Effects of power ultrasound on the activity and structure of ß-D-glucosidase with potentially aroma-enhancing capability

Authors: SUN, YUJING - Zhejiang University Of Technology; ZENG, LI - Zhejiang University Of Technology; XUE, YUANZHONG - Zhejiang University Of Technology; Yang, Tianbao; CHENG, ZHONGMING - University Of Tennessee; SUN, PEILONG - Zhejiang University Of Technology

Submitted to: Journal of Food Science and Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2019
Publication Date: 5/15/2019
Citation: Sun, Y., Zeng, L., Xue, Y., Yang, T., Cheng, Z., Sun, P. 2019. Effects of power ultrasound on the activity and structure of ß-D-glucosidase with potentially aroma-enhancing capability. Journal of Food Science and Nutrition. 7:2043-2049. https://doi.org/10.1002/fsn3.1035.
DOI: https://doi.org/10.1002/fsn3.1035

Interpretive Summary: Flavor compounds in fruit occurs in free forms, in which they contribute directly to fruit flavor, and in bound forms that have attached sugars. Bound forms of aroma compounds are non-volatile and odorless and do not influence flavor. ß-D-glucosidase is a key enzyme that removes the bound sugar, thus enhancing fruit flavor. However, the activity of the enzyme under normal fruit storage condition is low. The purpose of this study was to evaluate the effects of temperature and ultrasound treatments for improving enzyme activity. Moderate temperature (20 -45 °C), low ultrasonic intensity (less than 181.53W/cm2), and short treatment time (less than15 min) led to the activation of ß-D-glucosidase, whereas high temperature (45 -60 °C), high ultrasonic intensity (greater than 181.53W/cm2), and long treatment time (greater than 15 min) led to its inhibition. This study suggests that ultrasound treatment is an effective approach to regulate the activity of ß-D-glucosidase and can be used by researchers to develop commercial practices to enhance fruit aroma.

Technical Abstract: Flavor compounds in fruit occurs in free forms, in which they contribute directly to fruit flavor, and in bound forms. Glycosidically bound aroma compounds are non-volatile and odorless glycosides. ß-D-glucosidase is a key enzyme to remove the bound sugar, and improve fruit flavor. However, the hydrolysis efficiency of the enzyme is low. The purpose of this study was to improve the enzyme activity using ultrasound treatment. Low temperature (20 -45 °C), low ultrasonic intensity (< 181.53W/cm2), and short treatment time (<15 min) led to the activation of ß-D-glucosidase, whereas high temperature (45 -60 °C), high ultrasonic intensity (> 181.53W/cm2), and long treatment time (> 15 min) led to its inhibition. Application of ultrasound lowered the optimum temperature for ß-D-glucosidase activity from 50 to 40 °C. Ultrasound did not change the primary structures of the enzyme, but changed the secondary structures. When ultrasound activated ß-D-glucosidase, the a-helix contents were increased by 22 folds, and the ß-fold and irregular coil content were reduced. When ultrasound inhibited ß-D-glucosidase, the contents of ß-fold were increased, and the a-helix and irregular coil contents were reduced. Hence activation or inhibition of ß-D-glucosidase under ultrasound was determined by the ultrasound conditions. This study suggests that ultrasound treatment is an effective approach to regulate the activity of ß-D-glucosidase and can be used in aroma-enhancing.