Ultrasound‐Assisted Extraction of Lychee (Litchi chinensis Sonn.) Seed Starch: Physicochemical and Functional Properties

Abstract

Abstract High‐power ultrasound (HPU) is a non‐thermal processing method that has been researched and used in the last years. The application of ultrasound can modify and improve some technologically important compounds such as starch. This research aimed to examine the effect of ultrasound treatment on yield, physicochemical, and functional properties of lychee seed starch (LS). HPU experimental conditions used were sonication time (5 and 20 min) and amplitude (40% and 70% ). Starch yield significantly increased with increasing ultrasound amplitude and time. The ultrasound did not change the morphology and shape of the granules but caused cracks in their surface. Surface damage induced an increase in amylose content, relative crystallinity, enthalpy of gelatinization, swelling power, solubility index, and acid hydrolysis of the starch. These results indicate that ultrasound mainly affected the amorphous starch region. The morphology, size, color, rheological and thermal characteristics, crystal structure, and structural order features of the untreated and ultrasound‐treated LSs were compared. A principal component analysis was carried out to assess the effect of the ultrasound treatment on LS characteristics.