Optimization of Ultrasound-Assisted Extraction via Sonotrode of Phenolic Compounds from Orange By-Products.

María Del Carmen Razola-Díaz,Ana María Gómez-Caravaca,Celia Rodríguez-Pérez,Vito Verardo,Eduardo Jesús Guerra-Hernández,Belén García-Villanova

doi:10.3390/foods10051120

María Del Carmen Razola-Díaz, Ana María Gómez-Caravaca + Show 4 more

Open Access

https://doi.org/10.3390/foods10051120

Copy DOI

Abstract

Orange peel is the main by-product from orange juice industry. It is a known source of bioactive compounds, mostly phenolic compounds, and it has been widely studied for its healthy activities. Thus, this research focuses on the establishment of ultrasound-assisted extraction of phenolic compounds in orange peel using a sonotrode. For this purpose, a Box–Behnken design of 27 experiments was carried out with four independent factors—ratio ethanol/water (v/v), time (min), amplitude (%), and pulse (%). Quantitative analyses of phenolic compounds were performed and the antioxidant activity was measured by ABTS and DPPH methods. The validity of the experimental design was confirmed by ANOVA and the optimal sonotrode extraction conditions were obtained by response surface methodology (RSM). The extracts obtained in the established conditions were analyzed by High Performance Liquid Chromatography (HPLC) coupled to mass spectrometer detector and 74 polar compounds were identified. The highest phenolic content and antioxidant activity were obtained using 45/55 ethanol/water (v/v), 35 min, amplitude 90% (110 W), and pulse 100%. The established method allows an increment of phenolics recovery up to 60% higher than a conventional extraction. Moreover, the effect of drying on phenolic content was also evaluated.

Highlights

The minimum value with both methods was obtained using only ethanol (100%), whereas the highest ones were observed by using a mixture of 50% ethanol and 50% water, to the results described for TPC
An extraction based on ultrasound-assisted extraction by sonotrode has been optimized for obtaining the higher amounts of phenolic compounds with high antioxidant activity from the orange by-products
The results of this study have shown that applying the sonotrode extraction is possible to increase 60% more the phenolic recovery compared to a conventional extraction procedure as maceration

Summary

Introduction

Orange is the second most produced fruit in the European Union, mainly in the countries of the Mediterranean basin where it supposes 6 million tons, almost 10% of the world production. Orange juice is the main product processed by the beverage industry and consumed throughout the world due to its high nutritional value and desirable sensory characteristics. Orange fruit processing to obtain juices or citrus-based beverages generates large amounts of waste by-products, such as peels, which are a rich source of soluble sugars, phenolic compounds, flavonoids, dietary fibers (cellulose, hemicelluloses, and pectin), vitamins, enzymes, and essential oils [1,2,3,4,5], which can be used for the production of nutritional dietary supplements [6]. Several authors successfully used the orange by-products as ingredients with rheological and functional properties for the formulation of biscuits [7] and jams [8], and as fat replacer [9]

Objectives

Results

Conclusion