Optimization of an Ultrasound-Assisted Extraction Condition for Flavonoid Compounds from Cocoa Shells (Theobroma cacao) Using Response Surface Methodology.

Arief Md Yusof,Siti Abd Gani,Uswatun Zaidan,Mohd Halmi,Badrul Zainudin

doi:10.3390/molecules24040711

Arief Md Yusof, Siti Abd Gani + Show 3 more

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https://doi.org/10.3390/molecules24040711

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Abstract

This study investigates the ultrasound-assisted extraction of flavonoids from Malaysian cocoa shell extracts, and optimization using response surface methodology. There are three variables involved in this study, namely: ethanol concentration (70–90 v/v %), temperature (45–65 °C), and ultrasound irradiation time (30–60 min). All of the data were collected and analyzed for variance (ANOVA). The coefficient of determination (R2) and the model was significant in interaction between all variables (98% and p < 0.0001, respectively). In addition, the lack of fit test for the model was not of significance, with p > 0.0684. The ethanol concentration, temperature, and ultrasound irradiation time that yielded the maximum value of the total flavonoid content (TFC; 7.47 mg RE/g dried weight (DW)) was 80%, 55 °C, and 45 min, respectively. The optimum value from the validation of the experimental TFC was 7.23 ± 0.15 mg of rutin, equivalent per gram of extract with ethanol concentration, temperature, and ultrasound irradiation time values of 74.20%, 49.99 °C, and 42.82 min, respectively. While the modelled equation fits the data, the T-test is not significant, suggesting that the experimental values agree with those predicted by the response surface methodology models.

Highlights

Waste from the cocoa industry, such as cocoa shells and cocoa pod husk, is usually discarded during the processing of cocoa (Theobroma cacao L.)
All of the data recorded from the experiments were analyzed using analysis of variance (ANOVA)
ultrasound-assisted extraction (UAE) was used in the extraction of the flavonoid compounds from Malaysian cocoa shell extracts (MCSE), and was optimized by using the center composite design for the response surface methodology

Summary

Introduction

Waste from the cocoa industry, such as cocoa shells and cocoa pod husk, is usually discarded during the processing of cocoa (Theobroma cacao L.). 75% of the cocoa fruit is wasted during this process. To reduce this amount of waste and to increase the value of the waste products, several strategies have been investigated. Abundant of waste from this industry can be turned into a value-added product. This by-product of cocoa production is used as boiler fuel [1]. Other applications of the cocoa shell include particle board making [2], dietary fiber [3], fertilizer and animal feed [4], and activated carbon [5].

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