Evaluation of gels formulated with whey proteins and sodium dodecyl sulfate as a fat replacer in low-fat sausage

Emulsified sausages with yeast protein as an animal fat replacer: Effects on nutritional composition, spatial structure, gel performance, and sensory quality

This paper investigated the effect of yeast protein (YP)-fat replacement on the nutritional composition, spatial structure, gel performance, and sensory quality of emulsified sausages. YP is enriched with essential amino acids (36.49 g/100 g), which improved the nutritional quality of sausages whereas reducing its fat content. Moreover, YP could absorb water and fat, thus the YP-added sausages exhibiting an amount-dependent increase in emulsion stability and water migration. The microstructure illustrated that YP acted as a filler to improve structural homogeneity and compactness of the pork gel network. And YP-fat replacement could significantly enhance the hardness, gel strength and elasticity of sausages whereas decreasing the viscosity. Additionally, at partial or full YP-fat replacement (25-100%), the YP-added sausages scored higher in odor and texture, as well as better antioxidant stability than controls. Overall, YP can be employed as a new fat substitute for the preparation of healthy and nutritional sausages, while maintaining the sensory quality.

Development of novel heat-treated sausage with Pleurotus ostreatus: Low energy, enhanced bioactivity, reduced amount of meat and fat

The use of Pleurotus ostreatus to reduce calories and increase bioactivity in processed meat products is an increasingly common practice. In this study, a novel sausage containing P. ostreatus was developed based parameters like protein, antioxidants, total phenolic content, cohesiveness, energy, fat, ΔE, hardness, and gumminess values using a D-optimal mixture design. The results showed that over 20% of P. ostreatus could be used in sausage production. Moreover, it was concluded that the optimized sausages contain less fat (33.05%) and meat (18.6%) and therefore have a lower calorie value (19.03%). In addition, P. ostreatus added to the sausage formulation decreased the use of animal raw materials, increased the bioactive properties of the sausages, and did not cause a significant change in the amino acid profile.

Impact of κ-Carrageenan on the Cold-Set Pea Protein Isolate Emulsion-Filled Gels: Mechanical Property, Microstructure, and In Vitro Digestive Behavior

More understanding of the relationship among the microstructure, mechanical property, and digestive behavior is essential for the application of emulsion gels in the food industry. In this study, heat-denatured pea protein isolate particles and κ-carrageenan were used to fabricate cold-set emulsion gels induced by CaCl2, and the effect of κ-carrageenan concentration on the gel formation mechanism, microstructure, texture, and digestive properties was investigated. Microstructure analysis obtained by confocal microscopy and scanning electron microscopy revealed that pea protein/κ-carrageenan coupled gel networks formed at the polysaccharide concentration ranged from 0.25% to 0.75%, while the higher κ-carrageenan concentration resulted in the formation of continuous and homogenous κ-carrageenan gel networks comprised of protein enriched microdomains. The hydrophobic interactions and hydrogen bonds played an important role in maintaining the gel structure. The water holding capacity and gel hardness of pea protein emulsion gels increased by 37% and 75 fold, respectively, through increasing κ-carrageenan concentration up to 1.5%. Moreover, in vitro digestion experiments based on the INFOGEST guidelines suggested that the presence of 0.25% κ-carrageenan could promote the digestion of lipids, but the increased κ-carrageenan concentration could delay the lipid and protein hydrolysis under gastrointestinal conditions. These results may provide theoretical guidance for the development of innovative pea protein isolate-based emulsion gel formulations with diverse textures and digestive properties.

Physicochemical properties of Pickering emulsion fabricated with polysaccharides/pea protein isolate complex and its application in plant-based patty

Incorporation of structured liquid oil within plant-based patties can be achieved through the utilization of food-grade Pickering emulsion (PE). Therefore, the aim of this study was to evaluate the quality characteristics of PE and its application in plant-based patty. The PEs were formulated using sunflower oil (SO), polysaccharides and protein, and the specific ratios employed were as following: methylcellulose (MC) 2 % only (MP0); MC 1.5 % + pea protein isolate (PPI) 0.5 % (MP1); MC 1 % + PPI 1 % (MP2); xanthan gum (XG) 2 % only (XP0); XG 1.5 % + PPI 0.5 % (XP1); XG 1 % + PPI 1 % (XP2). MP0 and MP1 were unstable as PEs, whereas MP2 and XP groups (XP0, XP1, and XP2) exhibited stability as a PE. In addition, MP2 and all XP groups showed increased oil binding capacity, hydrophobic interaction, thermal stability, crystallization, rheological properties, and oxidative stability, compared to MP0 and MP1. In PE-applied plant-based patties, MP2 and all XP groups had significantly lower cooking loss and higher emulsion stability than SO. Particularly, MP2-employed plant-based patties exhibited significantly improved textural and sensory properties. Therefore, our data suggest that PEs with methylcellulose and pea protein isolate could be an effective replacement of plant oil in plant-based meat analogs.

Elevating meat products: Unleashing novel gel techniques for enhancing lipid profiles

Rising health concerns and the diet-health link drive demand for healthier foods, prompting meat manufacturers to reformulate traditional products. These manufacturers have reduced fat content to enhance nutritional quality, which is essential for maintaining desired product features. As a result, numerous strategies have emerged over recent decades to decrease fat and enhance the lipid profiles of meat products. Among these strategies, using hydrocolloids, emulsification, encapsulation, or gelation of oils to produce fat substitutes stands out. Using gels allows fat replacers with characteristics similar to animal fat (similar rheological, physical, or appearance properties) but with a much healthier lipid profile (by incorporating highly unsaturated oils). Therefore, this manuscript aims to comprehensively describe the main fat replacers used to prepare meat products. In addition, an in-depth review of the latest studies (2022-2023) that use novel gels to reform meat products has been made, indicating in each case the implications that the reformulation produces at a physicochemical, nutritional, and sensory level. Given the reported results, it seems clear that the strategy of using bigels or emulgels is very promising and allows obtaining nutritionally highly improved meat products without affecting their sensory or physicochemical properties. However, the best conditions to obtain a novel gel suitable for use as a fat substitute for each meat product still need to be studied and correctly defined. Moreover, these advancements can pave the way for more extensive studies on using novel gel techniques in other food industries, expanding their applicability and leading to healthier consumer options across various food categories.

Improved antioxidant properties of pork patties by replacing fat with resveratrol-loaded MP-CS complex stabilized pickering emulsion

The characterization and antioxidant ability of Res-loaded MP-CS stabilized Pickering emulsion, and its effects of fat reduction (25%, 50%, 75%, and 100%) in meat patties on pH, color, texture, cooking yield and antioxidant activity were investigated. Fat substitute using emulsion had no significant effect on pH and cooking yield. The addition of emulsion increased L* value and reduced a* value. a* value of meat patties with resveratrol added were higher than those without resveratrol group. Hardness and chewiness of meat patties with 25% and 100% fat replacement was lower than 50% and 75% fat replacement. The addition of emulsion could improve the network structure of meat patties and enhance oxidative stability. Oxidative stability of meat patties was improved by Res-loaded MP-CS stabilized Pickering emulsion. The results showed that MP-CS stabilized Pickering emulsion had great potential to be used as fat substitute for developing low-fat meat products, and the addition of resveratrol can improve the antioxidant ability of substitute fat meat products.

Utilization of different by-products to produce nutritionally rich gelled products

Yellow corn cooking water with yerba mate (Ilex paraguariensis) extract, obtained as a by-product of snack manufacture, was combined with whey protein concentrate (7 g/100 g), flaxseed (Linum usitatissimum L.) flour (2 g/100 g), and honey (8 g/100 g) to obtain different gelled products. The effect of the composition on the physicochemical parameters was analyzed. Flaxseed flour was added directly or with a previous pre-heating, and, in both cases, it increased the solid behavior of gels. On the contrary, honey increased the gel liquid-like behavior, and both ingredients modified the color of the gels. Elastic and loss modulus decreased after storage for 7 and 14 days. Some of the textural parameters also changed during storage. Principal component analysis and cluster analysis revealed three groups of formulations according to their composition, and those samples containing only flaxseed flour were best described with the textural and rheological parameters. Yerba mate extract, mainly, flaxseed flour, and honey increased the phenolic composition of gels but decreased the sensory acceptability, despite the sweetness of honey. A variety of gelled products with different textures and flavors was obtained using by-products of the food industry. These gels could be used either for dessert formulations or as a matrix for gelled products.

Formation and characterization of solid fat mimetic based on pea protein isolate/polysaccharide emulsion gels

The emulsion gels that can be used as solid fat replacers were produced with different polysaccharides (κ-carrageenan, κC; high-acyl gellan, HA; konjac glucomannanon, and KGM), pea protein isolate (PPI) and sunflower seed oil. The effect of polysaccharide concentration on the texture, rheological property, microstructure, and water holding capacity of the mixed emulsion gels were investigated. Rheological results showed that the presence of polysaccharides enhanced the hardness, storage modulus and resistance against deformation of emulsion gel, where PPI/κC system exhibited superior hardness with a similar level of pig back fat, due to the self-gelation behavior of κC. CLSM and SEM results showed that the presence of κC, HA, and KGM broke the uniform structure of gel network and formed irregular, threadlike, and oval shaped inclusions respectively, resulting in the broken and coalescence of oil droplets. The α-helix content of emulsion gels decreased, while β-sheet, β-turn and random coils slightly increased due to the unfolding of protein during gel formation. This study may offer a valuable strategy for the development of solid fat mimetic with the characteristics closing to the pig back fat.

Main animal fat replacers for the manufacture of healthy processed meat products

The technological, sensory, and nutritional characteristics of meat products are directly related to their animal fat content. Adding animal fat to meat products significantly influences their sensory properties, such as color, taste, and aroma. In addition, the physicochemical properties of fat decisively contribute to the texture of meat products, playing a fundamental role in improving the properties of viscosity, creaminess, chewiness, cohesiveness, and hardness. However, meat products' high animal fat content makes them detrimental to a healthy diet. Therefore, reducing the fat content of meat products is an urgent need, but it is a challenge for researchers and the meat industry. The fat reduction in meat products without compromising the product's quality and with minor impacts on the production costs is not a simple task. Thus, strategies to reduce the fat content of meat products should be studied with caution. During the last decades, several fat replacers were tested, but among all of them, the use of flours and fibers, hydrocolloids, mushrooms, and some animal proteins (such as whey and collagen) presented promising results. Additionally, multiple strategies to gel oils of vegetable origin are also a current topic of study, and these have certain advantages such as their appearance (attempts to imitate animal fat), while also improving the nutritional profile of the lipid fraction of the products meat. However, each of these fat substitutes has both advantages and limitations in their use, which will be discussed in subsequent sections. Therefore, due to the growing interest in this issue, this review focuses on the main substitutes for animal fat used in the production of meat products, offering detailed and updated information on the latest discoveries and advances in this area.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.

Development of β-Cyclodextrin/Konjac-Based Emulsion Gel for a Pork Backfat Substitute in Emulsion-Type Sausage

Emulsion gel has been used to replace animal fats in meat products. Konjac is a widely used gelling agent; however, its low emulsion stability limits its use in meat products. This study aimed to examine the quality characteristics of β-cyclodextrin (CD)-supplemented konjac-based emulsion gel (KEG) (CD-KEG) and its application as a fat substitute in emulsion-type sausages. The supplementation of CD increased hydrogen bonds and hydrophobic interactions with konjac and oil in the gels, respectively. Additionally, CD increased the structural complexity and strength of KEG. Since adding more than 6% of CD to KEG did not increase the gel strength, 6% CD-added KEG was adopted to substitute for pork backfat in manufacturing low-fat emulsion-type sausages. The following formulations of the sausages were prepared: pork backfat 20% (PF20); pork backfat 10% + KEG 10% (KEG10); KEG 20% (KEG20); pork backfat 10% + CD-KEG 10% (CD-KEG10); CD-KEG 20% (CD-KEG20); and pork backfat 5% (PF5). The CD-KEG20 formulation exhibited higher viscosity and viscoelasticity than KEG20, which suggested that CD improves the rheological properties and the thermal stability of meat batter. Additionally, CD-KEG20 showed similar emulsion stability, cooking yield and texture parameters compared with PF20. Therefore, 6% CD-added KEG is a suitable fat substitute for preparing low-fat emulsion-type sausages.

Comparative Study of Heat- and Enzyme-Induced Emulsion Gels Formed by Gelatin and Whey Protein Isolate: Physical Properties and Formation Mechanism

Emulsion gels have received increasing attention due to their unique physicochemical properties. In this paper, gelatin and whey protein isolate (WPI) were used to construct emulsion-filled gels by heat-induced or enzyme-induced methods, and their rheology, texture properties and microstructure were explored and compared. The effect of the preparation methods, emulsion droplet characteristics and gel matrix concentration on the elastic modulus and hardness of the gels were firstly investigated, then the key control factors were picked out by calculating the Pearson correlation index, and the design principle was constructed by combining these factors flexibly for emulsion gels with adjustable texture. The results show that the emulsion gels formed by different preparation methods have completely distinct microstructures and emulsion distributions, as well as the macroscopic properties of the gels, specifically the enzyme-induced gels exhibited greater elastic modulus and hardness, while heat-induced gels were softer and more delicate. In addition, the droplet sizes of filled emulsions and matrix concentration mainly affected the rheological properties and hardness of the gels. This study successfully established the design principles of emulsion gels with tunable texture structure, which provided a reference for targeted gels preparation according to the texture properties required by specific application scenarios.

Recent advances in the development of healthier meat products

Meat products are an excellent source of high biological value proteins, in addition to the high content of minerals, vitamins, and bioactive compounds. However, meat products contain compounds that can cause a variety of adverse health effects and pose a serious health threat to humans. In this sense, this chapter will address recent strategies to assist in the development of healthier meat products. The main advances about the reduction of sodium and animal fat in meat products will be presented. In addition, strategies to make the lipid profile of meat products more nutritionally advantageous for human health will also be discussed. Finally, the reduction of substances of safety concern in meat products will be addressed, including phosphates, nitrites, polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, as well as products from lipid and protein oxidation.

Chemical, technological, instrumental, microstructural, oxidative and sensory properties of emulsified sausages formulated with microparticulated whey protein to substitute animal fat

The current study was conducted to investigate the utilization of microparticulated whey protein (MWP) in different levels (5% or 10%) as partial fat replacers in emulsified beef sausage formulations. Inclusion of MWP resulted in sausages having decreased amounts of fat and energy while increased amounts of protein. Both emulsion stability and processing yield were the highest in samples containing MWP. No differences were recorded in L* values of the sausages although both a* and b* values were higher in MWP sausages than in full-fat sausages regardless of MWP level. Increased amounts of MWP led to lower hardness, chewiness and adhesiveness. Micrographs brought out the organized and reticulated structure of the sausages containing 10% MWP. MWP did not cause unfavorable impacts in general sensory acceptance, besides, it was associated with increased oxidative stability. Overall, the findings highlighted the favorable effects of MWP in terms of nutritional, technological, sensory and oxidative quality indicating the possibility to design low-fat emulsified meat product formulations.

Effect of electrolytes and surfactants on generation and longevity of carbon dioxide nanobubbles

The objective of this research was to investigate the effect of individual additions of mono- and divalent electrolytes (NaCl and CaCl₂), anionic (sodium dodecyl sulfate, SDS) and non-ionic surfactants (polysorbate 80, Tween 80) at varied concentrations on the generation and stability of bulk nanobubbles (NBs) from carbon dioxide (CO₂) gas in aqueous system. Overall, NBs generated in the small-amount salt fluids exhibited significantly (p ≤ 0.05) lower size range (150-350 nm). Smaller diameter and higher zeta potential magnitudes (18-24 mV) of the NBs in SDS medium were also observed and related to the higher CO₂ concentration (~1850 ppm) and lower surface tension (~64 mN/m) of the solution. However, the gas NBs were disappeared with the incorporation of Tween 80. The outcomes provide some more research-based details about the impact of potential nano-bubble stabilising agents on characteristics of NBs contributing to the green and sustainable NB-related applications in food sectors.