Abstract: In this work, we optimized the preparation of purple potato granule for minimizing free starch content and maximizing pigment retention. It was found that the appropriate preparation process involved two-step cooking and subsequent backfill pulverizing. The optimal two-step cooking conditions were precooking in 30 × 10-6 g/mL CaCl2 solution at 70 ℃ for 28 min and then cooking for 32 min. The optimal backfill pulverizing conditions were backfill in a proportion of 1:2 followed by emulsifier addition at 0.3% and stirring for 2.5 min. Purple potato granules of 80, 100 and 120 mesh in granularity were prepared under the optimized conditions, and a comparative analysis was carried out on their color difference (δE) values and iodine values. The purple potato granule of 80 mesh showed the lowest free starch content and the best color retention.

Key words: purple potato, granule, processing technique