Improvements in emulsion stability of dairy beverages treated by high pressure homogenization: A pilot-scale feasibility study

Leveraging new opportunities and advances in high-pressure homogenization to design non-dairy foods

High-pressure homogenization (HPH) and ultrahigh-pressure homogenization (UHPH) are emerging food processing techniques for stabilizing emulsions and food components under the pressure range from 60 to 400 MPa. Apart from this, they also support increasing nutritional profile, food preservation, and functionality enhancement. Even though the food undergoes the shortest processing operation, the treatment leads to modification of physical, chemical, and techno-functional properties, in addition to the formation of micro-sized particles. This study focuses on recent advances in using HPH/UHPH on plant-based milk sources such as soybeans, almonds, hazelnuts, and peanuts. Overall, this systematic review provides an in-depth analysis of the principles of HPH/UHPH, the mechanism of action, and their applications in other nondairy areas such as fruits and vegetables, meat, fish, and marine species. This work also deciphers the role of HPH/UHPH in modifying food components, their functional quality enhancement, and their provision of oxidative resistance to many foods. HPH is not only perceived as a technique for size reduction and homogenization; however, it does various functions like microbial inactivation, improvement of rheologies like texture and consistency, decreasing of lipid oxidation, and making positive modifications to proteins such as changes to the secondary structure and tertiary structure thereby enhancing the emulsifying properties, hydrophobicity of proteins, and other associated functional properties in many nondairy sources at pressures of 100-300 MPa. Thus, HPH is an emerging technique with a high throughput and commercialization value in food industries.

Trends in functional beverages: Functional ingredients, processing technologies, stability, health benefits, and consumer perspective

The World Health Organization's emphasis on the health benefits of functional foods and beverages that has contributed to the rise in its popularity globally. Besides these consumers have become more aware of the importance of their food composition and nutrition. Among the fastest-growing market segments within the functional food industries, the functional drinks market focuses on fortified beverages or products that are novel with improved bioavailability of bioactive compounds, and their implicated health benefits. The bioactive ingredients in functional beverages include phenolic compounds, minerals, vitamins, amino acids, peptides, unsaturated fatty acids, etc. which can be obtained from plant, animal and microorganisms. The types of functional beverages which are globally intensifying the markets are pre-/pro-biotics, beauty drinks, cognitive and immune system enhancers, energy and sports drink produced via several thermal and non-thermal processes. Researchers are focusing on improving the stability of the active compounds by encapsulation, emulsion, and high-pressure homogenization techniques to strengthen the positive consumer perspective in functional beverages. However, more research is needed in terms of bioavailability, consumer safety, and sustainability of the process. Hence, product development, storage stability, and sensory properties of these products are vital for consumer acceptance. This review focuses on the recent trends and developments in the functional beverages industry. The review provides a critical discussion on diverse functional ingredients, bioactive sources, production processes, emerging process technologies, improvement in the stability of ingredients and bioactive compounds. This review also outlines the global market and consumer perception of functional beverages with the future perspective and scope.

Impact of ultra-shear technology on quality attributes of model dairy-pea protein dispersions with different fat levels

This study investigated the impact of ultra-shear technology (UST) processing on dairy-pea protein dispersions with different fat levels. Raw milk, skim milk, and cream, as well as model dispersions with combinations of dairy products and pea protein (i.e., raw milk with pea protein, skim milk with pea protein, and cream with pea protein) were employed as test samples. UST experiments were conducted at a pressure of 400 MPa and 70 °C shear valve exit temperature. The UST treatment increased the viscosity of the dispersions and the increases depended on the fat level. Dairy-pea protein dispersions from raw milk and skim milk were shear thinning and mathematically described by the power-law model defined by the consistency coefficient, K (Pa·sⁿ) and the flow behavior index, n. UST treated cream + pea protein dispersions produced structures with gel-like characteristics. Microstructure and particle size analysis determined by laser scanning microscope revealed a reduction in particle size after UST treatment in raw milk + pea protein and skim milk + pea protein dispersions up to 7.55 and 8.30 μm, respectively. In contrast, the particle mean diameter of cream + pea protein dispersions increased up to 77.20 μm after the UST treatment. Thus, the effect of UST on the particle size and rheological behavior of the dispersions depended on the fat level. UST-treated dispersions were stable with no visible phase separation or sedimentation upon centrifugation at 4000×g for 30 min (4 °C). Heat treatment and freeze-thaw treatment of UST-treated samples showed stable blends immediately after the treatments, but subsequent centrifugation showed solid separation. Results from the study suggest that UST is a potential technology to produce stable dairy + pea protein liquids foods with different rheological characteristics for diverse applications.

Dispersion assisted pretreatment for enhanced anaerobic biodegradability and biogas recovery -strategies and applications

Disperser assisted homogenization is a promising mechanical based disintegration process to improve the substrate biodegradability and biogas recovery from biomass. During dispersion, the extent of liquefaction relies on the dispersion parameters and biomass properties. Hence, assessment of the optimal parameters varies with type of disperser and biomass. Dispersion assisted homogenization of some biomass such as sludge is not only studied in lab scale but also investigated in full scale plants providing positive outcome. For instance, the large-scale investigation of disperser homogenization has attained nearly 40-50 percent increment in bioenergy recovery. However, research gaps in terms of energy and cost efficiency still exists. This review paper outlines the impact of disperser parameters, its efficiency in biomass disintegration and biogas recovery. It has been proposed to combine homogenization process in the bioenergy generation to investigate the energy and cost efficiency of the entire process.

High internal phase oil-in-water emulsions stabilized by supercritical carbon dioxide extruded whey protein concentrate

High Internal Phase Emulsions (HIPEs) were stabilized by functionalized whey protein concentrate (WPC-80). Functionalization of WPC-80 was done by supercritical CO2 assisted extrusion technology. HIPEs were formed by 80% oil and 1-4 wt% of control (untreated) whey protein concentrate, extruded/functionalized whey protein concentrates (f-WPC-80) at pH 3.0 and 5.4, and sodium caseinate (NaCas) separately and were characterized for their stability at two temperatures (25 and 40 °C) for 20 days. Results indicated that f-WPC-80-pH3.0 formed self-standing gels at 1 wt% concentrations which were more stable, without phase separation, than those stabilized by commercially used stabilizer NaCas and native c-WPC. At 4% concentration of f-WPC-80-pH3.0, the compressed droplets produced emulsions with self-standing and viscoelastic features. While control WPC-80, could not form stable HIPEs at any investigated concentrations. The reported high internal phase oil-in-water emulsions, offer a potential new system for delivery of nutritionally superior and clean-label products of commercial utility.

Nutritional Function and Flavor Evaluation of a New Soybean Beverage Based on Naematelia aurantialba Fermentation

The soy beverage is a healthy product rich in plant protein; however, its unpleasant flavor affects consumer acceptance. The aim of this study was to determine the feasibility of using Naematelia aurantialba as a strain for the preparation of fermented soybean beverages (FSB). Increases in Zeta potential, particle size, and viscosity make soy beverages more stable. We found that nutrient composition was increased by fermenting N. aurantialba, and the antioxidant activity of soybean beverages significantly increased after 5 days of fermentation. By reducing the content of beany substances such as hexanal and increasing the content of 1-octen-3-ol, the aroma of soybean beverages fermented by N. aurantialba changed from “beany, green, and fatty” to “mushroom and aromatic”. The resulting FSB had reduced bitterness but considerably increased sourness while maintaining the fresh and sweet taste of unfermented soybean beverages (UFSB). This study not only provides a theoretical basis for the market promotion of FSB but also provides a reference for basidiomycetes-fermented beverages.

Proteins in Food Systems-Bionanomaterials, Conventional and Unconventional Sources, Functional Properties, and Development Opportunities

Recently, food companies from various European countries have observed increased interest in high-protein food and other products with specific functional properties. This review article intends to present proteins as an increasingly popular ingredient in various food products that frequently draw contemporary consumers' attention. The study describes the role of conventional, unconventional, and alternative sources of protein in the human body. Furthermore, the study explores proteins' nutritional value and functional properties, their use in the food industry, and the application of proteins in bionanomaterials. Due to the expected increase in demand for high-protein products, the paper also examines the health benefits and risks of consuming these products, current market trends, and consumer preferences.

Physical properties of UHT light cream: impact of the high-pressure homogenization and addition of hydrocolloids

The beneficial effects of a healthy diet on the quality of life have prompted the food industry to develop low-fat variants, but fat content directly affects the physicochemical and sensory properties of food products. The utilization of high-pressure homogenization (HP) and incorporation of hydrocolloids have been suggested as strategies to improve the physical stability and rheological properties of light cream. Thus, this study aims to analyze the associated effect of high-pressure homogenization (80 MPa) and three different hydrocolloids: microcrystalline cellulose, locust bean gum and xanthan gum, on emulsion stability and rheological properties of ultra-high-temperature (UHT) light cream (ULC) with a 15% w/w fat content. The stability of ULC was determined by the ζ potential of oil droplets and emulsion stability percentage. Rheological characterization was based on flow behavior tests and dynamic oscillatory measurements, which were carried out in a rheometer. Results showed that the high-pressure homogenization process did not influence the emulsion stability of the treatments. Moreover, the hydrocolloids added to systems present weak interactions with milk proteins since all ULC showed macroscopical phase separation. The samples presented the same rheological behavior and were classified as pseudoplastic fluids (n < 1). ULC treated at 80 MPa was significantly (P ≤ 0.05) more consistent than the treatments at 20 MPa. All ULC showed a predominant elastic behavior (G' > G″), and a remarkable increase in both G' and G″ at 80 MPa. The results presented in this study highlight the potential of HP for altering some rheological characteristics of UHT light cream, for example, to increase its consistency. These results are important for the dairy industry and ingredient suppliers, in the standardization of UHT light cream and/or to develop low-fat products.

Microstructure and Physicochemical Properties of Light Ice Cream: Effects of Extruded Microparticulated Whey Proteins and Process Design

This study aimed to understand the influence of extruded microparticulated whey proteins (eMWPs) and process design in light ice cream processing by evaluating the microstructure and physicochemical properties. The inulin (T1), a commercial microparticulated whey protein (MWP) called simplesse (T2), a combination (T3), as well as eMWPs (as 50% volume of total particles): d50 < 3 µm (T4), and d50 > 5 µm (T5) were used as fat replacers. The first process design was pasteurization with subsequent homogenization (PH). The second process was homogenization with subsequent pasteurization (HP) for the production of ice cream (control, 12% fat, w/w; T1 to T5, 6% fat, w/w). The overrun of light ice cream treatments of PH was around 50%, except for T4 (61.82%), which was significantly higher (p < 0.01). On the other hand, the overrun of HP was around 40% for all treatments except T1. In both the PH and HP groups, the color intensities of treatments were statistically significant (p < 0.001). The melting behavior of light ice cream was also significantly different. The viscosity of all treatments was significant (p < 0.05) at a shear rate of 64.54 (1/s) for both cases of process design. A similar firmness in both the PH and HP groups was observed; however, the products with eMWPs were firmer compared to other light ice creams.

Effects of pressure, shear, temperature, and their interactions on selected milk quality attributes

The effects of pressure, temperature, shear, and their interactions on selected quality attributes and stability of milk during ultra-shear technology (UST) were investigated. The UST experiments include pressure (400 MPa) treatment of the milk sample preconditioned at 2 different initial temperatures (25°C and 15°C) and subsequently depressurizing it via a shear valve at 2 flow rates (low: 0.15-0.36 g/s; high: 1.11-1.22 g/s). Raw milk, high-pressure processed (HPP; 400 MPa, ~40°C for 0 and 3 min) and thermal treated (72°C for 15 s) milk samples served as the controls. The effect of different process parameters on milk quality attributes were evaluated using particle size, zeta potential, viscosity, pH, creaming, lipase activity, and protein profile. The HPP treatment did not cause apparent particle size reduction but increased the sample viscosity up to 3.08 mPa·s compared with 2.68 mPa·s for raw milk. Moreover, it produced varied effects on creaming and lipase activity depending on hold time. Thermal treatment induced slight reduction in particle size and creaming as compared with raw milk. The UST treatment at 35°C reduced the effective diameter of sample particles from 3,511.76 nm (raw milk) to 291.45 nm. This treatment also showed minimum relative lipase activity (29.93%) and kept milk stable by preventing creaming. The differential effects of pressure, shear, temperature, and their interactions were evident, which would be useful information for equipment developers and food processors interested in developing improved food processes for dairy beverages.

Effect of high pressure homogenization treatment on the rheological properties of citrus peel fiber/corn oil emulsion

BACKGROUND

Citrus fiber is a main component in the peel of citrus and contains natural dietary fiber. It is often used as a functional additive to improve the texture or nutritional property of food. It is also widely used to reduce the content of absorbable fat in sausages and other meat products, and to improve food stability as an emulsifier. In this research, the dynamic rheological properties (linear and non-linear) of citrus peel fiber/corn oil (CF/CO) emulsion system under high pressure homogenization (HPH) treatment was investigated.

RESULT

Rheological results illustrated HPH treatment significantly increased the apparent viscosity of the emulsion, reduced the activation energy of the emulsion and distinctly improved the viscoelasticity of the emulsion. Meanwhile, HPH treatment increased the linear viscoelastic region of the sample, and the behavior of the emulsion converted from strain thinning (without HPH treatment) to weak strain overshoot (with HPH treatment). Lissajous curves indicated the viscosity of the sample increased first and then decreased with strain increasing and the third harmonic contributed much more to the first harmonic compared with the fifth harmonic. Chebyshev stress decomposition revealed that, as strain increased, the samples with HPH treatment showed internal-cycle strain hardening behavior first, then turned to internal-cycle softening behavior.

CONCLUSION

HPH treatment can significantly improve the processing performance of CF/CO emulsion as well as the stability against large periodic oscillations in food processing. © 2020 Society of Chemical Industry.

Application of time–intensity analysis in model system submitted to homogenization

The use of the high pressure homogenizer has been studied in fruit juices, but researches in model system for application in fruit nectar are scarce. Therefore, it is necessary to evaluate the application of these technologies and how the homogenization pressure (PH) can interfere in the sensorial profile of the samples. To prepare the solutions we used guar gum (0.1%), organic acids (0.3%), and sucrose (10%), which were later homogenized (0—control, 25 and 50 MPa) at 25 ℃. The rheological behavior and the temporal profile of the samples were evaluated. The model systems presented pseudoplastic behavior without residual tension and were fitted to the Ostwald–de Waele model. The consistency index reduced and the flow behavior index increased with processing. Apparent viscosity also decreased due to homogenization. In the time–intensity sensorial analysis, it was observed that the samples differed among the evaluated parameters, demonstrating that the samples with tartaric acid presented higher intensity for the sour taste. However, for sweetness, no change was observed. In the viscosity attribute, the model systems presented similar temporal profiles. Therefore, it was noted that the homogenization process favored a greater temporal profile of sour taste, making sensory perception more lasting in a model system for fruit nectar.

Stability of oil-in-water emulsions performed by ultrasound power or high-pressure homogenization

Emulsifiers are added to enhance product stability to obtain a satisfactory shelf-life. For this reason, stable emulsions that do not form peroxides nor change the fatty acid composition of food, as well as safe treatments to obtain them, are aspects of utmost importance. High-pressure homogenization is a conventional approach to prepare emulsions because of its high efficiency. In addition, the beneficial effects of ultrasound on the processing efficiency are known. Therefore, the impact of high-pressure homogenization (30 MPa, 50M Pa) or ultrasound power (270 W) on the emulsion stability and emulsifying properties of 5% coconut oil-in-water emulsion were discussed in this study. The complexes (3:7and 4:6, by weight) of propylene glycol alginate and xanthan gum were selected as emulsifier. The apparent viscosity, particle size and distribution, emulsifying properties and ζ-potential of 5% coconut oil-in-water emulsion before and after ultrasound treatment or high-pressure homogenization were investigated and compared. The micro structure of the emulsion was observed under the fluorescence microscope. The experimental results showed that both high-pressure homogenization and ultrasonic treatment effectively reduced the apparent viscosity, average droplet size and narrowed the distribution range of the emulsion, compared with the pre-emulsion. However, aggregation in the emulsion appeared only after being subjected to high-pressure homogenization, while the emulsion made by the ultrasound treatment remained stable during 30 days storage. In conclusion, this study provides valuable information regarding emulsion preparation methods that can be feasible in food and beverage industries, demonstrating a better performance of ultrasound in optimizing and extending food shelf-life in food and beverage industries.

Investigation of the effects of mechanical treatments on cellular structure integrity and vitamin C extractability of broccoli (Brassica oleracea L. var. italica) by LF-NMR

Extraction of nutrients from plants is an important unit operation in the food and biological industries. The target nutrient is usually spatially distributed throughout the plant tissue. The intact cell wall and adhering membranes are the main resistances to molecular diffusion. Therefore, disintegration of the intact structure, which in turn increases the permeability of adhering membranes, can significantly improve the nutrient extraction yield and efficiency. In this study, different physical treatments (homogenization, high pressure homogenization, and ball mill grinding) were applied to investigate their effects on the tissue microstructure and the release of vitamin C. The changes in the microstructure were reflected by LF-NMR based on T2 distribution, particle size distribution, and microscopy images. The extraction yield of vitamin C obtained by high-pressure homogenization was increased by 75.69% for floret and 28.84% for stalk, respectively, as compared to that obtained by mechanical homogenization. The degradation of vitamin C was significant due to prolonged operation of the ball mill grinding method although the integrity of the tissues was similar to that of the high-pressure homogenization-treated tissues. This study confirms that the degree of tissue disintegration has a positive correlation with the release of the nutrient (vitamin C) within a limited operating time. LF-NMR has been proven to be an effective method to study the impact of different physical treatments on the cellular structure integrity of plant-originated food materials.