Located in Chatsworth, NJ and directed by Dr. Nicholi Vorsa, the Philip E. Marucci Center for Blueberry and Cranberry Research and Extension is where the majority of Rutgers blueberry research takes place. Thanks to Rutgers research, improvements have been made to the overall quality of New Jersey blueberries.
Blueberry selections must possess a range of horticultural characteristics before being considered suitable to release as a cultivar. These characteristics include:
- soil adaptability
- consistently high yields
- high quality fruit
- disease resistance
These characteristics are interrelated and in some cases subjective. This project was initiated to streamline the selection process for fruit quality and to minimize subjectivity in selection. Specifically, to determine:
- what fruit characteristics consumers consider to be important
- if those characteristics could be measured objectively
Twelve cultivars for analysis, including both highbush and rabbiteye blueberries. Cultivars were chosen to span the season and included newer varieties as well as traditional favorites. All fruit were picked at the peak of ripeness for that particular cultivar and evaluated in groups of four (early, mid, and late season). Berries were evaluated in the lab for color, size, firmness, brix and titratable acidity. Berries from the same lot were shipped to Beltsville, MD for volatile analysis (volatiles are important flavor compounds) and taste-panel evaluation. Panelists were untrained blueberry consumers. Each panelist was given a questionnaire that included a rating scale for several sensory characteristics including skin toughness, texture during eating, juiciness, acceptability of appearance, color, fruit size, flavor and overall eating quality.
Cultivars varied in most sensory tests. ‘Hannah’s Choice’ and ‘Coville’ scored as high or higher than the other cultivars in sensory scores for intensity of blue color, juiciness, sweetness, and flavor. These cultivars also scored high for acceptability of appearance, color, fruit size, sweet/tart balance, and overall eating quality. The rabbiteye cultivars, ‘Coastal’ and ‘Montgomery’, scored as low as or lower than most highbush cultivars in all sensory scores Sensory intensity and acceptability scores for ‘Elliott’ and ‘Weymouth’ were generally similar to those of the two rabbiteye cultivars. However, since sensory acceptability scores for all cultivars were around 40 or higher on a scale of 0 to 100, all cultivars had an acceptable or better sensory quality from a practical standpoint.
Among cultivars, sensory scores for acceptability of overall eating quality were highly correlated with sensory scores for flavor acceptability and flavor intensity and less well correlated with sensory scores for intensity of juiciness and bursting energy and for acceptability of appearance. Sensory scores for intensity of blueberry-like flavor and acceptability of flavor were correlated with sensory scores for intensity of juiciness and sweetness, and was at best only weakly correlated with any sensory or laboratory measurement. Likewise, sensory scores for acceptability of appearance were correlated with sensory scores for acceptability of fruit size and color and with average fruit weight, but not well correlated with other sensory or laboratory measurements. While fruit size and color are important criteria for determining acceptability of fruit appearance, the juiciness, sweetness and flavor of the fruit are the most important criteria for predicting the overall eating quality of blueberries.
The results indicate that despite the wide range in values among laboratory quality attributes evaluated, all fruit from all cultivars had acceptable or better sensory quality with ‘Hannah’s Choice’ and ‘Coville’ scoring highest in overall eating quality.
ORGANOLEPTIC ANALYSIS OF BLUEBERRY CULTIVARS
James Polashock1, Robert Saftner2 and Mark Ehlenfeldt1
1USDA-ARS Fruit Lab, 125 A Lake Oswego Rd., Chatsworth, NJ 08019
2USDA-ARS Produce Quality and Safety Lab, Beltsville, MD 20705