High-pressure processing (HPP) is a novel nonthermal pasteurization technology that is being increasingly applied in food industries worldwide, primarily as an alternative to thermal treatment. This is due to its capacity to inactivate microorganisms while preserving both nutritional and bioactive components of foods. This review describes human milk composition and preservation, and critically discusses HMB importance and practices, highlighting HPP as a potential nonthermal pasteurization technology for human milk preservation. HPP technology is described and the few currently existing studies of its effects in human milk are presented.     

Complexation of curcumin with soy protein isolate and its implications on solubility and stability of curcumin

Curcumin, a natural polyphenolic food colourant, suffers a low bioavailability because of its low solubility and instability in aqueous solutions. Our study demonstrates that the food derived soy protein isolate (SPI) can form a complex with the curcumin. Fluorescence spectroscopy of the SPI–curcumin complex revealed that the complex is formed through hydrophobic interactions. Moreover, curcumin molecules quench the intrinsic fluorescence of SPI upon binding. Upon complexation, curcumin showed increased water solubility. Stability studies by UV spectroscopy showed that >80% of the curcumin was stable in the SPI–curcumin complex when dissolved in water, simulated gastric and intestinal fluids for 12 h, which would provide sufficient time for intestinal absorption. SPI–curcumin complex exhibits enhanced antioxidant activity and is capable of forming foam and emulsion, indicating its possible utilisation in food product formulation. This study suggests that SPI, being an edible protein, could be used as a material to encapsulate water-insoluble bioactive compounds in functional foods.     

脉冲电场在固体食品加工中的应用

脉冲电场(pulsed electric field, PEF)技术被视为21世纪食品非热加工技术发展史上的里程碑之一。迄今为止, PEF已广泛应用于果汁、牛奶和液态蛋等液体食品的杀菌和钝酶,并朝着商业化道路前进。然而,与PEF在液体食品中的应用相比,其在固体食品中的应用还处于起步阶段。固体食品的表面虽然也富含微生物,但PEF处理这类食品对微生物的影响较小,因此不能将其应用于固体食品的杀菌保鲜。仅管如此, PEF诱导的细胞电穿孔使其可作为一种预处理方法 ,通过增加质量和能量传递效率的方式来进行辅助固体食品的干燥、冻融、烹饪等。因此,本文重点介绍基于PEF细胞响应的高品质食品加工应用,总结PEF处理室的特点及PEF预处理固体食品的相关机制。最后,本文探讨了PEF在固体食品加工中的主要障碍和前景,为PEF未来在食品行业的发展拓宽研究方向。     

Effect of plasma activated water (PAW) on rocket leaves decontamination and nutritional value

Plasma Activated Water (PAW) obtained by exposing water to cold atmospheric pressure plasma, has recently emerged as a promising alternative for food decontamination, compared to the use of traditional chemical sanitizers. The aim of the study was to evaluate the efficacy of PAW treatments for rocket salad decontamination. Washing with PAW for 2, 5, 10 and 20 min was assessed against different endogenous spoilage microorganisms and compared to untreated water and hypochlorite solution. The chemical composition of PAW as a function of treatment and delay time was characterized and the effect on product quality and nutritional parameters was evaluated.Results showed that PAW allowed an average reduction of 1.7–3 Log CFU/g for total mesophilic and psychrotrophic bacteria and Enterobacteriaceae following 2–5 min washing with minimal variation of qualitative and nutritional parameters. Overall, experimental results highlighted the potentiality of PAW treatments as a promising alternative to chlorine having the advantage of a minor adverse impact on environment and consumers' health.Industrial relevanceTo meet consumers demand, the minimally processed fruit and vegetable industry needs to find sustainable solutions as alternative to the use of traditional chemical sanitizers that allow to increase product shelf-life and preserve safety, qualitative and nutritional characteristics.Plasma activated water represents a promising strategy for food decontamination, but its effects on foods have been only limitedly investigated. The present research is the first study on the use of plasma activated water on fresh rocket leaves, providing new and important information on microbial inactivation and quality of the fresh cut product.     

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.     

Application of Light‐Emitting Diodes in Food Production,Postharvest Preservation,and Microbiological Food Safety

Light‐emitting diodes (LEDs) possess unique properties that are highly suitable for several operations in the food industry. Such properties include low radiant heat emissions; high emissions of monochromatic light; electrical, luminous, and photon efficiency; long life expectancy, flexibility, and mechanical robustness. Therefore, they reduce thermal damage and degradation in crops and foods and are suitable in cold‐storage applications. Control over spectral composition of emitted light results in increased yields and nutritive content of horticultural or agricultural produce. Recently, LEDs have been shown to preserve or enhance the nutritive quality of foods in the postharvest stage, as well as manipulate the ripening of fruits, and reduce fungal infections. LEDs can be used together with photosensitizers or photocatalysts to inactivate pathogenic bacteria in food. UV LEDs, which are rapidly being developed, can also effectively inactivate pathogens and preserve food in postharvest stages. Therefore, LEDs provide a nonthermal means of keeping food safe without using chemical sanitizers or additives, and do not accelerate bacterial resistance. This article provides a review of the technology of LEDs and their role in food production, postharvest preservation, and in microbiological safety. Several challenges and limitations are identified for further investigation, including the difficulty in optimizing LED lighting regimens for plant growth and postharvest storage, as well as the sensory quality and acceptability of foods stored or processed under LED lighting. Nevertheless, LED technology presents a worthy alternative to current norms in lighting for the growth and storage of safe and nutritious food.     

食品运载体系包埋姜黄素的研究进展

姜黄素具有抗氧化、抗肿瘤、降血脂和预防老年痴呆等多种生理功能,还可以用作天然着色剂、食品防腐剂、抗氧化剂等;然而水溶性差、不稳定、代谢速度快、生物利用率低等缺陷限制了其在食品领域中的应用。利用食品运载体系,以天然生物分子为材料制备姜黄素的传递载体可以解决上述问题。本文介绍了姜黄素的结构特征和理化性质,以及限制其利用的主要因素和原理,对现有的运载体系及其在提高姜黄素生物利用度方面的研究现状进行综述,最后针对目前研究中存在的问题对未来姜黄素运载体系的研究方向提出合理建议。     

超声波与过氧乙酸的杀菌机制及在食品保鲜中的应用进展

果蔬、肉类、水产品等食品中微生物的生长繁殖会引起食品腐败变质,引发食品安全问题,造成经济损失与食物浪费。超声波作为一种绿色环保的非热加工技术,可利用空化效应消灭微生物。过氧乙酸是一种环境友好型的清洗剂,可作为含氯清洗剂的良好替代物。超声波与过氧乙酸均为环境友好型保鲜方式,二者联合使用在食品保鲜中具有巨大的应用潜力。本文就超声波、过氧乙酸单独使用或者二者联合处理的杀菌机制、对微生物生长的抑制作用、及在食品保鲜中的应用进行综述,并展望了未来的发展趋势,以期为新型绿色环保保鲜技术的创建与应用提供参考。     

Opportunities and challenges in application of ultrasound in food processing

The demand for convenience foods of the highest quality in terms of natural flavor and taste, and which are free from additives and preservatives, has spurred the need for the development of a number of non-thermal approaches to food processing, of which ultrasound technology has proven to be very valuable. Increasing number of recent publications have demonstrated the potential of this technology in food processing. A combination of ultrasound with pressure and/or heat is a promising alternative for the rapid inactivation of microorganisms and enzymes. Therefore, novel techniques like thermosonication, manosonication, and manothermosonication may be a more relevant energy-efficient processing alternative for the food industry in times to come. This review aims at identifying the opportunities and challenges associated with this technology. In addition to discussing the effects of ultrasound on foods, this review covers various areas that have been identified as having great potential for future development. It has been realized that ultrasound has much to offer to the food industry such as inactivation of microorganisms and enzymes, crystallization, drying, degassing, extraction, filtration, homogenization, meat tenderization, oxidation, sterilization, etc., including efficiency enhancement of various operations and online detection of contaminants in foods. Selected practical examples in the food industry have been presented and discussed. A brief account of the challenges in adopting this technology for industrial development has also been included.     

Basic aspects of food preservation by hurdle technology

Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. Since about 20 years the intelligent application of hurdle technology became more prevalent, because the principles of major preservative factors for foods (e.g., temperature, pH, a(w), Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behaviour of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multitarget food preservation emerged. In the present contribution a brief introduction is given on the potential hurdles for foods, the hurdle effect, and the hurdle technology. However, emphasis is placed on the homeostasis, metabolic exhaustion, and stress reactions of microorganisms related to hurdle technology, and the prospects of the future goal of a multitarget preservation of foods.     

High pressure treatment: applications in cheese manufacture and ripening

High pressure (HP) treatment has emerged as a food processing technology primarily due to increasing interest in novel methods for preservation of foods. Applying HP to food products modifies interactions between individual components, influences rates of enzymatic reactions and can inactivate microorganisms. This paper reviews studies of HP induced changes in milk relevant to cheesemaking, including the effects of HP on rennet coagulation time, rate of curd formation and cheese yield. Published studies on the effects of direct HP treatment of cheese and specifically the effects of HP on cheese ripening characteristics, functionality and microbiology, are also reviewed.     

植物精油稳定性的改善及其在食品中应用研究进展

食物是一个复杂且营养丰富的体系,会给微生物生长提供一个优越的环境,因而易使食品感染微生物而导致腐败变质。将植物天然提取物用于食物保鲜已成为近年来食品保鲜业界的研究热点,植物精油作为一种无毒、无害、纯天然的提取物,具有很好的抗氧化和抑菌防腐的特性,其在食品保鲜领域的应用前景十分巨大。但植物精油存在着极易挥发、水溶性差,对光、热、温度敏感等特性,使其在食品保鲜中的应用受到限制。本文综述了提高植物精油稳定性的四种方法微胶囊、微乳液、纳米乳和脂质体及其在果蔬、谷物类、肉类等食品保鲜中的应用,为植物精油的进一步开发研究及应用提供参考。