Phenolic Compounds from Cricket Powder and Its Protein Extract after Passing through the Simulated In vitro Digestion

Abstract

Phenolic compounds found in edible insects is due to plant-derived phenolics present in their diet and the ability of insects to synthesize through the sclerotization process. This study aimed to examine the loss of phenolic compounds from cricket powder (CP) and cricket crude protein extract (CCP) after passing through the simulated in vitro digestion. CCP was prepared by alkali extraction of CP, followed by isoelectric point precipitation at pH 4.0. The protein content of CP and CCP was determined as 54.95 and 61.12% dry basis (d.b.), respectively, with moisture content approx. 3-5%. The total phenolic content (TPC) via Folin-Ciocalteu’s reagent of both samples were measured. CP contained less TPC than CCP at the respective 5.87 and 30.64 mg gallic acid equivalent (GAE)/g. Gallic acid, isoquercetin, quercetin and tannic acid were phenolic compounds found in both CP and CCP. During the simulated in vitro digestion, TPC in both samples dramatically reduced after passing the gastric condition at pH 3. The TPC at small intestinal condition at pH 7 of CCP reduced whereas that of CP slightly increased. As phenolic compounds have been widely known for their antioxidant activity, thus DPPH and FRAP antioxidant assays were used for the assessment in this study. The results showed that the reduction of antioxidant activity was in proportion to TPC. Suggesting that the pH and digestive enzymes could affect the loss of phenolic compounds in CP and CCP.