Piment d’Espelette – Basque Pepper
During a visit to France earlier this month, I mentioned visiting the Basque region of France. Although we sampled some charcuterie during that trip, the reason for flying there in the first place was to visit a regional association of Piment d’Espelette producers. Piment d’Espelette is a mild pepper grown in the hills around the tiny rural town of Espelette, France. Although bunches of deep red peppers can be seen adorning the buildings around Espelette, the real value in the crop is a ground up form of the pepper used as a seasoning in fine cooking. The pepper is renowned for its lingering sweet flavor, and has been recognized with “AOC” and “AOP” certification. This is a French convention for certifying specific products as being made in a specific region using specific techniques.
We actually visited a farm where peppers are grown, harvested, dried, and ground into powder. This is done on a rather small scale at each farm by the farmer. The main issue the association asked us to investigate is why a few of the batches produced late in the harvest went “bad” in a matter of months. By “bad” they meant that the fiery red/orange of the pepper powder turned to sandy brown. This process also renders the powder unpalatable.
We had a couple of theories. The first is just that the degradation of the spice is some sort of enzymatic reaction, so as water activity increases, so does the reaction rate. This makes sense if the humidity is higher near the end of the harvest, so grinding the peppers into powder would increase its water activity. The other theory was that this is a lipid oxidation reaction. A test the association conducted seemed to support this theory, because when they put the powder in desiccators (water activity <0.03) it all turned into the sandy brown powder. Lipid oxidation increases at high or low water activities, showing a minimum around 0.4 aw.
We still don’t know exactly what is going on with these samples but our first clue is the water activity. I took readings on 3 samples the association gave us: the “good” sample (0.193 aw), the “going bad sample (0.194 aw) and the “bad” sample (o.264 aw). This suggests that higher water activity leads to sample degradation, but we have some complicating factors. One is that the association ran some tests where they held pepper powder samples in closed containers with desiccant, meaning the water activity was below 0.03. All of these samples degraded to sandy brown in relatively short order. We will need to do some studies here to determine how water activity affects this product, and we’ll post our findings when we know more.