¹²¹⁷Physicochemical and Techno-Functional Characterization of Protein Extract from Fermented Soybean by Product (Okara) and Its Application in Mayonnaise

Sri Herliyanti¹, Filia A Meylana¹, Andriati Ningrum¹, Arima Diah Setiowati¹ , Manikharda¹, Achmat Sarifudin², Rima Kumalasari², Riyanti Ekafitri² , Dita Kristanti³, Woro Setiaboma³, Heli Siti Halimatul Munawaroh⁴, Siti Zaharah Sakimin⁵ , Aunchalee Aussanasuwannakul⁶, Lena Breitenmoser⁷

¹Department of Food and Agricultural Product Technology, Faculty of Agricultural Technology,Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
²Research Centre for Appropriate Technology, National Research and Innovation Agency, Subang 41213, Indonesia
³Research Center for Food Technology and Processing, National Research and Innovation Agency, Yogyakarta 55861, Indonesia
⁴Chemistry Program, Department of Chemistry Education, Faculty of Mathematics and Science Education, Indonesia University of Education, Bandung 40154, West Java, Indonesia
⁵Department of Crop Science, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia
⁶Department of Food Chemistry and Physics, Institute of Food Research and Product Development, Kasetsart University, Bangkok 10903, Thailand
⁷Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts, Northwestern Switzerland (FHNW), Hofackerstrasse 30, 4132 Muttenz, Switzerland

Abstract body - Tempeh gembus is a traditional Indonesian fermented food, but it typically has a short shelf life and low economic value. These limitations can be addressed by processing it into flour or hydrolysates, followed by protein extraction to improve its physicochemical and techno-functional properties. Tempeh protein possesses excellent techno-functional traits such as water holding capacity (WHC), oil holding capacity (OHC), and emulsion stability. This study explores the application of protein extract from tempeh gembus flour as an emulsifier in mayonnaise, a semi solid oil in water (O/W) emulsion that relies on emulsifiers for stability. The research aims to evaluate the functional properties of the protein extract, including its suitability as a plant based emulsifier in mayonnaise formulations. The physicochemical (color, protein, fat, moisture, ash, carbohydrates, amino acid composition) and functional (WHC, OHC, emulsifying activity and stability) characteristics of the protein extract were analyzed. Additionally, mayonnaise formulated with varying concentrations of the protein extract was assessed for physicochemical properties, rheological behavior, emulsion stability, and sensory acceptance. Results showed that the protein extract had a lighter color and higher protein, ash, fat, and amino acid content than the flour. It also exhibited superior WHC, OHC, and emulsifying properties. Increasing extract concentration in mayonnaise increased protein and ash content while decreasing fat content, with no significant difference in overall consumer preference compared to the control. This suggests that tempeh gembus protein extract is a promising functional ingredient for more nutritious and stable mayonnaise products.