Enhancing tamarind seed starch characteristics through infrared heating and moisture pre-conditioning

Native starches generally have fewer advantages for industrial applications and often require physical or chemical alterations to perform effectively. In the present investigation, response surface methodology was applied with two factors namely, moisture pre-conditioning and infrared heating time, to study the functional characteristics of tamarind seed starch. The factors included moisture levels (10–40 g/100 g starch) and infrared heating time (750 W, 10–60 min) at a constant temperature of 100 °C, resulting in 13 experimental runs. Functional properties and transmittance were defined as response variables. Initial optimization was performed on modified starch samples prepared under ideal conditions, then compared with both modified and native starches based on their physicochemical characteristics. The optimally prepared modified tamarind seed starch (MTSS) (25.12% moisture content, dry basis; 60-min heating time) demonstrated enhanced functional and pasting properties compared to its native starch. Infrared heating led to substantial changes in the gelatinization temperatures of tamarind seed starch. The degree of crystallinity and the double helix-ordered structure of tamarind seed starch were also reduced after modification. Consequently, modified starch demonstrated a larger granule size, a higher swelling capacity, increase in water absorption capacity and light transmittance. The infrared heating process is one of the new and effective modification techniques for enhancing the swelling factor in starch.