Effectiveness of rinses in alleviating bitterness and astringency residuals in model solutions

A two-part study determined the effectiveness of gum-based rinses with or w ithout oil for alleviating residuals of a hitter (0.8 g/L caffeine solution ) and an astringent (1g/L alum solution) stimuli in serial responses using a sip and spit method. In Experiment I, rinsing with deionized water was co mpared to rinsing with 0.3% xanthan gum in water alone or with 5% corn oil and 0.55% carboxymethyl cellulose (CMC) in water alone or with 5% or 10% co rn oil. The 0.3% xanthan gum and 5% corn oil mixture resulted in the highes t stimulus intensity difference before and after rinsing, whereas 0.55% CMC had a value of nearly zero for residual effect. Results of a two-alternati ve forced choice test used in Experiment 2 indicated that both were equally effective for reducing bitterness residuals, but 0.55% CMC solution result ed in the lowest (p = 0.007) residual effect for astringency. Therefore, th e 0.55% CMC rinse was considered an effective interstimulus rinse to use fo r assessing both bitterness and astringency in model solutions.