Separation of Active Compounds from Food by-Product (Cocoa Shell) Using Subcritical Water Extraction

Abstract

Large amounts of residues are produced in the food industries. The waste shells from cocoa processing are usually burnt for fuel or used as a mulch in gardens to add nutrients to soil and to suppress weeds. The objectives of this work were: (a) to separate valuable compounds from cocoa shell by applying sustainable green separation process—subcritical water extraction (SWE); (b) identification and quantification of active compounds, sugars and sugar degradation products in obtained extracts using HPLC; (c) characterization of the antioxidant activity of extracts; (d) optimization of separation process using response surface methodology (RSM). Depending on applied extraction conditions, different concentration of theobromine, caffeine, theophylline, epicatechin, catechin, chlorogenic acid and gallic acid were determined in the extracts obtained by subcritical water. Furthermore, mannose, glucose, xylose, arabinose, rhamnose and fucose were detected as well as their important degradation products such as 5-hydroxymethylfurfural (5-HMF), furfural, levulinic acid, lactic acid and formic acid.

An Approach to Value Cocoa Bean By-Product Based on Subcritical Water Extraction and Spray Drying Using Different Carriers

“…Regarding the catechin and gallic acid, their presence was detected in the aforementioned study, but SWE+WP enabled the recovery of higher amounts of these phenols comparing to conventional extraction+MD+gum Arabic, demonstrating the potential of SWE technique coupled with spray drying (WP) for the recovery and stability of phenolic compounds. The results concerning methylxanthines, caffeine, and theobromine in CBS powders were in accordance with the range of data previously reported for the cocoa bean by-product [5,68,69]. Higher content of methylxanthines was obtained when WP was used as a carrier.…”

“…Higher content of methylxanthines was obtained when WP was used as a carrier. The caffeine content in obtained powders was not far from the values observed in other works dealing with different cocoa shell extracts [5,68]. Okiyama et al [5] determined a slightly higher concentration of theobromine (9.89 mg/g) in CBS extracts obtained by pressurized liquid extraction when compared with the present study.…”

Cocoa Bean Shell—A By-Product with Nutritional Properties and Biofunctional Potential

“…Again, these values show great variability depending on the research work, mainly due to the polyphenolic extraction conditions and the employed solvents, although the total flavonoid content (TFC) and total tannin content (TTC) are in general well correlated with the TPC values [13,59]. Indeed, several authors have taken interest in this fact and have studied several possibilities in order to optimize different types of CBS polyphenol extraction, using techniques such as supercritical CO 2 , water extraction [60,61,63,90,91], pulsed electric fields [59], high-voltage electric discharges [58,66], pressurized ethanol [36,60,64], or ultrasound techniques [92]. Macroporous resins have been used to increase the total polyphenol content of a CBS extract from 2.23% to 62.87% w/w CBS [93].…”

“…The main methylxanthines found in CBS are theobromine (3,7-dimethylxanthine) and caffeine (1,3,7-dimethylxanthine). Both are alkaloids that are characteristic of cocoa, although theophylline has also been detected, mostly at trace level, however [63]. Both theobromine and caffeine are known for acting on the central nervous system and influencing mood positively, being one of the reasons for the high cocoa acceptance between consumers.…”

“…Concretely, these values were 0.39-1.83 mg/100 g of dried CBS for theobromine and 0.04-0.42 mg/100 g of dried CBS for caffeine. As well as polyphenols, several techniques for methylxanthine extraction optimization from CBS have been proposed [57,58,63,66,67].…”