Response Surface Optimization of Inulin and Polyphenol Extraction from Artichoke (Cynara scolymus (L.)) Solid Wastes

Abstract

Artichoke wastes after processing represent 60–70% of the raw material and are a potential source of inulin and polyphenols, bioactive compounds that can be valorized as food ingredients or nutraceutical products. The aim of this work was to assess and optimize the extraction of these compounds from artichoke wastes using water or water–ethanol mixtures as extracting agents. For simultaneous inulin and polyphenol extraction and to achieve high antioxidant activity in extracts, the best process conditions using water as an extracting agent were T = 89 °C and t = 139 min, where 80% of the inulin content, 60% of the total phenolic content (TPC) and 56% of the antioxidant activity (Aox) were obtained. For water–ethanol extractions, the best results were obtained with EtOH = 22.4%, T = 81 °C and t = 217 min, leading to extraction yields of 90% of TPC, 38% of Aox and 58% of inulin content. From these results, we recommend the use of water for the recovery of inulin and polyphenols from artichoke wastes. Although the extraction yield of polyphenols is lower in water treatments, the amount extracted is considerable and it is a greener option when compared with water–ethanol mixtures.

Gluten-Free Bread Enriched with Artichoke Leaf Extract In Vitro Exerted Antioxidant and Anti-Inflammatory Properties

“…Jiménez-Moreno and co-workers recovered around 2500 ppm of phenolic components from the waste material of artichoke bracts, outer leaves, and stems [ 25 ]. By setting a water-based extraction protocol, Garcia-Castello et al [ 26 ] revealed that it was possible to recover 60% of the polyphenolic quantity and 56% of antioxidant activity from the solid waste of artichoke by-products. Using ultrasound-assisted procedures, Turker et al [ 27 ] extracted a remarkable quantity of polyphenols from artichoke waste in a shorter time than traditional extraction methods.…”

“…Unfortunately, the rate of artichoke-derived waste (i.e., roots, stems, bracts, and external leaves) generated during industrial processes is around 70–85% of the plant weight [ 24 ]. Because artichoke by-products are still enriched in beneficial phenols with recognized antioxidant, antiradical, anticarcinogenic, and antiapoptotic properties, the recent literature supports the application of various methodologies involving phenolic molecule recovery [ 25 , 26 , 27 ].…”

Functional Oligosaccharides Derived from Fruit-and-Vegetable By-Products and Wastes

“…Approximate Percentage of Waste from Raw Material (w/w) References Banana peel 30 [5] Apple (pomace, skin, seeds, stem) 25-30 [6,7] Citrus (orange, lemon, grapefruit-pomace, peel, seeds) 50 [8,9] Exotic fruits (pineapple, mango, mangosteen-skin, core, peel, stone) 35-60 [10][11][12] Artichoke (bracts, stem, leaves) 60 [13,14] Asparagus spear 40-50 [15] Potato peel 15-40 [5] Corn cob 20-30 [16] Nevertheless, considering the market value of these components, fertilisers and animal feeds are not necessarily making the most of these resources. Realising the values of the compounds that can be derived from horticultural by-products, shifting in residue handling, has arisen during the last few decades [17].…”

“…Another study (ultrasonic-assisted extraction at 70 • C, 37 Hz for 30 min) reported the bracts gave 7.5 g inulin/100 g waste whereas the stem gave insignificant amounts and demonstrated that the yield was affected by seasonality [64]. Garcia-Castello et al [13] compared the effectiveness of water and ethanol-water extraction in recovering inulin from artichoke waste. These authors demonstrated that, at optimal conditions, higher inulin yield (approximate 40%) was obtained from water extraction (89 • C, 139 min) than from ethanol-water extraction (22.4% ethanol, 80 • C, 217 min) [13].…”

Valorisation, Green Extraction Development, and Metabolomic Analysis of Wild Artichoke By-Product Using Pressurised Liquid Extraction UPLC–HRMS and Multivariate Data Analysis

“…However, these by-products are high in many phytochemicals similar to those of its edible flower heads including phenolic compounds, [ 14 , 15 , 16 ], inulin [ 17 ], and dietary fibre [ 18 ]. Based on interest in renewable resources of pharmaceutically active biomolecules, many investigations have been conducted on recycling and the optimisation of the downstream processes for maximal exploitation of artichoke biowastes [ 10 , 19 , 20 , 21 , 22 , 23 ]. However, most of these studies have focused their attention mainly on the bracts, giving little importance to the leaves which, although to a lesser extent, represent a huge waste.…”