INCREASED EXTRACTION OF PHENOLICS IN AQUEOUS CHICKPEA EXTRACTS BY THE ACTION OF PLANT-DERIVED PROTEASES

Chickpeas (Cicer arietinum) are a legume that continues to attract interest in the scientific community and the food industry due to their high nutritional value and functional potential. They stand out mainly for their high protein content and other bioactive compounds, such as phenolic compounds, associated with various health benefits. Aqueous extracts based on chickpeas represent a promising alternative for the formulation of plant-based beverages, especially because they can carry many of these water-soluble compounds. However, although many compounds are soluble, enzyme-assisted extraction is considered a promising process step because it favors the increased release of compounds from the food matrix, potentially increasing the concentration of bioactive compounds in the extracts. The use of proteases, one of the enzyme classes to be applied, is a known process that allows both an increase in protein concentration in the final extract and the generation of bioactive peptides from chickpea proteins. However, the application of proteases, by disrupting the food matrix, could also favor the release of other bioactive compounds. In this context, this work aimed to evaluate the application of papain and bromelain in the production of aqueous extracts, observing their impacts on the amounts of solubilized phenolics.
Desi chickpeas (var. GB Cappuccino), supplied by AgroGarbanzo (Brazil), were ground and the resulting flour suspended in water and treated with papain in an enzyme-protein ratio of 1:100, incubated for 2 minutes at 25°C. The reaction was stopped by boiling for 5 minutes. A hydrolysis "blank" was prepared by applying a solution of previously inactivated enzymes. The total phenolic content was determined spectrophotometrically using the Folin-Ciocalteu reagent, and absorbance was measured at 750 nm after 60 minutes in the dark. A gallic acid standard curve (0-16 µg/ml) was used, with results expressed in mg gallic acid equivalents per gram of chickpeas. It was observed that for both enzymes there was an increase in the extraction of phenolic compounds, with papain showing values ​​that increased from 154.91 to 764.04 µg EAG/g of sample, respectively for the inactive and active forms, representing a gain of 406.7%. For bromelain, the values ​​increased from 179.73 to 319.76, respectively, representing a gain of 77.8%. Thus, the data indicate that, in addition to affecting protein extraction, the application of proteases can also affect the availability of other matrix components, such as phenolics, adding benefits to the final product.