Agronomical traits, phenolic compounds and antioxidant activity in raw and cooked potato tubers growing under saline conditions.

Potatoes yield and tubers compositions are linked to mechanisms adopted by plants to cope with salinity and often can change after cooking. The current study aimed to evaluate the effects of salinity, variety and cooking method in composition of potato tubers. Three potato varieties (Spunta, Bellini and Alaska) grown under distinct salt levels (T1: 2.2 ms cm^-1 EC, T2: 8.5 ms cm^-1 EC before electromagnetic treatment and 6.3 ms cm^-1 EC after electromagnetic treatment, T3: 8.5 ms cm^-1 EC) were studied. Yield and tuber quality attributes (starch, dry matter, specific density and tuber size) were evaluated. Carotenoids, total and individual phenolics determined by HPLC, relative antioxidant capacity (RAC) and ions content were analyzed, in both raw and water boiled tubers.

Tuber yield, starch, dry matter, ions and antioxidants were significantly influenced by the salinity level and variety. The least production and the highest antioxidants were obtained under T3. Antioxidants were influenced by cooking method, the interactions treatment × cooking method and variety × cooking method. Individual phenolic compounds exhibited different response to cooking as quercetin, caffeic acid and catechin decreased significantly after boiling. However, coumaric acid increased in Alaska tubers.Salinity level, variety and cooking method are important determinants of tuber yield and composition. Electromagnetic water may be useful to enhance potato production and tuber quality in areas suffering from water salinization. This article is protected by copyright. All rights reserved.