Those who buy semi-processed citrus products for the food industry know that the price says nothing about the final quality. The real control lever is theBrix/acidity ratio, the indicator that predicts how that fruit will behave in your recipe.
What does the Brix degree mean
The Brix degree measures the percentage of soluble solids present in the juice: sugars (sucrose, fructose, glucose), organic acids, vitamins, mineral salts. It is measured with a digital refractometer at a controlled temperature (20°C) and is expressed in °Bx.
For the Calabria Plain, the natural reference values are:
- External Tarocco Navel Oranges: 10-13 °Bx
- Whole clementines: 11-14 °Bx
- Ciaculli late mandarin: 12-15 °Bx
- Primofiore lemons: 7-9 °Bx
- Bergamot from Reggio Calabria: 8-10 °Bx
Titratable acidity
Total acidity is expressed in grams of citric acid per 100 ml of juice (g/100 mL) or per kilogram. For sweet citrus fruits such as oranges and clementines the normal values are 0.8-1.5 g/100 mL; for lemons we are at 4.5-6.5 g/100 mL; for bergamot up to 7 g/100 mL.
Acidity alone is not enough. What matters above all is how much acidity is balanced by sugars.
The Brix/acidity ratio (E/A)
The relationship between Brix degree and titratable acidity (expressed as anhydrous citric acid) is the true indicator of maturity and sensory balance of the fruit. In acronym it is also called “ratio”.
Indicative values for sweet citrus fruits intended for industry:
- Oranges for juice: ratio 12-16. Below 10 the juice is sour; above 18 it is flat.
- Whole frozen clementines: ratio 14-18, for a sweet balance with a good perception of freshness.
- Mandarin: ratio 13-17.
- Pulp for ice cream making: ratio 11-13, where a little more acidity helps not to saturate the palate after frost.
When to ask the supplier for these analyzes
Analyzes must be requested for each incoming batch, not just the supplier’s approval. Seasonality and climatic conditions significantly modify these values even in a week of production.
A good practice is to require theCertificate of Analysis (CoA)accompanying the delivery note, with stamp of the accredited internal or external laboratory. Sample verification with a portable refractometer (cost: a few hundred euros) allows your QC to confirm the data upon arrival of the goods in less than 5 minutes.
What to do when values go out of range
An out-of-range Brix does not always mean poor fruit: in some extraordinarily rainy climatic years, Sicilian and Calabrian oranges naturally produce below 10 °Bx. The difference is made by a transparent supplier who communicates the deviation in advance and proposes alternatives (mix batches, wait for the next batch, compensatory discount) instead of delivering in silence.
Talk to us about it: we process Calabrian citrus fruits traced from the field and provide the CoA for each batch delivered.
