Emulsifying Properties of Dried Soy-Whey, Dried Tofu-Whey, and Their Isolated Proteins

Abstract

http://creativecommons.org/licenses/by-nc-nd/3.0/).ABBREVIATIONS BBTI: Bowman-Birk trypsin inhibitor; BS: backscattering; BS bottom : mean value of backscattering at the bottom of the measurement cell; BS 0, bottom : initial (t=0) mean value of backscattering at the bottom of the measurement cell; BS top : mean value of backscattering at the top of the measurement cell; CH/P T-TCA :carbohydrate-protein mass ratio in the total aqueous dispersion; CH/P S-TCA: carbohydrate-protein mass ratio in the soluble aqueous dispersion; D 4,3 : De Brouckere, volume-weighted mean diameter; D 4,3 -SDS : De Brouckere, volume-weighted mean diameter measured in the absence of sodium dodecyl sulfate; D 4,3 +SDS : De Brouckere, volume-weighted mean diameter measured in the presence of sodium dodecyl sulfate; K: gravitational separation kinetic constant; KTI: Kunitz trypsin inhibitor; SDS: sodium dodecyl sulfate; TCA: trichloroacetic acid; TIA: trypsin inhibitor activity; r-TIA: relative trypsin inhibitor activity; Vr: relative cream layer volume. This paper focuses on the comparative study of emulsifying properties of dried tofu-whey, dried soy-whey and their isolated proteins. Oil-in-water emulsions were prepared at equivalent protein concentration (0.1, 0.5 and 1.0 g/100 mL), using sunfl ower oil as lipid phase (oil mass fraction = 0.33). Tofu-whey and soy-whey were dehydrated by freeze-drying (LTW and LSW, respectively) or thermal-drying (DTW and DSW, respectively). Moreover, a heated LSW sample in anhydrous condition (h-LSW) was included. The emulsion formation and stability at rest was evaluated using a vertical scan analyzer, according to multiple light scattering theory, particle size and oiling off measurements. Even though the stability to gravitational separation and coalescence increased with increasing protein concentration, freeze-dried whey samples exhibited a higher ability to form and stabilize emulsions respect to that of thermally-dried ones, especially for those obtained from soy-whey. Moreover, h-LSW emulsions were more stable than that of LSW sample presumably due to protein glycosylation. The global emulsion stability decreased in the order: LTW>DTW>h-LSW>LSW>DSW. Moreover, at equivalent protein concentration in the continuous phase, the isolation of proteins from lyophilized whey-samples by treatment with cold acetone (LTW-P, LSW-P and h-LSW-P, respectively) improved their emulsifying properties. Again, this improvement was more pronounced for samples obtained from soy-whey, probably due to partial protein denaturation associated to treatment with the organic solvent. In conclusion, this paper should be considered as basis for further studies concerned with the potential application of soy-whey and tofu-whey proteins as emulsifi ers in different systems.

Impact of environmental stresses on the stability of acidic oil-in-water emulsions prepared with tofu whey concentrates

“…Although KTI and lectin are known antinutritional bioactive compounds, they are totally denatured and inactivated during the hydrothermal treatments of tofu manufacturing ( Vagadia et al, 2017 ). As was observed in a previous work, tofu-whey proteins obtained by precipitation with organic solvents exhibited good emulsifying properties in model oil-in-water emulsions ( Sobral et al, 2018 ). In another article, the emulsifying properties of tofu-whey proteins were improved by conjugation with soy polysaccharides through Maillard-type glycosylation ( Matemu et al, 2009 ).…”

Sensory quality of upcycled legume water: Expectation vs. reality

“…Based on the results shown in Table 1, SBPW and TW were strong emulsifiers, but SBPW had greater emulsifying capacity. Previous research has examined the greater emulsifying ability of TW than soy whey due to the presence of soy proteins (around 15%-20% on the dry weight basis) (Sobral et al, 2018;Sun et al, 2022). Apart from that, legumes like soybeans are a good source of lecithin, a type of lipid compound that is known for its ability to interact with both water and oil (Gan et al, 2014).…”

Plant protein ingredients with food functionality potential

“…However, when soy whey is heat‐treated to eliminate anti‐nutritional properties, it can have good technological functionality for use in foods (Sobral et al . 2018; Chua & Liu 2019).…”