TY - JOUR A1 - Figueroa Campos, Gustavo A. A1 - Perez, Jeffrey Paulo H. A1 - Block, Inga A1 - Tchewonpi Sagu, Sorel A1 - Saravia Celis, Pedro A1 - Taubert, Andreas A1 - Rawel, Harshadrai Manilal T1 - Preparation of activated carbons from spent coffee and coffee parchment and assessment of their adsorbent efficiency JF - Processes N2 - The valorization of coffee wastes through modification to activated carbon has been considered as a low-cost adsorbent with prospective to compete with commercial carbons. So far, very few studies have referred to the valorization of coffee parchment into activated carbon. Moreover, low-cost and efficient activation methods need to be more investigated. The aim of this work was to prepare activated carbon from spent coffee grounds and parchment, and to assess their adsorption performance. The co-calcination processing with calcium carbonate was used to prepare the activated carbons, and their adsorption capacity for organic acids, phenolic compounds and proteins was evaluated. Both spent coffee grounds and parchment showed yields after the calcination and washing treatments of around 9.0%. The adsorption of lactic acid was found to be optimal at pH 2. The maximum adsorption capacity of lactic acid with standard commercial granular activated carbon was 73.78 mg/g, while the values of 32.33 and 14.73 mg/g were registered for the parchment and spent coffee grounds activated carbons, respectively. The Langmuir isotherm showed that lactic acid was adsorbed as a monolayer and distributed homogeneously on the surface. Around 50% of total phenols and protein content from coffee wastewater were adsorbed after treatment with the prepared activated carbons, while 44, 43, and up to 84% of hydrophobic compounds were removed using parchment, spent coffee grounds and commercial activated carbon, respectively; the adsorption efficiencies of hydrophilic compounds ranged between 13 and 48%. Finally, these results illustrate the potential valorization of coffee by-products parchment and spent coffee grounds into activated carbon and their use as low-cost adsorbent for the removal of organic compounds from aqueous solutions. KW - coffee by-products KW - spent coffee grounds KW - parchment KW - valorization KW - calcination KW - activated carbon KW - organic compounds adsorption Y1 - 2021 U6 - https://doi.org/10.3390/pr9081396 SN - 2227-9717 VL - 9 IS - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Figueroa Campos, Gustavo A. A1 - Sagu Tchewonpi, Sorel A1 - Saravia Celis, Pedro A1 - Rawel, Harshadrai Manilal T1 - Comparison of batch and continuous wet-processing of coffee BT - changes in the main compounds in beans, by-products and wastewater JF - Foods N2 - Many technical challenges still need to be overcome to improve the quality of the green coffee beans. In this work, the wet Arabica coffee processing in batch and continuous modus were investigated. Coffee beans samples as well as by-products and wastewaters collected at different production steps were analyzed in terms of their content in total phenols, antioxidant capacity, caffeine content, organic acids, reducing sugars, free amino group and protein content. The results showed that 40% of caffeine was removed with pulp. Green coffee beans showed highest concentration of organic acids and sucrose (4.96 ± 0.25 and 5.07 ± 0.39 g/100 g DW for the batch and continuous processing). Batch green coffee beans contained higher amount of phenols. 5-caffeoylquinic Acid (5-CQA) was the main constituent (67.1 and 66.0% for the batch and continuous processing, respectively). Protein content was 15 and 13% in the green coffee bean in batch and continuous processing, respectively. A decrease of 50 to 64% for free amino groups during processing was observed resulting in final amounts of 0.8 to 1.4% in the processed beans. Finally, the batch processing still revealed by-products and wastewater with high nutrient content encouraging a better concept for valorization. KW - Arabica coffee beans KW - coffee by-products KW - batch process KW - continuous process KW - nutritional characteristics Y1 - 2020 U6 - https://doi.org/10.3390/foods9081135 SN - 2304-8158 VL - 9 IS - 8 PB - MDPI CY - Basel ER -