Extraction of Natural Pigments from Gardenia Jasminoides J.Ellis Fruit Pulp Using CO2-Expanded Liquids and Direct Sonication

Hiroki Sakai,Taku Michael Aida,Kento Ono,Kenji Mishima,Tanjina Sharmin,Shinichi Tokunaga

doi:10.3390/separations8010001

Abstract

In this work, a carbon dioxide-expanded liquid (CXL) extraction system was used with or without direct sonication for the extraction of highly polar natural pigments (crocin-1 and crocin-2) from Gardenia jasminoides Ellis fruit pulp. The effects of different parameters, including modifiers (ethanol, water, aqueous ethanol), temperature (5–25 °C), pressure (8–14 MPa), and sonication time (0–200 s) on extraction concentrations were examined using the CXL system. Aqueous ethanol (50% or 80%, v/v) was selected for the CXL system as a modifier due to its efficiency. The best conditions for extraction were found at 25 °C and 10 MPa. The CXE 80% extraction system with direct sonication extracted a significantly higher amount of crocin-1 and crocin-2, 13.63 ± 0.5 and 0.51 ± 0.05 μg/mL, respectively, compared to conventional solid–liquid methanol extraction (10.43 ± 0.3 and 0.37 ± 0.02 μg/mL, respectively). Under these conditions, a water-rich phase, an ethanol-rich phase, and a CO2-rich gas phase coexisted in the high-pressure cell in the CXE 80% extraction system, which was vigorously disrupted by the addition of sonication, resulting in a compressed aqueous ethanol phase and an aqueous ethanol-modified CO2-rich phase, and may have a positive influence on extraction.

Highlights

Received: 4 December 2020 Accepted: 21 December 2020 Published: 24 December 2020Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Natural pigments extracted from natural resources are less toxic, less polluting, and noncarcinogenic and tend to have potential positive health effects [1,2,3,4]
The objective of this work was to develop a green extraction method based on the use of CO2-expanded liquids (CXLs) with or without direct sonication to enhance the concentrations of crocin-1 and crocin-2 from gardenia fruit pulp powder
Gardenia fruit pulp milled powder (10 mg) and 10 mL of the modifier, ethanol or water, or 50 to 80% of aqueous ethanol solution were placed in the high-pressure extractor (150 cc, 34 mm id 165 mm long; Toyo Koatsu Co., Ltd., Hiroshima, Japan) equipped with a titanium ultrasound horn driven by electrical signals from a 20 kHz ultrasound processor (VC-505, Sonic and Materials, Inc., Suffolk, UK) with a maximum power capability of 500 W

Summary

Introduction

Received: 4 December 2020 Accepted: 21 December 2020 Published: 24 December 2020Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Natural pigments extracted from natural resources (plants, minerals, insects, microorganisms such as algae, cyanobacteria, fungi, etc.) are less toxic, less polluting, and noncarcinogenic and tend to have potential positive health effects [1,2,3,4]. Crocins from gardenia fruits have long been used as natural yellow dyes in food coloring, especially in Japan and China, receiving government approval in both countries for use as a food additive [6,7]. Due to their powerful antioxidant ability and capacity to absorb free radicals [8], crocins are widely used in the treatment of inflammatory [9,10] and cardiovascular [11] diseases, suppression of growth of cancer cells [12], diabetes treatment [13], and in the prevention of Alzheimer’s disease [14]. With so much potential, very little research has been conducted to find an effective extraction method

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