RATIONALE The espresso coffee (EC) quality is driven by several variables related to water, roasting profile, particle sizes and barista skills. Previous research has demonstrated that the sizes of coffee particles greatly affect on extraction kinetics. In fact, some studies highlighted that bigger particles could ease the percolation during the brewing process (Kuhn et al. 2017). However, the fine particles generate intensity of taste and can clog the filter baskets (Khamitova et al. 2020a). In this context, researchers have not studied yet in depth how different tools can be adjusted complementarily in coffee extraction, as how different filter baskets and perforated disc heights could be chosen according to the different particle sizes of ground coffee. METHODS The present project was based on the study and comparison of ECs prepared by decreasing the amount (from 14 to 12 g for double EC extraction) of specific particle sizes (from 200 to 1000 µm) of ground coffee in three variously designed filter baskets. The second part of the work was to investigate various heights of perforated disc under the shower (4-7 mm), and to prepare coffee with 14 and 12 g of ground coffee. The perforated disc is a perforated metal plate, assembled under the shower of each serving group of EC machine, which assures a homogeneous water diffusion over the coffee cake surface and adjusts the distance between the coffee cake and the shower. Thus, perforated disc can influence EC extraction, even if no studies have been reported yet; in fact, this parameter has been investigated for the first time by our research group (Khamitova et al. 2020b). ECs were analysed for the content of TDS, bioactive compounds, and organic acids with HPLC-VWD, while volatiles with HS-SPME-GC-MS. RESULTS Extracting with smaller particles escalates the quantity of bioactive compounds. The amount of caffeine per cup increased moving from 500–1000 μm to 200–300 μm particle size, both in Arabica and Robusta for all filter baskets. Using lower amount of ground coffee permitted to obtain the same extraction yield increasing the height of perforated disc. Keeping constant the volume of EC at various heights of perforated disc, the amount of bioactive compounds at 12 g were only around 9% lower than at 14 g. CONCLUSIONS & PERSPECTIVES The right implementation on EC machine of these tools, simple and feasible as they are, could lead to a more sustainable consumption of the beverage by reducing the amount of used R&G coffee and by producing lower spent coffee ground, while maintaining the same cup quality. References: • Kuhn et al. 2017 Journal of Food Engineering DOI: 10.1016/j.jfoodeng.2017.03.002. • Khamitova et al. 2020a Food Chemistry DOI: 10.1016/j.foodchem.2020.126220. • Khamitova et al. 2020b Food Research International DOI: 10.1016/j.foodres.2020.109220.
Optimization of espresso coffee extraction to lower the amount of coffee. S8-PO-09. Book of Abstracts, p. 168. 28th Conference ASIC 2021.
S Angeloni;G Caprioli;G Khamitova;G Sagratini;S Vittori
2021-01-01
Abstract
RATIONALE The espresso coffee (EC) quality is driven by several variables related to water, roasting profile, particle sizes and barista skills. Previous research has demonstrated that the sizes of coffee particles greatly affect on extraction kinetics. In fact, some studies highlighted that bigger particles could ease the percolation during the brewing process (Kuhn et al. 2017). However, the fine particles generate intensity of taste and can clog the filter baskets (Khamitova et al. 2020a). In this context, researchers have not studied yet in depth how different tools can be adjusted complementarily in coffee extraction, as how different filter baskets and perforated disc heights could be chosen according to the different particle sizes of ground coffee. METHODS The present project was based on the study and comparison of ECs prepared by decreasing the amount (from 14 to 12 g for double EC extraction) of specific particle sizes (from 200 to 1000 µm) of ground coffee in three variously designed filter baskets. The second part of the work was to investigate various heights of perforated disc under the shower (4-7 mm), and to prepare coffee with 14 and 12 g of ground coffee. The perforated disc is a perforated metal plate, assembled under the shower of each serving group of EC machine, which assures a homogeneous water diffusion over the coffee cake surface and adjusts the distance between the coffee cake and the shower. Thus, perforated disc can influence EC extraction, even if no studies have been reported yet; in fact, this parameter has been investigated for the first time by our research group (Khamitova et al. 2020b). ECs were analysed for the content of TDS, bioactive compounds, and organic acids with HPLC-VWD, while volatiles with HS-SPME-GC-MS. RESULTS Extracting with smaller particles escalates the quantity of bioactive compounds. The amount of caffeine per cup increased moving from 500–1000 μm to 200–300 μm particle size, both in Arabica and Robusta for all filter baskets. Using lower amount of ground coffee permitted to obtain the same extraction yield increasing the height of perforated disc. Keeping constant the volume of EC at various heights of perforated disc, the amount of bioactive compounds at 12 g were only around 9% lower than at 14 g. CONCLUSIONS & PERSPECTIVES The right implementation on EC machine of these tools, simple and feasible as they are, could lead to a more sustainable consumption of the beverage by reducing the amount of used R&G coffee and by producing lower spent coffee ground, while maintaining the same cup quality. References: • Kuhn et al. 2017 Journal of Food Engineering DOI: 10.1016/j.jfoodeng.2017.03.002. • Khamitova et al. 2020a Food Chemistry DOI: 10.1016/j.foodchem.2020.126220. • Khamitova et al. 2020b Food Research International DOI: 10.1016/j.foodres.2020.109220.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
