Production and Evaluation of Green Soybean (Glycine max L.) Powder Fortified with Encapsulated Crude Procyanidin Extract Powder

Green soybean (Glycine max L.), commonly known as edamame, is recognized for its rich phytochemical content and nutritional and functional benefits. However, its limited shelf life and susceptibility to quality degradation restrict its commercial potential in fresh form. To address this, green soybean seeds can be processed into extract and powder forms, which offer greater stability and added value. The preparation of crude procyanidin extract was examined in this study along with the effects of three distinct extraction techniques: enzyme incubation, ultrasonic-assisted extraction (UAE), and enzymatic hydrolysis followed by ultrasonic-assisted extraction (EUAE). Additionally, the effects of two drying methods (drum-drying and spray-drying) on the retention of bioactive compounds and antioxidant activity were assessed. Optimal conditions for each drying method were selected to enhance antioxidant properties by fortifying instant green soybean powder (GSP) with encapsulated crude procyanidin extract (ECPE). The chemical, physical, and sensory properties of ECPE-fortified GSP were analyzed. Results indicated that the EUAE method was the most effective for procyanidin extraction. Encapsulation allowed for procyanidin retention of over 83% after storage at 25 and 35 °C for 12 weeks. The optimal conditions were determined to be drum-drying at 3 rpm and spray-drying at an inlet temperature of 200 °C for the drying techniques. Fortification of GSP with 3–5% ECPE powder positively correlated with increased phytochemical content and antioxidant activity. Both drum- and spray-dried GSP maintained color integrity comparable to the control. Drum-dried GSP preserved greater concentrations of bioactive compounds and exhibited superior antioxidant activity compared to spray-dried GSP. All powdered products had acceptable water activity (≤0.60) and moisture content (≤12%), suggesting suitability for long-term storage. Although spray-dried powders exhibited greater hygroscopicity, they demonstrated lower emulsion stability and solubility compared to drum-dried powders. Drum-dried GSP retained higher levels of carbohydrate, fat, fiber, and ash compared with spray-dried powder, while protein content was similarly preserved by both methods. In conclusion, ECPE powder serves as a promising functional ingredient in instant green soybean powder. Both drum-dried and spray-dried GSP products exhibit potential for application in a variety of functional food products.