Effects of added fruit polyphenols and pectin on the properties of finished breads revealed by HPLC/LC-MS and Size-Exclusion HPLC

Extracts with Nutritional Potential and Their Influence on the Rheological Properties of Dough and Quality Parameters of Bread

Formulating basic food to improve its nutritional profile is one potential method for food innovation. One option in formulating basic food such as bread is to supplement flours with specified amounts of non-bakery raw materials with high nutritional benefits. In the research presented here, we studied the influence of the addition of curcumin and quercetin extracts in amounts of 2.5% and 5% to wheat flour (2.5:97.5; 5:95). The analysis of the rheological properties of dough was carried out using a Mixolab 2. A Rheofermentometer F4 was used to assess the dough's fermentation, and a Volscan was used to evaluate the baking trials. The effect of the extracts on the rheological properties of dough was measured and found to be statistically significant, with curcumin shortening both dough development time and dough stability. Doughs made with greater quantities of extract had a greater tendency to early starch retrogradation, which negatively affects the shelf life of the end products. The addition of extracts did not significantly affect either the ability to form gas during fermentation or its retention, which is important because this gas is prerequisite to forming a final product with the required volume and porosity of crumb. Less favourable results were found on sensory evaluation, wherein the trial bread was significantly worse than the control wheat bread. The panel's decision-making might have been influenced by the atypical colour of the bread made with additives, and in case of a trial bread made with quercetin, by a bitter taste. From the technological point of view, the results confirmed that the composite flours prepared with the addition of extracts of curcumin and quercetin in amounts of 2.5% and 5% can be processed according to standard procedures. The final product will be bread with improved nutritional profile and specific sensory properties, specifically an unconventional and attractive colour.

Plant-Based Protein-Phenolic Interactions: Effect on different matrices and in vitro gastrointestinal digestion

This review summarizes the literature on the interaction between plant-based proteins and phenolics. The structure of the phenolic compound, the plant source of proteins, matrix properties (pH, temperature), and interaction mechanism (covalent and non-covalent) change the secondary structure, ζ-potential, surface hydrophobicity, and thermal stability of proteins as well as their functional properties including solubility, foaming, and emulsifying properties. Studies indicated that the foaming and emulsifying properties may be affected either positively or negatively according to the type and concentration of the phenolic compound. Protein digestibility, on the other hand, differs depending on (1) the phenolic concentration, (2) whether the food matrix is ​​solid or liquid, and (3) the state of the food-whether it is heat-treated or prepared as a mixture without heat treatment in the presence of phenolics. This review comprehensively covers the effects of protein-phenolic interactions on the structure and properties of proteins, including functional properties and digestibility both in model systems and real food matrix.

Changes in the Polyphenolic Profile and Antioxidant Activity of Wheat Bread after Incorporating Quinoa Flour

Quinoa is a trend and a promising functional food ingredient. Following previous research into the impact of incorporating quinoa flour on the polyphenol content and antioxidant activity of bread, this study aimed to bridge an existing gap about the qualitative and quantitative polyphenolic profiles of such bread. The UPLC-MS/MS analysis showed that quinoa bread, made with 25% quinoa flour of a black variety, presented more compounds than refined-wheat bread, and levels were remarkably higher in many cases. Consequently, the quinoa bread presented clearly improved polyphenolic content than the wheat bread (12.8-fold higher considering the sum of extractable and hydrolyzable polyphenols), as supported by greater antioxidant activity (around 3-fold). The predominant compounds in the extractable fraction of quinoa bread were p-hydroxybenzoic acid and quercetin (50- and 64-fold higher than in wheat bread, respectively) and rutin (not detected in wheat bread), while ferulic and sinapic acids were the most abundant compounds in the hydrolyzable fraction (7.6- and 13-fold higher than in wheat bread, respectively). The bread-making impact was estimated, and a different behavior for phenolic acids and flavonoids was observed. Extractable phenolic acids were the compounds that decreased the most; only 2 of 12 compounds were enhanced (p-hydroxybenozoic and rosmarinic acid with increments of 64% and 435%, respectively). Flavonoids were generally less affected, and their concentrations considerably rose after the bread-making process (7 of the 13 compounds were enhanced in the extractable fraction) with especially noticeably increases in some cases; e.g., apigenin (876%), kaempferol (1304%), luteolin (580%) and quercetin (4762%). Increments in some extractable flavonoids might be explained as a consequence of the release of the corresponding hydrolyzable forms. The present study provides new information on the suitability of quinoa-containing bread as a suitable vehicle to enhance polyphenols intake and, hence, the antioxidant activity in daily diets.

Effects of anthocyanins on bread microstructure, and their combined impact on starch digestibility

Several studies have confirmed the reduction of starch digestibility with anthocyanins in food systems via mechanisms of enzyme inhibition. However, starch-polyphenol interactions may also contribute to this reduction, by modifying food microstructures and physicochemical properties of starch. The interactions among anthocyanins, starch digestibility, and food microstructures are significant to clarify the digestion processes of fortified food systems, but its interrelationship lacks clarity. Hence, we aim to evaluate the effects of black rice anthocyanin extract (BRAE) incorporation on the microstructural changes of wheat bread, in relation to overall digestibility. Overall, BRAE incorporation demonstrated a dose-dependent reduction in starch digestibility. Physicochemical analyses reflected that BRAE incorporation decreased starch gelatinisation and increased crystallinity. Microscopic imaging revealed differentiating microstructural characteristics of starch and gluten with BRAE incorporation, supporting the reduction in digestibility. Our results conclusively demonstrate that BRAE incorporation in bread suppresses starch digestibility not only through enzyme inhibition, but also food microstructural modifications.

Changes in Antioxidant Properties and Amounts of Bioactive Compounds during Simulated In Vitro Digestion of Wheat Bread Enriched with Plant Extracts

Cereal preparation can be an excellent source of substances with proven health-promoting properties. Unfortunately, some types of bread, such as white flour bread, are devoid of many valuable nutrients. Therefore, it is necessary to look for ways to increase its density and nutritional value. The aim of the study was to investigate the effect of stabilized plant extracts on the quality of bread, its antioxidant activity and polyphenol content, and to evaluate the stability of bioactive compounds and antioxidant activity during in vitro digestion. The research material was the wheat bread baked with spray dried microcapsules of hawthorn bark, soybeans and onion husks in maltodextrin or inulin carriers. The addition of plant extracts resulted in the presence of phenolic compounds in the wheat bread, and its antioxidant activity significantly increased. There was no significant difference in antioxidant activity between breads containing microcapsules with different carriers. During in vitro digestion, procyanidins and isoflavones in bread were more resistant to the digestive processes than other compounds. The antioxidant activity during simulated digestion was the highest at the stage of gastric digestion, and its value depended on the extract used and the analytical method applied.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

High Protein Substitutes for Gluten in Gluten-Free Bread

Gluten-free products have come into the market in order to alleviate health problems such as celiac disease. In this review, recent advances in gluten-free bread are described along with plant-based gluten-free proteins. A comparison with animal-based gluten-free proteins is made reporting on different high protein sources of animal origin. Sea microorganisms- and insect-based proteins are also mentioned, and the optimization of the structure of gluten-free bread with added high protein sources is highlighted along with protein digestibility issues. The latter is an issue for consideration that can be manipulated by a careful design of the mixture in terms of phenolic compounds, soluble carbohydrates and fibres, but also the baking process itself. Additionally, the presence of enzymes and different hydrocolloids are key factors controlling quality features of the final product.

The effect of γ-[Glu](1≤n≤5)-Gln on the physicochemical characteristics of frozen dough and the quality of baked bread

This study was the first to examine the effects of γ-[Glu]_(1≤n≤5)-Gln (GGP, a taste enhancer; added at 0.5% or 5.0%) on the breadmaking using frozen dough. γ-[Glu]_(1≤n≤5)-Gln was produced using the method established in our research center. The addition of GGP at either level increased yeast viability, freezable water content and storage and loss moduli, decreased the free sulfhydryl content of dough during the frozen storage and freeze-thaw cycles, and improved the microstructure of frozen dough and texture of the baked bread. The addition of GGP at 0.5% led to a dough having the highest extensibility, and most complete and uniform starch-gluten network, and a baked bread crumb with the lowest hardness, best texture, and most uniform organization. These results indicated that GGP has great potential as a food-derived cryoprotectant/antifreeze agent for the baking industry.

The hepatoprotective effect of breads with extracts of plants growing in the Far East

Breads with proven hepatoprotective properties can make a significant contribution to preventing liver disease. This work aimed to study hepatoprotective and antioxidant effects of breads enriched with water and ethanol extracts of polyphenol-containing viburnum (Viburnum sargentii Koehne L.), magnolia-vine (Schisandra chinensis L.), and grapes (Vitis amurénsis L.). It was based on an experimental model of toxic hepatitis in mice intoxicated with carbon tetrachloride. Experimental groups of animals were fed on bread with extracts for 7 days and control groups had a bread-free diet. We analysed their body weight, liver lipid metabolism, “lipid peroxidation – antioxidant protection” system, and antiradical activity. The level of reduced glutathione and malonic dialdehyde was determined by micro-thin-layer chromatography. Superoxide dismutase, glutathione reductase, and glutathione peroxidase activity was measured to analyse the antioxidant system. The total content of common polyphenols in breads was determined by the colorimetric method with the Folin-Chocalteu reagent. The animals on a bread-free diet showed an impaired lipid metabolism and higher activity of liver enzymes. They had a 22% increase in liver weight and a 1.9 times depletion of antiradical protection (6.65 ± 0.15 Trolox units/mg protein vs. 13.15 ± 0.21 Trolox units/mg protein in the control; P < 0.001). We also registered a 2.5 times decrease in superoxide dismutase, a key enzyme of the antioxidant defence system. The animals fed on breads with the above extracts showed a statistically significant normalization of the parameters, compared to the bread-free group. We found that those breads had hepatoprotective and antioxidant effects on the animals, stabilizing their general condition and normalizing their biochemical parameters and antioxidant system.

Plant-Based Food By-Products: Prospects for Valorisation in Functional Bread Development

The industrial and small-scale processing of plant-based food materials is associated with by-products that may have a negative impact on the environment but could add value to bread-based products. The bioactivity of plant-based food by-products, their impact on the properties of functional bread, and their bioavailability/bioaccessibility leading to potential health effects when consumed was reviewed. Plant-based food by-products which may be added to bread include rice bran, wheat bran, corn bran, grape pomace/seed extract, tomato seed/skin, and artichoke stems/leaves. These by-products contain high concentrations of bioactive compounds, including phenolics, bioactive peptides, and arabinoxylan. Pre-treatment procedures, including fermentation and thermal processing, impact the properties of plant-based by-products. In most cases, bread formulated with flour from plant-based by-products demonstrated increased fibre and bioactive compound contents. In terms of the sensory and nutritional acceptability of bread, formulations with an average of 5% flour from plant-based by-products produced bread with acceptable sensory properties. Bread enriched with plant-based by-products demonstrated enhanced bioavailability and bioaccessibility and favourable bioactive properties in human blood, although long-term studies are warranted. There is a need to investigate the bioactive properties of other underutilised plant-based by-products and their potential application in bread as a sustainable approach towards improving food and nutrition security.

Enhancing the antioxidative effects of foods containing rutin and α-amino acids via the Maillard reaction: A model study focusing on rutin-lysine system

Rutin is a bioflavonoid found in many plants and derived foods, accordingly, rutin likely interacts with α-amino acids such as Lys, Ile, His or Glu to give Maillard reaction products (MRPs). The heated rutin-Lys system exhibited highest brown intensity and in vitro antioxidant activities. The 30-50 kDa rutin-Lys fraction had higher in vitro antioxidant activities than the other fractions, and at a dose of 0.4 mg/ml preserved over 90% cell viability for HepG2 cells exposed to H₂ O₂ . The dose-dependent protective effects against H₂ O₂ -induced oxidative stress of the rutin-Lys MRPs may involve the inhibition of reactive oxygen species generation, enhancement of the superoxide dismutase and catalase activities, along with the activation of the Nrf2-dependent pathway and upregulation of phase II antioxidant genes (including NQO1, HO-1, GCLG, and GCLM). PRACTICAL APPLICATIONS: Rutin is widely distributed in vegetables and grains. The Maillard reaction is a common reaction occurring during food processing, and produces Maillard reaction products (MRPs) with distinct processing and biological properties. This study shows that a 30-min thermal treatment at 120°C generates antioxidative MRPs in the rutin-Lys, rutin-His, rutin-Ile and rutin-Glu model systems, which can directly inhibit reactive oxygen species generation and enhance SOD and CAT activities while activating the Nrf2-dependent pathway and upregulating the expression of phase II detoxifying antioxidant genes. Therefore, for food systems containing phenolic antioxidants and proteins (such as rutin and Lys), one may enhance the antioxidant properties of these food systems through a 30-min thermal treatment at 120°C. Also, the resultant rutin-Lys MRPs may be isolated and used as commercial preparations of natural antioxidants.

RECENT ADVANCES IN STUDYING TANNIC ACID AND ITS INTERACTION WITH PROTEINS AND POLYSACCHARIDES

The purpose of this review was to gain a deeper understanding of tannic acid (TA) and its properties, which could be important for improving the technology of gluten-free food. TA is widely used in agriculture, food, medicine, and other fields due to its unique physiological functions (anti-tumor, anti-oxidation, antibacterial, anti-viral, etc.). It can closely interact with proteins and polysaccharides, which can significantly influence the structure, function, and nutritional properties of compounds. In this article, TA is chosen as a polyphenol model, and the structure of tannins and the degree of their extraction have been considered systematically. Prospective application of interaction between TA and common biological macromolecules have been presented. In this review, different classes of tannins are summarized. Advantages and disadvantages of different methods of extracting tannins have also been described. This review provides detailed information about the mechanisms of interaction of TA with biological macromolecules such as proteins and polysaccharides. Maize, buckwheat, rice flour and starch should be introduced as non-traditional raw materials in production of pasta for people ill with coeliac disease. Pasta dough from unconventional raw materials has non-standard rheological characteristics, and it is difficult to impart good plastic properties to it. That is why, studying the properties of tannins is necessary to improve the technology of gluten-free pasta. However, due to the different nature and composition of proteins, gluten-free foods do not have a network structure. So, they can hold neither water nor starch granules, their prepared dough is loose, with low viscosity, and is not easily moulded. That is why, the use of tannin to form a strong structure when developing a gluten-free pasta technology has become the main purpose of the research. Some potential problems of gluten-free dough processing can be solved by using new technical means. In view of this, the authors put forward the idea of using TА to form cross-links and a strong gluten-free dough structure.

Effect of Degree of Konjac Glucomannan Enzymatic Hydrolysis on the Physicochemical Characteristic of Gluten and Dough

Influences of different enzymatic hydrolysis degrees of konjac glucomannan (KGM) with various addition proportions on the structural characteristic of gluten protein and dough properties were evaluated. Results revealed that addition of KGM decreases the free sulfhydryl and freezable water content of dough, and KGM with different enzymatic hydrolysis degrees had more beneficial effects on strengthening the gluten structure by the raised molecular weight of gluten proteins and the increased disulfide bonds and β-sheet content, especially KGM with 15 min enzymatic hydrolysis treatment (KGM II). Besides, microstructure observation and thermal analysis results illustrated that addition of KGM promotes gluten cross-linking and improves the thermal stability of the gluten network structure. Dough possessed better elasticity, as well as tensile and texture properties with the addition of KGM than the control sample. And the KGM with 15 min enzymatic hydrolysis showed the most positive effect on dough quality than others, and 2.0% addition proportion is the most acceptable.

A Critical Review of the Characterization of Polyphenol-Protein Interactions and of Their Potential Use for Improving Food Quality

BACKGROUND

Interest in protein-phenol interactions in biological systems has grown substantially in recent decades.

METHODS

The interest has focused largely on food systems in response to reports on the prominent roles of phenolic compounds in nutrition and health.

RESULTS

Phenolic compounds can have both favourable and adverse nutritional effects. Polyphenols are widely known for their antioxidant, anti-inflammatory, anticancer and antiaging properties; however, they have also been ascribed anti-nutritional effects resulting from interactions with some proteins and enzymes. Interactions between proteins and polyphenols can additionally influence food quality by altering some physical-chemical and sensory properties of foods. These effects may be useful to develop new products in food science and technology provided the nature of physical-chemical interactions between proteins and phenols is accurately elucidated. In this paper, we review the different possible modes of interaction between selected food proteins and phenolic compounds.

CONCLUSION

Existing knowledge on the mechanisms behind polyphenol-protein reactions, the structures of the resulting products and their potential uses is reviewed.

Physicochemical stability and antioxidant activity of soy protein/pectin/tea polyphenol ternary nanoparticles obtained by photocatalysis

The ternary nanoparticles were fabricated by soy protein, pectin and tea polyphenol through photocatalysis. The particulate characteristics, including particle size, polydispersity index, and zeta potential were monitored for ternary nanoparticles formed under different photocatalysis time. Photocatalysis was favorable to form ternary nanoparticles with moderate particle size (310-370 nm), uniform distribution, spherical shape, and improved antioxidant activity. It was found that the fluorescence intensity of soy protein decreased with the increase in photocatalysis time in the ternary nanoparticles. Far-UV circular dichroism results indicated that increasing photocatalysis time could alter the secondary structure of soy protein with an increase in the proportion of β-sheet and β-turn structure at the cost of unordered coil and α-helix structure. According to FT-IR results, photocatalysis time could also modulate the conjugation between pectin and soy protein. In addition, photocatalysis could increase the binding affinities among the components, leading to better environmental stability of the ternary nanoparticles. The ternary nanoparticles in this study could be used as a good alternative to understand and consequently improve the physicochemical stability in food, pharmaceutical, and cosmetic matrices.

Transglutaminase-set colloidal properties of wheat gluten with ultrasound pretreatments

The low solubility of wheat gluten limits its accessibility. This work aimed to study the impact of ultrasonic pretreatments on the gelation of wheat gluten. The pretreatments included ultrasound combined with alkali, urea, Na₂SO₃, with or without the addition of transglutaminase (TGase). The gel strength of wheat gluten was 287g/cm² after treatment with Na₂SO₃/ultrasound/TGase. The free sulfhydryl and disulfide bond content was significantly affected by ultrasound treatment. After treatments including TGase crosslinking, the molecular weight of wheat gluten complexes became larger. The network formed by the wheat gluten was transformed into a dense and homogenous structure after the pretreatment with Na₂SO₃/ultrasound/TGase. The content of random coil of wheat gluten increased. The gelation of wheat gluten could also be significantly enhanced by Na₂SO₃/ultrasound treatment followed by TGase treatment. Using physical and chemical pretreatments to allow TGase to enhance the gelation of wheat gluten may increase its uses as a food additive.

Fabrication mechanism and structural characteristics of the ternary aggregates by lactoferrin, pectin, and (-)-epigallocatechin gallate using multispectroscopic methods

The ternary aggregates were fabricated by lactoferrin (LF), pectin (high methylated pectin (HMP)/low methylated pectin (LMP)), and (-)-epigallocatechin gallate (EGCG) through three different fabrication methods at pH 5.0. The turbidity, particle size, and ζ-potential of ternary aggregates were influenced by the types of pectin, the concentration of EGCG, and fabrication methods. The fluorescence intensity of LF decreased with an increase in EGCG concentration for all ternary aggregates. Far-UV circular dichroism results indicated that EGCG could alter the secondary structure of LF with an increase in the proportion of β-sheet structure at the cost of unordered coil structure. According to near-UV circular dichroism results, EGCG could also modulate the tertiary structure of LF at the presence of pectin. In addition, EGCG could increase the viscoelasticity of the ternary aggregates with HMP, leading to better stability of the ternary aggregates. An opposite result was observed for the ternary aggregates with LMP. These findings should provide an insight into the fabrication mechanism and applications of ternary aggregates formed by protein, polysaccharide, and polyphenol in the food, pharmaceutical, and cosmetic industries.

Nature and consequences of non-covalent interactions between flavonoids and macronutrients in foods

Many of the potential health benefits of flavonoids have been associated with their specific chemical and biological properties including their ability to interact and bind non-covalently to macronutrients in foods. While flavonoid-protein interactions and binding have been the subject of intensive study, significantly less is understood about non-covalent interactions with carbohydrates and lipids. These interactions with macronutrients are likely to impact both the flavonoid properties in foods, such as their radical scavenging activity, and the food or beverage matrix itself, including their taste, texture and other sensorial properties. Overall, non-covalent binding of flavonoids with macronutrients is primarily driven by van der Waals interactions. From the flavonoid perspective, these interactions are modulated by characteristics such as degree of polymerization, molecular flexibility, number of external hydroxyl groups, or number of terminal galloyl groups. From the macronutrient standpoint, electrostatic and ionic interactions are generally predominant with carbohydrates, while hydrophobic interactions are generally predominant with lipids and mainly limited to interactions with flavonols. All of these interactions are involved in flavonoid-protein interactions. While primarily associated with undesirable characteristics in foods and beverages, such as astringency, negative impact on macronutrient digestibility and hazing, more recent efforts have attempted to leverage these interactions to develop controlled delivery systems or strategies to enhance flavonoids bioavailability. This paper aims at reviewing the fundamental bases for non-covalent interactions, their occurrence in food and beverage systems and their impact on the physico-chemical, organoleptic and some nutritional properties of food.

Effect of new synthetic PEGylated ferulic acids in comparison with ferulic acid and commercial surfactants on the properties of wheat flour dough and bread

BACKGROUND

Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g mol(-1)) was studied in bread-making. The effects of these antioxidants on the properties of wheat flour dough and bread were analysed and compared with those obtained with ferulic acid and two commercial surfactants, the diacetyl tartaric acid ester of mono- and diglycerides and sodium stearoyl lactylate. Farinographic and alveographic methods as well as weight, volume and bread firmness measurements were used for this purpose.

RESULTS

Similar to ferulic acid, when the PEGylated derivatives were implemented in the dough (5000 ppm), it accelerated the breakdown of the dough and decreased its rheological properties. However, the important diminution of loaf volume, observed when dough supplemented with ferulic acid was baked, was avoided. That decrease in volume was related to the inhibition of the yeast (Saccharomyces cerevisae) by the unesterified ferulic acid. Moreover, two of the PEGylated ferulic acids even contributed to an increase of loaf volumes (5-6%) and demonstrated crumb softener properties.

CONCLUSION

The addition of ferulic acid to wheat flour dough caused the inhibition of the yeast, which resulted in decreased bread volume. That effect could be avoid by the esterification of ferulic acid with poly(ethylene glycol).