谷物中多酚与多糖之间相互作用的研究进展

谷物中多酚与细胞壁多糖相互作用的束缚使得多酚在谷物细胞壁中的释放受到阻碍,因此破坏多酚与多糖的相互作用成为促进多酚释放的有效途径.本文综述了谷物中多酚与细胞壁多糖之间的共价相互作用与非共价相互作用.共价相互作用,如酯键、醚键以及糖苷键;非共价相互作用,如氢键和疏水相互作用.本文还介绍了能够破坏多酚与细胞壁多糖相互作用的...     

多糖与多酚相互作用机制及其对多酚特性的影响研究进展

随着多酚、多糖营养和功能特性研究的日益深入,多酚与多糖间相互作用及其机制引起食品学术界的广泛关注。本文对多酚与多糖间的非共价相互作用和共价相互作用及机制、影响因素及其对多酚理化特性、功能特性的影响进行综述,并对两者相互作用在食品加工中的应用进行展望。     

Interactions between polyphenols and macromolecules: quantification methods and mechanisms

Non-covalent and covalent associations of polyphenols with food macromolecules are two of the most fundamental factors affecting the quality of polyphenol-rich food products. This review therefore describes the biochemical bases of associations between polyphenols and macromolecules, that is, proteins and polysaccharides. Our intent is to provide a level of understanding that can be used to underpin future research directions. This will help to resolve existing issues that limit organoleptic and nutritional qualities of polyphenol-rich foods and drinks. It will also allow a better understanding of the functional consequences of these interactions on food/biological systems. The methods used to study non-covalent and covalent interactions are described, and the limiting factors of each method are emphasized. The biochemical mechanisms of interaction between polyphenols and macromolecules are also described. In processed food, non-covalent polyphenol/macromolecule interactions are largely due to weak associations, and result from a combination of hydrogen bonds and hydrophobic interactions. The biochemical mechanisms for covalent interactions involve oxidation of phenolic compounds, whether enzymatically mediated or not, with the formation of o-quinones or o-semi-quinones, or the cleavage of procyanidin interflavanic bonds in acid medium with the formation of carbocations. The effects of factors such as polyphenol structure, macromolecule structure, relative concentrations of both polyphenol and macromolecule, solvent composition, ionic strength, temperature, and pH are discussed.     

The analysis of dietary fibre—the choices for the analyst

The analysis of dietary fibre (which is defined as the sum of lignin and the polysaccharides not digested by the endogenous secretions of the human digestive tract) presents several problems to the analyst. Dietary fibre is a mixture of substances derived from the structural materials of the plant cell wall and a range of polysaccharides of a non-structural nature either present naturally in foods or derived from food additives. The complete analysis of such a complex mixture would be difficult and time consuming and a number of practical alternatives have been used. These include methods based on the enzymatic removal of protein and starch to give an ?indigestible residue’? and procedures based on extraction with neutral detergent solutions. These procedures in their present form do not measure water-soluble components and therefore underestimate dietary fibre. More detailed methods in which the water-soluble and water-insoluble non-cellulosic polysaccharides, cellulose and lignin were measured separately are described. In these the non-cellulosic fraction was characterised in terms of its component sugars. It is suggested that methods of this type are necessary to characterise dietary fibre analytically in order to account for the properties of dietary fibre.     

Food‐Grade Covalent Complexes and Their Application as Nutraceutical Delivery Systems: A Review

Food proteins, polysaccharides, and polyphenols are 3 major food constituents with distinctly different functional attributes. Many proteins and polysaccharides are capable of stabilizing emulsions and foams, thickening solutions, and forming gels, although they differ considerably in their abilities to provide these functional attributes. Many plant polyphenols exhibit beneficial physiological functions, such as antitumor, antioxidant, antibacterial, and antiviral properties. Proteins, polysaccharides, and polyphenols can form complexes with each other, which leads to changes in the functional and nutritional properties of the combined systems. Recently, there has been considerable interest in understanding and utilizing covalent interactions between polyphenols and biopolymers (proteins and polysaccharides). The binary or tertiary conjugates formed may be designed to have physicochemical properties and functional attributes that cannot be achieved using the individual components. This article provides a review of the formation, characterization, and utilization of conjugates prepared using proteins, polysaccharides, and polyphenols. It also discusses the relationship between the structural properties and functionality of the conjugates, and it highlights the bioavailability of bioactive compounds loaded in conjugate‐based delivery systems. In addition, it highlights the main challenges to be considered when preparing and analyzing conjugates. This article provides an improved understanding of the chemical reactions that occur between major food ingredients and how they can be utilized to develop biopolymer‐based delivery systems with enhanced functional attributes.     

Combined calcium pretreatment and ultrasonic/microwave drying to dehydrate black chokeberry: Novel mass transfer modeling and metabolic pathways of polyphenols

In this study, black chokeberries were dehydrated by sequential calcium pretreatment and ultrasonic/microwave drying. The investigation focused on exploring the mechanisms of water transport and metabolic pathways of polyphenols. A diffusional model was modified by considering the factors such as shrinkage, porosity and temperature-dependent water diffusivity to simulate the moisture transport. Accordingly, the Spatio-temporal evolutions of cytoplasm water, extracellular water and total water content in black chokeberry throughout drying were successfully revealed. On the other hand, the quality attributes involved in the metabolic pathways of polyphenols, i.e., free/bound phenolics, cell wall pectin, polyphenol oxidase (PPO) or peroxidase (POD), and viscoelastic properties under these drying treatments were intensively analysed. Through correlation analysis, it was found that CaCl₂ pretreatment strengthened the oxidation of free procyanidin B₂ by PPO. In contrast, both ultrasound and microwave drying weakened the negative influence of PPO on the stability of free rutin. Besides, temperature rise promoted the loss of free polyphenols and the degradation of cell wall pectin, weakening the attachment of bounded-caffeic acid on the cell wall. This investigation provides new physical and chemical understandings about fruit drying and reveals the potential benefits of hybrid drying technologies.     

Interactions between tea polyphenols and nutrients in food

Tea polyphenols (TPs) are important secondary metabolites in tea and are active in the food and drug industry because of their rich biological activities. In diet and food production, TPs are often in contact with other food nutrients, affecting their respective physicochemical properties and functional activity. Therefore, the interaction between TPs and food nutrients is a very important topic. In this review, we describe the interactions between TPs and food nutrients such as proteins, polysaccharides, and lipids, highlight the forms of their interactions, and discuss the changes in structure, function, and activity resulting from their interactions.     

珊瑚菌子实体和菌丝体营养成分与抗氧化活性的比较

采用国标及常规分析方法对珊瑚菌子实体和菌丝体中营养成分和活性物质多糖、多酚含量及其抗氧化活性进行分析,结果表明:珊瑚菌子实体与菌丝体碳水化合物含量分别为38.74±1.27%和63.55±3.17%;脂肪含量分别为2.52±0.14%和3.21±0.19%;蛋白含量分别为11.02±1.21%和22.30±1.18%;灰分含量分别为5.77±0.14%和5.98±0.11%。子实体矿质元素含量普遍高于其菌丝体,Mg元素除外;必须氨基酸,菌丝体含量(7.08±0.15)g/100 g高于其子实体(2.55±0.24)g/100 g。子实体多糖含量(23.22±1.60)mg/g低于其菌丝体(35.51±1.78)mg/g,多酚含量(6.85±0.41)mg/g高于其菌丝体(3.66±0.29)mg/g。比较珊瑚菌多糖、多酚体外抗氧化活性强弱依次为子实体多酚菌丝体多酚菌丝体多糖子实体多糖。研究表明对于珊瑚菌菌丝体多糖,有望代替子实体应用于食药产品,而菌丝体多酚仍有待进一步开发利用。     

细胞壁多糖对真空冷冻干燥再造型苹果脆片质构的影响

细胞壁多糖作为果蔬干物质的主要成分,是决定干制果蔬质构形成的物质基础.为探究植物细胞壁多糖物质对真空冷冻干燥再造型苹果脆片质构的影响,采用分步提取法获得苹果细胞壁的不同多糖组分,即醇不溶性物质(AIR)、可溶性膳食纤维(SDF)和不溶性膳食纤维(IDF),通过调节这3种细胞壁多糖组分在苹果脆片中的相对含量,探讨其对苹果...     

亚临界水提取植物源生物活性物质的研究进展

植物源生物活性物质如多酚、多糖等,因具有抗氧化和抗肿瘤等特性在功能性和保健食品中发挥着重要作用。多糖、多酚类物质通过氢键、疏水键等非共价键与蛋白质、脂质等物质在植物组织中紧密结合。如何利用绿色高效的方法从植物组织中提取生物活性成分已成为食品行业的研究热点。亚临界水不仅与有机溶剂溶解生物活性物质的能力接近,能削弱多糖、多酚与其他物质间的紧密结合,而且具有无毒、无污染、无溶剂残留的特点,可广泛用于生物活性物质的提取。本文介绍了亚临界水提取技术的特点和影响因素,其中重点综述了亚临界水提取植物源生物活性物质的效果及机理,以及其与物理技术（如微波、超声、强脉冲光）联用的优势。这为生物活性物质的高效制备提供技术支持,也为亚临界水技术在食品中应用提供理论依据和参考。     

Control of ice crystal nucleation and growth during the food freezing process

Freezing can maintain a low-temperature environment inside food, reducing water activity and preventing microorganism growth. However, when ice crystals are large, present in high amounts, and/or irregularly distributed, irreversible damage to food can occur. Therefore, ice growth is a vital parameter that needs to be controlled during frozen food processing and storage. In this review, ice growth theory and control are described. Macroscopic heat and mass transfer processes, the relationship between the growth of ice crystals and macroscopic heat transfer factors, and nucleation theory are reviewed based on the reported theoretical and experimental approaches. The issues addressed include how heat transfer occurs inside samples, variations in thermal properties with temperature, boundary conditions, and the functional relationship between ice crystal growth and freezing parameters. Quick freezing (e.g., cryogenic freezing) and unavoidable temperature fluctuations (e.g., multiple freeze–thaw cycles) are both taken into consideration. The approaches for controlling ice crystal growth based on the ice morphology and content are discussed. The characteristics and initial mechanisms of ice growth inhibitors (e.g., antifreeze proteins (AFPs), polysaccharides, and phenols) and ice nucleation agents (INAs) are complex, especially when considering their molecular structures, the ice-binding interface, and the dose. Although the market share for nonthermal processing technology is low, there will be more work on freezing technologies and their theoretical basis. Superchilling technology (partial freezing) is also mentioned here.     

Aspects of material science in food processing: changes in plant cell walls of fruits and vegetables

 Foods can be regarded as complex, dispersed systems which are normally metastable. Food processing causes state transitions (second-order transitions) when raw materials, food components or food systems are subjected to external stresses. The state transitions occurring during processing are detectable as changes in structure and properties of the investigated systems. The processing of fruits and vegetables is often connected with changes in cell walls. Cell wall materials in dispersed fruit and vegetable systems can be regarded as a model substrate of the dispersed phase. During processing, cell walls undergo modifications in terms of their physical state, macrostructure, microstructure, and composition, as well as structure-dependent changes in their functional and material properties. The interactions and connections (dependencies) between state transitions, and various changes in structure and properties, are very complex and multivariate and are not well understood as yet. For the evaluation of changing material properties during processing, examination of hydration, rheological (external mechanical stress) and thermal (external thermal stress) characteristics is important. The changes occurring during the processing of fruits and vegetables are determined by external factors (especially various mechanical and thermal stresses) and by internal factors. External stress in many cases causes solubilisation of the cell wall, loss of firmness and favours cell separation. Thermal processing increases pectin degradation by β-elimination. Internal factors such as pH and modified ionic strength, e.g. by applying soak solutions, can have an important influence on the changes in the cell wall during processing. So, calcium ions on the one hand can favour cell wall degradation by β-elimination and, on the other hand, after low temperature blanching and de-esterification of the pectin by activated pectin methyl esterase, can contribute to stabilisation of the texture by formation of a calcium-pectin complex. Knowledge about cell wall degradation mechanisms can be markedly improved by studies using model substrates such as pectin, or cell wall materials like the alcohol-insoluble residue and materials with cellular structure. This knowledge has been used to improve the technology used to process fruits and vegetables and to produce products with better properties. Moreover, testing and applying cell wall materials as ingredients for the production of textured foods and potential health-related foods is suggested. Received: 21 July 1998     

Aspects of material science in food processing: changes in plant cell walls of fruits and vegetables

 Foods can be regarded as complex, dispersed systems which are normally metastable. Food processing causes state transitions (second-order transitions) when raw materials, food components or food systems are subjected to external stresses. The state transitions occurring during processing are detectable as changes in structure and properties of the investigated systems. The processing of fruits and vegetables is often connected with changes in cell walls. Cell wall materials in dispersed fruit and vegetable systems can be regarded as a model substrate of the dispersed phase. During processing, cell walls undergo modifications in terms of their physical state, macrostructure, microstructure, and composition, as well as structure-dependent changes in their functional and material properties. The interactions and connections (dependencies) between state transitions, and various changes in structure and properties, are very complex and multivariate and are not well understood as yet. For the evaluation of changing material properties during processing, examination of hydration, rheological (external mechanical stress) and thermal (external thermal stress) characteristics is important. The changes occurring during the processing of fruits and vegetables are determined by external factors (especially various mechanical and thermal stresses) and by internal factors. External stress in many cases causes solubilisation of the cell wall, loss of firmness and favours cell separation. Thermal processing increases pectin degradation by β-elimination. Internal factors such as pH and modified ionic strength, e.g. by applying soak solutions, can have an important influence on the changes in the cell wall during processing. So, calcium ions on the one hand can favour cell wall degradation by β-elimination and, on the other hand, after low temperature blanching and de-esterification of the pectin by activated pectin methyl esterase, can contribute to stabilisation of the texture by formation of a calcium-pectin complex. Knowledge about cell wall degradation mechanisms can be markedly improved by studies using model substrates such as pectin, or cell wall materials like the alcohol-insoluble residue and materials with cellular structure. This knowledge has been used to improve the technology used to process fruits and vegetables and to produce products with better properties. Moreover, testing and applying cell wall materials as ingredients for the production of textured foods and potential health-related foods is suggested.     

The past decade findings related with nutritional composition,bioactive molecules and biotechnological applications of Passiflora spp. (passion fruit)

BackgroundFor centuries, Passiflora species have been used in folk medicine, especially as sedatives and anxiolytics, and in recent decades have been exploited by the food, pharmaceutical and cosmetics industries. Currently, the concentrated juice manufacture is the most impacting activity involving Passiflora spp., since its market is expanding worldwide. Such a wide-scale passion fruit processing inevitably ends up generating huge amounts of wastes (i.e., seeds, rinds and bagasse), as it corresponds to more than a half of the fruit mass.Scope and ApproachThe present review aims to summarize and evaluate the past decade findings related with nutritional composition, bioactive molecules and biotechnological applications of Passiflora spp., with special attention to the potentialities of its co-products.Key Findings and ConclusionsA series of emerging technologies firmed on non-thermal principals, along with encapsulation by nanoparticles methods, have been studied for the sustainable recovery of some target high added-value compounds from Passiflora spp. and their co-products, which include biologically active components such as polyphenols, terpenes, peptides, polysaccharides and dietary fibers. In addition, the passion fruit co-products are promising (and still underutilized) agents of bioconversion and bioremediation, besides low-cost functional ingredients for both cosmetic and food industry.     

Apple pomace liquefaction with pectinases and cellulases:analytical data of the corresponding juices

Apple juices were produced by way of a two-stage process consisting of traditional enzyme treatment of the mash with pectinases for the premium juices and pomace liquefaction with different pectinases and cellulases for the extraction juices. Premium and extraction juices were analysed separately. Calculated to an equal juice strength of 12° Brix, there was an increase of D-galacturonic acid and cellubiose in the extraction juices. Released galacturonic acid from cell wall material was found at levels ranging from 107 mg/l to 1239 mg/l. This was an essential contribution to the total titrable acid of the extraction juices. The sum of phenolic substances determined by high performance liquid chromatography was significantly higher in all the extraction juices than in the corresponding premium juices. Among the phenolics, the dihydrochalcone phloretin 2′-glucoside (92–110 mg/l) showed an increase of 4 to 5 times the concentration in the respective premium juices. Quercetin derivatives were mainly present in the extraction juices; here the values were between 32 mg/l and 38 mg/l. Under the influence of strong pectolytic or cellulolytic enzyme activities, oligo- and polysaccharides are released from the apple cell wall material, resulting in colloid concentrations of up to 15 g/l in the extraction juices. High concentrations of polyphenols and pectic polysaccharides can lead to technological problems. However, pomace liquefaction may also turn out to be suitable for obtaining value-added foods. In respect to nutritional aspects, enzymatic treatment of pomace offers the opportunity of releasing apple polyphenols and polysaccharides contained in the pomace to a greater extent and obtaining them preparatively. Received: 2 December 1999     

Reactivity of flavanols: Their fate in physical food processing and recent advances in their analysis by depolymerization

Flavanols, a subgroup of polyphenols, are secondary metabolites with antioxidant properties naturally produced in various plants (e.g., green tea, cocoa, grapes, and apples); they are a major polyphenol class in human foods and beverages, and have recognized effect on maintaining human health. Therefore, it is necessary to evaluate their changes (i.e., oxidation, polymerization, degradation, and epimerization) during various physical processing (i.e., heating, drying, mechanical shearing, high-pressure, ultrasound, and radiation) to improve the nutritional value of food products. However, the roles of flavanols, in particular for their polymerized forms, are often underestimated, for a large part because of analytical challenges: they are difficult to extract quantitatively, and their quantification demands chemical reactions. This review examines the existing data on the effects of different physical processing techniques on the content of flavanols and highlights the changes in epimerization and degree of polymerization, as well as some of the latest acidolysis methods for proanthocyanidin characterization and quantification. More and more evidence show that physical processing can affect content but also modify the structure of flavanols by promoting a series of internal reactions. The most important reactivity of flavanols in processing includes oxidative coupling and rearrangements, chain cleavage, structural rearrangements (e.g., polymerization, degradation, and epimerization), and addition to other macromolecules, that is, proteins and polysaccharides. Some acidolysis methods for the analysis of polymeric proanthocyanidins have been updated, which has contributed to complete analysis of proanthocyanidin structures in particular regarding their proportion of A-type proanthocyanidins and their degree of polymerization in various plants. However, future research is also needed to better extract and characterize high-polymer proanthocyanidins, whether in their native or modified forms.     

微生物多糖的结构与应用研究进展

微生物多糖是一类具有抗氧化、抗肿瘤、免疫调节等多种生物活性的天然聚合物,已受到众多学者的关注与研究。微生物胞外多糖如结冷胶、黄原胶等性状优良,易于生产,已被广泛应用于农业、医药、食品等领域。微生物胞壁多糖中脂多糖和肽聚糖存在多种潜在功能,具有可观的开发与利用价值。该文对常见微生物多糖的结构性质与应用现状进行总结,并探讨微生物多糖研究的发展方向。     

Influence of factors on release of antimicrobials from antimicrobial packaging materials

Antimicrobial packaging materials (films or coatings) (APMs) have aroused great interest among the scientists or the experts specialized in material science, food science, packaging engineering, biology and chemistry. APMs have been used to package the food, such as dairy products, poultry, meat (e.g., beef), salmon muscle, pastry dough, fresh pasta, bakery products, fruits, vegetables and beverages. Some materials have been already commercialized. The ability of APMs to extend the shelf-life of the food depends on the release rate of the antimicrobials (AMs) from the materials to the food. The optimum rate is defined as target release rate (TRR). To achieve TRR, the influencing factors of the release rate should be considered. Herein we reviewed for the first time these factors and their influence on the release. These factors mainly include the AMs, food (or food simulant), packaging materials, the interactions among them, the temperature and environmental relative humidity (RH).     

Effects of composition and processing variables on the oxidative stability of protein-based and oil-in-water food emulsions

Because many common foods are emulsions (mayonnaise, coffee creamers, salad dressing, etc.), a better understanding of lipid oxidation mechanisms in these systems is crucial for the formulation, production, and storage of the relevant consumer products. A research body has focused on the microstructural and oxidative stability of protein-stabilized oil-in-water emulsions that are structurally similar to innovative products that have been recently developed by the food industry (e.g., non-dairy creams, vegetable fat spreads, etc.) This review presents recent findings about the factors that determine the development of lipid oxidation in emulsions where proteins constitute the stabilizing interface. Emphasis is given to “endogenous” factors, such as those of compositional (e.g., protein/lipid phases, pH, presence of transition metals) or processing (e.g., temperature, droplet size) nature. Improved knowledge of the conditions that favor the oxidative protection of protein in emulsions can lead to their optimized use as food ingredients and thereby improve the organoleptic and nutritional value of the related products.     

食品基质及加工方式对多酚生物利用度影响的研究进展

酚类化合物是植物性食品中的重要成分,具有多种功能活性,但因其生物利用度低,不能在体内完全发挥其生物活性。因此寻找到一条有效的途径来提高其生物利用率非常必要。本文综述了多糖、蛋白质、脂质三种食品基质及不同加工方式对多酚生物利用度的影响,以期为食品加工中提高多酚生物利用度提供借鉴和思考。