The food industry has faced a growing trend of replacing animal-based foods with plant-based substitutes, since consumption of high amounts of certain animal products is linked to adverse health outcomes in addition to ethical and environmental concerns.(McClements et al., 2019) Hence, developing high-quality plant-based milk substitutes includes selecting appropriate functional attributes according to consumer expectations of current commercial products. Plant-based milk substitutes are complex colloidal dispersions, and so many of their properties are determined by the nature of the polymers and particles they contain, as well as by individual extractions (i.e., from a single vegetable such as oat, soybean, or rice) or through vegetable mixtures that allow nutritionally balancing the dairy substitute. Stability of plant-based beverages depended on the number of particles within it (e.g., oil bodies, fat droplets, and/or plant carbohydrates traces), the nature of the aqueous solution (e.g., pH, mineral composition, sugar content, viscosity, and density), as well as on mechanical forces and temperature (ambient 25°C or refrigerated 4°C) the beverage experiences throughout its lifetime. This study aims to optimize the formulation of a plant-based beverage (almond, pea, and rice combination) with high protein content, and high acceptance in appearance, texture, and flavor required to create a high-quality plant-based milk substitute. Vegetable concentrates of pea, rice, and almond powder concentrates were obtained from a commercial distributor. A simple lattice design (10 runs with 100, 50:50, 25:25:50, and 33:33:33% using studied vegetable powders) was utilized for the beverage reconstitution with 10% of solids (of which 1% was xanthan gum as thickening agent) and 90% distilled water; each tested sample (total volume of 100mL) was homogenized (3000 rpm) during 10 min. Determination of tested beverage attributes included light scattering, color, particle size (d3,2), shear viscosity, density, water activity, protein content, and pH stability; every measurement was carried out in triplicate. Statistical analyses, mixture designs, and optimization were carried out in Matlab R2020b. Visual attributes became more intense as the number of molecular components of the plant-based beverage were increased. Colorimetry measurements exhibited that their whiteness index (calculated from L*a*b* values) ranged from around 65 to 78, being below the value of 82 reported for cow’s milk. In addition, controlling the pH, as well as the type and level of mineral ions and thickening agents, can also have a significant influence on the stability of studied plant-based beverages. Beverages’ shear viscosities were range between 15-100 cP and densities below 1.07g/mL. Using the empirical model from the experimental design, the optimal formulation under established constraints should contain 60.4% rice powder, 12.12% almond powder, 27.4% pea powder, reaching a total protein content of with 8% in the milk beverage with a density value of 1.069 g/mL, a viscosity of 64.9 cP, pH 6.73 and water activity of 0.996. and a particle size D4,3 of 20.92 um, similar to the study of (da Silva et al., 2023; Kimura et al., 2008)who reported Pea mean diameter of 23.56 um.
Furthermore, theoretical models based on group contribution methods were utilized to estimate the different physicochemical properties of the individual components and obtained mixtures. These estimations were then compared with the experimental results. This approach will help in developing a semi-empirical model that can be combined with the experimental design to improve the optimization formulation (Pua et al., 2022).
Keywords
Optimal design, plant-based beverage, physicochemical heuristics
References
da Silva, L. R., Velasco, J. I., & Fakhouri, F. M. (2023). Use of rice on the development of plant-based milk with antioxidant properties: From raw material to residue. LWT, 173, 114271. https://doi.org/10.1016/j.lwt.2022.114271
Kimura, A., Fukuda, T., Zhang, M., Motoyama, S., Maruyama, N., & Utsumi, S. (2008). Comparison of Physicochemical Properties of 7S and 11S Globulins from Pea, Fava Bean, Cowpea, and French Bean with Those of Soybean—French Bean 7S Globulin Exhibits Excellent Properties. Journal of Agricultural and Food Chemistry, 56(21), 10273-10279. https://doi.org/10.1021/jf801721b
McClements, D. J., Newman, E., & McClements, I. F. (2019). Plant-based Milks: A Review of the Science Underpinning Their Design, Fabrication, and Performance. Comprehensive Reviews in Food Science and Food Safety, 18(6), 2047-2067. https://doi.org/10.1111/1541-4337.12505
Pua, A., Tang, V. C. Y., Goh, R. M. V., Sun, J., Lassabliere, B., & Liu, S. Q. (2022). Ingredients, Processing, and Fermentation: Addressing the Organoleptic Boundaries of Plant-Based Dairy Analogues. Foods, 11(6), Article 6. https://doi.org/10.3390/foods11060875
