Changes in raspberry sensory quality after harvest as affected by CO2 atmospheres

CO₂ atmospheres have the potential to influence raspberry (Rubus idaeus L.) sensory quality after harvest. Our study determined the optimal postharvest atmosphere to extend shelf life without negatively impacting sensory quality. Raspberry fruit were stored at 5 ℃ in 15, 8, 5 or 0.03 kPa CO₂ in combination with 6, 13, 16 or 21 kPa O₂, respectively. A trained sensory panel conducted a descriptive sensory evaluation of the raspberry fruit after 5, 10, and 13 d of storage. Raspberries stored in 15 kPa CO₂ with 6 kPa O₂ (15 kPa) atmosphere followed by that in 8 kPa CO₂ with 13 kPa O₂ (8 kPa) atmosphere had higher firmness than that in 5 kPa CO₂ with 16 kPa O₂ (5 kPa) and 0.03 kPa CO₂ with 21 kPa O₂ (0.03 kPa) atmosphere. Panelists found that raspberries stored in 8 kPa and 15 kPa CO₂ atmosphere had the least off-flavor and highest tartness. Raspberries stored in 8 kPa scored highest in raspberry flavor with substantial juiciness and sweetness scores. The fermentative volatiles acetaldehyde and ethanol were higher in raspberries stored in 15 kPa despite the low off-flavor scores, while most other raspberry volatiles decreased with increasing CO₂ concentration, including flavor-related volatiles α-ionone, α-terpineol, limonene and linalool. After 10 d, the quality of raspberries stored in 0.03 kPa or 5 kPa atmosphere had degraded considerably. While 15 kPa atmosphere prolonged shelf life the longest, 8 kPa atmosphere prolonged shelf life to 10 d while maintaining sensory quality and was the best overall atmosphere.