Functional Characterization of Tofu Protein Extract and Its Application in Gluten-free Food Product Riska Leila Amaria 1, Erni Sofia Murtini, S.TP., MP., Ph.D. 1, Prof. Dr. Ir. Sudarminto Setyo Yuwono, M.App.Sc. 1, Asst. Prof. Suphat Pongthai, Ph.D. 2, Dr.nat.techn. Elok Waziiroh, S.TP., M.Si 1*.
1 Faculty of Agricultural Technology, Brawijaya University
Jl. Veteran 10, Malang 65145, Indonesia
*Email : elokwz[at]ub.ac.id
2 Faculty of Agro-Industry, Chiang Mai University
Huay Kaew Road 239, Chiang Mai 50200, Thailand
Abstract
Soybeans are a widely used source of vegetable protein in the food sector and processed into derivative products such as tofu. This study examined the extraction of tofu and soybean proteins using the alkali method, followed by functional characterization of the proteins. The proteins were also analyzed molecularly. The soy and tofu protein extracts were applied to food products which are steamed bread, pukis cake, and white bread. This study aimed to determine the effect of soybean and tofu processing on protein characteristics and the suitability of adding tofu protein extract to gluten-free products with different processing methods.
The study showed that the functional characteristics of tofu protein extract differed from those of soy protein. An increase in emulsion properties, surface hydrophobicity, and solubility which was supported by the presence of hydrophobic amino acids. The application of tofu protein extract had different effects based on gluten-free product processing. For example, in steamed bread, the extract produced a low specific volume and porosity, as well as a decrease in baking loss and hardness, compared to gluten-free products without added protein. In pukis cake, baking loss increased, porosity decreased, and hardness increased, though elasticity was similar to that of gluten-containing pukis. Tofu protein extract produced high specific volume, good expansion, low hardness, high elasticity, and good pore size in white bread compared to gluten-free controls, though baking loss was high. These results demonstrate the potential suitability of tofu protein extract for gluten-free products processed by the oven baking method, particularly white bread.
