Preparation of ferulic acid from agricultural wastes: its improved extraction and purification.

Ferulic acid (FA) is a phenolic antioxidant present in plants, which is widely used in the food and cosmetic industry. In the present study, various agricultural wastes such as maize bran, rice bran, wheat bran, wheat straw, sugar cane baggasse, pineapple peels, orange peels, and pomegranate peels were screened for the presence of esterified FA (EFA). Among the sources screened, maize bran was found to contain the highest amount of EFA. Pineapple peels, orange peels, and pomegranate peels were also found to contain traces of EFA. Alkaline extraction of EFA from maize bran was carried out using 2 M NaOH. Response surface methodology (RSM) was used for optimization of EFA extraction, which resulted in a 1.3-fold increase as compared to the unoptimized conventional extraction technique. FA was analyzed by means of high-performance liquid chromatography (HPLC). Purification was carried out by adsorption chromatography using Amberlite XAD-16 followed by preparative high-performance thin-layer chromatography (HPTLC). The recovery of Amberlite XAD-16 purified FA was up to 57.97% with HPLC purity 50.89%. The fold purity achieved was 1.35. After preparative HPTLC, the maximum HPLC purity obtained was 95.35% along with an increase in fold purity up to 2.53.