Rheology and microstructure of low-fat yoghurt produced with whey protein microparticles as fat replacer

Unlocking the potential of rice bran oil body as fat replacement in cookies: single and double crosslinked binary emulsion-filled gels based on lutein-loaded rice bran oil body emulsion

BACKGROUND

Rice bran oil body is rich in nutritional value, which is a byproduct of rice processing. The aim of this study is to develop a novel emulsion-filled gel with lutein-loaded rice bran oil body and investigate its functionality as a fat replacer in cookies. The effects of incorporating structured oil body in the form of emulsion-filled gel instead of butter in cookies with a ratio of 0, 10, 20 and 50 wt% formulation were determined by measuring appearance, texture, thermodynamic properties, moisture distribution and microstructure.

RESULTS

The results demonstrated the relationship between geometry, moisture and structure. The 20 wt% emulsion-filled gel substitution ratio yielded mobility and distribution abilities of melted fat and sugar in the cookies that were closest to those of butter. The addition of emulsion-filled gel increased the L* value and decreased the a* value, while the b* value of the cookie increased due to the advanced delivery of lutein by oil body. By controlling the addition ratio, the texture of the cookies can be adjusted. Starch granules were separated due to colloidal particles, reducing saturated fat content and decreasing cookie gelatinization enthalpy. The fat coating on starch particles enhanced the binding capacity of free water, improving air entrapment and forming a constrained gluten network structure.

CONCLUSION

These findings provide a theoretical basis for rice bran oil body as a novel substitute for butter in the development of healthy, high-quality cookies. © 2024 Society of Chemical Industry.

Fortified chocolate mousse with powder and extract from Moringa oleifera leaves for nutritional value improvement

This study focuses on the characterisation and incorporation of Moringa oleifera leaf powder (MOP) from Luanda (Angola) and its extract (MOE) in fortified chocolate mousse. Dark green (DG) leaves presented superior nutritional values compared to other leaves. DG contained a higher concentration of mineral salts (10 ± 1 mg/100 g of dry leaves), phenolic compounds (267 ± 4 mg GAE/g), vitamins (1.9 ± 0.2 mg/g of dry extract) and strong antioxidant capacity (IC50, 115 ± 8 µg/mL). Therefore, DG leaves were used to fortify the chocolate mousse. The leaves were prepared in three samples: control, 2 % MOP (w/w) and 2 % MOE (v/v). Textural and rheological analysis of chocolate mousse samples revealed a pseudoplastic profile for all samples, with decreased texture attributes and viscosity due to the incorporation. The sensory evaluation demonstrated that MOP and MOE samples presented 93 % and 88 % resemblance to the original product regarding general acceptance, respectively.

Perspectives on the yogurt rheology

The oral processing of yogurt is a dynamic process involving a series of deformation processes. Rheological knowledge is essential to understand the structure and flow properties of yogurt in the mouth and to explore its relationship with sensory perception. Yogurt is rheologically characterized as a non-Newtonian viscoelastic material. The rheological properties of yogurt are affected by many factors, from production to consumption. Therefore, rheological measurements are widely used to predict and control the final quality and structure of yogurts. Recent studies focus on the elucidation of the effects of cultures and processes used in production, as well as the design of different formulations to improve the rheological properties of yogurts. Moreover, the science of tribology, which dominates the surface properties of interacting substances in relative motion to evaluate the structural sensation in the later stages of eating in addition to the rheological properties that give the feeling of structure in the early stages of eating, has also become the focus of recent studies. For a detailed comprehension of the rheological properties of yogurt, this review deals with the factors affecting the rheology of yogurt, analytical methods used to determine rheological properties, microstructural and rheological characterization of yogurt, and tribological evaluations.

Core-shell starch as a platform for reducing starch digestion and saturated fat intake

Ill-balanced diets, especially high-carbohydrate and high-fat diets, have led to an explosion of diabetes and cardiovascular diseases worldwide, posing great threats to human health. The structural design of functional foods can offer promising solutions to these afflictions. Here, we introduce a versatile core-shell starch made from food-grade starch and alcohol-soluble protein to reduce starch digestion and saturated fat intake. The fabrication of core-shell structure is realized through an anti-solvent method, assisted by electrostatic interaction, which is generalizable to starches and proteins from different sources and feasible for scale-up production. The protein shell imparts a higher gelatinization temperature and a lower pasting viscosity to the starch, suggesting restricted granule swelling, which leads to a reduced starch digestibility as proved by in vitro digestion studies. The hypoglycemic effect of core-shell starch is demonstrated in vivo. We also show that the application of core-shell starch can be extended to oil encapsulants and saturated fat replacers due to the impact of protein shell on the surface hydrophobicity of the starch. These results may advance the establishment of healthy diets and the tackling of diet-related diseases.

Preparation of fat substitute based on maize starch hydrolysates and application in reduced-fat acidified milk gel

Reduced-fat food has become a popular choice among contemporary consumers. This study aims to develop a starch-based fat substitute and incorporate it into reduced-fat milk gel acidified with glucono-δ-lactone (GDL) to achieve similar rheological properties as a full-fat gel. The gel properties of the fat substitute were assessed. The study examined the rheological properties, syneresis, textural properties and microstructure of acidified milk gels while also monitoring acidification process. Starch hydrolysates with low dextrose equivalent (DE) (<5.1 %) can serve as an effective fat substitute due to their excellent gelling properties The rheological and textural properties of the reduced-fat acidified milk gel with DE at 3.1 % of starch hydrolysate and 30 % fat substitution are similar to those of the full-fat milk gel. The syneresis and confocal laser scanning microscopy (CLSM) results indicated that the microstructure of the reduced-fat acidified milk gel was similar to the full-fat version. Moreover, the sensory properties of the reduced-fat acidified milk gel were acceptable when the DE was 3.1 %, and 30 % fat was replaced. In our study, we utilized hydrolyzed starch to produce reduced-fat acidified milk gels, which could potentially be used in the development of reduced-fat yogurt formulations.

Protein-Based Fat Replacers: A Focus on Fabrication Methods and Fat-Mimic Mechanisms

The increasing occurrence of obesity and other non-communicable diseases has shifted the human diet towards reduced calorie intake. This drives the market to develop low-fat/non-fat food products with limited deterioration of textural properties. Thus, developing high-quality fat replacers which can replicate the role of fat in the food matrix is essential. Among all the established types of fat replacers, protein-based ones have shown a higher compatibility with a wide range of foods with limited contribution to the total calories, including protein isolate/concentrate, microparticles, and microgels. The approach to fabricating fat replacers varies with their types, such as thermal-mechanical treatment, anti-solvent precipitation, enzymatic hydrolysis, complexation, and emulsification. Their detailed process is summarized in the present review with a focus on the latest findings. The fat-mimic mechanisms of fat replacers have received little attention compared to the fabricating methods; attempts are also made to explain the underlying principles of fat replacers from the physicochemical prospect. Finally, a future direction on the development of desirable fat replacers in a more sustainable way was also pointed out.

Production and Evaluation of Yogurt Colored with Anthocyanin-Rich Pigment Prepared from Jabuticaba (Myrciaria cauliflora Mart.) Skin

Yogurt is known as a healthy food, but some synthetic additives that are commonly added to it can be one of the factors that restricts yogurt’s consumption. The aims of this study were to prepare and evaluate yogurts with the addition of spray-dried, anthocyanin-rich colorant extracted from jabuticaba (Myrciaria cauliflora Mart.) skin. The concentrated extract was spray-dried using maltodextrin (20 g/100 g w/w) as a carrier and added to yogurts in the concentrations of 0.5, 1.0, 1.5, and 2.0 g/100 g w/w. The yogurts were stored for up to 28 days under refrigeration and periodically evaluated. Except for the yogurts to which 1.5 g of extract was added, all samples had a slight pH reduction in the first 7 days of storage. Throughout the yogurts’ storage period, the anthocyanin and a* values were slightly reduced (p < 0.05), indicating some anthocyanin instability. The rheological behavior was typical for yogurts, but the casein gel network was probably disrupted by the jabuticaba extract incorporation, reducing the yogurt’s apparent viscosity. Panelists showed good acceptance for the attributes of taste, color, aroma, appearance, texture, and overall impression, indicating that this natural pigment has the potential to be a substitute synthetic color additive for the production of mixed berry yogurts, contributing to the reduction of waste.

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.

Roles of Proteins/Enzymes from Animal Sources in Food Quality and Function

Animal proteins are good sources of protein for human, due to the composition of necessary amino acids. The quality of food depends significantly on the properties of protein inside, especially the gelation, transportation, and antimicrobial properties. Interestingly, various kinds of molecules co-exist with proteins in foodstuff, and the interactions between these can significantly affect the food quality. In food processing, these interactions have been used to improve the texture, color, taste, and shelf-life of animal food by affecting the gelation, antioxidation, and antimicrobial properties of proteins. Meanwhile, the binding properties of proteins contributed to the nutritional properties of food. In this review, proteins in meat, milk, eggs, and fishery products have been summarized, and polysaccharides, polyphenols, and other functional molecules have been applied during food processing to improve the nutritional and sensory quality of food. Specific interactions between functional molecules and proteins based on the crystal structures will be highlighted with an aim to improve the food quality in the future.

Assessing Whey Protein Sources, Dispersion Preparation Method and Enrichment of Thermomechanically Stabilized Whey Protein Pectin Complexes for Technical Scale Production

Whey protein pectin complexes can be applied to replace fat in food products, e.g., pudding and yogurt, contributing to creaminess while adding a source of protein and fiber. Production of these complexes is usually conducted on the laboratory scale in small batches. Recently, a process using a scraped-surface heat exchanger (SSHE) has been employed; however, dispersion preparation time, feasibility of using different whey protein sources and enrichment of the complexes for subsequent drying have not been assessed. Preparing whey protein pectin dispersions by solid mixing of pectin and whey protein powders resulted in larger complexes than powders dispersed separately and subsequently mixed after a hydration time. Dispersions without hydration of the mixed dispersions before thermomechanical treatment had the largest particle sizes. The targeted particle size of d_90,3 < 10 µm, an important predictor for creaminess, was obtained for five of the six tested whey protein sources. Dispersions of complexes prepared using whey protein powders had larger particles, with less particle volume in the submicron range, than those prepared using whey protein concentrates. Efficiency of complex enrichment via acid-induced aggregation and subsequent centrifugation was assessed by yield and purity of protein in the pellet and pectin in the supernatant.

Surface adsorption and lubrication properties of plant and dairy proteins: A comparative study

The aim of this work was to compare the surface adsorption and lubrication properties of plant and dairy proteins. Whey protein isolate (WPI) and pea protein isolate (PPI) were chosen as model animal and plant proteins, respectively, and various protein concentrations (0.1-100 mg/mL) were studied with/without heat treatment (90 °C/60 min). Quartz crystal microbalance with dissipation monitoring (QCM-D) experiments were performed on hydrophilic (gold) and hydrophobic polydimethylsiloxane (PDMS) sensors, with or without a mucin coating, latter was used to mimic the oral surface. Soft tribology using PDMS tribopairs in addition to wettability measurements, physicochemical characterization (size, charge, solubility) and gel electrophoresis were performed. Soluble fractions of PPI adsorbed to significantly larger extent on PDMS surfaces, forming more viscous films as compared to WPI regardless of heat treatment. Introducing a mucin coating on a PDMS surface led to a decrease in binding of the subsequent dietary protein layers, with PPI still adsorbing to a larger extent than WPI. Such large hydrated mass of PPI resulted in superior lubrication performance at lower protein concentration (≤10 mg/mL) as compared to WPI. However, at 100 mg/mL, WPI was a better lubricant than PPI, with the former showing the onset of elastohydrodynamic lubrication. Enhanced lubricity upon heat treatment was attributed to the increase in apparent viscosity. Fundamental insights from this study reveal that pea protein at higher concentrations demonstrates inferior lubricity than whey protein and could result in unpleasant mouthfeel, and thus may inform future replacement strategies when designing sustainable food products.

Review on fat replacement using protein-based microparticulated powders or microgels: A textural perspective

Background

Due to the growing rise in obesity and food-linked diseases, the replacement of calorie-dense fat has been a key focus of food industries in the last few decades with proteins being identified as promising fat replacers (FRs).

Scope and approach

This review aims to provide an overview of animal and plant protein-based FR studies that have been performed in the last 5 years. Protein isolates/concentrates, their microparticulated forms and protein microgels in model and real foods have been examined. Special emphasis has been given on the characterisation techniques that have been used to compare the full fat (FF) and low fat (LF) versions of the foods using FRs.

Key findings and conclusions

Microparticulated whey protein (MWP) has been the preferred choice FR with some success in replacing fat in model foods and dairy applications. Plant proteins on the other hand have attracted limited research attention as FRs, but show success similar to that of animal proteins. Key characterisation techniques used to compare full fat with low fat products containing FRs have been apparent viscosity, texture profile analysis, microscopy, particle size and sensory properties with oral tribology being a relatively recent undertaking. Coupling tribology with adsorption techniques (muco-adhesion) can be effective to bridge the instrumental-sensory property gap and might accelerate the development cycle of designing low/no fat products. From a formulation viewpoint, sub-micron sized microgels that show shear-thinning behaviour and have boundary lubrication properties offer promises with respect to exploiting their fat replacement potential in the future.

Effect of anthocyanin-absorbed whey protein microgels on physicochemical and textural properties of reduced-fat Cheddar cheese

Reduced-fat foods have become more popular due to their health benefits; however, reducing the fat content of food affects the sensory experience. Therefore, it is necessary to improve the sensory acceptance of reduced-fat foods to that of full-fat equivalents. The aim of this study was to evaluate the effect of adding whey protein microgels (WPM) with an average diameter of 4 μm, or WPM with adsorbed anthocyanins [WPM (Ant)] on the textural and sensory properties of reduced-fat Cheddar cheese (RFC). Reduced-fat Cheddar cheese was prepared in 2 ways: (1) by adding WPM, designated as RFC+M, or (2) by adding WPM (Ant), designated as RFC+M (Ant). For comparison, RFC without fat substitutes and full-fat Cheddar cheese were also prepared. We discovered that the addition of WPM and WPM (Ant) increased the moisture content, fluidity, and meltability of RFC, and reduced its hardness, springiness, and chewiness. The textural and sensory characteristics of RFC were markedly inferior to those of full-fat Cheddar cheese, whereas addition of WPM and WPM (Ant) significantly improved the sensory characteristics of RFC. The WPM and WPM (Ant) showed a high potential as fat substitutes and anthocyanin carriers to effectively improve the acceptance of reduced-fat foods.

Combined Use of Trisodium Citrate and Transglutaminase to Enhance the Stiffness and Water-Holding Capacity of Acidified Yak Milk Gels

In this research, the synergistic effect of trisodium citrate (TSC) and microbial transglutaminase (TGase) treatment on the textural properties of acidified yak skim milk gels was investigated. TSC was added to yak skim milk to concentrations of 0, 20, and 40 mmol/L, followed by adjusting the pH to 6.7. The samples were incubated with TGase for the cross-linking reaction, after which the samples were acidified with 1.4% (w/v) gluconodelta-lactone (GDL) at 42°C for 4 h to form gels. The stiffness and water holding capacity (WHC) of gels exhibited higher values at 20 or 40 mmol/L than without TSC. The final storage modulus (G′) of yak milk gels was positively related to the concentration of TSC prior to TGase treatment. Cryoscanning electron microscopy observations showed that the gel networks were more rigid with higher TSC concentrations. Overall, TSC dissociated particles in yak milk into smaller ones. The newly formed particles in yak skim milk could form acid-induced gels with greater stiffness and higher WHC in the presence of TGase.