AQUALAB Research Report | July 2026
This month, AQUALAB repeatedly appeared in the same experiment, run by different groups. Take plant material nobody uses — fruit peels and seeds, underripe fruit, wheat milling by‑products — dry it into a powder, and prove the powder will keep. In four of July’s five citations, water activity is the number that settles whether the stabilization worked.
In the literature
Turning by-products into useful powders
Brazilian researchers processed genipap pulp, peel, and seeds into three separate flours by convective drying at 70 °C, using an AQUALAB to confirm all three sat below 0.3 aw — low enough to rule out microbial growth across a seven‑day hygroscopicity trial. Peel flour, normally discarded, carried the highest antioxidant activity of the three.
A second Brazilian team optimized a water‑only extraction of ascorbic acid from green acerola, then spray‑dried the extract with gum arabic. An AQUALAB measured the finished powder at 0.213 aw, comfortably under the 0.6 threshold for microbial stability, with no significant loss of antioxidant activity through the dryer. About three quarters of a gram covers an adult’s daily vitamin C.
In Italy, fermented wheat bran and germ were freeze‑dried and used to replace 24% of the wheat flour in yeast‑leavened bread, a far higher inclusion rate than previous work has managed. Water activity was tracked on an AQUALAB. The germ‑based loaf came out significantly drier than its controls: the freeze‑dried particles are porous and hygroscopic enough to take up free water during kneading and hold onto it through baking.
Work on spray-dried pequi pulp treated water activity as something more than a final check. Measured on an AQUALAB, aw was one of the modeled response variables in a factorial design covering wall material composition and outlet air temperature. It landed between 0.29 and 0.34, with outlet temperature the dominant factor driving it down.
When the useful result is no result
The fifth paper is the inverse case. Researchers followed dry-fermented sausages carrying millet-immobilized probiotics across 121 days of ripening and storage, measuring water activity on an AQUALAB. It moved with time and not with treatment: every formulation dried the same way.
That null result is what makes the rest of the study legible. Because drying was uniform, the lower lipid oxidation in the millet formulations could be credited to millet’s phenolic compounds rather than to one batch simply drying harder than another. Water activity is doing the least visible job in the paper and one of the more important ones.
AQUALAB Research Report is a monthly roundup of notable citations, mentions, and technical references involving AQUALAB instruments and water activity science.
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