Valorization of Artichoke Industrial By-Products Using Green Extraction Technologies: Formulation of Hydrogels in Combination with Paulownia Extracts.

Herminia Domínguez,Paula Rodríguez-Seoane,María Elvira Zúñiga,Gabriela Órbenes,María Dolores Torres,Rolando Chamy

doi:10.3390/molecules26144386

Abstract

The integral valorization of artichoke bracts generated during industrial canning of artichoke was assessed. The extraction of bioactive compounds was addressed with pressurized hot water under subcritical conditions. The performance of this stage on the extraction of phenolics with antioxidant properties and the saccharidic fraction using conventional and microwave heating was compared. The microwave assisted process was more efficient than the conventional one regarding extraction yields of total solubles, and glucose and fructose oligomers and phenolics, because lower operational temperatures and shorter times were needed. Degradation of fructose oligomers was observed at temperatures higher than 160 °C, whereas the maximal phenolic content occurred at 220 °C. Both the extracts and the residual solids, obtained at conditions leading to maximum phenolics yields, were evaluated for the production of starch-based hydrogels, supplemented with Paulownia leaves’ aqueous extracts.

Highlights

The agri-food industry generates millions of tons of waste each year, leading to serious environmental problems and a loss of valuable compounds [1]
Attempts have been made to find possible uses for artichoke by-products [4]. These by-products are a source of fatty acids [5], inulin, fiber, minerals [6], inositols [7], and phenolic compounds [2,6,7,8,9,10,11], suitable for the production of dietary supplements and food additives
Ethanol, and water have been used for the extraction of sugar and phenolics from bracts [3,5,8,9]

Summary

Introduction

The agri-food industry generates millions of tons of waste each year, leading to serious environmental problems and a loss of valuable compounds [1]. Attempts have been made to find possible uses for artichoke by-products (bracts, leaves, and stems) [4] These by-products are a source of fatty acids [5], inulin, fiber, minerals [6], inositols [7], and phenolic compounds [2,6,7,8,9,10,11], suitable for the production of dietary supplements and food additives. Pressurized hot water extraction was used to extract caffeoylquinic acids and flavone glycosides without formation of artefacts at high temperatures [10] Both techniques, subcritical water extraction (or autohydrolysis) and microwave assisted extraction, are efficient and promising methods for recovering natural compounds from raw plants or their by-products. Subcritical water refers to water at temperatures ranging from the boiling point (100 ◦C) to critical point (374 ◦C), and pressure high enough sisted extraction, are efficient and promising methods for recovering natural compound from raw plants or their by-products.

Results and Discussion

Extraction of Bioactive Fractions

Rheology of the Formulated Hydrogels

Hydrogels

Statistical Analysis

Conclusions