Isolation and Characterization of Starch from Different Potato Cultivars Grown in Croatia

Abstract

Starch is a polysaccharide that is widely used in food and other industries; therefore, due to its great potential, it is attempted to be maximally isolated from various foods rich in starch. Commonly, potatoes are used for starch production due to the relatively high starch content in tubers, and the process itself is complex and includes several steps. The aim of this study was to isolate and characterize starch from eight potato varieties. First, the basic chemical composition of the potato samples was determined, and then the isolation was carried out under laboratory conditions. The isolated starch was air dried, then ground and sieved through a 400 µm sieve. The basic chemical composition, amylose content, starch color, swelling capacity and solubility index, clarity of starch pastes, texture of starch gels and thermo-physical properties (gelatinization and retrogradation) were determined in the obtained starch samples. The results showed that the SL 13–25 potato variety had the lowest starch content, while the Stilleto variety had the highest starch content. The content of protein, fat, ash and crude fiber was relatively low in all of the isolated starches, indicating their high purity. Also, the difference in the color of the isolated starches was difficult to see. The highest amylose content had starch from Saprodi, while the lowest was observed in starch from SL 13–25. Starch from the cv. Dartiest had the highest, while starch from the cv. Sereno had the lowest gel strength. The starch of the cv. Dartiest also had the highest clarity value. The retrogradation transition temperatures and enthalpies were lower compared to the gelatinization temperatures and enthalpies. With the increasing temperature, both the swelling capacity and the solubility index of all the samples increased. According to the obtained differences, this study confirmed the significant influence and role of different cultivars on starch characteristics.