Optimization of ultrasonic-assisted enzymatic extraction of β-carotene from orange processing waste

摘要

In this research, extraction of beta-carotene pigment from orange processing waste was investigated by combining ultrasonic and enzymatic processes using ethanol solvent. In order to optimize the extraction conditions, the effect of pectinase enzyme concentration [0-5% (w/w)], ultrasonic time (10-120 min), and pH of solution (3.5-6) on dependent variables of beta-carotene content, antioxidant activity, color parameters of L*, a*, and b*, and browning index (BI) of extracts was investigated using response surface methodology. Optimal condition of ultrasonic-assisted enzymatic extraction treatment using ethanol solvent was estimated as pectinase concentration of 0.40% (w/w), ultrasonic time of 115.55 min, and pH of 5.11 to achieve the highest amounts of beta-carotene content, antioxidant activity, color parameters of L*, a*, and b*, and the lowest amount of BI parameter. The results of scanning electron microscopy images showed that using ultrasound waves and the pectinase enzyme, in particular in the case of using ethanol solvent, disrupted the sample tissue. The results of Fourier transform infrared spectroscopy showed that the functional groups of the extracts were not degraded during the ultrasonic and enzymatic processes. Practical applications The increasing awareness and demand of consumers for enriched functional foods with bioactive compounds such as beta-carotene pigment is promising. It has resulted in an improved interest in extracting beta-carotene pigment from food processing waste sources. In addition, it has led to application of novel extraction methods such as ultrasonic-assisted enzymatic extraction. The results of this study showed that optimal treatment of ultrasonic-enzymatic treatment using ethanol solvent compared to maceration treatment using ethanol solvent resulted in a higher beta-carotene content.