Changes in Physicochemical Properties of Wild and Cultivated Blackberry during Postharvest Cold Storage

Blackberry is a seasonal harvested fruit that is also very fragile and perishes quickly. A comparative study was conducted to find out influence of cold storage on physicochemical parameters of wild and cultivated blackberry over a period of 12 days.

The plant materials were composed of the blackberry fruit, including a compound of cultivated blackberry (Rubus spp.), and wild blackberry (Rubus fruticosus L. agg) which were harvested in the North of Morocco. The temperature of the storage of wild and cultivated blackberry was 5 °C for 4, 8, and 12 days, and then transferred to 25 °C for 1 day to simulate transport and commercialization. After that, the physicochemical parameters were analyzed. Statistical analyses were performed using SAS.

During 12 days of storage, the pH of samples was decreased from 3.69 to 3.22 for wild blackberry, and from 4.85 to 3.43 for cultivated blackberry. The titratable acidity was increased from 1.61 to 3.28 for wild blackberry, and from 2.07 to 3.25 for cultivated blackberry. Flavonoids also showed a remarkable increase in values from 30 to 70.66 mg QE/100g of wild blackberries and from 25.33 to 60.66 mg QE/100g in cultivated ones between harvest and the last day of storage. The variation in skin color revealed a decrease during storage of L* brightness, a* redness, and yellowness b* for both blackberries. 

The most suitable storage time of blackberry components during cold storage at 5 °C was 12 days. The temperature at 5 °C preserves the quality of the blackberry for both wild and cultivated ones. However, the wild blackberry was more resistant than cultivated one to cold storage.