Ozone treatment to red raspberry stored up to 15 days

Nowadays to promote and market fruits in a competitive way it's necessary to develop and to apply processes and strategies within of the environmental and sustainability issue. With improvements in storage technologies and the increase in global trade, today's consumer expects to find fresh berries available for purchase outside of the local harvest season.

Red soft fruits such as raspberry are quite appreciated by consumers for their organoleptic and nutraceutical properties, but they are highly perishable thus the storage time is restricted to few days. The raspberry fruits if stored at 0–0.5°C and 90–95% relative humidity (RH) can be maintained in normal atmospheric conditions for 5–7 days

Italian scientists at University of Torino in collaboration with Agrifrutta Soc. Coop. SRL (Piedmont, Italy) investigated the effects of two different ozone (O3) treatments, applied as an environmental sanitation tool, on the quality traits and the nutraceutical compounds of red raspberry (Rubus idaeus L. cv Grandeur) stored up to 15 days.

Raspberry fruits stored in the cold room were exposed to two different flushing of O3 (S1 and S2 treatment) and compared with control thesis where berries were stored under normal atmosphere. Fruits with the S1 and S2 treatment were maintained respectively under exposure to 500 ppb O3 supplied by a generator (Biofresh, Northumberland) used in a continuous cycle and a constant flushing of 200 ppb (12 hours) and 50 ppb (12 h); both flushing treatments were maintained up to the end of storage. The fruits were stored at 1±1°C and 90–95% RH for 3, 6, 9 and 13 days. After each time at low temperature the same berries were held in shelf life for different additional days (respectively +6, +3, +9 and +2) at 20±1°C to simulate retailer conditions.

The O3 treatments tested resulted in being able to preserve red raspberries for a long time (15 days) without significant changes in the most important qualitative and nutraceutical traits, however, the S2 treatment (constant flushing of 200 ppb (12 hours) and 50 ppb (12 hours) showed the best performance ensuring the best visual appearance in terms of more attractive colour and the best control of off-flavour.

Source: Giuggioli N., Briano R., Girgenti V., Peano C., 'Quality effect of ozone treatment for the red raspberries storage', 2015, Chemical Engineering Transactions, Vol. 44, pages 25-30 DOI: 10.3303/CET1544005

Contacts:
Nicole Roberta Giuggioli
DISAFA, Università degli Studi di Torino
Largo Braccini 2
10095 Grugliasco, Italy
Email: nicole.giuggioli@unito.it