Wheat starch structure–function relationship in breadmaking: A review

Bread dough and bread are dispersed systems consisting of starch polymers that interact with other flour components and added ingredients during processing. In addition to gluten proteins, starch impacts the quality characteristics of the final baked product. Wheat starch consists of amylose and amylopectin organized into alternating semicrystalline and amorphous layers in granules that vary in size and are embedded in the endosperm protein matrix. Investigation of the molecular movement of protons in the dough system provides a comprehensive insight into granular swelling and amylose leaching. Starch interacts with water, proteins, amylase, lipids, yeast, and salt during various stages of breadmaking. As a result, the starch polymers within the produced crumb and crust, together with the rate of retrogradation and staling due to structural reorganization, moisture migration, storage temperature, and relative humidity determines the final product's textural perception. This review aims to provide insight into wheat starch composition and functionality and critically review recently published research results with reference to starch structure–function relationship and factors affecting it during dough formation, fermentation, baking, cooling, and storage of bread.     

Functional implications of bound phenolic compounds and phenolics–food interaction: A review

Sizeable scientific evidence indicates the health benefits related to phenolic compounds and dietary fiber. Various phenolic compounds-rich foods or ingredients are also rich in dietary fiber, and these two health components may interrelate via noncovalent (reversible) and covalent (mostly irreversible) interactions. Notwithstanding, these interactions are responsible for the carrier effect ascribed to fiber toward the digestive system and can modulate the bioaccessibility of phenolics, thus shaping health-promoting effects in vivo. On this basis, the present review focuses on the nature, occurrence, and implications of the interactions between phenolics and food components. Covalent and noncovalent interactions are presented, their occurrence discussed, and the effect of food processing introduced. Once reaching the large intestine, fiber-bound phenolics undergo an intense transformation by the microbial community therein, encompassing reactions such as deglycosylation, dehydroxylation, α- and β-oxidation, dehydrogenation, demethylation, decarboxylation, C-ring fission, and cleavage to lower molecular weight phenolics. Comparatively less information is still available on the consequences on gut microbiota. So far, the very most of the information on the ability of bound phenolics to modulate gut microbiota relates to in vitro models and single strains in culture medium. Despite offering promising information, such models provide limited information about the effect on gut microbes, and future research is deemed in this field.     

Production,structure–function relationships,mechanisms, and applications of antifreeze peptides

Growth of ice crystals can cause serious problems, such as frozen products deterioration, road damage, energy losses, and safety risks of human beings. Antifreeze peptides (AFPs), a healthy and effective cryoprotectant, have great potential as ice crystal growth inhibitors for a variety of frozen products. In this review, methods and technologies for the production, purification, evaluation, and characterization of AFPs are comprehensively summarized. First, this review describes the preparation of AFPs, including the methods of enzymatic hydrolysis, chemical synthesis, and microbial fermentation. Next, this review introduces the major methods by which to evaluate AFPs’ antifreeze activity, including nanoliter osmometer, differential scanning calorimetry, splat-cooling, the biovaluation model, and novel technology. Moreover, this review presents an overview of the molecular characteristics, structure–function relationships, and action mechanisms of AFPs. Furthermore, advances in the application of AFPs to frozen food, including frozen dough, meat products, fruits, vegetable products, and dairy, are summarized and holistically analyzed. Finally, challenges of AFPs and future perspectives on their use are also discussed. An understanding of the production, structure–function relationships, mechanisms and applications of AFPs provides inspiration for further research into the use of AFPs in food science and food nutrition applications.     

A comprehensive review on polarity,partitioning, and interactions of phenolic antioxidants at oil–water interface of food emulsions

There has been a growing interest in developing effective strategies to inhibit lipid oxidation in emulsified food products by utilization of natural phenolic antioxidants owing to their growing popularity over the past decades. However, due to the complexity of emulsified systems, the inhibition mechanism of phenolic antioxidants against lipid oxidation is rather complicated and not yet fully understood. In order to highlight the importance of polarity of phenolic antioxidants in emulsified systems according to the polar paradox, this review covers the recent progress on chemical, enzymatic, and chemoenzymatic lipophilization techniques used to modify the polarity of antioxidants. The partitioning behavior of phenolic antioxidants at the oil–water interface, which can be influenced by the presence of synthetic surfactants and/or antioxidant emulsifiers (e.g., polysaccharides, proteins, and phospholipids), is discussed. In addition, the emerging phenolic antioxidants among phenolic acids, flavonoids, tocopherols, and stilbenes applied in food emulsions are elaborated. As well, the interactions of polar–nonpolar antioxidants are stressed as a promising strategy to induce synergistic interactions at oil–water interface for improved oxidative stability of emulsions.     

Preparation and potential applications of casein–polysaccharide conjugates: a review

Glycation of casein and caseinates with polysaccharides via Maillard reaction is a simple and environmentally safe way to prepare new food ingredients of improved functional properties. Sodium caseinate has been used mainly to prepare conjugates with several polysaccharides particularly maltodextrins and dextrans. The functional properties of these conjugates are influenced by the used polysaccharides and heating conditions. Under optimal heating conditions substantial improvements have been evident in their emulsification and foam properties of these conjugates. Casein–polysaccharide conjugates have several potential applications in food processing and microencapsulation. This article gives an overview on their formation and potential uses. © 2019 Society of Chemical Industry     

Rheological properties and structure of inulin–whey protein gels

The rheological properties, structure and synergistic interactions of whey proteins (1–7%) and inulin (20% and 35%) were studied. Gelation of whey proteins was induced with Na⁺. Inulin was dissolved in preheated whey protein solutions (80 °C, 30 min). Inulin gel formation was strongly affected by whey proteins. The presence of whey proteins at a level allowing for protein gel network formation (7%) significantly increased the G′ and G″ values of the gels. Scanning electron micrographs showed a thick structure for the mixed gel. Whey proteins at low concentrations (1–4%) were not able to form a gel; further, these low concentrations partly or wholly impaired formation of a firm inulin gel. Although interactions between inulin and whey proteins may be concluded from hydrophobicity measurements, the use of an electrophoretic technique did not show any inulin–whey protein complexes.     

Invited review: A systematic review of the effects of prolonged cow–calf contact on behavior,welfare, and productivity

Separation of calves from cows within hours or days of birth is common on dairy farms. Stakeholders have conflicting perspectives on whether this practice is harmful or beneficial for the animals' welfare and production. Our objective was to critically evaluate the scientific evidence for both acute and long-term effects of early separation versus an extended period of cow–calf contact. The outcomes investigated were the behavior, welfare (excluding physical health), and performance (milk yield and growth, respectively) of dairy cows and calves. Primary research papers were found through targeted Web of Science searches, the reference lists of recent reviews for each topic, and the reference lists of papers identified from these sources. Studies were included if they were published in English, the full text was accessible, and they compared treatments with and without contact between dairy cows and calves for a specified period. Early separation (within 24 h postpartum) was found to reduce acute distress responses of cows and calves. However, longer cow–calf contact typically had positive longer-term effects on calves, promoting more normal social behavior, reducing abnormal behavior, and sometimes reducing responses to stressors. In terms of productivity, allowing cows to nurse calves generally decreased the volume of milk available for sale during the nursing period, but we found no consistent evidence of reduced milk production over a longer period. Allowing a prolonged period of nursing increased calf weight gains during the milk-feeding period. In summary, extended cow–calf contact aggravates the acute distress responses and reduces the amount of saleable milk while the calves are suckling, but it can have positive effects on behaviors relevant to welfare in the longer term and benefit calf growth. The strength of these conclusions is limited, however, given that relatively few studies address most of these effects and that experimental design including timing of contact and observations are often inconsistent across studies. Few studies presented indicators of long-term welfare effects other than abnormal and social behavior of the calves.     

Food proteins: A review on their emulsifying properties using a structure–function approach

Proteins are of great interest due to their amphiphilic nature, which allows them to reduce the interfacial tension at the oil–water interface. The incorporation of proteins at the oil–water interface has allowed scientists to utilise them to form emulsions (O/W or W/O), which may be used in food formulations, drug and nutrient delivery. The systematic study of the proteins at the interface and the factors that affect their stability (i.e., conformation, pH, solvent conditions, and thermal treatment) has allowed for a broader use of these emulsions tailored for various applications. In this review, the factors affecting the stability of emulsions using food proteins will be discussed. The use of polysaccharides to complex with proteins will also be explored in relation to enhancing emulsion stability.     

Formation and functionality of whey protein isolate–(kappa-, iota-, and lambda-type) carrageenan electrostatic complexes

The formation of electrostatic complexes between whey protein isolate (WPI) and (κ-, ι-, λ-type) carrageenan (CG) was investigated by turbidimetric measurements as a function of pH (1.5–7.0), biopolymer weight-mixing ratio (1:1–75:1 WPI:CG) and NaCl addition (0–500 mM) to better elucidate underlying mechanisms of interaction. Emulsion stabilizing effects of formed complexes was also studied to assess their potential as emulsifiers. Complex formation followed two pH-dependent structure-forming events associated with the formation of soluble (pH_c) and insoluble (pH_?1) complexes. For both the WPI–κ-CG and WPI–ι-CG mixtures, pH_c and pH_?1 occurred at pH 5.5 and 5.3, respectively, whereas in the WPI–λ-CG mixture values were slightly higher (pH_c = 5.7; pH_?1 = 5.5). In all mixtures, maximum turbidity was found to occur near pH 4.5, before declining at lower pHs. Biopolymer mixing ratios corresponding to maximum OD was found to occur at the 12:1 ratio for both the WPI–κ-CG and WPI–λ-CG mixtures, and 20:1 ratio for WPI–ι-CG mixture. The addition of NaCl disrupted complexation within WPI–κ-CG mixtures as levels were raised, whereas when ι-CG and λ-CG was present, complexation was enhanced up to a critical Na⁺ concentration before declining. Adsorption of CG chains to the small WPI–WPI aggregates during complexation was proposed to be related to both the linear charge density and conformation of the CG molecules involved. Emulsion stability in the mixed systems (12:1 mixing ratio), regardless of the CG type (κ, ι, λ), was significantly higher than individual WPI solutions indicating enhanced ability to stabilize the oil-in-water interface.     

Structure,stability, rheology,and texture properties of ε-polylysine-whey protein complexes

ε-Polylysine (ε-PL) is a natural preservative of antimicrobial peptides with broad spectrum and high antibacterial properties. The electrostatic complex delivery system formed by ε-PL and whey protein can be used to maintain the stability of ε-PL and solve the problem of limited application of protein-based food. This work aimed to study the interaction between ε-PL and whey protein by multiple characterization methods. The spectroscopy results showed static quenching type and new stretching of C=O for ε-PL–whey protein complexes. Microstructure studies showed that the combination of ε-PL and whey protein made the structure of the complexes become rough and dense. The interaction between ε-PL and whey protein could improve the stability of the complexes system during storage. Additionally, the interaction affected critical gel temperatures and gel texture properties of complexes with change of whey protein concentration, mass ratio of ε-PL to whey protein, pH value in alkaline solutions, and ion concentration. Overall, this study confirmed the interaction between ε-PL and whey protein, and it will provide a reference for the application of ε-PL in protein food matrix.     

Glucose,fructose and sucrose increase the solubility of protein–tannin complexes and at high concentration,glucose and sucrose interfere with bisulphite bleaching of wine pigments

Wines were modified with increasing sugar concentrations and decreasing tannin concentrations and analysed by a combination of protein precipitation and bisulphite bleaching. Increasing sugar concentration decreased the precipitation of tannin and protein-precipitable polymeric pigments (PPP). The use of a hydrogen bond disruptor (urea) to reduce protein–tannin and protein–pigment complex formation showed that the effect of sugar concentration occurred by increasing the solubility of the tannin–protein complex, not by interfering with protein–tannin complex formation. By increasing the solubility of pigment–protein complexes, non-protein-precipitable polymeric pigments (nPPP) appeared to increase. There was also an increase in total polymeric pigments at each tannin concentration with increasing glucose and sucrose concentration, indicating that sugar concentration might also affect bisulphite bleaching of wine pigments. While a significant effect of sugar concentration on tannin–protein complex solubility was observed, these effects were greatest at sugar concentrations far in excess of normal wine making conditions. Under normal wine making conditions, sugar concentration will have a negligible effect on protein-precipitable tannin, PPP and nPPP concentrations.     

Is air-drying of plant-based food at low temperature really favorable? A meta-analytical approach to ascorbic acid,total phenolic,and total flavonoid contents

The aim of this work was to review the studies that evaluated the effect of drying temperature on the content of ascorbic acid (AA), total phenolic (TPC), and total flavonoid contents (TFC) in fruits and vegetables, and quantify whether drying at 40 °C is more favorable than at higher temperatures. For the purpose of this study, AA, TPC, and TFC values for 40 °C were compared with those obtained at 50 °C, 60 °C, and 70–80 °C. A meta-analysis was performed using the weighted response ratio calculated for each experiment. Despite the fact that other variables significantly influenced the nutrient content in individual experiments, the meta-analysis provided a general view on the effect of air-drying temperature on the quality of plant-based food products from outcomes of various studies.     

Effect of pH on the functional behaviour of pea protein isolate–gum Arabic complexes

The functional behaviour (solubility, emulsifying and foaming properties) of pea protein isolate (PPI) and gum Arabic (GA) mixtures were investigated as a function of pH (4.30–2.40) within a region dominated by complex coacervation. Emulsion stability was also investigated using a one- and two-step emulsification approach. Complex coacervation was monitored by turbidimetric acid titration at a 2:1 PPI–GA ratio to reveal the formation of soluble (pH 4.23) and insoluble (pH 3.77) complexes, maximum biopolymer interactions (pH 3.60), and dissolution of complexes (pH 2.62). Emulsion stability was greater for mixed systems relative to PPI alone at pHs between 3.10 and 4.00, and in those prepared using the one-step method. Foam expansion was independent of both biopolymer content and pH, whereas foam stability was improved for the mixed system between pH 3.10 and 4.00. The pH-solubility minimum was broadened relative to PPI to more acidic pHs. Findings suggest that admixtures of PPI and GA under complexing conditions could represent a new blended food and/or biomaterial ingredient.     

Use of ultrasounds in the food industry–Methods and effects on quality,safety, and organoleptic characteristics of foods: A review

The use of ultrasounds has recently gained significant interest in the food industry mainly due to the new trends of consumers toward functional foods. Offering several advantages, this form of energy can be applied for the improvement of qualitative characteristics of high-quality foods as well as for assuring safety of a vast variety of foodstuffs, and at the same time minimizing any negative effects of the sensory characteristics of foods. Furthermore, the non-destructive nature of this technology offers several opportunities for the compositional analysis of foods. However, further research is required for the improvement of related techniques and the reduction of application costs in order to render this technology efficient for industrial use. This review paper covers the main applications of ultrasounds as well as several advantages of the use of the technology in combination with conventional techniques. The effects of ultrasounds on the characteristics, microbial safety, and quality of several foods are also detailed     

Influence of ligand structure and water interactions on the physical properties of β-cyclodextrins complexes

The water sorption and physical properties of freeze-dried β-cyclodextrin (BCD) and 2-hydroxypropyl-β-cyclodextrin (HBCD) were studied. The stability of the inclusion complexes of these cyclodextrins with different hydrophobic ingredients, such as myristic acid and α-terpineol, was investigated as a function of the storage time and water content of the systems. Besides increasing its solubility, BCD ring modification with hydroxypropyl groups conferred amorficity to the dehydrated matrices, and modified the sorption properties and their ability to form hydrates.