Changes in Composition and Descriptive Sensory Attributes of Blackberries during Postharvest Storage

Five blackberry cultivars (Natchez, Osage, Ouachita, Prime Ark^® 45 and Prime Ark^® Traveler) from the University of Arkansas blackberry breeding program were evaluated to measure changes in composition and sensory attributes during postharvest storage. Berries were harvested in June 2015 at the shiny-black stage of maturity and placed in 240-g vented clamshells in triplicate. Data were collected on berries both before and after storage at 2 °C (90% RH) for 7 d. A trained descriptive sensory panel (n=9) evaluated sensory attributes of the blackberry cultivars, each panelist evaluated four berries for each cultivar in duplicate, served monadically and randomized. The descriptive panelists identified and evaluated the basic tastes (sweet and sour) and texture (firmness) of fresh blackberries using a 15-point scale (0=less of the attribute and 15=more of the attribute). Analytically, firmness, soluble solids content (SSC) and titratable acidity (TA) were also evaluated. At day 0, the cultivars had firmness from 4.9 to 7.2 N, SSC from 7.9 to 9.2% and TA from 0.7 to 1.2%. At day 0 panelists scaled hardness of blackberry from 3.5 to 3.9, sourness from 3.6 to 5.5 and sweetness from 4.0 to 4.9. Storage did not affect firmness as cultivars averaged 5.7 N at day 0 and 5.4 N at day 7, nor could panelists differentiate firmness differences (day 0 = 3.75 or day 7 = 3.77). The level of SSC did not differ among genotypes and was not affected by storage, however panelists detected differences in sweetness between stored berries and among genotypes. Results for TA before and after storage indicated that TA was reduced in storage, an average across genotypes of 1.0% before storage to 0.8% after storage. However, ‘Osage’ showed an increase of TA (day 0 = 0.7% and day 7 = 1.1%), while ‘Ouachita’ showed a decrease of TA (day 0 = 1.2% and day 7 = 0.7%). Panelists did not detect changes in sourness for ‘Ouachita’, but perceived an increase of sourness for ‘Osage’ (day 0 = 3.6 and day 7 = 4.5) and a decrease of sourness for ‘Natchez’, ‘Prime Ark^® 45’ and ‘Prime Ark^® Traveler’. The cultivars analyzed showed great fresh-market potential due to their maintenance of firmness, along with SSC and TA after storage.