Ultrasound‐Assisted Extraction of Phenolic Compounds From Blue Corn Cob: Effects on Thermal Stability and Color Properties

ABSTRACT The comprehensive utilization of agricultural waste has become a major industrial challenge in recent years. This study aimed to evaluate the extraction of bioactive compounds from blue corn cobs of the “Chalqueño” variety, a native species of great importance and high consumption in central Mexico. Currently, few studies evaluate color, thermal properties, and FTIR spectroscopy. Two extraction methods were compared: ( a ) conventional maceration and ( b ) ultrasound‐assisted extraction (UAE). Total phenol content (TPC) and total anthocyanin content (TAC) were assessed spectrophotometrically. Changes in the color profile and spectrum, thermal properties, and modifications in molecular vibrations were observed using FTIR‐ATR spectroscopy. The combination of wavelength amplitude and processing time was observed to play a determining role during the process. In this sense, at an amplitude of 80% for 15 min the best conditions ( p < 0.05) were presented in terms of concentrations obtained from the compounds (TAC > 100% and TPC > 50%), color stability (∆E < 1.0) and in the molecular structures, thus reflecting that the use of ultrasound does not generate significant changes that suggest the structural modification of these compounds, which will allow preserving their functionality and create perspectives for the application of this technology in a safe way, reducing times and resources that will enable diversifying its use in the food industry.