Optimisation of Ultrasonic Conditions as an Advanced Extraction Technique for Recovery of Phenolic Compounds and Antioxidant Activity from Macadamia (Macadamia tetraphylla) Skin Waste

Adriana Dailey,Quan Vuong

doi:10.3390/technologies3040302

Abstract

Thousands of tons of macadamia skin waste are generated annually with very limited utilisation of this extensive by-product. The aim of this study was to develop optimal ultrasonic extraction conditions for maximized recovery of phenolic compounds and antioxidant properties from macadamia skin using Response Surface Methodology (RSM). Three ultrasonic parameters, including temperature (30–50 °C), time (10–50 min) and power (150–250 W), were tested for their impact on the extraction of total phenolic compounds (TPC), flavonoids, proanthocyanidins and antioxidant properties. The results showed that ultrasonic temperature, time and power had an impact on TPC and antioxidant capacity; however, the effects varied. The optimum ultrasonic conditions for the maximum recovery of phenolic compounds and antioxidant properties from macadamia skin were found to be a temperature of 40 °C, a time of 35 min and a power of 80%/200 W. Under these optimal conditions, approximately 168 mg of TPC, 135 mg of flavonoids and 188 mg of proanthocyanidins can be extracted from one gram of dried macadamia skin.

Highlights

IntroductionPolyphenols are derived from plant materials such as fruits, vegetables, cereals, oilseeds and nuts
Polyphenols are derived from plant materials such as fruits, vegetables, cereals, oilseeds and nuts.They have been reported to possess potent antioxidant properties, as well as being associated with different health benefits through their inherent redox properties [1]
It is important to check the fitting of the Response Surface Methodology (RSM) mathematical models to make sure that they are reliable in the prediction of Ultrasonic-assisted extraction (UAE) extraction conditions for total phenolic compounds (TPC), flavonoids, proanthocyanidins and antioxidant properties from the skin of the Macadamia tetraphylla

Summary

Introduction

Polyphenols are derived from plant materials such as fruits, vegetables, cereals, oilseeds and nuts They have been reported to possess potent antioxidant properties, as well as being associated with different health benefits through their inherent redox properties [1]. It is worthy to identify, extract and isolate polyphenols from the plant materials, especially from the waste of the food industry, for further utilization This can minimize the number of problems associated with waste as well as adding more value for the food industry. Only the kernel is known as the commercial section; whereas, the skin and husk, which account for approximately

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Conclusion