Interaction of hydroxypropylmethylcellulose with gluten proteins: Small deformation properties during thermal treatment

Effects of wheat starch content on its flour and frozen dough bread

The refined wheat flour was mixed with different types of wheat starch in different addition levels, their microstructure, chemical bonds in the dough and baking characteristics of 0-8 weeks frozen dough bread were studied. With the increase of A-Type starch granules and whole wheat starch, the pores of gluten network first decreased and then increased. Conversely, an increase in B-Type starch granules consistently reduced gluten network porosity. With the increase of whole wheat starch, the content of free sulfhydryl group and hydrophobic interaction decreased gradually. Minimal additions of B-Type granules were found to enhance the specific volume of fresh bread, whereas increased quantities improved the specific volume of frozen dough bread. The addition of a small quantity of A- or B-Type granules enhances the freezing stability of bread. This study provides effective information for elucidating the effects of wheat starch on the frozen dough and bread properties in protein-starch matrix.

Enhancing Gluten-Free Bread Production: Impact of Hydroxypropyl Methylcellulose, Psyllium Husk Fiber, and Xanthan Gum on Dough Characteristics and Bread Quality

The demand for gluten-free products has increased due to improved diagnoses and awareness of gluten-related issues. This study investigated the effect of HPMC, psyllium, and xanthan gum in gluten-free bread formulations. Three tests were conducted, varying the amount of these ingredients: in the first formulation, the amount of HPMC was increased to 4.4 g/100 g of flour and starch; in the second, psyllium husk fiber was increased to 13.2 g/100 g of flour and starch; and in the third formulation, xanthan gum was removed. Differences were observed among the formulations: increasing HPMC reduced extrusion force without affecting bread quality; adding psyllium increased dough elasticity but also crumb gumminess and crust hardness. Eliminating xanthan gum altered dough rheology, resulting in a softer and less gummy crumb, and a less reddish color in the final bread.

Development of Oleogel-Based Fat Replacer and Its Application in Pan Bread Making

In recent years, the bakery industry has been exploring alternative fats to replace traditional solid fats. Shortening, a common baking ingredient, is produced through the hydrogenation of vegetable oils, resulting in high levels of saturated and trans fatty acids, despite its vegetable oil origin. The excessive consumption of these fats has been associated with negative health effects, including dyslipidemia and cardiovascular issues. Oleogels, incorporating hydroxypropyl methylcellulose (HPMC), xanthan gum (XG), and olive oil, were utilized to replace shortening in the production of white pan bread. The substitution of shortening with oleogel in the white pan bread preparation demonstrated potential reductions in saturated fat, trans fat, and the ratio of saturated fat to unsaturated fatty acids. Specifically, with the complete substitution of shortening with oleogel, saturated fatty acids decreased by 52.46% and trans fatty acids by 75.72%, with unsaturated fatty acids increasing by 57.18%. Our findings revealed no significant difference in volume between bread made with shortening and bread with up to 50% shortening substitution. Moreover, when compared to bread made with shortening and 50% oleogel substitution, no adverse effects on the quality characteristics of volume and expansion properties were observed, and the retrogradation rate was delayed. This study suggests that incorporating oleogels, formed with hydrocolloids such as HPMC and XG, to replace shortening in bread, in conjunction with traditional solid fats, provides positive effects on the quality and nutritional aspects of the bread compared to using oleogel alone. Through this study, we demonstrate the use of oleogels as a healthier alternative to shortening, without reducing the bread's quality, thus offering a practical solution to reduce unhealthy fats in bakery products.

Improvement on wheat bread quality by in situ produced dextran-A comprehensive review from the viewpoint of starch and gluten

Deterioration of bread quality, characterized by the staling of bread crumb, the softening of bread crust and the loss of aroma, has caused a huge food waste and economic loss, which is a bottleneck restriction to the development of the breadmaking industry. Various bread improvers have been widely used to alleviate the issue. However, it is noteworthy that the sourdough technology has emerged as a pivotal factor in this regard. In sourdough, the metabolic breakdown of carbohydrates, proteins, and lipids leads to the production of exopolysaccharides, organic acids, aroma compounds, or prebiotics, which contributes to the preeminent ability of sourdough to enhance bread attributes. Moreover, sourdough exhibits a "green-label" feature, which satisfies the consumers' increasing demand for additive-free food products. In the past two decades, there has been a significant focus on sourdough with in situ produced dextran due to its exceptional performance. In this review, the behaviors of bread crucial compositions (i.e., starch and gluten) during dough mixing, proofing, baking and bread storing, as well as alterations induced by the acidic environment and the presence of dextran are systemically summarized. From the viewpoint of starch and gluten, results obtained confirm the synergistic amelioration on bread quality by the coadministration of acidity and dextran, and also highlight the central role of acidification. This review contributes to establishing a theoretical foundation for more effectively enhancing the quality of wheat breads through the application of in situ produced dextran.

Effect of starch granule size on the properties of dough and the oil absorption of fried potato crisps

Starch is a key element in fried potato crisps, however, the effect of starch granule size on oil absorption of the product have yet to be fully investigated. The study explored the impact of starch granule size on both the dough characteristics and oil absorption in potato crisps. The dough composed of small-sized potato granules showed more compact and uniform network system. Additionally, X-ray Microscope analysis showed that potato crisps prepared with small-sized potato granules had limited matrix expansion and fewer pores, cracks, and voids. The small-sized potato and small-sized wheat starches granule addition crisps displayed a significantly greater average cell thickness (52.05 and 53.44 μm) than other samples, while exhibiting notably lower average porosity (61.37 % and 60.28 %) compared to other samples. Results revealed that potato crisps with medium and small potato granules had 12.91 % and 21.92 % lower oil content than those containing large potato starch. Potato crisps with B-type wheat starch showed 16.36 % less oil absorption than those with A-type wheat starch. Small-sized starches significantly influence the dough structure and contribute to the reduction of oil absorption in fried products. The generated insights may provide monitoring indexes for cultivating potato varieties with low oil absorption.

Heat-triggered shape recovery, EMI shielding and flame retardant: A novel cellulose/M(OH)(OCH3)@dopamine@Ag (M=Co, Ni) nanopaper for early fire alarm

Fire alarm systems are essential for protecting lives and properties from fire hazards. However, most of the existing fire alarm nanopapers rely on the resistance reduction after heating, which requires direct contact with the flame. In this study, we present a novel fire alarm nanopaper (CMPA) based on heat-triggered shape recovery. The CMPA is composed of hydroxypropyl methyl cellulose (HPMC) as the matrix and 2D nanomaterials M(OH)(OCH3) as fillers. When the temperature of CMPA exceeded the glass transition, the thrice-folded CMPA-1.0 flattened in 30s and connected to the alarm circuit based on its conductive surface. According to the results, the CMPA-1.0 with a thickness of about 0.2 mm had an efficient electromagnetic shielding of 42.1 dB. Moreover, the CMPA-1.0 self-extinguished rapidly after being ignited with its original shape preserved. The peak heat release rate of CMPA-1.0 was 108.9 W/g, which was 61.9 % lower than that of HPMC. Furthermore, the thermal conductivity of CMPA-1.0 reached to 0.317 W m-1 K-1, which was 40.8 % higher than that of HPMC, reducing the heat accumulation effectively. This work shows that CMPA is an ideal material for sensitive and safe early fire alarm, and the strategy based on heat-triggered shape recovery is promising in fire alarm application.

Effect of Damaged Starch and Wheat-Bran Arabinoxylans on Wheat Starch and Wheat Starch-Gluten Systems

This study investigated the impact of damaged starch and arabinoxylans on the thermal and pasting behavior of mixtures containing starch and gluten. The mixtures containing starch, arabinoxylans, and gluten were dispersed in water and a 50% sucrose solution. When arabinoxylans were added to native starch in water, it did not modify the viscosity profiles. An increase in viscosity parameters was observed due to the addition of arabinoxylans to starch with a higher level of damage. Gluten did not influence the effects caused by arabinoxylans. In the sucrose solution, arabinoxylans caused an increase in the viscosity parameters of native starch and starch with higher damage content dispersions. Gluten caused greater viscosity increases when arabinoxylans were added. In water, the addition of arabinoxylans to native starch caused a decrease in the enthalpy of gelatinization and an increase in the onset temperature. Adding arabinoxylans to starch with a higher level of damage caused the opposite effects. In the presence of sucrose, arabinoxylans caused a decrease in the enthalpy of gelatinization. These results lay the foundations for studying the influence of damaged starch and arabinoxylans in water-rich systems characterized by the presence of substantial proportions of sucrose, such as batter formulations.

Classification, gelation mechanism and applications of polysaccharide-based hydrocolloids in pasta products: A review

Polysaccharide-based hydrocolloids (PBHs) are a group of water-soluble polysaccharides with high molecular weight hydrophilic long-chain molecules, which are widely employed in food industry as thickeners, emulsifiers, gelling agents, and stabilizers. Pasta products are considered to be an important source of nutrition for humans, and PBHs show great potential in improving their quality and nutritional value. The hydration of PBHs to form viscous solutions or sols under specific processing conditions is a prerequisite for improving the stability of food systems. In this review, PBHs are classified in a novel way according to food processing conditions, and their gelation mechanisms are summarized. The application of PBHs in pasta products prepared under different processing methods (baking, steaming/cooking, frying, freezing) are reviewed, and the potential mechanism of PBHs in regulating pasta products quality is revealed from the interaction between PBHs and the main components of pasta products (protein, starch, and water). Finally, the safety of PBHs is critically explored, along with future perspectives. This review provides a scientific foundation for the development and specific application of PBHs in pasta products, and provides theoretical support for improving pasta product quality.

Starch granules and their size distribution in wheat: Biosynthesis, physicochemical properties and their effect on flour-based food systems

Starch is a vital component of wheat grain and flour, characterized by two distinct granule types: A-type starch (AS) with granules larger than 10 µm in diameter, and B-type starch (BS) with granules measuring no more than 10 µm in diameter. This review comprehensively evaluates the isolation, purification, and biosynthesis processes of these types of granules. In addition, a comparative analysis of the structure and properties of AS and BS is presented, encompassing chemical composition, molecular, crystalline and morphological structures, gelatinization, pasting and digestive properties. The variation in size distribution of granules leads to differences in physicochemical properties of starch, influencing the formation of polymeric proteins, secondary and micro-structures of gluten, chemical and physical interactions between gluten and starch, and water absorption and water status in dough system. Thus, starch size distribution affects the quality of dough and final products. In this review, we summarize the up-to-date knowledge of AS and BS, and propose the possible strategies to enhance wheat yield and quality through coordinated breeding efforts. This review serves as a valuable reference for future advancements in wheat breeding.

Study of Physico-Chemical Properties of Dough and Wood Oven-Baked Pizza Base: The Effect of Leavening Time

The research objective was to investigate the morpho-rheological, chemical, and structural changes of dough and Neapolitan pizza TSG as the leavening time varies and to evaluate their effects on the digestibility of starch and on the formation of acrylamide during baking. Pizza dough leavening was monitored for 48 h at 22 °C/80% RH, and the analyses were conducted at selected leavening times (0, 4, 8, 16, 24, and 48 h). It was observed that in 30 h the volume tripled and the viscoelastic dough relaxed in the first 4 h, as evidenced by the lower value of the relaxation percentage “a” and the higher rate of decay “b”, associated with a high value of the compression work, indicating the presence of a very strong gluten mesh. In the following hours, the dough lost elasticity, and in fact, the G’ modulus decreased due to the weakening of the weak interactions between the gluten proteins and the starch. This suggests that a long leavening improved the extensibility of the pizza disc, facilitating the action of the pizza maker. Thermal (TGA and DSC) and morphological (SEM) analyses evidenced the highest water removal rate from the dough, a wider starch gelatinization temperature range, a ∆H of 0.975 ± 0.013 J/g, and a more open and weak gluten structure in dough balls leavened for 16 h. As the leavening time increased, both dough and pizza base samples showed an increase in reducing sugars and free amino groups, while the rapidly digestible starch decreased in the dough following the metabolism of the yeasts and increased in the pizza base due to the starch gelatinization that occurs during baking, which makes it much more susceptible to α-amylase. Finally, the levels of acrylamide remained at the same values despite the higher availability of reducing sugars and its precursors during leavening.

Effect of hydrocolloids on gluten proteins, dough, and flour products: A review

Hydrocolloids are among the most common components in the food industry, which are used for thickening, gel formation, emulsification, and stabilization. Previous studies have also found that hydrocolloids can affect the structures and properties of gluten proteins, dough, and flour products. In this review, hydrocolloids were separated into three categories: anionic, nonionic, and other hydrocolloids, and reviewed the effects of common hydrocolloids on gluten proteins, dough, and flour products. Hydrocolloids can affect the structures and properties of gluten proteins through gluten-hydrocolloids interaction, secondary structures, disulfide bonds, environment of aromatic amino acids, and chemical bonds. The properties of dough are affected by rheological, fermentation, and thermomechanical properties. Hydrocolloids are widely used in bread, Chinese steamed bread, noodles, yellow layer cake, and so on, which mainly affect their appearance, texture, and aging speed. This comprehensive review provides a scientific guide for the development and utilization of hydrocolloids and their applications in flour products, and provides a theoretical basis for improving the processing characteristics of products.

Comparison of rheological properties between Mixolab-driven dough and bread-making dough under various salt levels

The properties of wheat dough according to salt level and type of mixer were investigated, and parameters derived from each analysis were comprehensively compared. Mixolab analysis showed that water absorption decreased with salt level while the dough strength increased. In the Mixolab C2 stage, related with thermal strength, C2 temperature and time had stronger correlation with other dough strength parameters than C2 torque. Thickness increase of gluten strand was dominant in the doughs prepared by vertical mixer (VMD) than in those prepared by Mixolab device (MLD), for the same salt level. In large deformation, increase in resistance to extension by salt level was much greater in VMD than in MLD. In small deformation, relationships of salt level with G', G'' and power-law exponent (n) were linear and non-linear in MLD and VMD, respectively. Since MLD could not perfectly reflect VMD, properties of dough should be considered in multiple ways for its comprehensive understanding.

The effects of whey protein fibrils on the linear and non-linear rheological properties of a gluten-free dough

The increasing awareness of the celiac disease, an autoimmune disorder caused by the consumption of products containing gluten, has led to a growing interest in the development of gluten-free bakery products. In this study, whey protein fibrils (WPFs) were incorporated to mimic the fibrous network of gluten. The rheological properties and microstructure of the developed gluten-free doughs were evaluated and compared with gluten doughs. Protein fibrils were prepared by heating a whey protein isolate (WPI) solution at 80°C in an acidic environment with low salt concentration, and then the fibril lengths were adjusted by leveling up the solution pH to 3.5 and 7. The dimensions of the fibrils were measured by atomic force microscopy (AFM). Rice and potato starches were mixed with fibrils, WPI, gluten, or without protein, to form different doughs for further investigation. Shear tests, including stress sweep, frequency sweep, and creep recovery, were performed to study the viscoelastic properties of doughs under small or large deformation. The strain-hardening properties of doughs under biaxial extension were studied by the lubricated squeezing flow method. The microstructure of the doughs was characterized by cryo-scanning electron microscopy (cryo-SEM). Compared with doughs prepared with WPI and no proteins, doughs incorporating fibrils showed comparable linear viscoelasticity to gluten dough tested with stress sweep, frequency sweep, and creep recovery in the linear viscoelastic region. More differences between the protein fibril doughs were revealed in the rheological properties in the non-linear region. Creep recovery parameters, such as compliance, elastic moduli during the creep, and recovery stages of gluten dough, were like those of WPF pH7 dough, but significantly different from those of the WPF pH3.5 dough. Strain-hardening properties were found in the WPF pH7 dough, although not in WPF pH3.5 dough. Microstructural characterization showed that both fibrils prepared with the different conditions formed a continuous protein phase for the improvement of dough cohesiveness, but the structure of the phase was different between the two fibrils. To summarize, whey protein fibril at pH 7 seemed to have the potential of being used as an ingredient with similar functions to gluten in gluten-free bakery products.

Impact of celluloses and pectins restrictions on gluten development and water distribution in potato-wheat flour dough

The addition of potato to wheat flour extends the nutritional values of bread. However, the adverse effects mediated by high dietary fiber in potato flour could affect the formation of gluten matrix. The water dynamics and distribution determined by the Low field nuclear magnetic resonance (LF-NMR) demonstrated a competitive water binding of dietary fiber, resulting in the partial dehydration and conformational changes of gluten protein complexes. Besides, the microstructure of the dough characterized by Scanning electron microscope (SEM) suggested that the insoluble cellulose could block the continuity of gluten from the spatial position, thereby negative affecting the mechanical properties of the dough. In our study, addition of cellulase and/or pectinase apparently mitigated the gluten aggregation and dehydration, contributing to the formation and the continuity of the three-dimensional gluten network. As a consequence, the specific volume of the bread was increased by 40.2%, and the hardness was reduced by 64.48%.

Gluten proteins: Enzymatic modification, functional and therapeutic properties

Glutens are potential proteins with multifunctional therapeutic effects. Their covalence network structures with and without protease inhibitors are expected to enhance or to serve further properties and further technological points such as increased bioactive surfaces, gelatinization, gelation and pasting properties. The depletion of the allergic peptide sequences of gluten proteins comprising sometimes protease inhibitors are valid via the enzymatic ingestion using proteolytic enzymes that might enhance these functional and technological processes by producing active peptides having osmoregulation and regular glass transitions, surface activity for coating and encapsulation properties. In addition to further therapeutic functions such as immunoregulatory, antithrombin and opioidal activities, particularly in eradicating most of the free radicals, suppressing diabetes Mellitus II complications and inhibiting angiotensin converting enzyme cardiovascular growth diseases.

Extrusion of wheat gluten-peanut oil complexes and their rheological characteristics

In order to clarify the effects of extrusion treatment on the processing properties of extrudates, providing a theoretical basis for the production of gluten-based extrudates with favorable sensory quality. This study examined the effects of various extrusion temperatures on the rheological properties of wheat gluten-peanut oil complexes (WPE) and wheat gluten (WG). At the extrusion temperature conditions of this study, the dynamic moduli of gluten in WG and WPE reached the maximum, and the creep strain reached a minimum at 160 °C. Extrusion treatment resulted in the decrease in β-sheet and α-helix content and an increase in the amount of β-turns and random coils. The secondary structural changes and increase in the number of disulfide bonds led to gluten aggregation, thus affecting their rheological properties. These results enhance our understanding of the variations in the rheological properties of extrudates and promote the potential application of gluten-based complexes in extrusion.

Interaction between A-type/B-type starch granules and gluten in dough during mixing

To explore the interaction between A/B starch and gluten, the rheological and structural properties of starch-gluten dough with varied A/B starch ratios during mixing were investigated. The G' and G″ values of under- and overdeveloped dough with an A/B starch ratio of 5:5 were higher than those of dough with other ratios and decreased as the A/B starch ratio increased in optimized dough. B starch enhanced extension resistance and dough firmness. Small B starch granules promoted continuous gluten network formation, while large A starch granules readily separate from the gluten network. B starch promoted GMP polymerization. Covalent bonds were the main force involved in A starch-gluten interactions. Hydrophobic interactions were the main force in the under- to optimum-mixing stages, whereas hydrogen and covalent bonds were involved in B starch-gluten interactions from the optimum- to over-mixing stages. A model describing the interactions between gluten and starch components was proposed.

A Systematic Review on Gluten-Free Bread Formulations Using Specific Volume as a Quality Indicator

This study aimed to perform a systematic review on gluten-free bread formulations using specific volumes as a quality indicator. In this systematic review, we identified 259 studies that met inclusion criteria. From these studies, 43 met the requirements of having gluten-free bread with a specific volume greater than or equal to 3.5 cm³/g. Other parameters such as the texture profile, color (crumb and crust), and sensory analysis examined in these studies were presented. The formulations that best compensated the lack of the gluten-network were based on the combination of rice flour, rice flour with low amylose content, maize flour, rice starch, corn starch, potato starch, starch with proteins and added with transglutaminase (TGase), and hydrocolloids like hydroxypropylmethylcellulose (HPMC). Of the 43 studies, three did not present risk of bias, and the only parameter evaluated in common in the studies was the specific volume. However, it is necessary to jointly analyze other parameters that contribute to the quality, such as texture profile, external and internal characteristics, acceptability, and useful life of the bread, especially since it is a product obtained through raw materials and unconventional ingredients.

Interactions between gluten and water-unextractable arabinoxylan during the thermal treatment

This study aimed to investigate the interactions between gluten and water-unextractable arabinoxylan (WUAX), which changed the conformation and aggregation of gluten during the thermal treatment. In this work, the interactions between water-unextractable arabinoxylan and wheat gluten during thermal treatment were extensively evaluated by different techniques. The results showed that the extra WUAX could impair the viscoelasticity as well as weaken the thermal properties of gluten. The fluorescence spectra revealed the extra WUAX changed the conformation of gluten molecules. Besides, chemical interaction measurement indicated that the extra WUAX prevented the formation of partial disulfide bonds and had a major effect on the hydrophobic interaction of gluten. In summary, these results indicated that WUAX disrupted the covalent crosslinking by affecting disulfide bonds between gluten proteins, and dominated the folding/unfolding process of gluten via the competition with gluten for water, resulting in the poor quality of whole wheat-based foods.

Glycemic Response and Bioactive Properties of Gluten-Free Bread with Yoghurt or Curd-Cheese Addition

The influence of flour replacement by yogurt or curd-cheese additions (from 10% to 20%, w/w) on the glycemic response and bioactivity improvements of gluten-free bread was evaluated. Starch digestibility, measured by an in vitro digestion model, was applied to determine the effect on starch fractions. The bread glycemic index was calculated. Bread antioxidant capacity (2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and ferric-ion-reducing antioxidant power (FRAP) methods) and total phenolic compounds were assessed. Anti-inflammatory properties according to enzymatic matrix metalloproteinase (MMP)-9 inhibitory activity were also studied. Considering the higher level of both dairy products tested (20%, w/w) and comparing with control bread results, a reduction of around 35% in the glycemic response of curd cheese bread was achieved, resulting in intermediate index level (glycemic index (GI) 55-69), with yogurt bread still showing a high glycemic index (GI > 70). In terms of bread bioactivity, curd cheese bread expressed better reducing power effects, whereas yogurt bread showed more effective radical-scavenging capacity. An increase in bread phenolic compounds by yogurt (55.3%) and curd cheese (73.0%) additions (at 20%) were also registered. MMP-9 inhibition activity was higher in the dairy bread than in control bread, suggesting an improvement in terms of anti-inflammatory properties. The supplementation of the gluten-free bread by yogurt or curd cheese was shown to be a promising strategy to reduce the glycemic response and to improve the bioactive properties of the bread, that which can contribute to preventive diets of celiac patients and irritable bowel syndrome individuals.

Enhancing the nutritional profile of regular wheat bread while maintaining technological quality and adequate sensory attributes

Plant proteins, and legume proteins in particular, have become the centre of attention moving towards a more sustainable and, therefore, more plant-based human diet. Especially hybrid products, containing wheat and legume proteins, promise a balanced amino acid composition and an upgraded nutritional value of both protein sources. This study investigates a high-protein hybrid bread (HPHB) formulation, where wheat flour was partially replaced by high-protein ingredients from faba bean, carob and gluten. In addition to a detailed characterisation of technological quality and sensory profile, also the formulation's nutritional value was examined in comparison to regular wheat bread. Therefore, macronutrient composition, antioxidant potential, amino acid profile and contents of antinutritional compounds were analysed. Furthermore, protein digestibility was determined in an in vitro model and in vivo. Dough analysis revealed significant differences of the HPHB formulation compared to regular wheat dough. However, results obtained for bread quality characteristics prove HPHB to be equal to regular wheat bread and sensory results and the determined sensory attributes suggest high consumer acceptance. Nutritional analyses of HPHB showed a more favourable macronutrient composition in comparison to regular wheat bread; as well as low contents of antinutritional compounds and high antioxidant potential linked to high levels of phenolics. Also an improved amino acid profile, increased nitrogen utilisation rate (by 69%) and higher protein efficiency ratio were determined, which are associated with enhanced protein quality. This suggests HPHB, and similar formulations of its kind, as a valuable and healthy food choice, which can contribute to adequate protein supply in predominantly plant-based diets.

Changes on physicochemical and rheological properties of biscuits substituted with the peel and alcohol-insoluble solids (AIS) from cactus pear (Opuntia ficus-indica)

Cactus pear fruit consists of the peel, seeds and pulp. The peel is a major waste in cactus pear pulp based products accounting about 37.72% of the fruit weight. The aim of this study was to utilized and characterized the physicochemical and rheological properties of biscuits substituted with extracted cactus pear peel (CPP) and alcohol-insoluble solids (AIS) from cactus pear (Opuntia ficus-indica). To prepare AIS, peels were shredded and dropped in ethanol (70%) for 15 min. The mixture was boiled at 70 °C for 30 min, filtered and washed with ethanol 70% and the washing repeated until no sugars. The residue was washed and dried at room temperature. Changes in physiochemical and rheological properties of extracted CPP and AIS from cactus pear to qualify determine their use in the production of them to produce a fiber-rich food product. The water-holding capacity was 3.7 ml/g for the peel and 1.5 ml/g for the AIS, and the oil-holding capacity was approximately the same for both the CPP and AIS. The protein content was 3.5% for the CPP and 3.72% for the AIS. The CPP and AIS contained little fat (1.22% and 1.44%, respectively). Potassium and calcium in the AIS had the highest concentration, at 21.49 g/kg and 44.04 g/kg, respectively, and these minerals were found at 22.07 g/kg and 16.66 g/kg, respectively, in the CPP. The dominant phenolic compounds found in the CPP were pyrogallol, catechol, catechin, and alpha-coumaric acid. The results showed that the AIS contained pyrogallol (61.67 ppm), benzoic acid (10.68 ppm), vanillic acid (7.66 ppm), catechin (4.65 ppm) and salicylic acid (4.51 ppm). The CPP was rich in glucose (25.95%) and fructose (21.36%) compared to the AIS. The sensory evaluation indicated that 7.5% dried cactus pear peel or 7.5% AIS can be successfully used in substitution of wheat flour biscuits. It could be conducted cactus pear as major by-product can be important for the industrial utilization.

Effects of Water-Extractable Arabinoxylan on the Physicochemical Properties and Structure of Wheat Gluten by Thermal Treatment

This study investigated the effects of water-extractable arabinoxylan (WEAX) on gluten by thermal treatment. Fourier transform infrared spectroscopy (FTIR) results showed that heating significantly decreased β-sheets and β-turn structures in gluten proteins between 25 and 55 °C. The addition of WEAX caused a transition from β-turn to β-sheets at >55 °C. The ratio of weakly hydrogen-bonded β-sheets to strongly hydrogen-bonded β-sheets demonstrated an increasing trend with temperature increasing, but WEAX can hinder this process. FT-Raman results revealed that a hydrophilic environment was developed with 5% WEAX at 25 °C, and phenolic hydroxyl on ferulic acid can form new H-bonds with the phenyl groups of the nondissociated Tyr residues. A 5% WEAX content is helpful for gluten to maintain its original gauche-gauche-gauche conformation of disulfide bond upon heating. In addition, WEAX can reduce the elasticity of gluten and form a soft texture at 25, 55, and 75 °C.

Interactions between plant proteins/enzymes and other food components, and their effects on food quality

Plant proteins are the main sources of dietary protein for humans, especially for vegetarians. There are a variety of components with different properties coexisting in foodstuffs, so the interactions between these components are inevitable to occur, thereby affecting food quality. Among these interactions, the interplay between plant proteins/enzymes from fruits and vegetables, cereals, and legumes and other molecules plays an important role in food quality, which recently has gained a particular scientific interest. Such interactions not only affect the appearances of fruits and vegetables and the functionality of cereal products but also the nutritive properties of plant foods. Non-covalent forces, such as hydrogen bond, hydrophobic interaction, electrostatic interaction, and van der Waals forces, are mainly responsible for these interactions. Future outlook is highlighted with aim to suggest a research line to be followed in further studies.

Effect of gluten, egg and soy proteins on the rheological and thermo-mechanical properties of wholegrain rice flour

The effect of protein addition on the rheological, thermo-mechanical and baking properties of wholegrain rice flour was investigated. Gluten, powdered eggs and soy protein concentrate were first analyzed in terms of rheological properties, alone and in admixture with rice flour. The temperature ramp tests showed clear differences in the rheological behavior of the batters supplemented with different proteins. The highest thermal stability was observed in case of soy protein samples. Frequency sweep tests indicated significant improvements of the rheological properties of rice flour supplemented with 15% gluten or soy proteins. The thermo-mechanical tests showed that, due to the high fat contents and low level of free water, the dough samples containing powdered eggs exhibited the highest stability. Addition of gluten resulted in a significant decrease of the dough development time, whereas samples with powdered eggs and soy proteins were more difficult to hydrate. The incorporation of proteins into the rice flour-based dough formulations significantly affected starch behavior by decreasing the peak consistency values. Concerning the quality of the rice flour-based breads, soy protein addition resulted in lighter crumb color and increased texture attributes, samples with gluten had better resilience and adhesiveness, whereas breads with egg protein were less brittle.