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The objective of the presented study is to valorize cocoa shell, one of the main by-product of the roasting process, in order to enhance the effective extraction of high value-added compounds by means of sustainable protocols. Aiming to define the best solvent and technology, a range of extraction procedures have been tested. Used solvents were hexane, hydro-alcoholic solution (ethanol/water) and ternary mixture (hexane/ethanol/ water). Ultrasound (US) and hydrodynamic cavitation (HC) were compared with conventional methods. High temperature and pressure microenvironments generated by cavitation promote fast biomass deconstruction with low energy consumption. The optimized protocol combine a pilot flow HC reactor with a ternary mixture, simultaneously providing a hydrophilic product, which is rich in polyphenols and methylxanthines, and a lipid layer. Sequential milling and sieving pretreatment provided an enriched cocoa shell fraction trough the partial removal of husk fibers (54.45 vs. 81.36 w/w % total fibers). The disposal of the fibers reduces mass balance, but they can be applied as animal feedstock components and crop mulching. The aforementioned protocols produce valuable extracts, which are rich in flavanols (catechins and epicatechins), theobromine, caffeine and cocoa butter, in a simple and easy manner. This valorization process provided 20.5 % (w/w) and 15.8 % (w/w) hydrophilic and lipophilic fractions, respectively. The hydrophilic extract shows an extremely high total phenolic content of 197.4 mg/g extract (gallic acid eq.), with a radical scavenging activity of 62.0 ± 3.1 μg/mL (expressed in DPPH EC50). The fatty acids, obtained in a great yield (forming the 96.4 % (w/w) of the total lipophilic fraction) well match the commercial cocoa butter profile. These results run in the direction of zero waste chocolate industry by means of low cost, fast, efficient and scalable procedures.

Objectives Polyphenols from wine industry by-products and wastes may be active components of interest for food, cosmetics and pharmaceutical production. The recovery of these compounds is commonly performed by solvent-extraction procedures with conventional techniques, that may show drawbacks in term of environmental impact. Aiming to design a green extraction procedure for grape marc polyphenols, simultaneous ultrasound and microwave (US/MW) assisted extractions were optimized by response surface methodology (RSM). As a green alternative to conventional solvents, a natural deep eutectic solvent (NADES) was used. Methods Based on the preliminary experiments, the NADES choline chloride:citric acid (Ch:Cit) with 30 % of water (w/w) was selected. The extractions were performed under simultaneous US/MW irradiation. The parameters studied were: time of extraction (5 to 15 min), MW power (200 to 400 W) and temperature (50 to 90 °C). Total polyphenolic content (TPC) was determined using Folin-Ciocalteu assay and HPLC analysis. The optimization of aforementioned parameters was carried out by RSM using Design Expert 7.0.0 software based on experimental data derived by implementing Box- Behnken experimental plan. Detailed statistical analysis of the obtained model, analysis of variance (ANOVA), was also provided using Design Expert 7.0.0. Results Optimal extraction conditions for achieving the maximum TPC are: time 10 min, MW power 300 W and temperature 80 °C. By applying the listed conditions, TPC yield was 59.53 mgGAE gDW-1. RSM using experimental data, could provide the extraction model. By ANOVA statistical analysis, it has been proven that the approximation of the experimental TPC yields with the modelled TPC yields is statistically significant, which means that the model application is justified for the investigated area. The two variables with the greatest impact on the TPC yield are extraction time and temperature. This study presents a fast and environmentally friendly extraction process of valuable biologically active compounds from grape marc, paving the way for further industrial development.

BACKGROUND Microalgae are one of the most promising biofuel sources that the world has to offer; nevertheless the conversion process is hampered by technical and economic problems that are mainly related to de-watering and extraction. The efficiency of the process can be dramatically improved by means of non-conventional techniques such as ultrasound (US) and microwaves (MW). Scaling-up feasibility is strictly linked to reactor efficiency, energy consumption, environmental impact and overall cost. In the present work, the optimization of lipid extraction from Nannochloropsis gaditana microalga is investigated. RESULTS A series of selected solvent mixtures and procedures have been tested and compared. Conventional extraction procedures with chloroform/methanol mixtures and fast US- and MW-assisted extractions with methanol gave comparable fatty acid (FA) w/w% from dried microalgae. The highest extraction yield and lowest energy consumption was found to occur under MW irradiation, especially at high temperatures and under pressure. CONCLUSION This study highlights the advantages of US- and MW-assisted lipid extraction from microalgae, both in terms of efficiency and operational costs., JMB acknowledges the support received from the CSIC JAE Program. Financial support from the CDTI and Exeleria S.L. (Project CENIT VIDA) is also acknowledged. GC acknowledges the Regione Piemonte and the Interreg-ALCOTRA 2007-2013 (project: eco-extraction transfrontaliere).