Combined effect of ultrasound and enzymatic pretreatment on yield and functional properties of taro (Colocasia esculenta) starch

Abstract

A combined effect of ultrasound and enzymatic pretreatment on yield and functional properties of taro starch was investigated. A 3 × 2 × 2 factorial design was employed with three factors, i.e., sonication time (0, 10, and 20 min), concentration of cellulase (0 and 100 U/100 g fresh tuber) and xylanase (0 and 100 U/100 g fresh tuber). Starch yield varied from 14.60 to 20.81%. The highest yield of 20.81% was obtained, when ultrasonication time was 20 min and concentration for both cellulase and xylanase was 100 U/100 g taro tubers, which was an increase of 42.53% from conventional method. An increase in swelling, solubility and pasting properties of the isolated starches pretreated only with ultrasound was observed, but no such difference was observed with enzymes alone, or when ultrasound was applied in combination with enzymes. A slight decrease in clarity of the starch pastes was also observed after ultrasonication. Freeze‐thaw stability of the starches was found to be better when ultrasound was used as pretreatment for extraction. Higher yield of starch with better functional properties can be achieved from taro tubers by using combination of ultrasound and enzymes.

Modification of Taro Starch and Starch Nanoparticles by Various Physical Methods and their Characterization

“…Starch was extracted from the tubers by the method as described by Sit et al. [ 37 ] with modifications. Briefly, the washed and peeled tubers were cut into cubes of equal size and ground using a laboratory blender (Philips HL 1632, India) for 2 min.…”

“…Swelling and solubility of the samples were determined by the method Sit et al.. [ 37 ] Sample (0.5 g) was added to 20 mL of distilled water in a previously weighed centrifuge tube and heated in a water bath for 30 min at 90°C, then cooled to room temperature and centrifuged at 12 000 × g for 10 min. Supernatant were transferred into petri plate and dried at 105°C for 3 h to obtain the value of dissolved starch.…”

Structure, properties, and applications of aroid starch

“…Extraction method can affect the yield and properties of starch (John et al, 1999;Deka, 2014a and2014b). Diverse chemicals (sodium chloride (1e5 %), sodium hexametaphosphate (1e5 %), potassium metabisulfite (1e5 %), ammonia (1e5 %), and glycerol monostearate (0.025e0.125 %)) in steeping solutions have been tested to extract starches from X. sagittifolium and A. paeoniifolius for higher yield and purity (e.g., inhibiting microbial growth and enzymatic browning) (John et al, 1999;Rani, John, Moorthy, & Raja, 1998).…”

“…Ultrasound (30 kHz, 100 W, up to 10 min) has been applied to pre-treat the slurry to increase the starch yield of C. esculenta from 15% to 19% (Sit et al, 2014a). Ultrasound pretreatment was also combined with cellulase and xylanase to isolate starch from corms of C. esculenta, and a yield of 20.8% was achieved using a 3 Â 2 Â 2 factorial design (Sit, Deka, & Misra, 2014b). However, the ultrasound treatment could alter the starch properties as a result of cavitation (Zhu, 2015c).…”

Application of ultrasound in combination with other technologies in food processing: A review

“…Since current time, combined ultrasound with enzyme-assisted separation process in bioactive components, referred as Ultrasound assisted enzymatic extraction (UAEE), has been explored in certain researches [8] , [37] , [61] , [107] , [120] , [159] . The UAEE is known to be combined complementary strategies of extraction, providing a few extra points of interest.…”