Improving the Composition and Bioactivity of Cocoa (Theobroma cacao L.) Bean Shell Extract by Choline Chloride-Lactic Acid Natural Deep Eutectic Solvent Extraction Assisted by Pulsed Electric Field Pre-Treatment.

An environmentally friendly method for the release of cocoa bean shell (CBS) extracts is proposed in this paper. This work aims to investigate the effect of pulsed electric field (PEF) pre-treatment on subsequent solid-liquid extraction (SLE) of metabolites with choline chloride-lactic acid natural deep eutectic solvent (NaDES) and bioactivity of cocoa bean shell (CBS) extract. Two different media for PEF application were evaluated: water and chlorine chloride-lactic acid. Total polyphenols (TPC), total flavonoids (TFC), individual major compounds, and antioxidant and antibacterial activity of CBS extracts were assessed. The performance of PEF-assisted extraction was compared with SLE and ultrasound-assisted extraction (UAE). The proposed method improved the release of TPC up to 45% and TFC up to 48% compared with the conventional extraction. The CBS extract showed medium growth inhibition of Escherichia coli and high growth inhibition of Salmonella sp, Listeria monocytogenes, and Staphylococcus aureus. Thus, an extract with enhanced antioxidant and antibacterial properties was obtained.

Effect of choline chloride-based deep eutectic solvents on polyphenols extraction from cocoa (Theobroma cacao L.) bean shells and antioxidant activity of extracts.

The effective extraction of natural compounds from cocoa bean shells using deep eutectic solvents could contribute to the sustainable valorization of this waste material. The objective of this study was to: (1) analyze the extraction kinetics of polyphenols released from cocoa (Theobroma cacao L.) bean shells (CBS) by the solid-liquid extraction method using choline chloride-based deep eutectic solvents (ChCl-DES) and their aqueous solutions; (2) investigate the effect of choline chloride-based deep eutectic solvents (ChCl-DES) aqueous solutions on in-vitro antioxidant capacity and the main individual compounds of the extracts. ChCl-DES were prepared with lactic acid, glycerol, and ethylene glycol in a 1:2 ratio. Aqueous solutions (30%, 40%, and 50% water) to obtain solvents with different physicochemical properties were performed. The total phenolic content (TPC) was determined by the Folin-Ciocalteu method. The solution of Fick's law model for plate geometry particles was applied to fit the experimental data and calculate the effective diffusivity coefficient (De). The antioxidant capacity of the extracts was analyzed by a combination of 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) free radical scavenging capacity and ferric-reducing antioxidant power (FRAP) assays. The main bioactive compounds were quantified by high-performance liquid chromatography. The results showed that the type of hydrogen bond donor influences the total phenolic content, antioxidant activity and the main individual compounds in the extracts. Moreover, the washing/diffusion mechanism adequately depicts the extraction kinetics data for total phenolic content. However, the influence of an additional mechanism that enhanced the extraction capacity of deep eutectic solvents compared with organic solvent was confirmed.

Bioactive Poly(lactic acid)-Cocoa Bean Shell Composites for Biomaterial Formulation: Preparation and Preliminary In Vitro Characterization.

The unique lignocellulosic and solvent-extractive chemical constituents of most natural fibers are rich in natural polymers and bioactive molecules that can be exploited for biomaterial formulation. However, although natural fibers' main constituents have been already incorporated as material reinforcement and improve surface bioactivity of polymeric materials, the use of the whole natural fibers as bioactive fillers remains largely unexplored. Thus, we put forward the formulation of natural fiber filling and functionalization of biomaterials by studying the chemical composition of cocoa bean shells (CBS) and proposing the fabrication and characterization of polylactic acid (PLA) and CBS-based composite by solvent-casting. As was expected from previous studies of agro-industrial wastes, the main components of CBS were to cellulose (42.23 wt.%), lignin (22.68 wt.%), hemicellulose (14.73 wt.%), and solvent extractives (14.42 wt.%). Structural analysis (FTIR) confirms the absence of covalent bonding between materials. Thermal degradation profiles (DSC and TGA) showed similar mass losses and thermal-reaction profiles for lignocellulosic-fibers-based composites. The mechanical behavior of the PLA/CBS composite shows a stiffer material behavior than the pristine material. The cell viability of Vero cells in the presence of the composites was above 94%, and the hemolytic tendency was below 5%, while platelet aggregation increased up to 40%. Antioxidant activity was confirmed with comparable 2,2-diphe-277 nyl-1-picryl-hydrazyl-hydrate (DPPH) free-radical scavenging than Vitamin C even for PLA/CBS composite. Therefore, the present study elucidates the significant promise of CBS for bioactive functionalization in biomaterial-engineering, as the tested composite exhibited high biocompatibility and strong antioxidant activity and might induce angiogenic factors' release. Moreover, we present an eco-friendly alternative to taking advantage of chocolate-industry by-products.

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites.

Natural filler-based composites are an environmentally friendly and potentially sustainable alternative to synthetic or plastic counterparts. Recycling polymers and using agro-industrial wastes are measures that help to achieve a circular economy. Thus, this work presents the development and characterization of a 3D printing filament based on recycled polypropylene and cocoa bean shells, which has not been explored yet. The obtained composites were thermally and physically characterized. In addition, the warping effect, mechanical, and morphological analyses were performed on 3D printed specimens. Thermal analysis exhibited decreased thermal stability when cacao bean shell (CBS) particles were added due to their lignocellulosic content. A reduction in both melting enthalpy and crystallinity percentage was identified. This is caused by the increase in the amorphous structures present in the hemicellulose and lignin of the CBS. Mechanical tests showed high dependence of the mechanical properties on the 3D printing raster angle. Tensile strength increased when a raster angle of 0° was used, compared to specimens printed at 90°, due to the load direction. Tensile strength and fracture strain were improved with CBS addition in specimens printed at 90°, and better bonding between adjacent layers was achieved. Electron microscope images identified particle fracture, filler-matrix debonding, and matrix breakage as the central failure mechanisms. These failure mechanisms are attributed to the poor interfacial bonding between the CBS particles and the matrix, which reduced the tensile properties of specimens printed at 0°. On the other hand, the printing process showed that cocoa bean shell particles reduced by 67% the characteristic warping effect of recycled polypropylene during 3D printing, which is advantageous for 3D printing applications of the rPP. Thereby, potential sustainable natural filler composite filaments for 3D printing applications with low density and low cost can be developed, adding value to agro-industrial and plastic wastes.

Characterization and Classification of Cocoa Bean Shells from Different Regions of Venezuela Using HPLC-PDA-MS/MS and Spectrophotometric Techniques Coupled to Chemometric Analysis.

The cocoa bean shell (CBS) is one of the main cocoa byproducts with a prospective to be used as a functional food ingredient due to its nutritional and sensory properties. This study aims to define the chemical fingerprint of CBSs obtained from cocoa beans of diverse cultivars and collected in different geographical areas of Venezuela assessed using high-performance liquid chromatography coupled to photodiodes array and mass spectrometry (HPLC-PDA-MS/MS) and spectrophotometric assays combined with multivariate analysis for classification purposes. The study provides a comprehensive fingerprint and quantitative data for 39 compounds, including methylxanthines and several polyphenols, such as flavan-3-ols, procyanidins, and N-phenylpropenoyl amino acids. Several key cocoa markers, such as theobromine, epicatechin, quercetin-3-O-glucoside, procyanidin_A pentoside_3, and N-coumaroyl-l-aspartate_2, were found suitable for the classification of CBS according to their cultivar and origin. Despite the screening methods required a previous purification of the sample, both methodologies appear to be suitable for the classification of CBS with a high correlation between datasets. Finally, preliminary findings on the identification of potential contributors for the radical scavenging activity of CBS were also accomplished to support the valorization of this byproduct as a bioactive ingredient in the production of functional foods.

Evaluation of Cocoa Beans Shell Powder as a Bioadsorbent of Congo Red Dye Aqueous Solutions.

The use of synthetic dyes in the textile, leather, and paper industries is a source of groundwater pollution around the world. There are different methods for the treatment of wastewater that has been contaminated with dyes, among which adsorption with agro-industrial wastes is gaining relevance. In the present study, the adsorption capacity of cocoa bean shell powder was evaluated when it was used as a bioadsorbent for Congo red dye in an aqueous medium. A 24 central factorial design with central and axial points was proposed to determine the adsorption capacity. The factors that were studied were the adsorbent (0.06-0.15 g), Congo red (40-120 mg L-1), pH (3-11), and time (4-36 h). The bioadsorbent was characterized through scanning electron microscopy and Fourier-transform infrared spectroscopy. The effects of the factors on the adsorption capacity for Congo red using cocoa bean shell were nonlinear, and they were modeled with a second-order polynomial (p < 0.05) and with an R2 of 0.84. The bioadsorbent obtained a maximum adsorption of 89.96% in runs. The process of optimization by using the surface response allowed the maximization of the adsorption, and the validation showed that 95.79% adsorption of the dye was obtained.

Authentication of cocoa bean shells by near- and mid-infrared spectroscopy and inductively coupled plasma-optical emission spectroscopy.

The aim of this study was to evaluate the efficacy of a multi-analytical approach for origin authentication of cocoa bean shells (CBS). The overall chemical profiles of CBS from different origins were characterized using diffuse reflectance near-infrared spectroscopy (NIRS) and attenuated total reflectance mid-infrared spectroscopy (ATR-FT-IR) for molecular composition identification, as well as inductively coupled plasma-optical emission spectroscopy (ICP-OES) for elemental composition identification. Exploratory chemometric techniques based on Principal Component Analysis (PCA) were applied to each single technique for the identification of systematic patterns related to the geographical origin of samples. A combination of the three techniques proved to be the most promising approach to establish classification models. Partial Least Squares-Discriminant Analysis modelling of fused PCA scores of three independent models was used and compared with single technique models. Improved classification of CBS samples was obtained using the fused model. Satisfactory classification rates were obtained for Central African samples with an accuracy of 0.84.