|Coffee junkies, recoice! The SuppVersity is back … and how can this be celebrated? With a research update on ☕ – a review discussing the latest science from coarsness to leaf-extracts, and beyond.|
Long time no read,… I know but after a period with a severe lack of motivation and a lot to do outside the virtual walls of the SuppVersity, I will try to come back with (not yet daily but) weekly articles on topics near and dear to your and my heart. And if you’ve been following the SuppVersity for some time, now, you will see that it’s only logical to do so with an article about coffee.
- Beyond grinding your coffee coarser | based on Khamitova 2020 — You probably will have read that coarser grinds make better espressos in the SuppVersity news or other news outlets. The grind is yet not the only set-screw for espresso quality (I’ve discussed several of them in my Coffee 101). That is also what the latest study from the University of Camerino in Italy suggests, a study that also shows clear benefits of finer particle size, when it comes to bioactive components (the previously referenced study investigated taste).
The Italians’ research aimed to investigate ground beans at specific particle sizes in three variously designed filter (new!) baskets and to compare the concentration of bioactive compounds while decreasing the amount of ground coffee.
Filter baskets and various heights of perforated disc influenced EC extraction.
As you can see in Table 1, the caffeine, trigonelline and chlorogenic acids (3-CQA, 5-CQA and 3,5-CQAs) content of the final product was significantly affected by the heights of perforated disc used for the espresso machines filter basket.
Table 1: Milligrams of caffeine, trigonelline and chlorogenic acids (3-CQA, 5-CQA and 3,5-CQAs) obtained in Arabica EC samples (n = 3, RSD% < 5.86) by using 12 and 14 g
of ground coffee with various heights of perforated disc used for filter basket A at a constant time (25sec) and volume (50 ml for double EC) | from Kamitova et al. 2020.
For you, the potential health benefits are probably most interesting. For Barrista, it could be the ability to reduce the amount of ground coffee during the extraction process – money, money, money 💲💲💲: if you sell 1,000 espressos per day the 2g reduction that’s facilitated by a reduced coarseness and the use of the “optimal” perforated disc, for example, it’ll save the company $40… probably better for business to use the tastier, coarser ground espresso beans.
- Coffee’s a hitherto largely ignored prebiotic prowesses – How to optimize/control the effect? | based on Sales 2020 — First study to investigate the effects of coffee species, roast degree and decaffeination on in vitro probiotic bacterial growth, and to identify the major coffee compounds responsible for such effects.
Figure 1: In view of its myriad of proven health benefits, it should hardly surprise you that coffee will also affect your microbiome in a positive way.
Six C. arabica aka ‘arabica’ and C. canephora extracts aka ‘robusta (regular medium and dark roasted and decaffeinated medium roasted), and five bioactive compounds (chlorogenic acid, galactomannan, type 2 arabinogalactan, caffeine, and trigonelline) were individually incorporated into a modified low-carbon broth medium-(mMRS), at different concentrations (0.5 to 1.5% soluble coffee and 0.05 to 0.8 mg/mL standard solutions). Inulin and fructooligosaccharides (FOS) were used as prebiotic references. MRS and mMRS were used as rich and poor medium controls, respectively. The effects on Lactobacillus rhamnosus GG ATCC 53103-(GG), L. acidophilus LA-5-(LA), Bifidobacterium animalis DN-173010-(BA) and B. animalis subsp. lactis BB12-(BB12) was investigated.
“Overall, after 48 h incubation, the medium roasted arabica coffee extract increased the growth of GG, LA and BA (range: Δlog CFU/mL = 0.5 to 1.8), while the dark roasted arabica coffee extract increased BB12 growth (range: Δlog CFU/ml = 0.9 to 1.7), in a dose dependent manner. Improved performances of GG, LA and BA were promoted by higher polysaccharides and CGA concentrations, with better performance for Lactobacillus sp,” …
the authors report. As far as the mechanisms are concerned, they were able to show that the tested coffee bioactive compounds promoted the poor growth of BB12. Plain caffeine did not promote Bifidobacterium sp. growth and limited the growth of Lactobacillus sp.
What’s important though, is this downside of decaffeinating coffee, i.e. the fact that arabica and robusta (learn more about differences) extracts inhibited the growth of the pathogenic E. coli bacteria, while the decaffeinated extracts promoted its growth – clearly not ideal!
- 😮 “a beverage prepared from leaves (coffee leaf tea) could be a rich source of phytochemicals and antioxidants with therapeutic and pharmacological values for human health” | quote from Acidri 2020 — In fact, the leaves outperformed the beans with respect to their antioxidant effects (TEAC and TROLOX assays).
Table 2: Total phenolic content (TPC) and antioxidant capacity of the coffee plant organs | from Acidri 2020
The leaves should be fresh/young, though, as “among the leaves, the youngest (L1) contained the highest content at 8.23 mg/g dry weight (DW), which gradually reduced with leaf age to 5.57 mg/g DW in the oldest (L6)” (Acidri 2020). The woody stem (WS) and the roots are less interesting for functional beverages, though.
- Acidri, Robert, et al. “Phytochemical Profile and Antioxidant Capacity of Coffee Plant Organs Compared to Green and Roasted Coffee Beans.” Antioxidants 9.2 (2020): 93.
- Khamitova, Gulzhan, et al. “Optimization of espresso coffee extraction through variation of particle sizes, perforated disk height and filter basket aimed at lowering the amount of ground coffee used.” Food Chemistry (2020): 126220.
- Sales, Amanda, et al. “Effect of regular and decaffeinated roasted coffee (Coffea arabica and Coffea canephora) extracts and bioactive compounds on in vitro probiotic bacteria growth.” Food & Function (2020).