Versatile Green Processing for Recovery of Phenolic Compounds from Natural Product Extracts towards Bioeconomy and Cascade Utilization for Waste Valorization on the Example of Cocoa Bean Shell (CBS)

Abstract

In the context of bioeconomic research approaches, a cascade use of plant raw materials makes sense in many cases for waste valorization. This not only guarantees that the raw material is used as completely as possible, but also offers the possibility of using its by-products and residual flows profitably. To make such cascade uses as efficient as possible, efficient and environmentally friendly processes are needed. To exemplify the versatile method, e.g., every year 675,000 metric tons of cocoa bean shell (CBS) accrues as a waste stream in the food processing industry worldwide. A novel green process reaches very high yields of up to 100% in one extraction stage, ensures low consumption of organic solvents due to double usage of ethanol as the only organic solvent, is adaptable enough to capture all kinds of secondary metabolites from hot water extracts and ensures the usage of structural carbohydrates from precipitation. A Design of Experiments (DoE) was conducted to optimize the influence of pH value and phase ratio on the yield and purity of the integrated ethanol/water/salt aqueous-two-phase extraction (ATPS) system.

Green Methods to Recover Bioactive Compounds from Food Industry Waste: A Sustainable Practice from the Perspective of the Circular Economy

“…Another novel green extraction process has been recently investigated, obtaining very high yields (up to 100%) of phenolic compounds, theobromine, caffeine, catechin and epicatechin in a single extraction step, reducing the consumption of conventional organic solvents [ 127 ]. This requires preliminary hot water extraction (PHWE) (140 °C, 10 CV/h, solvent ratio of 25), followed by anti-solvent (60% ethanol in water)-induced precipitation.…”

Cocoa Bean Shell: A By-Product with High Potential for Nutritional and Biotechnological Applications

“…In addition, Mellinas et al, 2020 [83] obtained extracts from CBS by means of MAE (5 min, 97 • C) with an amount of TPC of 35.5 mg GAE/g and an antioxidant activity of 33.6 mg TE/g, values 50-62% higher than those obtained through conventional heating. Jensch et al, 2022 [85] recovered a maximum of 5 mg/g of catechin and epicatechin from CBS submitted to pressurized hot water extraction (PHWE) at 140 • C. Table 2 summarizes different phenolic compounds obtained from CBS as well as the extraction techniques employed for this purpose. Procyanidin B1 Ethanol, water 0.5-0.8 mg/g CBS [48] Procyanidin B2 Ethanol, water 0.2-0.9 mg/g CBS [48] Protocatechuic acid Ethanol, water, MAE 0.9-2.1 mg/g CBS [28,48] Caffeic acid Ethanol, water, methanol, MAE Traces-0.9 mg/g CBS [28,61] Ferulic acid MAE 0.3-0.5 mg/g CBS [28] MAE…”

Green Manufacturing for Herbal Remedies with Advanced Pharmaceutical Technology

“…1/5. A reduction of 1/5 in the cost of goods and 1/5 in GWP is achievable by any switch from batch to continuous operation with water-based processing as well as process optimization due to yield maximation [ 26 ].…”

“… The influence of the extraction processes on the global warming potential and production costs [ 26 ]. …”