PROCESSING QUALITY OF POTATO VARIETIES GROWN AT TWO LOCATIONS AND STORED AT 4, 10 AND 12°C

Abstract

Seven varieties of potatoes grown at Jalandhar and Modipuram were stored at 4 and 10°C with and without CIPC (isopropyl N-(3-chlorophenyl) carbamate) treatment, and at 12°C with CIPC treatment (RH 85-90%) for 145 days. Changes in weight loss, dry matter, reducing sugars, sucrose, chip colour and phenols were determined. Weight loss was 26.4% at 10°C due to excessive sprout growth and it decreased to 7.7% when sprout growth was suppressed with CIPC treatment. A significant positive correlation (r = 0.84**) between weight loss and sprout growth was observed. There was little change in the dry matter content during storage. Reducing sugar level increased during storage and it was maximum at 4°C resulting in dark chips with colour scores of 9 to 10; while at 10 and 12°C with CIPC treatment, the increase in the reducing sugar content was relatively lower but higher than 150 mg/100g fresh wt, which resulted in unacceptable chip colour scores of 5 to 6.7. Sucrose content also increased during storage and there was no significant difference between 10 and 12°C with CIPC treatment. Phenol content generally increased during storage and was higher in tubers stored at 10 and 12°C. Out of the seven varieties grown at Modipuram, only Kufri Chipsona-1 showed lower level of reducing sugars and acceptable chip colour up to 115 days of storage when stored at 10 or 12°C with CIPC treatment. None of the seven varieties grown at Jalandhar gave acceptable chip colour. The maximum CIPC residue level observed in unpeeled tubers was 1.8 mg/kg fresh wt, which was much less than the acceptable limit of 30 mg/kg fresh wt.