Effect of superfine grinding on physicochemical and antioxidant properties of soybean residue powder.

Guanghui Li,Yonghui Wang,Xueli Gao,Sisheng Sun,Weiyun Guo

doi:10.1002/fsn3.1409

Abstract

Soybean residue is an underutilized, nutrient‐rich by‐product of soybean processing. To enhance its value, we subjected soybean residue to superfine grinding and measured the resulting physiochemical properties and antioxidant activities. We prepared powders with particle sizes of 115.35, 77.93, 39.38, 25.01, and 20.44 μm. As particle size decreased, the surface area (from 96.46 to 198.32 m2/kg) and swelling capacity (from 2.05 to 10.62 ml/g) increased. Conversely, we observed decreases in the surface‐number mean (from 23.07 to 11.20 μm), volume‐surface mean (from 141.70 to 27.96 μm), angles of repose (from 48.30° to 31.46°), water holding capacity (from 7.86 to 4.39 g/g), and oil binding capacity (from 1.78 to 1.42 g/g). The water solubility index and antioxidant activity (reducing power and free radical scavenging activities of 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐di‐(3‐ethylbenzthiazoline sulfonic acid)) improved as particle size decreased. In conclusion, superfine grinding improved some properties of soybean residue. Additionally, our findings provide theoretical support for using superfine grinding in industrial food applications.

Highlights

Soybean products, such as soy milk, tofu, yuba, and tofu skin, are the most popular foods worldwide (Chen et al, 2012; Thakur, Wei, & Tomar, 2020)
D50, represented the degree of powder cohesiveness, is the average median diameter, and the D50 values of the five powders were as follows: 115.35, 77.93, 39.38, 25.01, and 20.44 μm, respectively. This demonstrated that ultrafine soybean residue powders were obtained by superfine grinding, and their qualities such as bioavailability, absorption, and solubility would be improved
The results suggested that superfine grinding improved the radical scavenging capacity and reducing power; a decline in antioxidant activity would occur if the powder size was too small

Summary

Introduction

Soybean products, such as soy milk, tofu, yuba, and tofu skin, are the most popular foods worldwide (Chen et al, 2012; Thakur, Wei, & Tomar, 2020). Soybean residue is generated during processing (Li et al, 2013). Carbohydrates, dietary fiber, isoflavone, and minerals (Li et al, 2013; O'Toole, 1999). It has antioxidant activity and may aid in prevention of diabetes, obesity, and hyperlipidemia (Li et al, 2012; Li et al, 2017; Li et al, 2014; Wang, Zhou, Hou, Qi, & Zhang, 2013). Attempts have been made to use soybean residue as animal feed, fertilizer, and food ingredients (Li et al, 2012)

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Conclusion