Optimization of emulsification conditions with rice bran concentrates for the preliminary formulation of potential vegan dressings and their characterization.

A fraction of rice bran (RB), generated during the brown rice polishing, is utilized to extract oil, resulting in defatted RB (DRB). The aim of this study was to optimize the emulsification conditions to enhance the value of this byproduct by formulating potential vegan dressings and characterizing them. Enzymatic hydrolysis of the starch present in DRB yields the DRB concentrate (DRBC). A central composite design was applied and the results were analyzed using response surface methodology to select optimal conditions for an oil-in-water emulsion formula. Two formulations were chosen: one corresponds to the optimal conditions, with 26.5% of oil and 73.5% of DRBC dispersion (eoptimal), and the other one with 21.7% of oil and 78.3% of dispersion (eED8). The eoptimal formulation exhibited significantly lower mean De Brouckere diameter (D4,3) value and higher viscosity when compared with eED8. For both emulsions, the particle size distribution and D4,3 remained unchanged during storage, whereas viscosity decreased, and backscattering (BS) increased. Initially, both emulsions exhibited solid viscoelastic behavior, which was partially lost during quiescent storage. The increase in BS was attributed to particle disaggregation, ultimately leading to the aforementioned change in rheological behavior. In conclusion, although the designed emulsions underwent microstructural changes, they were stable against gravitational separation. To improve stability during quiescent storage, it is suggested to incorporate a thickening agent. Hence, it is propose to procced with the development of a vegan dressing based on the eoptimal emulsion, as it exhibits superior physicochemical properties.

Interfacial and emulsifying properties of whey protein concentrate by ultrafiltration.

The aim of this study was to concentrate whey protein by ultrafiltration process, evaluating the pressure at 1-3 bar and temperature of 10-20℃. In the conditions that show the more protein concentration were evaluated the interfacial and emulsifying properties at pH 5.7 and 7.0. The whey concentrate at 10℃ and 1.5 bar showed the higher protein value 36% (w/w), with soluble protein of 33.82% (solubility of 93.94%) for pH 5.7 and 34% (solubility of 94.4%) for pH 7.0, respectively. The whey concentrate powder present particle size distribution between 0.4-110 um. The whey at pH 5.7 and 7.0 was not observed significant differences in the resistance parameters of the oil/water layer interface. The interfacial film formed by the proteins presented an essentially elastic behavior in both pH, and in pH 5.7 the emulsion was more stable with lower diameter droplets. The concentrate whey showed techno-functional properties (emulsification and solubility), which allow the use as ingredients in products of industrial interest in food products such as mayonnaise, ice cream, sauces, and others.

Emulsifying properties of defatted rice bran concentrates enriched in fiber and proteins.

BACKGROUND: Rice bran (RB), a by-product of the rice milling industry, constitutes around 10% of the total weight of rough rice. The interest in the use of RB is centered on its nutritional quality, its low cost, and its extensive worldwide production. As RB is commonly used for oil extraction, the defatted rice bran (DRB) is obtained as a second by-product. The aim of this work was to obtain a defatted rice bran concentrate (DRBC), enriched in protein and fiber, from defatted rice bran flour (DRBF) and to determine its physicochemical and emulsifying properties. RESULTS: To obtain the DRBC, the starch was efficiently hydrolyzed (> 98%) with α-amylase and amyloglucosidase, with a concomitant increase in the proportions of crude protein (from 154.7 to 274.3 g kg-1 ) and total dietary fiber (from 276.1 to 492.3 g kg-1 ). Defatted rice bran concentrate exhibited a loss of protein solubility and increased surface hydrophobicity compared with DRBF. Defatted rice-bran concentrate dispersions with and without previous ultrasound treatment were prepared. The sonication led to an increase in the apparent viscosity. Emulsions were prepared with dispersions with and without previous ultrasound treatment and showed high stability in quiescent conditions over 28 days. However, the emulsions prepared with dispersions treated with ultrasound resulted in lower D4,3 values and higher elastic and viscous moduli. CONCLUSION: The rice bran concentrate can be used to obtain stable oil-in-water (O/W) emulsions, including both soluble and insoluble fractions, in acidic and neutral conditions. These innovative findings thus contribute to increasing the added value of this important by-product of the rice-milling industry. © 2019 Society of Chemical Industry.

Adsorption of chia proteins at interfaces: Kinetics of foam and emulsion formation and destabilization.

Chia proteins were extracted by solubilisation at pH 10 or 12 and precipitated at pH 4.5. Isolates were named as CPI10 and CPI12, according to their extraction pH, 10 or 12, respectively. The surface properties of both isolates were studied at neutral conditions. Foams were formed by air bubbling and both the formation and destabilization processes were analysed by conductimetry. The extraction pH significantly affected the interfacial properties of chia proteins. The higher surface hydrophobicity in CPI10 led to more flexible proteins with improved foaming properties. Foams formed by CPI10 were more stable than those by CPI12 due to the formation of a thicker interfacial film, which meant a greater ability to retard liquid drainage. Freshly-made coarse emulsions stabilized with CPI12 showed a lower mean droplet size and a significantly lower degree of overall destabilization than those stabilized with CPI10. None of the two emulsions showed flocculating effect.

Development and Structural Behaviour of Soybean Gelato.

The aim of this study is to elaborate and evaluate structural characteristics of soybean gelato by varying the content of soybean protein concentrate (2.95 to 17.05%) and vegetable fat (7.95 to 22.05%) using experimental design. The replacement of milk by hydrosoluble extract and soybean protein concentrate presented itself as an alternative to gelato production with unique characteristics, especially in terms of protein, solubility, viscosity, melting point, overrun and acceptability. The addition of up to 5% (m/V) protein concentrate, 14% (by volume) soybean hydrosoluble extract, and 15% (by mass) vegetable fat to gelato formulations resulted in better structural characteristics, with viscosity ranging from 0.45-0.70 Pa∙s at 10 °C, a non-Newtonian behaviour and protein stability (total protein content 8.44% and solubility 41%). Soybean gelato structural analysis using X-ray diffraction revealed 15° and 35° diffraction angles at 2Θ, characterizing the crystalline part of the product. The thermal analyses showed four bands of mass loss in the temperature range of 40-600 °C, characterizing loss of moisture, decomposition of the soy protein and the fat/emulsifier of the formulations. Thus, the soybean gelato is an innovative product, lactose and milk protein-free with outstanding characteristics for the general public, mainly, for the populations with intolerance to such components.

Whey protein concentration by ultrafiltration and study of functional properties / Concentração de proteínas de soro por ultrafiltração e estudo das propriedades funcionais

ABSTRACT: This paper aim to evaluate the ultrafiltration (UF) process for constituents recovery from whey. Sequences of factorial designs were performed by varying temperature (5 to 40°C) and pressure (1 to 3 bar), to maximize the proteins concentration using membrane of 100kDa in dead end system. Based on the best result new experiments were performed with membrane of 50kDa and 10kDa. With the membrane of 50 the protein retention was about 3 times higher than the membrane of 100kDa. The concentrated obtained by UF membrane of 10kDa, 10°C and 2 bar in laboratory scale showed a mean protein retention of 80 %, greater protein solubility, emulsion stability and the identification of β-lactoglobulins (18.3 kDa) and α-lactalbumin fractions (14.2kDa). Therefore, the use of membrane of 100 and 50kDa are became a industrially recommendable alternatives to concentration of whey proteins, and/or as a previous step to the fractionation of whey constituents using membrane ≤10kDa, aiming at future applications in different areas (food, pharmaceutical, chemical, etc.).

RESUMO: O objetivo do estudo foi avaliar o processo de Ultrafiltração (UF) na recuperação dos constituintes do soro de leite. Planejamentos fatoriais sequenciais foram realizados, variando a temperatura (5 a 40°C), a pressão (1 a 3 bar) e visando maximizar a concentração de proteínas usando membrana de 100kDa em sistema dead end. Baseados nos melhores resultados, foram realizados experimentos com de 50kDa e 10kDa. Em relação a membrana de 50kDa, a retenção de proteínas foi cerca de três vezes maior em relação a membrana de 100kDa. O concentrado obtido por membrana UF de 10kDa, 10°C e 2 bar, em escala laboratorial, mostrou uma retenção média de proteína de 80%, maior solubilidade protéica, estabilidade da emulsão e a identificação das frações β-lactoglobulins (18.3kDa) e α-lactalbumin (14.2kDa). Portanto, o uso de membranas de 100 e 50kDa são alternativas recomendáveis industrialmente à concentração de proteínas de soro de leite, e/ou como etapa anterior ao fracionamento de constituintes do soro usando membrana ≤10kDa, visando aplicações futuras em difentes áreas (alimentícia, farmacêutica, química, etc).