Rheological and microstructural characteristics of lentil starch–lentil protein composite pastes and gels

Important roles of coarse particles in pasting and gelling performance of different pulse flours under high-temperature heating

Dehulled pea, lentil, and faba bean grains were milled into flours with 0.5- to 2.5-mm sieves. As the particle size decreased, damaged-starch contents of the flours from the same pulse crop increased. At a holding temperature of 95 °C in RVA, peak and final viscosities and gelling ability of the flours generally increased as the particle size decreased. When the holding temperature increased from 95 to 140 °C, pasting viscosities of pea and lentil flours and gel hardness of lentil flours gradually decreased. In contrast, pasting viscosities and gel hardness of faba bean flours reached the highest values at 120 °C. The comparison of the pulse flours varying in particle size across the three market classes revealed that coarse particles comprising agglomerated starch, protein, and dietary fiber (i.e., particles of the second peak in the bimodal particle-size distribution curves) showed significant correlations with certain important functional properties of pulse flours.

Different effects of pea protein on the properties and structures of starch gel at low and high solid concentrations

In the context of starch-protein composite gels, the influence of protein on gel formation significantly shapes the textural attributes of starch gels, leading to distinct outcomes. This study aimed to evaluate how different ratios of pea protein (PP) affect the properties and structures of starch-protein composite gels at low (10 wt%) and high (40 wt%) solid concentrations. The addition of PP had opposite effects on the two gels. Compared to the pure starch gel, the low-concentration composite gel (LCG) with 20 % PP experienced a 48.90 ± 0.33 % reduction in hardness, and the storage modulus (G') decreased from 14,100 Pa to 5250 Pa, indicating a softening effect of PP on LCG. Conversely, the hardness of the high-concentration composite gel (HCG) with 20 % PP exhibited a 62.19 ± 0.03 % increase in hardness, and G' increased from 12,100 Pa to 41,700 Pa, highlighting the enhancing effect of PP on HCG. SEM and fluorescence microscopy images showed that PP induced uneven network sizes in LCG, while HCG with a PP content of 20 %, PP, together with starch, formed a three-dimensional network. This study provides valuable insights and guidance for the design and production of protein-enriched starch gel products with different textural properties.

Rheological, thermal, and structural properties of heat-induced gluten gel: Effects of starch with varying degrees of debranching

This study evaluated the effects of starch with varying degree of debranching on the rheological, thermal, and structural properties of heat-induced gluten gel. As the duration of starch debranching treatment increased from 0 to 8 h, the viscoelasticity of the gel containing debranched starch (DBS) improved. Compared with the gluten gel (G), the gel strength of the G + DBS (8 h) sample increased by 65.2 %. The degradation temperature of gluten was minimally affected by DBS, while the weight loss rate increased by 4.4 %. Furthermore, the α-helical structure of gluten decreased, concomitant with an increase in β-sheet content. Notably, DBS treated for 8 h exhibited more hydrogen bonds with the tyrosine of gluten and triggered disulfide bridge conformation to transition from g-g-g to t-g-g, thereby reducing the stability of the molecular conformation of gluten proteins, as evidenced by the decreased height and width of the molecular chains observed in atomic force microscopy images. Overall, the composite gel structure induced by DBS exhibited a more continuous and homogeneous owing to the improved compatibility between DBS and gluten proteins, favoring the formation of a robust gel. These findings provide valuable insights for utilizing DBS to enhance gluten gel properties.

Heat-Induced Gelation of Chickpea and Faba Bean Flour Ingredients

This study aimed to investigate the gelling behavior of faba bean (FB) and chickpea (CP) flour between 10 and 20% (w/w) concentration at pH 3.0, 5.0, and 7.0. Both sources formed at pH 3.0 and 5.0 self-standing gels with 12% (w/w) of flour, while 16% (w/w) of flour was required to obtain a gel at pH 7.0. During gelling between 40 and 70 °C, a sharp increase of the elastic modulus G' was observed in both flours, mainly due to water absorption and swelling of the starch, one of the major constituents in the ingredients. Increasing the temperature at 95 °C, G' increased due to the denaturation of globulins and therefore the exposure of their internal part, which allowed more hydrophobic interactions and the formation of the gel. After cooling, both FB and CP gels displayed a solid-like behavior (tan δ ranging between 0.11 and 0.18) with G' values at pH 3.0 and 5.0 significantly (p < 0.05) higher than those at pH 7.0, due to the lower electrostatic repulsions at pHs far from the isoelectric point. The rheological properties were supported by the water binding capacity values, confirming the better gels' strength described by rheological analysis. These results will enhance our understanding of the role of legume flours in formulating innovative and sustainable food products as alternatives to animal ones.

The addition of resistant starch and protein to the batter reduces oil uptake and improves the quality of the fried batter-coated nuts

The batter compositions can affect the oil uptake and texture of fried batter-coated nuts. In this study, the oil uptake and quality of fried batter-coated peanuts and sunflower seeds added with resistant starch and protein were investigated. The results demonstrated that the addition of resistant starch increased the batter hardness and fracturability of the fried batter-coated peanuts by 34.36 % and 33.73 %, respectively. The oil content of fried batter-coated peanuts and sunflower seeds were decreased by 17.98 % and 15.69 %, respectively, with the addition of protein. The microstructure and roughness of the batter revealed that the batter added with protein became denser and uniform. Furthermore, the protein in the batter added with 6 % soy protein isolate had a high surface hydrophobicity. In summary, the addition of resistant starch and protein in batter will be a promising strategy for reducing the oil content and improving the quality of fried batter-coated nuts.

Effect of soybean polysaccharide and soybean oil on gelatinization and retrogradation properties of corn starch

This investigation stems from the wide interest in mitigating starch retrogradation, which profoundly impacts the quality of starch-based food, garnering significant attention in the contemporary food industry. Our study delves into the intricate dynamics of soluble soybean polysaccharide (SSPS) and soybean oil (SO) when added individually or in combination to native corn starch (NCS), offering insights into the gelatinization and retrogradation phenomena. We observed that SSPS (0.5 %, w/w) hindered starch swelling, leading to an elevated gelatinization enthalpy change (∆H) value, while SO (0.5 %, w/w) increased ∆H due to its hydrophobicity. Adding SSPS and/or SO concurrently reduced the viscosity and storage modulus (G') of starch matrix. For the starch gel (8 %, w/v) after refrigeration, SSPS magnified water-holding capacity (WHC) and decreased hardness through hydrogen bonding with starch, while SO increased hardness with limited water retention. Crucially, the combination of SSPS and SO maximized WHC, minimized hardness, and significantly inhibited starch retrogradation. The specific ratio of SSPS to SO was found to significantly influence the starch properties, with a 1:1 ratio resulting in the most desirable quality for application in starch-based foods. This study offers insights for utilizing polysaccharides and lipids in starch-based food products to extend shelf life.

Construction of a soybean protein isolate/polysaccharide-based whole muscle meat analog: Physical properties and freeze-thawing stability study

A growing interest has arisen in recreating real meat by mimicking its texture characteristics and muscle fiber structure. Our previous work successfully created meat analog fiber based on soybean protein isolate (SPI) and sodium alginate (SA) with the wet-spinning method. In this work, we analyzed the microstructure, texture profile, and water retainability of the assembled plant-based whole muscle meat analog (PMA) made of SPI/SA-based meat analog fiber and systematically studied the effect of different combinations and contents of transglutaminase (TG), salt, and soybean oil on the rheological behavior of the formulated adhesive. The estimated optimal condition that has the most similar texture characteristic with real chicken breast meat is: for every 1:1 mass ratio of simulated plant meat fibers to the adhesive, add 0.1 % TG enzyme addition in the adhesive and 100 mM NaCl addition. The physical behavior of PMA during cryopreservation was investigated through freeze-thaw cycles and freezing times. The addition of a small amount of oil and salt can efficiently prevent the PMA through freezing conditions which is comparable with the addition of D-Trehalose (TD). Overall, this study not only created a plant-based whole muscle meat analog product that is similar in texture to real chicken breast meat but also provided a new direction for constructing fiber-rich structure protein-based muscle meat analogs and their further commercialization.

Changing the ionic strength can regulate the resistant starch content of binary complex including starch and protein or its hydrolysates

Ionic strength condition is a crucial parameter for food processing, but it remains unclear how ionic strength alters the structure and digestibility of binary complexes containing starch and protein/protein hydrolysates. Here, the binary complex with varied ionic strength (0-0.40 M) was built by native corn starch (NS) and soy protein isolate (SPI)/hydrolysates (SPIH) through NaCl. The inclusion of SPI and SPIH allowed a compact network structure, especially the SPIH with reduced molecule size, which enriched the resistant starch (RS) of NS-SPIH. Particularly, the higher ionic strength caused the larger nonperiodic structures and induced loosener network structures, largely increasing the possibility of amylase for starch digestion and resulting in a decreased RS content from 19.07 % to 15.52 %. In other words, the SPIH hindered starch digestion while increasing ionic strength had the opposite effect, which should be considered in staple food production.

Effect of the gelling mechanism on the physical properties of bigels based on whey protein isolate

The effect of the cold-set and heat-set gelling mechanism of whey protein isolate on bigel production was assessed. For this purpose, hydrogel phase was produced with whey protein isolated (10 % w/v) and for oleogel sunflower oil and glycerol monostearate (7.5 % w/v) were used. Bigels were produced by hot emulsification of different hydrogel:oleogel ratios (from 90:10 up to 10:90). For cold-set bigels (CSB) NaCl (200 mM) was added to the aqueous phase prior to the emulsification and the emulsion was cooled to promote the 3D network formation. On the other hand, heat-set bigels (HSB) were produced by heating the emulsion (80 °C, 60 min). Bigels were evaluated through microscopy, FTIR, thermal and texture analyzes. Results showed that depending on the hydrogel:oleogel ratio and gelling mechanism different structures organization were obtained. CSB were more organized, showing that the rate of gelation was the mechanism responsible for the structure. However, for HSB the heat treatment destabilized the emulsion and disorganized structures were observed for high oleogel content. FTIR corroborates the visual observation and showed that the arrangement was purely physical. In addition, the structural arrangement led to different mechanical properties. In general, HSB produced gels with rubber-like behavior, higher elasticity modulus and the presence of a breaking point. In contrast, CSB behaves as squeezing gel, with no breaking point and lower values of elasticity modulus. Moreover, for O/W bigels the dispersed oleogel particles disrupted the WPI network decreasing the gel strength in comparison to pure hydrogels. However, for systems where oleogel was the continuous phase, the gel strength was recovered due to the metastable and dynamic character of these systems. Thus, results showed that the gelling mechanism of the protein exerted an effect on the physical properties of bigels. In addition, the mechanical properties also can be modulated according to the bigel composition, allowing its application in products with different sensorial characteristics.

Research on corn starch and black bean protein isolate interactions during gelatinization and their effects on physicochemical properties of the blends

The interaction between starch and protein during food processing is crucial for controlling food quality. This study aims to understand the interactions between corn starch and black bean protein isolate (BBPI) at various gelatinization phases and their effects on the physicochemical properties of the blends. BBPI reduced the rheological properties of the corn starch/BBPI mixed system during gelatinization, increasing light transmittance and gelatinization temperature, while decreasing total viscosity and enthalpy change. The changes in starch and protein microstructure during gelatinization indicated that BBPI adhered to the starch particle surface or partially penetrated the swollen starch particles. Fourier transform infrared spectroscopy (FT-IR) revealed that BBPI decreased the number of hydrogen bonds within starch, with no newly formed functional groups in the mixed system. Furthermore, BBPI reduced the composite relative crystallinity (RC). The effect of protein addition on water migration in the mixed system demonstrates that protein and starch compete for water during gelatinization, preventing water molecules from diffusing into starch particles.

Interaction between potato starch and barley β-glucan and its influence on starch pasting and gelling properties

The interactions between potato starch (PtS) and barley β-glucan (BBG) were investigated by preparing PtS-BBG mixtures, and the pasting, rheological, gelling and structural properties were evaluated. Rapid viscosity analysis suggested that BBG reduced the peak and breakdown viscosity, while increasing the setback viscosity of PtS. PtS-12%BBG showed the lowest leached amylose content (12.02 ± 0.36 %). The particle size distribution pattern of PtS was not changed with the addition of BBG, and the median diameter of PtS-12%BBG (88.21 ± 0.41 μm) was smaller than that of PtS (108.10 ± 6.26 μm). Rheological results showed that PtS and PtS-BBG gels exhibited weak gel behaviors, and BBG could remarkably affect the elastic and viscous modulus of PtS gels. Textural analysis suggested that the strength and hardness of PtS gels were increased when few BBG (<6 %, w/w) was present in the system. BBG improved the freeze-thaw stability of PtS gels. Structural analysis indicated that hydrogen bonds were the main force in the PtS-BBG systems. These results indicated that BBG interacted with starch via hydrogen bonds, which delayed starch gelatinization and improved gelling properties of PtS gels. Overall, this study gained insights into starch-polysaccharide interactions and revealed the possible applications of BBG in food processing.

Effect of protein on the gelatinization behavior and digestibility of corn flour with different amylose contents

The effects of endogenous proteins on the gelatinization behavior and digestibility of waxy corn flour (WCF), normal corn flour (NCF) and high amylose corn flour (HCF) were systematically investigated. Microscopic characteristics showed that the proteins surrounded multiple starch granules, which led to an increase in the particle size of the corn flour, but no significant change in the relative crystallinity. Small angle x-ray scattering experiments during pasting revealed that the starch granules of NCF remained compact, while WCF and HCF were relatively loose. Carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) showed that the proteins retained the helical structure of starch allowing NCF to have a higher Resistant starch(RS) content. The presence of protein led to a decrease in swelling power, viscosity, and in vitro digestibility of starch, and a noticeable increase in gelatinization temperature and thermal stability. RS increased most significantly in NCF from 3.86 % to 15.27 %. The effect of protein on the water activity of starch with different amylose contents after pasting was also inconsistent. This study will contribute to the understanding of the interaction between starch and protein in corn flours with different amylose contents and contribute to the development of corn flours.

Legume protein/polysaccharide food hydrogels: Preparation methods, improvement strategies and applications

For the development of innovative foods and nutritional fortification, research into food gel is essential. As two types of rich natural gel material, both legume proteins and polysaccharides have high nutritional value and excellent application potential, attracting wide attention worldwide. Research has focused on combining legume proteins with polysaccharides to form hybrid hydrogels as their combinations show improved texture and water retention compared to single legume protein or single polysaccharide gels, and these properties can be tailored for specific applications. This article reviews hydrogels of common legume proteins and discusses heat induction, pH induction, salt ion induction, and enzyme-induced assembly of legume protein/polysaccharide mixtures. The applications of these hydrogels in fat replacement, satiety enhancement, and delivery of bioactive ingredients are discussed. Challenges for future work are also highlighted.

Effect of rice protein on the gelatinization and retrogradation properties of rice starch

In this study, rice starch (RS) was mixed with varying amounts of rice protein (RP; 0 % to 16 %) to explore the effects of protein on the gelatinization and retrogradation of starch during storage. The increased RP addition decreased the viscosity and gelatinization enthalpy of the mixtures but caused an upward trend in the gelatinization temperature, indicating that protein hampers the process of starch gelatinization. Furthermore, RP addition reduced gel hardness, decreased retrogradation enthalpy and crystallization rate constant, but increased Avrami exponent upon RS retrogradation. RP addition also facilitated the mobility of water molecules, weakened the conversion from bound water to free water in the gels, and moderately increased the uniformity and thickness of gel shape. In summary, RP had a dose-dependent effect on the gelatinization and retrogradation behavior of RS, although the anti-retrogradation concentration effect strongly weakened at protein levels exceeding 12 %. It is noteworthy, that excessive RP addition resulted in disulfide bond formation, which increased gel strength and network structure but reduced the ability of RP to facilitate water molecule mobility and restrict water migration, ultimately reducing its anti-retrogradation capability. This phenomenon can be partially attributed to spontaneous protein-protein interaction caused by excessive protein addition, replacing the starch-protein interaction.

A New Approach for the Development and Optimization of Gluten-Free Noodles Using Flours from Byproducts of Cold-Pressed Okra and Pumpkin Seeds

The significant protein and dietary fiber content of cold-pressed pumpkin (PSF) and okra (OSF) seed byproducts are well-known. However, their impact on noodles' nutritional quality has never been studied. For the first time, noodle formulation was developed employing a genetic algorithm in the R programming language to achieve the most optimal sensory attributes as well as nutritional composition, color, cooking, and textural properties. The optimized noodle formulation was detected for OSF, PSF, gluten-free flour, salt, and egg with the following amounts: 11.5 g, 87.0 g, 0.9 g, 0.6 g, and 40 g, respectively, with 10.5 mL of water. The total protein (TP%), total fat (TF%), total carbohydrate (TC%), total dietary fiber content (TDF%), ash (%), total phenolic content (TPC mg GAE/100 g), and ABTS (%) of PSF were found to be 39%, 17%, 7%, 18%, 3%, 19%, and 48%, respectively, whereas for OSF, 33%, 8%, 21%, 32%, 5%, 16%, and 38%, respectively, were detected. In addition, TP (42.88%), TF (15.6%), ash (5.68%), TDF (40.48%), TPC (25.5 mg GAE/100 g), and ABTS (70%) values were obtained for the noodles. Consequently, the valorization of the cold oil press industry's byproducts may be used as ingredients that add high value to gluten-free protein and fiber-rich noodle production, and they may gain interest from both processors and consumers.

Understanding effects of glutelin on physicochemical and structural properties of extruded starch and the underlying mechanism

This work studied effects of different amounts of rice glutelin (RG) on physicochemical and structural properties of extruded rice starch (ERS) and explored the underlying mechanism of interaction between rice starch and RG upon extrusion processing. The results showed that the addition of RG altered the pasting properties, improved the viscoelastic, and increased the water mobility of ERS. The weight loss of ERS decreased from 71.40 % to 62.61 %, while the degradation temperature increased from 290.48 °C to 296.25 °C as the RG content increased from 0 % to 12 %. The complex index of extruded starch-glutelin complexes significantly elevated from 10.40 % to 35.81 % when RG content increased from 6 % to 12 %. Fourier-transform infrared spectra confirmed that RG interacted with starch via Maillard reactions, and the binding strength between RG and starch was enhanced at a higher RG content. Furthermore, results of rheological property and chemical interactions demonstrated that hydrogen bonding, hydrophobic, and electrostatic interaction were formed between RG and starch during extrusion. In summary, the obtained results of this study can further enrich the theory of starch-protein interactions and show the possibility of RG applied in the extruded starchy foods.

Insight into the effect of garlic peptides on the physicochemical and anti-staling properties of wheat starch

The staling of wheat starch in storage seriously damages the quality of starch-based foods, and how to delay the staling has become a topic focus. To solve the problem, this study analyzed the effect of garlic peptides on the physical and retrogradation behaviors of wheat starch during storage. The rheological, pasting, swelling properties, molecular order, water migration, and microstructure of wheat starch gels were evaluated. Our results showed that garlic peptides effectively reduced the storage and loss modulus of wheat starch. The physical properties indicated that garlic peptides suppressed the swelling and gelatinization of starch, which exhibited higher water holding capacity and lower water migration. In addition, garlic peptides incorporated wheat starch exhibited the lowest gel hardness during storage. X-ray diffraction and Fourier Transform Infrared Spectroscopy analysis indicated that garlic peptides could reduce the crystallinity and inhibit the formation of ordered structures in wheat starch gel. The microstructure observation showed that the gel with garlic peptides maintained the integrity of the network structure. Consequently, garlic peptides are expected to be an effective natural additive to inhibit starch staling and provide new insights for starch-based foods.

Milling and differential sieving to diversify flour functionality: A comparison between pulses and cereals

In this study, pulse (pea, lentil) and cereal (barley, oats) seeds were firstly milled into whole flours, which were then sieved into coarse and fine flours. The particle sizes of the three generated flour streams followed a descending order of coarse > whole > fine, consistent with the observation under scanning electron microscopy (SEM). Among the four crops, the three flour streams showed the same rank order of fine > whole > coarse in starch and damaged-starch contents but the opposite order in ash and total dietary fiber contents. Thus, those functional properties closely related to starch occurring in flour, such as L* (brightness), starch gelatinization enthalpy change (ΔH), and gel hardness, followed the same order of fine > whole > coarse. By contrast, protein contents of the three flour streams did not vary in pea and lentil but showed a trend of coarse > whole > fine in barley and oats, which could partially explain generally comparable foaming and emulsifying properties of the three streams of pulse flours as well as an order of coarse > whole > fine in oil-binding capacity (OBC) of cereal flours, respectively. The different particle sizes and chemical compositions of the three flour streams only resulted in a descending order of fine > whole > coarse in the pasting viscosities of the pulse flours but did not lead to such a clear trend in the cereal flours, which could be partly attributable to the different microscopic structures of the pulse and cereal seeds and their corresponding flours. This research clearly demonstrated that particle size, chemical composition, and microscopic structure were important variables determining the specific techno-functional properties of pulse and cereal flours.

Modulation in Techno-Functional, Textural Properties, In Vitro Starch Digestibility and Macromolecular-Structural Interactions of Pasta with Potato (Solanum tuberosum L.)

The replacement of semolina with potato flour (PF) and potato mash (PM) at different levels was assessed for its effects on pasta quality. The results showed that the addition of PF and PM increased the pasting viscosity of the blends; in addition, PF enhanced the functional properties, while PM reduced them. The minimum cooking time decreased with PF and PM, while the PF pasta exhibited a higher cooking loss (5.02 to 10.44%) than the PM pasta, which exhibited a lower cooking loss. The pasta with PF and PM showed an increase in the total phenolic and flavonoid content, with reduced in vitro digestibility as confirmed by Fourier transform infrared spectroscopy. The PF pasta exhibited lower lightness and higher yellowness than the PM pasta, and its firmness and toughness also modulated owing to the complex interaction between potato starches and the gluten protein matrix, as evident from scanning electron microscopy. Sensory data revealed that pasta containing 30% PF and 16% PM was highly acceptable.

Physicochemical, Pasting, and Thermal Properties of Native Corn Starch-Mung Bean Protein Isolate Composites

Starch is widely used in food and non-food industries because of its unique characteristics. However, native starch shows some weaknesses that restrict its applications. Recently, some studies have demonstrated the benefits of using protein to overcome these limitations. Therefore, the aim of the present study was to investigate the effect of mung bean protein isolate (MBPI) (2%, 4%, 6%, and 8%) on the physicochemical, pasting, and thermal properties of native corn starch (NCS), as a novel starch-protein composite. Higher swelling power (SP), water absorbance capacity (WAC), and solubility values of NCS were observed with increasing MBPI concentration. Additionally, by the addition of MBPI, the rapid visco analyzer (RVA) showed a reduction in pasting temperature (77.98 to 76.53 °C), final viscosity (5762 to 4875 cP), and setback (3063 to 2400 cP), while the peak viscosity (4691 to 5648 cP) and breakdown (1992 to 3173 cP) increased. The thermal properties of NCS/MBPI gels investigated by differential scanning calorimetry (DSC) showed higher onset, peak, and conclusion temperatures (69.69 to 72.21 °C, 73.45 to 76.72 °C, and 77.75 to 82.26 °C, respectively), but lower gelatinization enthalpy (10.85 to 8.79 J/g) by increasing MBPI concentration. Fourier transform infrared spectroscopy (FT-IR) indicated that the addition of MBPI decreased the amount of hydrogen bonds within starch. Furthermore, after three cycles of freeze-thaw shocks, the syneresis of NCS-MBPI composites decreased from 38.18 to 22.01%. These results indicated that the MBPI could improve the physicochemical properties of NCS, especially its syneresis and retrogradation characteristics.

Formation and thermal and colloidal stability of oil-in-water emulsions stabilized using quinoa and lentil protein blends

BACKGROUND

The amino acid composition, and rheological, thermal and colloidal stability of plant protein-based oil-in-water emulsion systems containing 1.90, 3.50 and 7.70 g 100 mL^-1 protein, fat and carbohydrate, respectively, using quinoa and lentil protein ratios of 100:0 and 60:40 were investigated. The emulsion containing lentil protein showed lower initial, peak and final viscosity values (22.7, 61.7 and 61.6 mPa s, respectively) than the emulsion formulated with quinoa protein alone (34.3, 102 and 80.0 mPa s, respectively) on heat treatment.

RESULTS

Particle size analysis showed that both samples had small particle sizes (~1.36 μm) after homogenization; however, the sample with 60:40 quinoa:lentil protein ratio showed greater physical stability, likely related to the superior emulsifying properties of lentil protein. However, upon heat treatment, large aggregates (~100 μm) were formed in both samples, reducing the physical stability of the samples. This physical stability was increased with the addition of 0.20% sodium dodecyl sulfate (SDS), whereas it was negatively affected by the addition of α-amylase. Addition of α-amylase led to lower viscosity for both emulsion samples, with measured values of 41.8 and 46.0 mPa s for the 100:0 and 60:40 samples, respectively. This suggests that the heat-induced increases in particle size were partially due to hydrophobic interactions between the proteins as SDS disrupts hydrophobic bonds between proteins.

CONCLUSION

These results demonstrated that using a mixture of lentil and quinoa proteins positively affected the physical stability of plant protein-based emulsions, in addition to contributing to a more nutritionally complete amino acid profile - both important considerations in the development of plant-based beverages. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Physicochemical and functional properties of Lycium ruthenicum pectin by different extraction methods

Three different extraction methods were used to extract high-temperature water-extracted pectin (HWp), high-temperature acid-extracted pectin (HAp), and high-temperature alkali-extracted pectin (HALp) from Lycium ruthenicum. The physicochemical properties, structure, and functional properties of three different pectins were studied. The results showed that HWp and HALp can extract rhamnogalacturonan-I (RG-I) from L. ruthenicum better. Through structural feature analysis, HWp and HALp have a branched structure, and HWp has a higher degree of esterification than HAp and HALp. Zeta potential results show that HWp solution is more stable. The thermal analysis results show that the thermal stability is HALp > HAp > HWp. HWp has the highest viscosity. The inhibitory activity results showed that HWp, HAp, and HALp have a certain inhibitory effect on α-glucosidase activity. This study shows the effects of different extraction methods on the properties of L. ruthenicum pectin and aims to provide a theoretical basis for the pharmaceutical and food industries to choose more suitable pectin extraction methods.

Effects of Mung Bean (Vigna radiata) Protein Isolate on Rheological, Textural, and Structural Properties of Native Corn Starch

It is critical to understand the starch–protein interactions in food systems to obtain products with desired functional properties. This study aimed to investigate the influence of mung bean protein isolate (MBPI) on the rheological, textural, and structural properties of native corn starch (NCS) and their possible interactions during gelatinization. The dynamic rheological measurements showed a decrease in the storage modulus (G’) and loss modulus (G”) and an increase in the loss factor (tan δ), by adding MBPI to NCS gels. In addition, the textural properties represented a reduction in firmness after the addition of MBPI. The Scanning electron microscope (SEM) images of the freeze-dried NCS/MBPI gels confirmed that the NCS gel became softer by incorporating the MBPI. Moreover, X-ray diffraction (XRD) patterns showed a peak at 17.4°, and the relative crystallinity decreased with increasing MBPI concentrations. The turbidity determination after 120 h refrigerated storage showed that the addition of MBPI could reduce the retrogradation of NCS gels by interacting with leached amylose. Additionally, the syneresis of NCS/MBPI gels decreased at 14 days of refrigerated storage from 60.53 to 47.87%.

Fabrication of agarose/fish gelatin double-network hydrogels with high strength and toughness for the development of artificial beef tendons

Agarose/fish gelatin (AR/FGA) double-network hydrogels (DNs) were fabricated via a one-step heating-cooling method. The structure, mechanical and textural properties, water-holding capacity, swelling behavior and sensory characteristics of the DNs were analyzed and compared with the corresponding single-network hydrogels (SNs) and beef tendons. An increase in FGA concentration (10-40 wt%) significantly enhanced the mechanical strength and toughness of DNs, while a moderate increase in AR concentration (0.5-1.5 wt%) only improved their mechanical strength. The 1.5 wt% AR/40 wt% FGA DNs attained excellent fracture stress and strain compared with the single AR and single FGA gels. This can be attributed to the energy dissipation effect, intermolecular hydrogen bond interactions and higher entanglement density of molecule chains. Furthermore, AR/FGA DNs attained a higher hardness, water holding capacity and lower swelling rate compared with SNs. The principal component analysis and correlation analysis showed that the 1.5 wt% AR/30 wt% FGA DNs displayed the most comparable correlation with beef tendons, which was consistent with the results of the sensory evaluation, showing great potential as artificial beef tendons. Our findings provide guidance for the modulation of gel properties and development of artificial foods.

Effect of Homogenization Modified Rice Protein on the Pasting Properties of Rice Starch

Modification of plant-based protein for promoting wide applications is of interest to the food industry. Rice protein from rice residues was modified by homogenization, and its effect on pasting properties (including gelatinization and rheology) of rice starch was investigated. The results showed that homogenization could significantly decrease the particle size of rice protein and increase their water holding capacity without changing their band distribution in SDS-PAGE. With the addition of protein/homogenized proteins into rice starch decreased peak viscosity of paste. The homogenized proteins decreased breakdown and setback value when compared with that of original protein, indicating homogenized protein might have potential applications for increasing the stability and inhibiting short-term retrogradation of starch paste. The addition of protein/homogenized proteins resulted in a reduction in the viscoelasticity behavior of starch paste. These results indicate that homogenization would create a solution to alter the physicochemical properties of plant proteins, and the homogenized proteins may be a potential candidate for development of protein-rich starchy products.

Particle filled protein-starch composites as the basis for plant-based meat analogues

Rapid swelling, high amylopectin starches including Thermally Inhibited (TI), Chemically Modified (CM), and Granular Cold- Swelling (GCS) were assessed for their supporting matrix forming potential and properties. Starches displayed identical calorimetric profiles with no endothermic events, and completely amorphous structure as judged by powder X-ray diffraction. However, they each provided different textural attributes. The starches were combined with pea protein isolate at a total concentration of 47%w/w (d.b.) to create a proteinacious supporting matrix. The starch protein matrix was then tested in a non-cold-set dough state as well as in a cold-set state after storage for 24h at 5^oC. In the non-cold-set state, hardness increased with the addition of protein. CM was the softest dough and was difficult to work with, while TI and GCS were harder, with TI having the greatest resilience. Once cold-set, the textural properties changed, and GCS was not able to form a solid structure, instead remaining a viscoelastic dough. The hardness and storage modulus (G') of TI and CM displayed a negative correlation with the addition of protein due to matrix disruption. However, the combination of TI starch and pea protein at a ratio of 70% starch and 30% protein in the dry fraction displayed a synergistic effect, with increased resilience, chewiness, and ductility. FTIR of TI starch and protein at the same 70:30 ratio provided further evidence for the existence of an interaction between pea protein and TI starch. The results support the use of TI rapid swelling starch and pea protein isolate as a supporting matrix for application in meat analogue systems.

Effects of whey protein on the in vitro digestibility and physicochemical properties of potato starch

The aim of this study was to examine the effect of whey protein isolate (WPI) on the digestibility and physicochemical properties of potato starch (PS) after heat treatment. WPI reduced the digestibility of PS and increased the order and aggregation structure of gelatinized PS. Examination of the rheological properties of the PS-WPI mixed system before and after adding different chemicals (sodium chloride, urea, and sodium dodecyl sulfate) indicated an involvement of hydrogen bonds and hydrophobic interactions in the PS-WPI gelatinization system. The pasting properties, swelling power, and thermal properties indicated that WPI suppressed the swelling and gelatinization of PS. The addition of WPI reduced the amylose leaching rate from the starch granules, indicating that the presence of exogenous protein could prevent amylose diffusion from the starch granules. Native WPI and its hydrolysate also inhibited amyloglucosidase activity. These findings indicated that the mechanism by which WPI reduces PS digestion involves hydrophobic interactions and hydrogen bonding between WPI and PS, as well as enzyme activity inhibition.

Influence of whey protein isolate on pasting, thermal, and structural characteristics of oat starch

We investigated the effects of different concentrations of whey protein isolate (WPI) on oat starch characteristics in terms of pasting, thermal, and structural properties. The pasting properties of the starch showed that hot paste viscosity increased with the addition of WPI in the system, and relative breakdown decreased. Thermal analysis showed a significant effect of WPI on oat starch by increasing the peak temperature of differential scanning calorimeter endotherms. The X-ray diffraction and Fourier transform infrared spectroscopy studies revealed that WPI increased the ordered structuration of starch paste, as evident by an increase in relative crystallinity; in addition, a decrease in infrared bands at 1,024 cm^-1 and 1,080 cm^-1 suggested decreased gelatinization of oat starch granules. Overall, WPI at different concentrations affected the oat starch gelatinization properties.

Thermal, pasting and structural studies of oat starch-caseinate interactions

The effects of different concentrations of calcium caseinate (CaCn) on pasting, thermal and structural properties of oat starch were investigated. The effect of CaCn on oat starch was highly dependent on the concentration of CaCn in the mixtures. Characterizations of pasting properties revealed that breakdown, final and setback viscosities increased at high relative contents of CaCn (>50%, w/w), while setback and stability ratio were decreased. Thermal analysis showed an increase in gelatinization temperature and a decrease in enthalpy change. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) suggested significant effects of CaCn on oat starch gelatinization. Based on XRD results, a decreasing trend was observed on the relative crystallinity of the starch-protein mixtures containing high levels of CaCn (e.g. 50% and 75% relative CaCn contents). Increases in FT-IR bands at 1024 cm^-1 and 1152 cm^-1 suggested an increase in amorphous structuration of the mentioned starch-protein mixtures.

The Application of Pulse Flours in the Development of Plant-Based Cheese Analogues: Proximate Composition, Color, and Texture Properties

Despite the many benefits of pulses, their consumption is still very low in many Western countries. One approach to solving this issue is to develop attractive pulse-based foods, e.g., plant-based cheeses. This study aimed to assess the suitability of different types of pulse flour, from boiled and roasted yellow peas and faba beans, to develop plant-based cheese analogues. Different stabilizer combinations (kappa- and iota-carrageenan, kappa-carrageenan, and xanthan gum) were tested. The results showed that firm and sliceable pulse-based cheese analogues could be prepared using all types of pulse flour using a flour-to-water ratio of 1:4 with the addition of 1% (w/w) kappa-carrageenan. The hardness levels of the developed pulse-based cheese analogues were higher (1883–2903 g, p < 0.01) than the reference Gouda cheese (1636 g) but lower than the commercial vegan cheese analogue (5787 g, p < 0.01). Furthermore, the crude protein (4–6% wb) and total dietary fiber (6–8% wb) contents in the developed pulse-based cheese analogues were significantly (p < 0.01) higher than in the commercial vegan cheese analogue, whereas the fat contents were lower. In conclusion, flours from boiled and roasted yellow peas and faba beans have been shown to be suitable as raw materials for developing cheese analogues with nutritional benefits.

Plant Proteins for Future Foods: A Roadmap

Protein calories consumed by people all over the world approximate 15-20% of their energy intake. This makes protein a major nutritional imperative. Today, we are facing an unprecedented challenge to produce and distribute adequate protein to feed over nine billion people by 2050, in an environmentally sustainable and affordable way. Plant-based proteins present a promising solution to our nutritional needs due to their long history of crop use and cultivation, lower cost of production, and easy access in many parts of the world. However, plant proteins have comparatively poor functionality, defined as poor solubility, foaming, emulsifying, and gelling properties, limiting their use in food products. Relative to animal proteins, including dairy products, plant protein technology is still in its infancy. To bridge this gap, advances in plant protein ingredient development and the knowledge to construct plant-based foods are sorely needed. This review focuses on some salient features in the science and technology of plant proteins, providing the current state of the art and highlighting new research directions. It focuses on how manipulating plant protein structures during protein extraction, fractionation, and modification can considerably enhance protein functionality. To create novel plant-based foods, important considerations such as protein-polysaccharide interactions, the inclusion of plant protein-generated flavors, and some novel techniques to structure plant proteins are discussed. Finally, the attention to nutrition as a compass to navigate the plant protein roadmap is also considered.

Polysaccharide-reinforced amyloid fibril hydrogels and aerogels

β-Lactoglobulin amyloid fibrils are bio-colloids of high interest in many fields (e.g. water purification, cell growth, drug delivery and sensing). While the mechanical properties of pure amyloid fibril gels meet the needs of some applications, mechanical fragility often hinders a wider usage basin. In this work, we present a simple and sustainable approach for reinforcing amyloid fibril hydrogels and aerogels, upon the diffusion of polysaccharides (low-acetylated Gellan Gum and κ-carrageenan) inside their mesh. The formed hybrid materials show enhanced resistance upon compression, without any loss of the exquisite surface reactivity of the amyloid fibrils. The proposed approach can pave the way for designing composite materials that are both highly functional and environmentally friendly.

Intermolecular interaction in the hybrid gel of scallop (Patinopecten yessoensis) male gonad hydrolysates and κ-carrageenan

Various bond disrupting agents including NaCl, GuHCl, urea, and SDS were introduced to investigate the intermolecular interactions between scallop (Patinopecten yessoensis) male gonad hydrolysates (SMGHs) and κ-carrageenan (κ-C), which were monitored by changes in rheological property, water distribution, conformation characterization and microstructure by using rheometer, low field-NMR relaxometry, Fourier transform infrared (FTIR) spectroscopy, cryo-scanning electron microscopy (cryo-SEM), and confocal laser scanning microscopy. The results showed that the bond disrupting agents deteriorated the rheological property of SMGHs/κ-C in a dose-dependent manner. Indeed, at the same concentration of 2 M, NaCl deteriorated the SMGHs/κ-C more obviously than GuHCl and urea. In addition, SMGHs/κ-C with bond disrupting agents possessed higher relaxation times including T₂₁ and T₂₃ , indicating the migration to free water direction of bound and free water. Moreover, the FITR results showed the red-shift in water regions (amide A and B bands), amide I and II bands, and indicated the breakdown of hydrogen bonds and electrostatic interactions, indicating a disordered structure in SMGHs/κ-C by various bond disrupting agents. Furthermore, cryo-SEM results showed the change of SMGHs/κ-C from a homogeneous network to a looser and ruptured one with larger void spaces, and indicated the disrupted and tattered microstructure of SMGHs/κ-C by various bond disrupting agents. Additionally, SMGHs/κ-C as well showed less aggregates stained by RITC by bond disrupting agents. These results suggest that electrostatic interactions would be mainly involved in the maintenance of SMGHs/κ-C gel network. This study could provide theoretical and methodological basis for hydrogel products with modified gel strength and microstructure by understanding the intermolecular interactions in gel system. PRACTICAL APPLICATION: Scallop (Patinopecten yessoensis) male gonads as a high-protein part of scallop, is usually discarded during processing despite its edibility. In recent years, scallop male gonads are regarded as good sources to develop protein matrices due to their high protein content and numerous nutrients. In this study, scallop male gonad hydrolysates (SMGHs) were obtained by trypsin-treated process. The considerable gelation behavior of SMGHs indicated that the SMGHs could be potentially utilized as a novel thickener and additive in production of kamaboko gels, can, sausage and spread with marine flavor.

Starch-protein interplay varies the multi-scale structures of starch undergoing thermal processing

This work concerns how starch-protein interplay affects the multi-scale structures (e.g., short- and long-range orders, nanoscale structure and morphology) of starch undergoing thermal processing (pasting) involving heating and cooling at high water content. An indica rice starch (IRS) and three proteins (whey protein isolate, WPI; soy protein isolate, SPI; casein, CS) were used. By inspecting rheological profiles of mixed systems before and after adding chemicals, IRS-WPI and IRS-CS showed mainly hydrophobic molecular interaction; and IRS-SPI exhibited hydrophobic, hydrogen bonding and electrostatic interactions. The RVA results revealed that, with starch and proteins as controls, starch-globular protein (WPI or SPI) interplay accelerated the swelling of starch granules (faster viscosity increase at initial pasting stage), and reduced the paste stability during heating (higher breakdown) and during cooling (higher setback); however, the starch-casein interactions resulted in opposed effects. Moreover, starch-protein interactions varied the multi-scale chain reassembly of starch into different structures during cooling. Observed could be fewer short- and long-range starch orders, and larger nonperiod structure (or colloidal clusters) on the nanoscale. On even larger scale to micron, IRS-globular protein molecules generated larger grids (with reduced number) in the gel network, and IRS-casein formed a more continuous gel network with less prominent tunnel-like features.