Optimization of Volatile Compounds Extraction from Industrial Celery (Apium graveolens) By-Products by Using Response Surface Methodology and Study of Their Potential as Antioxidant Sources.

Mercedes Ponce Landete,Arantzazu Valdés García,María Soledad Prats Moya,María Isabel Domingo Martínez,Ana Beltrán Sanahuja

doi:10.3390/foods10112664

Abstract

In this study, the potential of industrial celery by-products (the stalk and root) serving as sources of aromatics and antioxidants was investigated. A headspace solid phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) procedure was optimized to isolate volatile compounds from celery by-products. A Box–Behnken experimental design was proposed to optimize the procedure through a response surface methodology. The optimal extraction conditions were found to be 1.6 g of homogenized fresh by-product at 30 °C for 60 min. Under these conditions, 26 volatile compounds in stalk and root samples were identified, monoterpenes and sesquiterpenes being the main components. The content of limonene and γ-terpinene found in the stalk was significantly higher in comparison with root samples. Total phenolic content and antioxidant activity (ABTS and FRAP) results underlined the celery wastes studied as good sources of free radical scavengers. This work suggests the potential application of these by-products in the food industry and opens new pathways to valorize celery residues, contributing to the circular economy.

Highlights

Almost 1.3 billion tons of food, a third of worldwide food production, is not used to be eaten
We propose the optimization of the volatile extraction step using a headspace solid phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC–MS) for the separation, identification and quantification of main volatile compounds
The HS-SPME extraction technique combined with GC–MS has been shown to be a rapid, automated and solvent-free method for the analysis of the volatility profile in celery by-products

Summary

Introduction

Almost 1.3 billion tons of food, a third of worldwide food production, is not used to be eaten. Several critical factors should be considered in order to improve the efficiency of HS-SPME analysis, such as the selection of the appropriate fiber coating, extraction temperature, sample weight, time of extraction, among others [14] For this purpose, a response surface methodology is proposed as a novel strategy for optimization of the most relevant HS-SPME operating factors with a reduced number of experimental runs, which has not been previously reported for celery samples [8,9,15,16]. The identification and quantification of the main volatile compounds of different celery cultivars and parts of the plants, such as leaves [8,9] and the stalk [17], have been reported in the literature None of these studies have applied optimization of the extraction of the HS-SPME procedure by using the experimental design methodology. The reported values of this parameter in studies carried out in celery samples are between 20–60 ◦C, while the most suitable extraction time is between 30 and 50 min and the sample weight is around 0.5 to 4.0 g, depending on the study

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