The bitter tastethat amino acidsgive to beveragescould be masked by adding alpha-cyclodextrin, according to new data frombrazil. writing in the journal food researchinternational , brazilian researchers report that alpha-cyclodextrin canform complexes with various amino acidsand hydrolysed soyprotein,and this results in a reduction in the bitter tasteof the ingredients.“alpha-cd alters the bitter tasteperception of the amino acidsand reduces the bitter tastefrom of hydrolyzed soyprotein,”wrote the researchers, led by giani andrea linde from universidade paranaensein brazil. “these results indicate a potential use of alpha-cd for de-bitteringproteinhydrolysates in acidicbeverages.” wacker chemie was granted novel foodsapproval for alpha-cyclodextrin by the european commission last year.according to background information in the article, hydrolysedproteins have a high functional value because of their bioactive peptidescontent. these compounds have important functional and technological aspects,including high solubility in acidic solutions and stability during thermaltreatments. however, the process of hydrolysis tends to liberate highly bitteramino acids,“limiting the use of these productsin human food”,explained the researchers. the new research suggests that adding alpha-cyclodextrinto an acidicbeverage solution (ph 4.5) could mask the bitter tasteprofile of amino acidssuch as phenylalanine, tryptophane, tyrosine, isoleucine, proline and histidine.linde and his co-workers prepared model beveragesusing the isolated soyprotein(donated by the solae company), and alpha-cd (donated by cargillfood& pharma specialties north america). the soyproteinwas hydrolysed using alcalase (donated by novozymes). analysis of the solutionsshowed that cyclodextrin formed inclusion complexes with the amino acids,with the greatest affinity for phenylalanine and tryptophane, followed bypraline, isoleucine, tyrosine, and histidine. furthermore, sensory tests showedthat addition of 5 and 10 per cent alpha-cyclodextrin to the soy proteinhydrolysate solution reduced the bitternessby 40 and 60 per cent, respectively, said the researchers. an improvement inthe “characteristic soyodour” was also recorded. at a lower level (3 per cent) alpha-cyclodextrinhad no affect on the bitter tasteof the soy proteinhydrolysate solution, they added. “the main bitterpeptideshold in their chains non-polaramino acids situated at the middle or the extremity of the peptidechain and this structural characteristic is fundamental for the interaction ofthese amino acidswith the tastesensitive cells at the tongue,” explained the researchers. “thus the higherproportions of alpha-cd, which have led to significant reduction in the bitternessof the soyhydrolysate, were sufficient to increase the amino acidand peptidecomplexed populations in the hydrolysate mixture up to the point ofsignificantly lowering the solution bitternessintensity.”