Date of Completion

Spring 5-3-2014

Thesis Advisor(s)

Arlene Albert; Valerie Duffy

Honors Major

Molecular and Cell Biology

Disciplines

Human and Clinical Nutrition | Other Food Science | Other Nutrition

Abstract

Background: Aronia berries (chokeberries) have very high levels of health-promoting polyphenols yet cause "choking" sensations due to bitterness and astringency. We aimed to describe oral sensations and palatability of aronia juice by variations in harvest time and oral sensory phenotype. Sensory blocking combinations were tested to improve juice acceptability. Methods: Ripe aronia berries were harvested at 7 time points and juiced for oral sampling by 50 adults who underwent bitter taste phenotyping. The adults reported quality intensities of prototypical tastes, foods, and aronia juices. Ethyl butyrate (10ppm) and/or sucrose (0.15 and 0.3M) were added to prototypical oral stimuli and aronia juice for changes in liking and oral sensation. Results: The hedonic ratings of juice averaged weakly dislike, ranging from ‘strongly dislike’ to ‘above moderately like.’ Astringency was the strongest sensation, yet sweetness was the primary driver of liking in multiple regression analysis. Those who liked the juice reported a greater balance between astringency and either sourness or sweetness. The level of negative taste and astringency sensations and liking of berry juiced varied with bitter phenotype. In the sensory blocking procedures, adding ethyl butyrate alone increased sweetness but failed to improve juice acceptance. Ethyl butyrate acted synergistically with added sugar to enhance perceived juice sweetness. However a substantial increase in palatability was not achieved because the sweet and ethyl butyrate did not block astringency. Conclusion: The negative sour/bitter and astringency sensations impede aronia juice liking. Adding sugar and sweet flavors improved palatability by blocking sour/bitter sensations. Future research is needed to determine methods to block astringency and achieve an acceptable aronia juice for consumption as an enjoyable and health-promoting beverage.

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