Influence of malting and lactic acid fermentation on functional bioactive components in cereal‐based raw materials: a review paper

Driven by increased health awareness among consumers, the production of foods and beverages enriched with functional bioactive components is gaining more attention. Malting and lactic acid fermentation are biotechnological processes having potential for producing functional foods and beverages. Due to various biochemical and enzymatic induced changes in raw materials, malting of cereal grains and probiotic lactic acid fermentation of plant‐based media increases the nutritional quality of treated raw materials. The improved nutritional quality is attributed to the accumulation of functional bioactive components along with the degradation of anti‐nutritional components. The selection of raw materials and process parameters are important factors to be considered for increasing the functional bioactive components such as dietary fibres, antioxidants and probiotics. This review article reports the current knowledge on the changes of bioactive components during malting and lactic acid fermentation using probiotic bacterial strains. Process parameters which affect the concentration of bioactive components in raw materials will also be described.     

Computer vision‐based analysis of foods: A non‐destructive colour measurement tool to monitor quality and safety

Computer vision‐based image analysis has been widely used in food industry to monitor food quality. It allows low‐cost and non‐contact measurements of colour to be performed. In this paper, two computer vision‐based image analysis approaches are discussed to extract mean colour or featured colour information from the digital images of foods. These types of information may be of particular importance as colour indicates certain chemical changes or physical properties in foods. As exemplified here, the mean CIE a^* value or browning ratio determined by means of computer vision‐based image analysis algorithms can be correlated with acrylamide content of potato chips or cookies. Or, porosity index as an important physical property of breadcrumb can be calculated easily. In this respect, computer vision‐based image analysis provides a useful tool for automatic inspection of food products in a manufacturing line, and it can be actively involved in the decision‐making process where rapid quality/safety evaluation is needed. © 2013 Society of Chemical Industry     

Occurrence and preventive strategies to control mycotoxins in cereal‐based food

Mycotoxins contamination in cereal‐based food is ubiquitous according to systematic review of the scientific documentation of worldwide mycotoxin contamination in cereal and their products between 2008 and 2018, thus representing food safety issue especially in developing tropical countries. Food processing plays a vital role to prevent mycotoxin contamination in food. Therefore, it is with great urgency to develop strategies to inhibit fungi growth and mycotoxin production during food processing. This review begins by discussing physicochemical properties of five most common mycotoxins (aflatoxins, fumonisins, ochratoxins, deoxynivalenol, and zearalenone) found in cereal grains, regulation for mycotoxins in food, and their potential negative impact on human health. The fate of mycotoxins during major cereal‐based food processing including milling, breadmaking, extrusion, malting, and brewing was then summarized. In the end, traditional mitigation strategies including physical and chemical and potential application of biocontrol agent and essential oil nanoemulsions that can be applied during food processing were discussed. It indicated that no single method is currently available to completely prevent mycotoxin contamination in cereal foods.     

发酵食品中生物胺检测技术研究进展

生物胺作为一类具有生物活性的小分子含氮化合物,是发酵食品中常见的代谢物之一,过量摄入会引起呼吸困难、心悸等不良反应,而在食品发酵过程中,由于原料中蛋白质含量高,且发酵微生物能够产生蛋白酶和氨基酸脱羧酶等因素,导致生物胺的产生和积累。同时生物胺与食品腐败密切相关,其含量可作为衡量食品质量和新鲜度的指标,因此,发酵食品中生物胺的定性和定量检测技术非常重要。本文综述了国内外目前针对发酵食品中生物胺的检测技术,分析其优缺点,并探讨了生物胺检测技术的发展趋势,为发酵食品中生物胺的检测提供技术基础和方法依据。     

Sensory characteristics of wholegrain and bran-rich cereal foods – A review

BackgroundWholegrain foods are known to be health-beneficial but their sensory characteristics may be a limiting factor for consumption. The scientific literature of factors influencing sensory quality of wholegrain foods is rather scarce.Scope and approachMany cereals like rye, oats, barley and sorghum are actually used mainly as wholegrain, whereas for wheat the situation is the opposite. This review deals with factors that differentiate the sensory properties of wholegrain and bran-rich foods from those of refined cereal foods.Key findings and conclusionsWholegrain and bran contain flavour-active compounds, flavour precursors and resistant cell wall structures causing changes in flavour and texture during processing. In wholegrain foods, different chemical constituents contribute to bitterness. Increased knowledge on flavour formation has led to the possibility to not only measure but actually also design the flavour. Structure and texture are also important determinants underlying eating quality and stability of cereal foods. Hitherto established means of modulating sensory quality and thus improving acceptability of wholegrain foods are presented.     

水产品贮藏过程中肌肉蛋白质降解规律的 研究进展

蛋白质是水产品肌肉的主要组成成分,水产品新鲜度等品质变化与其肌肉蛋白质的变化存在必然联系。水产品贮藏过程中,在一系列复杂的物理、化学、生物等变化影响(尤其是内源酶)作用下,肌肉蛋白质发生不同程度的降解,从而导致水产品新鲜度降低,影响其品质及加工适用性。本文从水产品死后肌肉的新陈代谢、肌肉蛋白质降解的一般规律、蛋白酶对肌肉蛋白质降解的贡献等方面综述了水产品贮藏过程肌肉蛋白质降解方面的研究进展,在此基础上讨论了肌肉蛋白质变化与水产品新鲜度之间的联系,重点介绍了以双向电泳技术、质谱分析为核心的蛋白质组学技术及其在基于指示蛋白的水产品新鲜度评价方法中的研究进展。最后提出了水产品肌肉蛋白质降解机制及其对水产品品质影响机制研究应关注的方向。旨在为水产品品质变化机制、控制技术开发、新鲜度评价等方面的研究提供理论依据和参考。     

新鲜度指示型智能包装的研究进展

食品新鲜度指示型智能包装是利用食品在贮藏过程中释放的某些特征气体与特定试剂产生的特征颜色反应、温度激活生物学反应及酶作用等引起指示剂发生明显的变化,从而帮助消费者直观、准确以及科学的判断食品品质与新鲜程度。因此,食品新鲜度指示剂在实际生活中具有重要的应用价值。本文在归纳和分析国内外新鲜度指示型智能包装的基础上,分别从食品新鲜度指示剂应用类型与新鲜度指示剂基材两个方面阐述了新鲜度指示剂的指示原理与研究现状以及指示剂基材的制作工艺与材料选择,对现有研究成果进行总结,指出了研究中依然存在的问题并对未来的研究方向进行展望以及提出合理性研究建议,旨在为今后更深入的食品新鲜度指示剂技术研究提供借鉴和参考。     

电子鼻和电子舌在鱼肉鲜度评价中的应用研究

鲜度是鱼肉及鱼类制品质量的一个重要指标。电子舌和电子鼻技术都能快速地评价鱼肉的品质和新鲜度。本文主要介绍了电子鼻和电子舌的在评价鱼肉鲜度时的工作原理以及研究现状和应用前景。     

Application of cereals and cereal components in functional foods: a review

The food industry is directing new product development towards the area of functional foods and functional food ingredients due to consumers' demand for healthier foods. In this respect, probiotic dairy foods containing human-derived Lactobacillus and Bifidobacterium species and prebiotic food formulations containing ingredients that cannot be digested by the human host in the upper gastrointestinal tract and can selectively stimulate the growth of one or a limited number of colonic bacteria have been recently introduced into the market. The aim of these products is to affect beneficially the gut microbial composition and activities. Cereals offer another alternative for the production of functional foods. The multiple beneficial effects of cereals can be exploited in different ways leading to the design of novel cereal foods or cereal ingredients that can target specific populations. Cereals can be used as fermentable substrates for the growth of probiotic microorganisms. The main parameters that have to be considered are the composition and processing of the cereal grains, the substrate formulation, the growth capability and productivity of the starter culture, the stability of the probiotic strain during storage, the organoleptic properties and the nutritional value of the final product. Additionally, cereals can be used as sources of nondigestible carbohydrates that besides promoting several beneficial physiological effects can also selectively stimulate the growth of lactobacilli and bifidobacteria present in the colon and act as prebiotics. Cereals contain water-soluble fibre, such as beta-glucan and arabinoxylan, oilgosaccharides, such as galacto- and fructo-oligosaccharides and resistant starch, which have been suggested to fulfil the prebiotic concept. Separation of specific fractions of fibre from different cereal varieties or cereal by-products, according to the knowledge of fibre distribution in cereal grains, could be achieved through processing technologies, such as milling, sieving, and debranning or pearling. Finally, cereal constituents, such as starch, can be used as encapsulation materials for probiotics in order to improve their stability during storage and enhance their viability during their passage through the adverse conditions of the gastrointestinal tract. It could be concluded that functional foods based on cereals is a challenging perspective, however, the development of new technologies of cereal processing that enhance their health potential and the acceptability of the food product are of primary importance.     

A comparison of the nutritional value, sensory qualities, and food safety of organically and conventionally produced foods

Given the significant increase in consumer interest in organic food products, there is a need to determine to what extent there is a scientific basis for claims made for organic produce. Studies comparing foods derived from organic and conventional growing systems were assessed for three key areas: nutritional value, sensory quality, and food safety. It is evident from this assessment that there are few well-controlled studies that are capable of making a valid comparison. With the possible exception of nitrate content, there is no strong evidence that organic and conventional foods differ in concentrations of various nutrients. Considerations of the impact of organic growing systems on nutrient bioavailability and nonnutrient components have received little attention and are important directions for future research. While there are reports indicating that organic and conventional fruits and vegetables may differ on a variety of sensory qualities, the findings are inconsistent. In future studies, the possibility that typical organic distribution or harvesting systems may deliver products differing in freshness or maturity should be evaluated. There is no evidence that organic foods may be more susceptible to microbiological contamination than conventional foods. While it is likely that organically grown foods are lower in pesticide residues, there has been very little documentation of residue levels.     

生物散斑激光技术无损检测原理及在食品中应用效果研究进展

生物散斑激光技术是通过He-Ne激光照射在样品表面,利用样品对光散射能力不同形成不同的散斑图案,从而实现对样品品质、营养成分的定性、定量分析的光谱学技术。散斑活性的大小与样品生化反应过程中的物理特性、化学成分及内部品质有关。该技术具有对样品破坏性小、检测时间短、可应用于农畜产品成熟度监测、新鲜度监测以及品质检测多方面的优势,但是其稳定性差、穿透深度浅也限制了它的应用。本文简述了生物散斑激光技术的特点,重点综述了其无损检测原理和在食品成熟度、新鲜度、品质检测中应用效果的研究进展,展望了其在食品检测方面的应用潜力和局限性,旨为此技术在食品无损检测领域应用提供理论和技术支持。     

A Review on Mycotoxins in Food and Feed: Malaysia Case Study

Fungi are distributed worldwide and can be found in various foods and feedstuffs from almost every part of the world. Mycotoxins are secondary metabolites produced by some fungal species and may impose food safety risks to human health. Among all mycotoxins, aflatoxins (AFs), ochratoxin A (OTA), trichothecenes, deoxynivalenol (DON and T‐2 toxin), zearalenone (ZEN), and fumonisins (FMN) have received much attention due to high frequency and severe health effects in humans and animals. Malaysia has heavy rainfall throughout the year, high temperatures (28 to 31 °C), and high relative humidity (70% to 80% during wet seasons). Stored crops under such conditions can easily be contaminated by mycotoxin‐producing fungi. The most important mycotoxins in Malaysian foods are AFs, OTA, DON, ZEN, and FMN that can be found in peanuts, cereal grains, cocoa beans, and spices. AFs have been reported to occur in several cereal grains, feeds, nuts, and nut products consumed in Malaysia. Spices, oilseeds, milk, eggs, and herbal medicines have been reported to be contaminated with AFs (lower than the Malaysian acceptable level of 35 ng/g for total AFs). OTA, a possible human carcinogen, was reported in cereal grains, nuts, and spices in Malaysian market. ZEN was detected in Malaysian rice, oat, barley, maize meal, and wheat at different levels. DON contamination, although at low levels, was reported in rice, maize, barley, oat, wheat, and wheat‐based products in Malaysia. FMN was reported in feed and some cereal grains consumed in Malaysia. Since some food commodities are more susceptible than others to fungal growth and mycotoxin contamination, more stringent prevention and control methods are required.     

Metal–oxide–semiconductor resistive gas sensors for fish freshness detection

Fish are prone to spoilage and deterioration during processing, storage, or transportation. Therefore, there is a need for rapid and efficient techniques to detect and evaluate fish freshness during different periods or conditions. Gas sensors are increasingly important in the qualitative and quantitative evaluation of high-protein foods, including fish. Among them, metal–oxide–semiconductor resistive (MOSR) sensors with advantages such as low cost, small size, easy integration, and high sensitivity have been extensively studied in the past few years, which gradually show promising practical application prospects. Herein, we take the detection, classification, and assessment of fish freshness as the actual demand, and summarize the physical and chemical changes of fish during the spoilage process, the volatile marker gases released, and their production mechanisms. Then, we introduce the advantages, performance parameters, and working principles of gas sensors, and summarize the MOSR gas sensors aimed at detecting different kinds of volatile marker gases of fish spoiling in the last 5 years. After that, this paper reviews the research and application progress of MOSR gas sensor arrays and electronic nose technology for various odor indicators and fish freshness detection. Finally, this review points out the multifaceted challenges (sampling system, sensing module, and pattern recognition technology) faced by the rapid detection technology of fish freshness based on metal oxide gas sensors, and the potential solutions and development directions are proposed from the view of multidisciplinary intersection.     

Antiplasticization by Water in Reduced-Moisture Food Systems

Antiplasticization of synthetic glassy polymers by low-molecular weight diluents at low concentrations is a well-known phenomenon which leads to increased rigidity rather than flexibility of the polymer-diluent blends. Based on the food polymer science approach, we hypothesized that increases (rather than decreases) in modulus and brittleness, commonly observed when certain solid food systems are humidified from the dry state, are synonymous with antiplasticization by water. Sugars and polyols, important components of foods, behave in much the same manner as water in acting as either antiplasticizers or plasticizers of food polymer systems. Several mechanisms may be involved in antiplasticization by low-molecular mass diluents. Simultaneous changes in various physical properties, resulting from antiplasticization or plasticization by water and other diluents, may profoundly influence the quality and acceptability of food products.     

High hydrostatic pressure (HHP) inactivation of foodborne pathogens in low‐acid juices

Consumption of unpasteurised fruit/vegetable juices has increased in recent years due to their freshness, low calorie contribution and good nutritional quality. However, unpasteurised fresh juices with low acidity (pH > 4.6) and high water activity (a_w > 0.85) can support the growth of pathogens. Hence, pasteurisation is a necessary process in the production of low‐acid juices. Consumer demand has required minimally processed high‐quality foods that are free from additives, that are fresh tasting and microbiologically safe, and with an extended shelf life. High hydrostatic pressure (HHP) treatment is considered to be an alternative to thermal pasteurisation for fruit and vegetable juices. HHP treatment could preserve nutritional value and the sensory properties of fruits and vegetables due to its limited effect on the covalent bonds of low‐molecular‐mass compounds such as colour, flavour compounds and vitamins. However, inactivation of important foodborne pathogens in low‐acid foods by HHP is most urgent and critical. More research should be performed in order to satisfy consumer demands for fresh‐tasting products while retaining safety.     

Phytic Acid Degradation in Complementary Foods Using Phytase Naturally Occurring in Whole Grain Cereals

Complementary foods based on cereals and legumes often contain high amounts of phytic acid, a potent inhibitor of mineral and trace element absorption. The possibility to degrade phytic acid during the production of complementary foods by using whole grain cereals as the phytase source was investigated. Whole grain rye, wheat, or buckwheat (10%) were added to cereal‐legume‐based complementary food mixtures, and phytic acid was shown to be completely degraded in a relatively short time (1.5 to 3 h) when incubated at optimal conditions for cereal phytase. The potential usefulness of the method for industrial production was demonstrated with a complementary food based on wheat and soybean.     

Development of a pH indicator composed of high moisture-absorbing materials for real-time monitoring of chicken breast freshness

A colorimetric bromocresol purple dye-based pH-responsive indicator was developed to monitor the quality of chicken breast meat by direct surface contact. To prevent direct contact of the dye with the chicken breast and to improve its color change sensitivity, it was immobilized with polyvinyl alcohol and a high-absorbance material. The color of the pH indicator changes from yellow to blue and finally purple to indicate spoilage, which can be easily detected by the naked eye. The asprepared pH indicator exhibited good response to pH changes on the surface of chicken breast meat, and no migration of the dye from the indicator onto the surface of the chicken was observed. This pH indicator exhibits excellent feasibility for real-time, direct-contact monitoring of the freshness and quality of various foods.     

Effects of high-voltage electrostatic fields on the quality of tilapia meat during refrigeration

Abstract: Fresh fish is typically brought to market refrigerated at approximately 4 °C, R‐storage. A storage method has been devised that combines refrigeration with a high‐voltage electrostatic field (100 kV/m; E‐storage). It was developed to improve the quality and prolong the shelf life of foods. This study investigated changes in the freshness of tilapia meat under E‐storage conditions. The total viable count of tilapia reached 10⁷ CFU/g on the 7th d of refrigeration in R‐storage. By the 6th d, K‐value had increased from 20% to 61.7% for E‐storage and to 94.7% for R‐storage. Volatile basic nitrogen had increased from 12.54 mg/100 g to about 24.34 and 25.03 mg/100 g for R‐ and E‐storage (on the 7th and 10th d), respectively. The sensory assessment also indicated that E‐storage yielded an improvement in quality over that of R‐storage. Practical application of the study model has the potential to prolong the freshness of fish.     

The Fate of Mycotoxins During the Processing of Wheat for Human Consumption

Mycotoxins are a potential health threat in cereals including wheat. In the European Union (EU), mycotoxin maximum levels are laid down for cereal raw materials and final food products. For wheat and wheat‐based products, the EU maximum levels apply to deoxynivalenol (DON), zearalenone, aflatoxins, and ochratoxin A. This review provides a comprehensive overview on the different mycotoxins and their legal limits and on how processing of wheat can affect such contaminants, from raw material to highly processed final products, based on relevant scientific studies published in the literature. The potential compliance with EU maximum levels is discussed. Of the four mycotoxins regulated in wheat‐based foods in the EU, most data are available for DON, whereas aflatoxins were rarely studied in the processing of wheat. Furthermore, available data on the effect of processing are outlined for mycotoxins not regulated by EU law—including modified and emerging mycotoxins—and which cover DON derivatives (DON‐3‐glucoside, mono‐acetyl‐DONs, norDONs, deepoxy‐DON), nivalenol, T‐2 and HT‐2 toxins, enniatins, beauvericin, moniliformin, and fumonisins. The processing steps addressed in this review cover primary processing (premilling and milling operations) and secondary processing procedures (such as fermentation and thermal treatments). A special focus is on the production of baked goods, and processing factors for DON in wheat bread production were estimated. For wheat milling products derived from the endosperm and for white bread, compliance with legal requirements seems to be mostly achievable when applying good practices. In the case of wholemeal products, bran‐enriched products, or high‐cereal low‐moisture bakery products, this appears to be challenging and improved technology and/or selection of high‐quality raw materials would be required.     

Food extrusion

Extrusion processing has become an important food process in the manufacture of pasta, ready‐to‐eat cereals, snacks, pet foods, and textured vegetable protein (TVP). An extruder consists of a tightly fitting screw rotating within a stationary barrel. Preground and conditioned ingredients enter the screw where they are conveyed, mixed, and heated by a variety of processes. The product exits the extruder through a die where it usually puffs and changes texture from the release of steam and normal forces. Mathematical models for extruder flow and torque have been found useful in describing extrusion operations. Scale‐up can be facilitated by the application of these models. A variety of food extruder designs have developed. The differences and similarity of design are discussed. Pertinent literature on the extrusion of cereal/snack products, full‐fat soy, TVP, pet foods (dry and semi‐moist), pasta, and beverage or other food bases are discussed. In many of these applications, the extruder is a high temperature, short time process which minimizes losses in vitamins and amino acids. Color, flavor, and product shape and texture are also affected by the extrusion process. Extrusion has been widely applied in the production of nutritious foods. Emphasis is placed on the use of extrusion to denature antinutritional factors and the improvement of protein quality and digestibility.