Publicação
Desenvolvimento de tecnologias biocompatíveis e circulares para a valorização de resíduos de Cerveja Artesanal
| Resumo: | In recent decades, the exponential growth of the global population and the adoption of linear models across most industrial sectors have led to the over-exploitation of available natural resources, causing various negative environmental impacts. One example is the food industry, specifically the brewing industry, which generates large amounts of waste, such as spent hops and sludge. These by-products, largely originating from the whirlpool and dry hopping stages of the beer production process, contain value-added products, such as essential oils and α-/β-acids, which are often discarded.In this context, this work aims to develop biocompatible technologies for the valorization of waste generated from the artisanal beer production process at Cervejaria Letra, enabling the company to adopt more circular and sustainable strategies. To achieve this, a preliminary analysis was conducted on the influence of pre-processing the dry hopping sludge from Letra D beer (Red Ale) on its composition, and a complete characterization was performed on the whirlpool and dry hopping sludge from Letra F beer (American India Pale Ale). Various extraction methods were tested for both types of sludge from Letra F beer, including Soxhlet extraction with hexane, solid-liquid extraction using different solvents/solvent mixtures, solid-liquid extraction with the aid of an extruder, hydrodistillation, and supercritical CO2 extraction. Additionally, all extracts obtained from these tests were characterized using chromatographic methods (gas chromatography and high-performance liquid chromatography) and colorimetric methods (quantifying the content of proteins, total sugars, total phenolic compounds, and their antioxidant activity).Regarding the extraction trials, the yields obtained from conventional solid-liquid extraction stood out, reaching 53.41 ± 1.238 % (w/w) and 35.98 ± 0.000 % (w/w) for whirlpool and dry hopping sludge, respectively. In contrast, supercritical CO2 extraction is characterized as a more selective method, resulting in lower extraction yields of 2.41 ± 1.052 % (w/w) and 5.57 ± 1.250 % (w/w) for whirlpool and dry hopping sludge, respectively. Essential oil extraction via hydrodistillation yielded the lowest values, at 0.34 ± 0.070 % (w/w) and 0.46 ± 0.167 % (w/w) for whirlpool and dry hopping sludge, respectively. Among the greener solvent extraction methods, solid-liquid extraction with ethanol proved to be the most promising, with extraction yields ranging between 17 % (w/w) and 30 % (w/w), and the resulting extracts containing a significant portion of the products of interest.In terms of the characterization of the extracts obtained through hydrodistillation, more products of interest were identified in the dry hopping sludge compared to the whirlpool sludge. For both types of sludge, β-caryophyllene, α-humulene, caryophyllene oxide, humulene epoxide II, and hexadecanoic acid were detected. However, ethyl octanoate, methyl geranate, ethyl decanoate, and ethyl hexadecanoate were exclusively identified in the dry hopping sludge. Regarding the chromatographic analyses for the identification of α-/β-acids, several compounds were identified in the extracts obtained via supercritical CO2 extraction from both whirlpool and dry hopping sludge of Letra F beer, including xanthohumol, cohumulone, humulone, adhumulone, colupulone, lupulone, and adlupulone. In contrast, the extracts from dry hopping sludge obtained via solid-liquid extraction with ethanol contained all of these compounds except for cohumulone, while solid-liquid extraction using conventional methods identified only four of these compounds: xanthohumol, humulone, adhumulone, and colupulone. The dry hopping sludge from Letra F beer contains more value-added products than the whirlpool sludge. Therefore, it would be more advantageous for Cervejaria Letra to focus on processing this sludge and capitalizing on its molecules, either by incorporating them into less hoppy beers or by marketing them to the cosmetic industry. |
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| Autores principais: | Amado, Íris Carnide |
| Assunto: | brewing industry whirlpool dry hopping α-/β-acids essential oils; hop indústria cervejeira whirlpool dry hopping α-/β-ácidos lúpulo |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Coimbra |
| Idioma: | português |
| Origem: | Estudo Geral - Universidade de Coimbra |
| Resumo: | In recent decades, the exponential growth of the global population and the adoption of linear models across most industrial sectors have led to the over-exploitation of available natural resources, causing various negative environmental impacts. One example is the food industry, specifically the brewing industry, which generates large amounts of waste, such as spent hops and sludge. These by-products, largely originating from the whirlpool and dry hopping stages of the beer production process, contain value-added products, such as essential oils and α-/β-acids, which are often discarded.In this context, this work aims to develop biocompatible technologies for the valorization of waste generated from the artisanal beer production process at Cervejaria Letra, enabling the company to adopt more circular and sustainable strategies. To achieve this, a preliminary analysis was conducted on the influence of pre-processing the dry hopping sludge from Letra D beer (Red Ale) on its composition, and a complete characterization was performed on the whirlpool and dry hopping sludge from Letra F beer (American India Pale Ale). Various extraction methods were tested for both types of sludge from Letra F beer, including Soxhlet extraction with hexane, solid-liquid extraction using different solvents/solvent mixtures, solid-liquid extraction with the aid of an extruder, hydrodistillation, and supercritical CO2 extraction. Additionally, all extracts obtained from these tests were characterized using chromatographic methods (gas chromatography and high-performance liquid chromatography) and colorimetric methods (quantifying the content of proteins, total sugars, total phenolic compounds, and their antioxidant activity).Regarding the extraction trials, the yields obtained from conventional solid-liquid extraction stood out, reaching 53.41 ± 1.238 % (w/w) and 35.98 ± 0.000 % (w/w) for whirlpool and dry hopping sludge, respectively. In contrast, supercritical CO2 extraction is characterized as a more selective method, resulting in lower extraction yields of 2.41 ± 1.052 % (w/w) and 5.57 ± 1.250 % (w/w) for whirlpool and dry hopping sludge, respectively. Essential oil extraction via hydrodistillation yielded the lowest values, at 0.34 ± 0.070 % (w/w) and 0.46 ± 0.167 % (w/w) for whirlpool and dry hopping sludge, respectively. Among the greener solvent extraction methods, solid-liquid extraction with ethanol proved to be the most promising, with extraction yields ranging between 17 % (w/w) and 30 % (w/w), and the resulting extracts containing a significant portion of the products of interest.In terms of the characterization of the extracts obtained through hydrodistillation, more products of interest were identified in the dry hopping sludge compared to the whirlpool sludge. For both types of sludge, β-caryophyllene, α-humulene, caryophyllene oxide, humulene epoxide II, and hexadecanoic acid were detected. However, ethyl octanoate, methyl geranate, ethyl decanoate, and ethyl hexadecanoate were exclusively identified in the dry hopping sludge. Regarding the chromatographic analyses for the identification of α-/β-acids, several compounds were identified in the extracts obtained via supercritical CO2 extraction from both whirlpool and dry hopping sludge of Letra F beer, including xanthohumol, cohumulone, humulone, adhumulone, colupulone, lupulone, and adlupulone. In contrast, the extracts from dry hopping sludge obtained via solid-liquid extraction with ethanol contained all of these compounds except for cohumulone, while solid-liquid extraction using conventional methods identified only four of these compounds: xanthohumol, humulone, adhumulone, and colupulone. The dry hopping sludge from Letra F beer contains more value-added products than the whirlpool sludge. Therefore, it would be more advantageous for Cervejaria Letra to focus on processing this sludge and capitalizing on its molecules, either by incorporating them into less hoppy beers or by marketing them to the cosmetic industry. |
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Atividades financiadas
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