Stabilisation of oil-in-water emulsions with non-chemical modified gelatinised starch

Unraveling the impact of starch granule-associated proteins on the emulsifying ability of quinoa starch granules at multiple scales

Total starch granule-associated proteins (tGAP), including granule-channel (GCP) and granule-surface proteins (GSP), alter the physicochemical properties of starches. Quinoa starch (QS) acts as an effective emulsifier in Pickering emulsion. However, the correlation between the tGAP and the emulsifying capacity of QS at different scales remains unclear. Herein, GCP and tGAP were selectively removed from QS, namely QS-C and QS-A. Results indicated that the loss of tGAP increased the water permeability and hydrophilicity of the starch particles. Mesoscopically, removing tGAP decreased the diffusion rate and interfacial viscous modulus. Particularly, GSP had a more profound impact on the interfacial modulus than GCP. Microscopically and macroscopically, the loss of tGAP endowed QS with weakened emulsifying ability in terms of emulsions with larger droplet size and diminished rheological properties. Collectively, this work demonstrated that tGAP played an important role in the structural and interfacial properties of QS molecules and the stability of QS-stabilized emulsions.

Influence of gelatinized octenyl succinic anhydride-modified waxy adlay seed starch on the properties of astaxanthin-loaded emulsions: Emulsion properties, stability and in vitro digestion properties

Octenyl succinic anhydride (OSA)-modified starch is a commonly used food emulsifier and its emulsifying properties are positively correlated with the degree of substitution (DS). However, the maximum concentration of OSA in starch approved by the FDA and the China National Food Safety Standards is 3%. This study aims to enhance the emulsifying properties of OSA-modified waxy adlay seed starch by gelatinization under a limited DS and investigate its use in preparing delivery systems. The gelatinized OSA starch exhibited a more flexible macromolecular structure and better emulsifying activity (20.19 m2/g). The gelatinized OSA starch-stabilized astaxanthin-loaded emulsions showed high retention of astaxanthin (>50%) and long-term stability (56 days). In vitro digestion, the emulsion system showed a protective effect on astaxanthin, and the bioaccessibility of astaxanthin was increased to 16.32%. This study indicated that gelatinization could enhance the emulsifying properties of OSA starch, and this starch-stabilized emulsion was an effective system for astaxanthin.

Oil-in-water emulsion activity and stability of short-term retrograded starches depend on starch molecular size, amylose content, and amylopectin chain length

BACKGROUND

Natural emulsifiers are increasingly preferred by the food industry to meet consumers' demand for 'clean-label' emulsion products. In the present study, 10 short-term retrograded starches with unique molecular structures were explored to examine the relationships between starch structures and their ability to form stable oil-in-water emulsions.

RESULTS

Waxy maize starch showed the largest value of contact angle and conductivity of emulsion, whereas potato and lentil starch showed the lowest value of contact angle and conductivity of emulsion, respectively. Emulsion prepared by rice starch showed the lowest, whereas that of sweet potato starch showed the highest value of viscosity. Consequentially, the emulsion stabilized with waxy maize and tapioca starch showed the smallest and less polydisperse droplets, resulting in a much higher emulsifying index. On the other hand, emulsion prepared with potato starch showed the highest stability compared to other starches. Correlation analysis suggested that starches with larger molecular size, a lower amylose content and shorter amylopectin short chains had a higher emulsification ability, whereas the amount of starch molecular interactions formed during short-term retrogradation revealed no obvious linking to emulsion performances.

CONCLUSION

These findings provided food industry with exciting opportunities to develop 'clean-label' emulsions with desirable properties. © 2024 Society of Chemical Industry.

Effects of different oil fractions and tannic acid concentrations on konjac glucomannan-stabilized emulsions

Polysaccharide-stabilized emulsions have received extensive attention, but emulsifying activity of polysaccharides is poor. In this study, konjac glucomannan (KGM) and tannic acid (TA) complex (KGM-TA) was prepared via non-covalent binding to increase the polysaccharide interfacial stability. The emulsifying stabilities of KGM-TA complex-stabilized emulsions were analyzed under different TA concentrations and oil fractions. The results indicated that hydrogen bonds and hydrophobic bonds were the main binding forces for KGM-TA complex, which were closely related to TA concentrations. The interfacial tension of KGM-TA complex decreased from 20.0 mN/m to 13.4 mN/m with TA concentration increasing from 0 % to 0.3 %, indicating that TA improved the interfacial activity of KGM. Meanwhile, the contact angle of KGM-TA complex was closer to 90° with the increasing TA concentrations. The emulsifying stability of KGM-TA complex-stabilized emulsions increased in an oil mass fraction-dependent manner, reaching the maximum at 75 % oil mass fraction. Moreover, the droplet sizes of KGM-TA complex-stabilized high-internal-phase emulsions (HIPEs) decreased from 82.7 μm to 44.7 μm with TA concentration increasing from 0 to 0.3 %. Therefore, high TA concentrations were conducive to the improvement of the emulsifying stability of KGM-TA complex-stabilized HIPEs. High oil mass fraction promoted the interfacial contact of adjacent droplets, thus enhancing the non-covalent binding of KGM molecules at the interfaces with TA as bridges. Additionally, the high TA concentrations increased the gel network density in the aqueous phase, thus enhancing the emulsifying stability of emulsions. Our findings reveal the mechanisms by which polysaccharide-polyphenol complex stabilized HIPEs. Therefore, this study provides theoretical basis and references for the developments of polysaccharide emulsifier with high emulsifying capability and high-stability emulsions.

The role of alginate in starch nanocrystals-stabilized Pickering emulsions: From physical stability and microstructure to rheology behavior

Sodium alginate (SA) was used as a co-stabilizer to improve the Pickering emulsions stabilized by starch nanocrystals (SNC). Compared with pure SNC, SNC/SA complexes possess better neutral wettability with the contact angle approaching to 90°, more surface negative charges, and lower oil-water interfacial tension. These properties of particles make as-prepared emulsion higher stability with the lower creaming index and average droplet size. Furthermore, the emulsion exhibited good stability against salt (0-600 mM) and pH (2.0-6.0) at higher SA concentration (1.0 wt%). Confocal laser scanning microscopy (CLSM) images proved that SNC could be effectively adsorbed at the oil-water interface with the aid of SA. Rheological analysis showed that higher content of SA resulted in improved strength and higher viscosity of emulsion system. Results from this work indicating that SA could be a useful co-stabilizer to fulfill the demands of Pickering emulsions stabilized by SNC with stable characteristics.

Replacement of milk fat by rapeseed oil stabilised emulsion in commercial yogurt

The incorporation of lipid droplets and further characterization of matrices within dairy products may be possible using such adjacent particles as protein complexes/lipids. Among the range of varied emulsions and their functionalities, great attention has recently focused on the fabrication of high internal phase types. Feasibly, stable alternatives structured with health-beneficial lipids like those derived from plants could replace saturated fatty acids. As a fat replacement strategy, the fate of incorporated HIPE would require some adjustments either with storage stability and/or structural feat for the food matrix. Therefore, the replacement of milk fat by rapeseed oil stabilised emulsion in commercial yogurt was investigated. This involved 25%, 50% and 75% rapeseed oil respectively assigned as low (LIPE), medium (MIPE), and high internal phase emulsion (HIPE). Specifically, emulsions were examined by droplet size, encapsulation, pH, zeta potential, phase separation, and rheology. The fat free yogurt supplemented by HIPE were examined by droplet size, zeta potential, pH, color, sensory, texture and microbiological aspects against positive (regular milk fat) and negative (fat free) yogurt controls. Results showed increasing rapeseed oil contents would form smaller droplet-like emulsions. Within the yogurt matrix however, incorporating HIPE would seemingly reduce oil droplet size without much compromise to bacterial viability, sensory, or texture. Overall, this simple method of lipid alternation shows promise in dairy products.

Formation Mechanism of Starch-Based Double Emulsions from the Interfacial Perspective

Double emulsions are of significant practical value in protecting the core material owing to their multicomponent structure and have thus been applied in various fields, such as food, cosmetics, and drugs. However, the mechanism of double emulsion formation by native starch is not well established. Herein, we demonstrate a facile route to develop type-A, type-B, and type-C double emulsions using native starch and develop an innovative design for a carrier. Interfacial interaction, enthalpy changes of starch, and interfacial properties are key factors governing the formation of double emulsions and controlling the type of double emulsions formed. Therefore, the results of this study provide a better understanding of how and what type of starch-based double emulsions are formed.

Foaming with Starch: Exploring Faba Bean Aquafaba as a Green Alternative

The demand for sustainable and functional plant-based products is on the rise. Plant proteins and polysaccharides often provide emulsification and stabilization properties to food and food ingredients. Recently, chickpea cooking water, also known as aquafaba, has gained popularity as a substitute for egg whites in sauces, food foams, and baked goods due to its foaming and emulsifying capacities. This study presents a modified eco-friendly process to obtain process water from faba beans and isolate and characterize the foam-inducing components. The isolated material exhibits similar functional properties, such as foaming capacity, to aquafaba obtained by cooking pulses. To isolate the foam-inducing component, the faba bean process water was mixed with anhydrous ethanol, and a precipitated fraction was obtained. The precipitate was easily dissolved, and solutions prepared with the alcohol precipitate retained the foaming capacity of the original extract. Enzymatic treatment with α-amylase or protease resulted in reduced foaming capacity, indicating that both protein and carbohydrates contribute to the foaming capacity. The dried precipitate was found to be 23% protein (consisting of vicilin, α-legumin, and β-legumin) and 77% carbohydrate (amylose). Future investigations into the chemical structure of this foam-inducing agent can inform the development of foaming agents through synthetic or enzymatic routes. Overall, this study provides a potential alternative to aquafaba and highlights the importance of exploring plant-based sources for functional ingredients in the food industry.

Physicochemical, Rheological, In-Vitro Digestibility, and Emulsifying Properties of Starch Extracted from Pineapple Stem Agricultural Waste

In this study, the physicochemical, rheological, in vitro starch digestibility, and emulsifying properties of starch extracted from pineapple stem agricultural waste were investigated in comparison with commercial cassava, corn, and rice starches. Pineapple stem starch had the highest amylose content (30.82%), which contributed to the highest pasting temperature (90.22 °C) and the lowest paste viscosity. It had the highest gelatinization temperatures, gelatinization enthalpy, and retrogradation. Pineapple stem starch gel had the lowest freeze-thaw stability, as evidenced by the highest syneresis value of 53.39% after five freeze-thaw cycles. Steady flow tests showed that pineapple stem starch gel (6%, w/w) exhibited the lowest consistency coefficient (K) and the highest flow behavior index (n), while dynamic viscoelastic measurements gave the gel strength in the following order: rice > corn > pineapple stem > cassava starch gel. Interestingly, pineapple stem starch provided the highest slowly digestible starch (SDS) (48.84%) and resistant starch (RS) (15.77%) contents compared to other starches. The oil-in-water (O/W) emulsion stabilized with gelatinized pineapple stem starch exhibited higher emulsion stability than that stabilized with gelatinized cassava starch. Pineapple stem starch could therefore be used as a promising source of nutritional SDS and RS, and as an emulsion stabilizer for food applications.

Starch physical treatment, emulsion formation, stability, and their applications

Pickering emulsions are increasingly preferred over typical surfactant-based emulsions due to several advantages, such as lower emulsifier usage, simplicity, biocompatibility, and safety. These types of emulsions are stabilized using solid particles, which produce a thick layer at the oil-water interface preventing droplets from aggregating. Starch nano-particles (SNPs) have received considerable attention as natural alternatives to synthetic stabilizers due to their unique properties. Physical formulation processes are currently preferred for SNP production since they are environmentally friendly procedures that do not require the use of chemical reagents. This review provides a thorough overview in a critical perspective of the physical processes to produce starch nano-particles used as Pickering emulsion stabilizers, fabricated by a 2-step process. Specifically, the reviewed physical approaches for nano-starch preparation include high hydrostatic pressure, high pressure homogenization, ultrasonication, milling and antisolvent precipitation. All the essential parameters used to evaluate the effectiveness of particles in stabilizing these systems are also presented in detail, including the hydrophobicity, size, and content of starch particles. Finally, this review provides the basis for future research focusing on physical nano-starch production, to ensure the widespread use of these natural stabilizers in the ever-evolving field of food technology.

Influence of spray drying parameters on the physicochemical characteristics of microencapsulated pomelo (Citrus grandis (L.) Osbeck) essential oil

This study aimed to evaluate the encapsulation of pomelo (Citrus grandis (L.) Osbeck) essential oils using the spray drying technique. The parameters of the process include concentration of maltodextrin (20-35% by wt%/wt%), concentration of essential oil (1-2.5% by wt%/wt%), inlet temperature of spray drying (120-180 °C), and feed flow rates (120-240 mL/h) were soundly examined. The utilization of suitable parameters as the concentration of maltodextrin at 30% (by wt%/wt%), the concentration of essential oil at 1.5% (by wt%/wt%), the inlet temperature of 140 °C, and feed flow rate of 120 mL/h showed the highest drying yields (90.05%), microencapsulation yield (75.59%), and microencapsulation efficiency (89.44%). TGA and DSC results verified higher stability of Citrus grandis essential oil after encapsulation. The encapsulation of pomelo essential oils maintained most of the major components in comparison with the non-encapsulated essential oils without any significant changing in powder-obtained quality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01161-5.

Effective Use of Plant Proteins for the Development of "New" Foods

Diversity in our diet mirrors modern society. Affluent lifestyles and extended longevity have caused the prevalence of diabetes and sarcopenia, which has led to the increased demand of low-carb, high-protein foods. Expansion of the global population and Westernization of Asian diets have surged the number of meat eaters, which has eventually disrupted the supply–demand balance of meat. In contrast, some people do not eat meat for religious reasons or due to veganism. With these multiple circumstances, our society has begun to resort to obtaining protein from plant sources rather than animal origins. This “protein shift” urges food researchers to develop high-quality foods based on plant proteins. Meanwhile, patients with food allergies, especially gluten-related ones, are reported to be increasing. Additionally, growing popularity of the gluten-free diet demands development of foods without using ingredients of wheat origin. Besides, consumers prefer “clean-label” products in which products are expected to contain fewer artificial compounds. These diversified demands on foods have spurred the development of “new” foods in view of food-processing technologies as well as selection of the primary ingredients. In this short review, examples of foodstuffs that have achieved tremendous recent progress are introduced: effective use of plant protein realized low-carb, high protein, gluten-free bread/pasta. Basic manufacturing principles of plant-based vegan cheese have also been established. We will also discuss on the strategy of effective development of new foods in view of the better communication with consumers as well as efficient use of plant proteins.

Pickering emulsion stabilized by hydrolyzed starch: Effect of the molecular weight

HYPOTHESIS

The emulsifying ability of starch is influenced by its molecular weight. Reducing the molecular weight of starch is expected to influence interfacial adsorption and membrane elasticities, thereby affecting its emulsifying ability through Pickering effects. Hence, it should be possible to tailor the emulsifying ability of starch by adjusting its molecular weight.

EXPERIMENTS

Waxy corn starch (CS) and rice starch (RS) were hydrolyzed with pullulanase to obtain high (HM) and low molecular weight (LM) fractions. After the molecular weight was determined by size exclusion chromatography, the fractions were used to prepare model oil-in-water emulsions. The stability, microscopy, and particle size of the emulsions were characterized, and the underlying emulsification mechanism was subsequently studied through dynamic laser scattering, surface tension analysis, interfacial rheology, and Pearson's correlation calculations.

FINDINGS

In the molecular weight range obtained in this study, the smaller the molecular weight of starch, the stronger its emulsifying ability. The decrease in molecular weight resulted in considerable different adsorption and interfacial elasticities with smaller fractions occupying less area on the interface and forming interfaces with higher elasticities, resulting in higher stabilities through Pickering effects. Results thus suggest that the emulsifying ability of starch may be tailored by adjusting its molecular weight.

Rheology, Microstructure, and Storage Stability of Emulsion-Filled Gels Stabilized Solely by Maize Starch Modified with Octenyl Succinylation and Pregelatinization

We prepared emulsion-filled gels stabilized using octenyl succinic anhydride-modified and pregelatinized maize starch (OSA-PGS). The effect of the oil volume fraction (Φ, 0.05–0.20) and OSA-PGS concentration (3–10% w/v) on the rheological and microstructural properties of the emulsion-filled gels was evaluated. Confocal fluorescence images showed that OSA-PGS stabilized the emulsion, indicated by the formation of a thick layer surrounding the oil droplets, and simultaneously gelled the aqueous phase. All of the emulsions exhibited shear-thinning flow behavior, but only those with 10% w/v OSA-PGS were categorized as Herschel–Bulkley fluids. The rheological behavior of the emulsion-filled gels was significantly affected by both the OSA-PGS concentration and Φ. The mean diameters (D1,0, D3,2, and D4,3) of oil droplets with 10% w/v OSA-PGS were stable during 30 days of storage under ambient conditions, indicating good stability. These results provide a basis for the design of systems with potential applications within the food industry.

Integrating biomaterials and food biopolymers for cultured meat production

Cultured meat has recently achieved mainstream prominence due to the emergence of societal and industrial interest. In contrast to animal-based production of traditional meat, the cultured meat approach entails laboratory cultivation of engineered muscle tissue. However, bioengineers have hitherto engineered tissues to fulfil biomedical endpoints, and have had limited experience in engineering muscle tissue for its post-mortem traits, which broadly govern consumer definitions of meat quality. Furthermore, existing tissue engineering approaches face fundamental challenges in technical feasibility and industrial scalability for cultured meat production. This review discusses how animal-based meat production variables influence meat properties at both the molecular and functional level, and whether current cultured meat approaches recapitulate these properties. In addition, this review considers how conventional meat producers employ exogenous biopolymer-based meat ingredients and processing techniques to mimic desirable meat properties in meat products. Finally, current biomaterial strategies for engineering muscle and adipose tissue are surveyed in the context of emerging constraints that pertain to cultured meat production, such as edibility, sustainability and scalability, and potential areas for integrating biomaterials and food biopolymer approaches to address these constraints are discussed. STATEMENT OF SIGNIFICANCE: Laboratory-grown or cultured meat has gained increasing interest from industry and the public, but currently faces significant impediment to market feasibility. This is due to fundamental knowledge gaps in producing realistic meat tissues via conventional tissue engineering approaches, as well as translational challenges in scaling up these approaches in an efficient, sustainable and high-volume manner. By defining the molecular basis for desirable meat quality attributes, such as taste and texture, and introducing the fundamental roles of food biopolymers in mimicking these properties in conventional meat products, this review aims to bridge the historically disparate fields of meat science and biomaterials engineering in order to inspire potentially synergistic strategies that address some of these challenges.

Preparation and stability mechanisms of double emulsions stabilized by gelatinized native starch

Double emulsions are promising carrier systems for foods, pharmaceuticals, and cosmetics. However, their limited stability hinders their practical applications. We used gelatinized starch to develop stable double emulsions as carrier materials. The oil/water/water (O/W/W) double emulsions were formed by 5 wt% native corn starch, while oil/water/oil (O/W/O) double emulsions were formed by 7 wt% native corn starch and high-amylose starch with 60 % and 75 % amylose contents investigated by optical microscopy. Furthermore, the storage stability of double emulsions was revealed by droplet size distribution, microstructure, backscattering, rheological profiles, and low-field nuclear magnetic resonance (LF-NMR) imaging. Results confirmed that the O/W/O double emulsions stabilized by 7 wt% native corn starch had a smaller mean droplet size (11.400 ± 0.424 μm) and excellent storage stability (14 days) than O/W/W and O/W/O double emulsions prepared with high-amylose starch. Such unique double emulsions prepared with gelatinized native corn starch are good candidates of carrier materials.

Deep eutectic solvent in water pickering emulsions stabilised by cellulose nanofibrils

Deep eutectic solvent (menthol : dodecanoic acid) in water (30 : 70) emulsions stabilised with partially oxidised cellulose nanoparticles remained stable for 200 days at room temperature. Deep eutectic-based emulsions offer potential for non-aqueous reaction systems, chemical extraction, and controlled release. Pickering emulsions using polysaccharides are less toxic and more stable than surfactant-stabilised emulsions.

Deep eutectic solvent in water emulsions stabilised with bio-macromolecules were stable for more than 200 days.

Effect of high-intensity ultrasound irradiation on the stability and structural features of coconut-grain milk composite systems utilizing maize kernels and starch with different amylose contents

In this paper, a coconut milk composite system (glycerin monostearate as an emulsifier) with different maize additives (e.g., maize kernels and starch with different amylose contents) was treated with high-intensity ultrasound irradiation (HIUS, frequency 20 kHz). The stability and structural features of the added coconut milk emulsion were studied. Comparing the mechanical emulsifications, coconut milk with maize kernels was similar to coconut milk with high-amylose maize starch. However, coconut milk with a high proportion of amylopectin had the best stability. After ultrasonic treatment, the particle sizes were found to be smaller than those in the nonultrasound-treated coconut milk, and the particles demonstrated a monomodal size distribution. The electronegativity of the compound system was significantly improved. The electronegativity of the maize kernel and high-amylose maize starch-coconut milk systems was significantly decreased, and this change was beneficial to the stability of the systems. However, ultrasonic treatment did not change the fluid type of the coconut milk compound system (which showed pseudoplastic fluid characteristics). The proportion of amylose in maize had an important influence on the stability of the compound system. The apparent viscosity and crystallization order of the high-amylose maize starch-coconut milk system were high. However, the waxy maize starch system showed high complex viscosity and tended to be liquid with ultrasonic treatment. Ultrasound treatment reduced the particle size of coconut milk and homogenized the distribution of the system. Additionally, the amylase of the system contained amylose encapsulated in the interfacial layer after ultrasound treatment. The tiny gel beads formed by waxy maize starch had a good fusion effect on coconut milk fat/protein droplets. The results indicated that the stability of coconut-grain milk composite systems can be enhanced with the use of maize additives and ultrasound irradiation through space effects, electrostatic effects and continuous phase viscosity.

Non-chemically modified waxy rice starch stabilised wow emulsions for salt reduction

Water-in-oil-in-water emulsions containing an internalised salt solution were stabilised with non-chemically modified waxy rice starch (WRS), and octinyl succinic anhydride (OSA) as reference, to release salt during oral processing due to amylase-induced destabilisation.