Production of Protein Hydrolysates From Wolffia ( Wolffia globosa ) Using Bromelain and Its Application to Oyster Sauce Imitation Products

Wolffia is a superfood. It is a fantastic source of alternative protein and is one of the aquatic food plants of the future. The determination of the optimum conditions for extracting protein hydrolysate from fresh Wolffia using bromelain revealed that a bromelain concentration of 0.75% ( w / w ), a digestion time of 6 h, and a digestion temperature of 55°C were the optimal conditions, as the protein hydrolysate produced under these conditions contained 4.42% protein. The obtained protein hydrolysate was developed into a Wolffia sauce product using a mixture design. The three factors studied included Wolffia protein hydrolysate content (55%–60%), salt (0%–5%), and low‐sodium soy sauce (0%–10%). The results indicated that WSF3, which was produced using 53.3% Wolffia protein hydrolysate, 3.3% salt, and 8.3% low‐sodium soy sauce, was given the highest ratings for texture and overall acceptability. All attributes rated this recipe at “like moderately‐like very much” levels. The resulting Wolffia sauce had a protein content of 2.29%, sodium content of 1252 mg or 2.81%, pH of 5.35, and viscosity of 8409 cPs, while commercial oyster sauce has a protein content of 0.52%, sodium content of 1853 mg or 4.73%, pH of 4.34, and viscosity of 9710 cPs, on average. This study confirmed that the Wolffia sauce had a low sodium content and a high protein content, similar to oyster sauce. The research indicated that the Wolffia sauce made with WSF3 to mimic oyster sauce could last at least 3 months at 35°C, and its viscosity, pH, and microbiological properties met the Thai Industrial Standard for Oyster Sauce (TIS 1317‐2538), Thailand.