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Inspired by the emulsion stability of sugar beet pulp pectin, the hydrophobic protein fraction in sugar beet pulp (SBP) is expected to feature high interfacial activity. This work retrieved alkaline extracted protein-polysaccharide conjugates (AEC) from partially depectinized SBP by hot alkaline extraction. AEC was protein-rich (57.20 %), and the polysaccharide mainly comprised neutral sugar, which adopted a rhamnogalacturonan-I pectin-like structure. The hydrophobic polypeptide chains tangled as a dense 'core' with polysaccharide chains attached as a hydrated 'shell' (hydrodynamic radius of ~110 nm). AEC could significantly decrease the oil-water interfacial tension (11.58 mN/m), featuring superior emulsification performance than three control emulsifiers, especially the excellent emulsifying stability (10 % oil) as the emulsion droplet size of 0.438 and 0.479 μm for fresh and stored (60 °C, 5 d) emulsions, respectively. The relationship of molecular structure to emulsification was investigated by specific enzymic modification, suggesting the intact macromolecular structure was closely related to emulsifying activity and that the NS fraction contributed greatly to emulsifying stability. Moreover, AEC was highly efficient to stabilize gel-like high internal phase emulsions (oil fraction 0.80) with low concentration (0.2 %) and even high ionic strength (0–1000 mM). Altogether, valorizing AEC as an emulsifier is feasible for high-value utilization of SBP. [Display omitted] • Protein-polysaccharide conjugates (AEC) was extracted from sugar beet pulp. • The macromolecule shows a protein 'core' and polysaccharide 'shell' structure. • AEC exhibited excellent emulsifying properties as superior to SBPP, GA, and WPI. • Neutral sugar chains play a crucial role in maintaining emulsion stability. • AEC was efficient in stabilizing finer HIPE and endured high ionic strength. [ABSTRACT FROM AUTHOR]

Pectin is a potential polysaccharide-based emulsifier, but the stabilized emulsions suffer from insufficient emulsion stability. Therefore, modification is needed to enhance its emulsification performance to cater to practical applications. The genipin-crosslinking strategy was used in this work to modify pectin with different sources and extraction conditions. Chemical composition analysis, molecular weight (Mw), and radius of gyration (Rg) measurement revealed that sugar beet pectin (SBP) has a more compact and flexible conformation than commercial citrus pectin (CP) and apple pectin (AP), indicated by the significantly (p < 0.05) larger Mw/Rg of SBP (18.1–11.3 kg/mol/nm) than CP (8.3 kg/mol/nm) and AP (8.0 kg/mol/nm). Crosslinking modification significantly increased the Mw, radius of gyration, and viscosity. This significantly (p < 0.05) improved the emulsifying stability (a smaller increase in droplets size) by the contribution of both thicker adsorbed hydrated layers at the oil-water interface with a stronger steric-hindrance effect and larger viscosity effect to slow down droplet collision. The formation of a blue-black substance from crosslinking reaction was able to block the UV radiation, which significantly improved the photostability of β-carotene-loaded emulsions. Altogether, genipin-crosslinking is feasible to modify pectin of different sources to enhance the emulsion stability and for use as a vehicle for delivering bioactive compounds. [ABSTRACT FROM AUTHOR]

Due to the complex composition and structure of plant polymers, a detailed investigation into the emulsification mechanism of pectin is still warranted. Herein, we aimed to clarify the relationship between the macromolecular structure (conformational flexibility and molecular weight (M w) and the emulsification performance of pectin, which was obtained from two sources (sugar beet pectin (SBP) and citrus pectin (CP) and treated by hydrothermal depolymerization (dominated by acid hydrolysis), following which the overall flexibility was assessed using the persistence length (L p)/ M w per unit contour length (M L) ratio. The results showed that depolymerization reduced the conformational flexibility of SBP (L p / M L increased from 0.0169 to 0.0219 nm2 mol/g) and improved the flexibility of CP (L p / M L decreased from 0.0551 to 0.0403 nm2 mol/g). Interfacial tension analysis revealed that the higher flexibility of pectin conferred superior surface activity, leading to decreased interfacial tension. Consequently, the fabricated emulsion was finer and more stable, with smaller changes in droplet size, as measured by a laser particle analyzer. The improved emulsification was attributed to the better exposure of hydrophobic proteins due to the conformational changes caused by the stretching and twisting of the more flexible polysaccharide chains in pectin, which facilitated higher interfacial adsorption of CP, increasing it from 43.4% to 61.8%. Moreover, the smaller interfacial concentration of the flexible pectins suggested that they had higher emulsification efficiency, in which the pectins might be densely packed at the interface to form a compact interfacial layer to stabilize the emulsion. [Display omitted] • Pectin was hydrothermally depolymerized to varying M w and conformations. • Depolymerization impairs the emulsification of SBP but could enhance that of CP. • Flexible pectin facilitates the exposure of protein and thus increase adsorption. • Flexible pectin densely packed as interfacial layer with higher compactness. [ABSTRACT FROM AUTHOR]

[Display omitted] • Thermomechanically micronized sugar beet pulp has soluble and insoluble fractions. • Microfludization was efficient to fabricate smaller and more stable emulsions. • Fibrous particles tangled as a network to warp droplets as a flocculated state. • Gel-like properties of MSBP emulsions enhanced after storage. • Hybrid coverage of soluble and insoluble fractions co-stabilized the emulsion. In this work, thermomechanically micronized sugar beet pulp (MSBP), a micron-scaled plant-based byproduct comprised of soluble elements (∼40 wt%) and insoluble fibrous particles (IFPs, ∼60 wt%), was used as a sole stabilizer for oil-in-water emulsion fabrication. The influence of emulsification parameters on the emulsifying properties of MSBP was investigated, including emulsification techniques, MSBP concentration, and oil weight fraction. High-speed shearing (M1), ultrasonication (M2), and microfludization (M3) were used to fabricate oil-in-water emulsions (20% oil) with 0.60 wt% MSBP as stabilizer, in which the d 4,3 value was 68.3, 31.5, and 18.2 μm, respectively. Emulsions fabricated by M2 and M3 (higher energy input) were more stable than M1 (lower energy input) during long-term storage (30 days) as no significant increase of d 4,3. As compared to M1, the adsorption ratio of IFPs and protein was increased from ∼0.46 and ∼0.34 to ∼0.88 and ∼0.55 by M3. Fabricated by M3, the creaming behavior of emulsions was completely inhibited with 1.00 wt% MSBP (20% oil) and 40% oil (0.60 wt% MSBP), showing a flocculated state and could be disturbed by sodium dodecyl sulfate. The gel-like network formed by IFPs could be strengthened after storage as both viscosity and module were significantly increased. During emulsification, the co-stabilization effect of the soluble elements and IFPs enabled a compact and hybrid coverage onto the droplet surface, which acted as a physical barrier to endow the emulsion with robust steric repulsion. Altogether, these findings suggested the feasibility of using plant-based byproducts as oil-in-water emulsion stabilizers. [ABSTRACT FROM AUTHOR]

Commercial emulsions are usually stabilized by multi-component formulations, such as particle and biopolymer, rather than single emulsifiers. However, their interactions and contributions to emulsification are complicated and lack elucidations. This work investigates the interaction between cellulose nanocrystal (CNC) and sugar beet pectin (SBP) and their performance in emulsion stabilization. The irreversible adsorption of SBP onto the CNC surface was verified by Quartz Crystal Microbalance with Dissipation (QCM-D) and atomic force microscopy. The molecular structure-based adsorption mechanism was elucidated by the enzymatic hydrolysis technique, revealing that the neutral sugar side chains (rich in protein and ferulic acid) were the main adsorbable components of SBP, which was predominately driven by hydrophobic interactions. At the CNC: SBP ratio of 3:1, the mixture of SBP-coated CNC and free SBP showed synergistic emulsification performance. The incorporation of CNC significantly improved the anchoring rate of SBP at the oil-water interface during emulsification to produce smaller emulsion droplets. The hybrid coverage of SBP-coated CNC and free SBP endowed the droplets with more robust repulsion to maintain long-term stability. These findings provide a feasible and convenient way for modulating the emulsifying properties of CNC by changing the compositional formulation. [Display omitted] • Cellulose nanocrystal (CNC) adsorbed with sugar beet pectin (SBP) in solution. • The adsorbable fractions of SBP were neutral sugar, protein, and ferulic acid. • The interaction was predominated by hydrophobic interaction. • CNC and SBP showed a synergistic stabilization effect to stabilized emulsions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sugar beet pulp (SBP) was micronized into fibrous particles with ultrasonication. • High-temperature pretreatment could soften the compact structure of SBP particles. • Porous SBP absorbed ultrasonic energy to prevent soluble substances degradation. • Micronization process improved the emulsifying capacity of SBP. • The flocculation of emulsion can be modulated by adjusting preparing parameters. Sugar beet pulp (SBP), the main by-product of the beet sugar industry, has gained increasing attention due to its potential functional properties as a clean-label food ingredient. The aim of the present work was to optimize a food-grade approach for SBP micronization via harsh thermal pretreatment and ultrasonication, after which the micronized SBP was used as an emulsifier. Harsh thermal pretreatment substantially softened the compact particle structure of SBP, thereby improving breakage efficiency by reducing the ultrasonication time to 10 min (suspension stability of ∼100%). During ultrasonication, the particle size of SBP declined from ∼34 to ∼25 μm, which showed long and tangled morphology as fibers (diameter of 50–300 nm). The increased solubility enlarged the specific surface area of SBP from ∼0.6 to ∼3.5 g/m2, endowing it with a porous structure for improved ultrasonic energy adsorption, thereby preventing the degradation of the dissolved pectic polymers. The dissociation of SBP particles contributed to the enhancement of emulsification and was correlated with an increase in suspension stability. These findings provide a feasible strategy for the high added-value utilization of SBP. [ABSTRACT FROM AUTHOR]

Food-grade polysaccharide-protein based nanoparticles receive considerable interest in food, pharmaceutical and cosmetic industries as Pickering emulsion stabilizer to satisfy the need of safety and emulsifying functionality. Here, we reported a type of novel sugar beet pectin-bovine serum albumin conjugate nanoparticles (S-BNPs) with a mean size of ~180 nm that were fabricated by the genipin-crosslinking strategy followed by facile ultrasonication. The as-prepared S-BNPs mainly consisted of 35.2% polysaccharide and 58.4% protein, showing a core-shell nanostructure with SBP chains surrounding the inner protein core, as unveiled by analyses of atomic force microscopy and transmission electron microscopy. S-BNPs had excellent colloidal stability under various pH (4.0–12.0) and ionic strength (μ , 0–500 mM) conditions. When used at a concentration (c) of 0.5 wt%, S-BNPs well stabilized Pickering emulsions (from creamed to gel-liked high internal phase emulsions/HIPEs) with different droplet characteristics and visual appearances with a maximum oil volume fraction (Ф) up to 0.84. At a lower c of 0.25 wt%, S-BNPs stabilized Pickering emulsions with a maximum Ф up to 0.70. Rheology measurements indicated that a higher c strengthened the stiffness of HIPEs (Ф = 0.80), thereby endowing the gel-like HIPEs with a self-supporting appearance. Owing to its unique nanostructure, S-BNPs displayed desirable emulsification properties at a wide range of pH (5.0–12.0) and μ (0–500 mM), whereas the two control samples, Crosslinked-BSA and SBP-BSA-Complex (electrostatically bound at pH 4.5), showed inferior emulsification properties in long-term storage, pH, and μ testings. In the repetitive freeze/thaw-induced demulsification cycles, a representative S-BNPs stabilized HIPE was re-emulsified 5 times. Altogether, this work demonstrates that the genipin-crosslinking is feasible to synthesize S-BNPs as an edible Pickering emulsion stabilizer for food and relating industries. Image 1 • Sugar beet pectin (SBP) and bovine serum albumin (BSA) were crosslinked by genipin. • Insoluble crosslinked SBP-BSA was ultrasonicated into well-dispersed nanoparticles. • SBP provided steric stabilization to the protein core by forming a hydrated shell. • As prepared SBP-BSA nanoparticles rendered Pickering emulsions stable at pH 5.0–12.0. • The prepared Pickering emulsions endured ionic strengths of 0–500 mM NaCl. [ABSTRACT FROM AUTHOR]

This work aimed to construct conjugates of sugar beet pectin (SBP) with exogenous proteins by adopting a genipin (GP) crosslinking strategy. The conversion processes of two protein, bovine serum albumin (BSA) and whey protein isolate (WPI) to the molecular chains of SBP were investigated using high-performance size-exclusion chromatography technology under varying SBP/exogenous protein weight ratios (SPR) (2:1–20:1) and crosslinking times (1–25 h). When prepared at SPR 10:1, the formed SBP-WPI/BSA-SBP conjugates had notably higher molecular weights of 2151 ± 68 kg/mol and 1758 ± 45 kg/mol, respectively, in comparison with that of SBP (289 ± 16 kg/mol). In terms of reactivity, WPI showed higher reactivity than BSA in crosslinking with SBP by GP. Two representative samples, SBP-WPI-Conjugate and SBP-BSA-Conjugate, prepared at SPR 10:1 after 25 h of crosslinking were further analyzed for surface hydrophobicity (S 0) and emulsifying properties. It was found that S 0 values of the SBP-WPI-Conjugate and SBP-BSA-Conjugate were significantly lower than that of the control blend samples. Furthermore, the selected conjugates showed superior emulsion stabilizing properties as compared with SBP-exogenous protein blends or individual SBP and exogenous proteins. After storage at 60 °C for 7 d, emulsions stabilized by SBP-WPI-Conjugate and SBP-BSA-Conjugate at concentration of 1 g/100 g emulsion had mean droplet diameters of 0.735 ± 0.023 μm and 0.733 ± 0.011 μm at pH 3.5, and 0.972 ± 0.020 μm and 1.07 ± 0.08 μm at pH 7.0, respectively. Altogether, the work demonstrates that the GP crosslinking method is suitable for upgrading SBP to SBP-protein conjugate with enhanced emulsification properties. Image 1 • The covalent conjugation between SBP and WPI/BSA was initiated by genipin. • Target sites of the conjugation were the primary amine groups of lysine residues. • The conjugation was verified by HPSEC-MALLS-RI-UV chromatography. • Geinpin-induced SBP-WPI/BSA conjugates had excellent emulsification properties. [ABSTRACT FROM AUTHOR]

This work aimed to enhance the emulsifying properties of sugar beet pectin (SBP) by adopting a crosslinking strategy that covalently bridged the amino groups (–NH 2) of lysine residues of the proteinaceous moiety using genipin (GP) as the crosslinker. Compared to control-SBP (C-SBP), GP crosslinked SBP (G-SBP) was larger in molecular weight (from 3.04 × 105 g/mol to 1.31 × 106 g/mol) and mean radius of gyration (from 34.8 nm to 39.2 nm), and showed a more compact conformation, as supported by analysis of high-performance size exclusion chromatography coupled with multiple angle light scattering (SEC-MALLS) and atomic force microscopy (AFM). G-SBP was featured by a new absorbance peak at ~595 nm, resulting in a distinct blue color of the aqueous solution. G-SBP suffered a slight decrease in interfacial properties and emulsifying activities in comparison to C-SBP, leading to a lower specific surface area and a larger volume-weighted mean diameter (d 4,3) for the fresh emulsion. Nevertheless, the G-SBP stabilized emulsion was more stable than the C-SBP stabilized emulsion during storage for 21 d with d 4,3 increasing from 0.541 μm and 0.425 μm to 0.625 μm and 1.66 μm for G-SBP and C-SBP, respectively. The improved emulsifying stability of G-SBP can be ascribed to the combination of the following two aspects: 1) G-SBP exerted a lager viscosity-enhancing effect to slow down droplet collision and flocculation; 2) the carbohydrate moiety of G-SBP formed a dense and compact hydrated layer providing strong steric stabilization for the oil droplets to resist flocculation and coalescence. Altogether, this work demonstrates that GP is a favorable agent to crosslink the side chains of SBP and modify its emulsification performance. Image 1 • Primary amine groups of lysine of SBP are target sites for crosslinking by genipin. • SBP was covalently crosslinked by genipin to show novel macromolecular properties. • Emulsion-stabilizing effects of SBP were enhanced by crosslinking with genipin. • Genipin crosslinked SBP provided steric stabilization against emulsion breakdown. [ABSTRACT FROM AUTHOR]

This work characterized the physicochemical properties of two carbohydrate fractions, ASP1 and ASP2, that were sequentially extracted using NaOH and then NaOH/H 2 O 2 from the pulp remained from the extraction of sugar beet pectin (SBP). It has been shown that ASP1 and ASP2 differed from SBP in terms of chemical and macromolecular features. The ability of the ASPs to stabilize oil-in-water emulsions containing 10% w/w oil was compared using SBP and gum arabic (GA) as reference emulsifiers. The volume weighted droplet size (d 4,3 value) decreased as the concentration of SBP, ASP1, ASP2 and GA, increased in series 1.25, 1.5, 1.5, and 9% w/w and after which it remained constant except for ASP2 where the d 4,3 increased at concentrations above 2.5%. At concentrations of 1.25, 1.5, 1.5, and 9% of SBP, ASP1, ASP2, and GA, critical d 4,3 values of 0.55, 0.52, 2.14 and 0.55 μm were obtained, and droplet size for ASP2 was about 4 times greater compared with the other polysaccharides. The effects of pH (2–5) and ionic strength (Na+ or Ca2+, 0–100 mM) on the emulsifying activity at the critical concentration of the polysaccharide were studied. Emulsions stabilized by either ASP1 or 2 were unstable in the presence of Ca2+ due to the occurrence of bridge flocculation between oil droplets. It is concluded that ASP1 and ASP2 possess relatively inferior emulsification properties and, thus, are potential emulsifiers for use in low-calcium systems. Image 1 • A pectin and two alkaline soluble polysaccharides (ASPs) were produced from the pulp. • Physicochemical and emulsifying properties of ASPs varied with extraction conditions. • Emulsifying properties of ASPs were compared with those of recognized emulsifiers. • The emulsifying mechanism of ASP2 is quite different from other investigated gums. [ABSTRACT FROM AUTHOR]

In our previous study, an alkaline soluble polysaccharide (ASP2), nearly non-methoxylated and non-acetylated, was prepared from the depectinized sugar beet pulp. Although displaying modest emulsion stabilizing properties, ASP2 had poor properties against calcium-induced droplet aggregation, which narrows its potential applications in food. This study aimed to overcome this limitation via esterifying ASP2 with methanol and acetic anhydride with carboxyl and hydroxyl groups of GalA residues, respectively. The results showed that the physicochemical properties, such as molecular weight, zeta-potential, neutral sugar (NS) content, etc., varied with degrees of methoxylation and acetylation. Emulsifying properties of methoxylated ASP2 (M-ASP2), acetylated ASP2 (A-ASP2), methoxylated-acetylated ASP2 (MAA), and acetylated-methoxylated ASP2 (AMA) were evaluated. Results showed that in an oil-in-water emulsion system containing 10% w/w MCT and 1% w/w emulsifier, A-ASP2 showed the best emulsifying activity as indicated by the lowest d 4,3 (0.29 μm), followed by M-ASP2 with a d 4,3 of 0.51 μm, while the emulsifying activities of MAA (5.25 μm) and AMA (11.1 μm) were unexpectedly worse than ASP2 (0.61 μm). The stability of A-ASP2-stabilized emulsion was comparable to that of original ASP2 but significantly better than others. M-ASP2 effectively inhibited calcium-bridged droplet aggregation, with a relatively small mean droplet size of 0.53 μm. Methoxylation or acetylation could solely enhance the hydrophobicity of ASP2, while dual modification resulted in deteriorated emulsifying properties. [Display omitted] • Emulsifying performance of ASP2 was improved by either methoxylation or acetylation. • Combined methoxylation and acetylation decreased emulsifying properties of ASP2. • Methoxylation offered ASP2 stability against calcium-induced droplet aggregation. [ABSTRACT FROM AUTHOR]

Alkaline soluble polysaccharide 1 (ASP1) was a polysaccharide extracted from residues remaining from the extraction of sugar beet pulp. This study aimed to separate ASP1 into five different fractions, named UP, UR, F50, F65 and F75, by using ultrafiltration membrane and stepwise alcohol-precipitation. The results showed that the fractions differed from each other regarding their chemical and macromolecular features. The Mw of these sub-fractions decreased in the order of F65 (340 kg mol−1), UR (325 kg mol−1), F75 (295 kg mol−1), F50 (278 kg mol−1) and UP (78 kg mol−1). The emulsifying properties of these fractions in oil-in-water systems containing 10% w/w MCT were compared, taking ASP1 as the reference. At concentrations of 1% of each polysaccharide, F75 showed the best emulsifying activity with the d 4,3 value of 0.35 μm, while the droplet size for UP was 10 times greater than the others. After storage at 60 °C for seven days, emulsion stability decreased in the order of F65, UR, ASP1, F75, F50 and UP, based on the d 4,3 value increment of 0.27 μm, 0.95 μm, 1.48 μm, 3.33 μm, 3.99 μm and 21.5 μm, respectively. Due to the occurrence of calcium bridge flocculation, most polysaccharides in this work could not stabilize oil-in-water systems into homogeneous emulsions, except F65 and F75, in which d 4,3 values were increased from 1.22 and 0.72 μm to 13.7 and 3.6 μm, respectively, after storage, demonstrating great resistance to calcium for F75. In conclusion, membrane filtration combined with alcohol-precipitation is feasible to separate the mother polysaccharide into sub-fractions with different emulsifying properties, among which selected fractions exhibiting superior emulsifying properties could be used as potential emulsifiers in low-calcium systems. Image 1 • ASP1 was fractioned into five components with different physicochemical properties. • The membrane permeated fraction from ASP1 showed poor emulsifying properties. • F75 showed better emulsifying activity and Ca2+ tolerance compared to the other ones. • Hydrophobic amino acid content of ethanol-fractioned samples could be regulated. [ABSTRACT FROM AUTHOR]

Ethanol-soluble polysaccharide (ESP) is a highly ethanol-soluble (85% v/v) fraction from the precipitation process of sugar beet pectin and holds the potential to be utilized for food purposes. This study aimed to explore ESP as a coating polymer to stabilize zein nanoparticles against agglomeration via co-dissolving ESP and zein in an ethanol/water mixture (85% v/v) and subsequently dispersing into the water to form composite nanoparticles. Structural analyses showed that the ESP contained 28.3 wt% galacturonic acid, 45.7 wt% neutral sugar, and 17.6 wt% protein, and that its average molecular weight was 93,157 Da. In this study, we fabricated ESP-coated zein (zein-ESP) nanoparticles with a diameter of around 248 nm using the antisolvent co-precipitation method. These zein-ESP nanoparticles were stable over a wide pH range of 2.0–8.0 when the ESP:zein mass ratio was higher than 0.6:1. Additionally, the nanoparticles exhibited good stability in environmental stresses such as sodium ion concentrations of 400 mM and high temperatures of 90 °C (for 120 min). The encapsulation efficiency of Cur improved significantly, from 68.5% with the zein nanoparticles to 88.7% with the zein-ESP nanoparticles. When encapsulated by zein-ESP nanoparticles, Cur presented as an amorphous form and was released in a sustained and controlled manner after exposure to simulated gastrointestinal fluids, resulting in enhanced solubility and in vitro bioaccessibility, as compared with the free Cur. Altogether, ESP has great potential to stabilize zein nanoparticles-based delivery systems for hydrophobic bioactive compounds with enhanced water solubility and encapsulation efficiency for use in the food and pharmaceutical industries. [Display omitted] • Small-sized polysaccharides (ESP) from sugar beet pulp were isolated and analyzed. • Composite ESP-zein nanoparticles (NPs) were formed via antisolvent precipitation. • ESP and zein well-solubilized in an 85% ethanol solution before nanonization. • ESP surface-decorated and stabilized zein NPs against environmental stress. • ESP-zein NPs are potential delivery vehicles with improved encapsulation efficiency. [ABSTRACT FROM AUTHOR]

Sugar beet pectin (SBP) was modified by alkaline at both 25 °C and 3 °C to produce gel-type pectins. The structure, rheological and gelation properties of series modified SBPs were then assessed. The results showed that low temperature effectively inhibited the β-elimination of SBP during alkali treatment, and the average molecular weight (M w) and galacturonic acid (GalA) content of the resulting SBP were much higher than that of the alkali-treated SBP at 25 °C. Due to the low degree of methylation (DM) (≦ 21.2) and degree of acetylation (DA) (≦ 14.6), SBP treated under pH 11 and 12 at 3 °C could successfully form stable elastic gels, and these gels were further confirmed to be frequency-independent through rheological analysis. The SEM and TG/DTG results showed that the corresponding gel of SBP treated under pH 12 at 3 °C for 120 min had the most uniform micro-network structure and the best thermal stability. This work for the first time demonstrated the effect of a wide pH range on the chemical structure, rheological and physical gelation properties of SBP, especially under alkaline conditions at a low temperature (3 °C). Findings from this work suggest that alkali treatment at low-temperature allows SBP to have the potential to become a gel-type commercial pectin. Image 1 • Alkali treatment at 3 °C markedly reduced the DM and DA of SBP. • β-elimination of SBP treated with alkali at 3 °C was suppressed to a certain extent. • SBP gels were elastic and frequency-independent. • Gel formation changed the crystallinity and thermal stability of SBP molecules. [ABSTRACT FROM AUTHOR]

Bovine serum albumin (BSA) was used as an auxiliary to improve the ethanol precipitation yield of sugar beet pulp pectin (SBPP). The adjunction of BSA reduced the zeta potential of SBPP solution to a certain extent, which indicated that they were related to each other by electrostatic interaction. The hydration radius (R h) of SBPP molecules decreased with the addition of BSA, reflecting the decrease of hydration degree of SBPP molecules. The effect of BSA on the ethanol precipitation yield of SBPP at different ethanol concentrations and different pH values was studied. The results showed that the presence of BSA could significantly reduce the dependence of SBPP on ethanol during the precipitation process. The effect of BSA on the precipitation behavior of SBPP was also regulated by system pH. The results of pectin structural analysis showed that there was no significant difference between SBPPs precipitated along with BSA and the original pectin samples in terms of galacturonic acid (GalA), neutral sugar (NS) and degree of methylation (DM). The high-performance size-exclusion chromatography (HPSEC) analysis showed that BSA could precipitate together with SBPP, but did not contribute to the precipitation of small-sized pectic fractions in SBPP solution. SBPP-BSA co-precipitation products were used to stabilize oil-in-water emulsions, and the storage stability of the resulting emulsions was significantly higher than that of the SBPP-stabilized emulsions. This method provided a new idea for reducing the consumption of ethanol in pectin precipitation. Meanwhile, the pectin-protein complex product obtained by co-precipitation had a good performance at stabilizing emulsions. Image 1 • BSA markedly aided the ethanol precipitation of SBPP. • The SBPP-BSA electrostatic complexes were formed and co-precipitated by ethanol. • Co-precipitated SBPP-BSA complexes showed improved emulsion stabilisation properties. [ABSTRACT FROM AUTHOR]