Cocoa Shell Extracts with Power Ultrasound

Cocoa waste such as cocoa fruit pulp and cocoa bean shells can be easily valorized by extracting cocoa butter, fruit sugar and bioactive compounds. Ultrasonic extraction has been proven to be a highly efficient technique to isolate valuable components from cocoa waste. Ultrasonic extractors release high yields of food-grade compounds from cocoa husk, shells and fruit pulp within a rapid, safe and simple treatment.

Cocoa By-Products
Cocoa (Theobroma cacao L.) is a valuable crop, which beans are used mainly for chocolate production. After harvesting the cocoa pods, either before or after roasting the cocoa beans, the beans are released from the shells (also known as hulls or husks) and fruit pulp. Cocoa shells and cocoa fruit pulp are considered a by-product of the cocoa industry. Depending on the cocoa fruit species, the beans make up approx. 25% wt. of the cocoa fruit. The pulp contributes to another 25% wt. and the rest is shell /husk, which is mostly discarded as waste. However, cocoa by-products such as shells and pulp are rich in fibres, antioxidants, polyphenols, flavour compounds, sugars and lipids, which can be used as additives in food and beverages.

Ultrasonic Extraction of Phyto-Nutrients from Cocoa Shells

Ultrasonic Cocoa Shell Extraction: Ultrasonic extraction turns cocoa biowaste (e.g., cocoa husk, pod husk) into valuable food products such as cocoa butter, flavour compounds, phyto-nutrients, fruit sugars, and dietary fibres. For an efficient ultrasonic extraction process, only a crude pretreatment of the cocoa shell biomass is required, i.e., milling of the cocoa shell.

Power Ultrasound for Extraction

The extraction intensifying mechanism of power ultrasound is mainly attributed to the phenomenon of acoustic cavitation. Ultrasonic cavitation causes collisions between particles of cocoa shell / husk, which results in interparticular fractioning and reduction of particle size. When cavitation bubbles collapse on the surface of the cocoa solids, erosion and sonoporation enlarge the particle surface further. The thereby intensified mass transfer facilitates the release of molecules such as proteins, lipids and phyto-chemicals. Ultrasonically generated shear forces improve the penetration of the solvent into the cellular matrix of the botanical matter and improve the permeability of the cell membranes, respectively. These mechanisms of power ultrasonics are responsible for the significant process intensification achieved when ultrasonication is applied for botanical extraction.

Ultrasonically-Assisted Cocoa Shell Extraction Proven by Research

Grillo et al. (2018) investigated the extraction of cocoa butter, polyphenols (e.g. catechin, epicatechin, procyanidin dimers, trimers and tetramers), antioxidants and methylxantine (e.g., caffeine, theobromine) from cocoa bean shells using ultrasonic extraction. As the table below shows, ultrasonication always increased both lipophilic and hydrophilic extracts yields resulting in extracts rich in antioxidant flavanols (catechins and epicatechins), theobromine (32.7 ± 0.12 mg/g shells), caffeine (1.76 ± 0.08 mg/g shells) and cocoa butter, in a simple and easy manner. Best results under sonication were reached using the ternary mixture, which gives slightly lower total hydrophilic fraction recovery and provides a 16-fold reduction in extraction time.

Ultrasound assisted extraction (UAE) and conventional process yields from the raw cocoa shells, expressed as w/w percentage. Ultrasonic extraction gives significantly higher yields.
Study and copyright by Grillo et al. 2019.

Yusof et al. (2019) could proof the efficiency of ultrasonic extraction of flavonoids from cocoa shell, too. They found following extraction parameters of ethanol concentration, temperature, and ultrasonication time most efficient, i.e. under following conditions highest extract yields were obtained: maximum value of the total flavonoid content (TFC; 7.47 mg RE/g dried weight (DW)) was achieved 80% ethanol concentration, 55ºC process temperature, and 45 min sonication.

High Performance Ultrasonic Extractors for Cocoa Waste Processing

High-performance ultrasonic extraction systems from Hielscher Ultrasonics are used worldwide on R&D, small, mid-size and fully-commercial production levels. High-performance ultrasonic extractors intensify the extraction process and increase yield and overall-efficiency of high-quality extract production. Hielscher Ultrasonics offers extraction equipment for any volume / process capacity. Having experience in botanical extraction for more than 25 years, Hielscher Ultrasonics is your trusted partner for high-performance ultrasonic extraction!

High-Performance, State-of-the-Art Ultrasonicators

The smart features of Hielscher ultrasonicators are designed to guarantee reliable operation, reproducible outcomes and user-friendliness. Operational settings can be easily accessed and dialled via intuitive menu, which can be accessed via digital colour touch-display and browser remote control. Therefore, all processing conditions such as net energy, total energy, amplitude, time, pressure and temperature are automatically recorded on a built-in SD-card. This allows you to revise and compare previous sonication runs and to optimize the cocoa bean shell extraction process to highest efficiency.
Hielscher Ultrasonics systems are used worldwide for the manufacturing of high-quality botanical extracts. Hielscher industrial ultrasonicators can easily run high amplitudes in continuous operation (24/7/365). Amplitudes of up to 200µm can be easily continuously generated with standard sonotrodes (ultrasonic probes / horns). For even higher amplitudes, customized ultrasonic sonotrodes are available. Due to their robustness and low maintenance, our ultrasonic extraction systems are commonly installed for heavy duty applications and in demanding environments.

Contact us now to learn more about ultrasonic extraction of polyphenols, antioxidants, sugars and cocoa butter from cocoa by-products. We would be glad to send you information about our ultrasonic extraction systems and pricing! Our well-experienced staff will be glad to discuss your application and processing requirements with you!
The table below gives you an indication of the approximate processing capacity of our ultrasonicators: