Characterization of promising natural blue pigment from Vaccinium bracteatum thunb. leaves: Insights of the stability and the inhibition of α-amylase

Mingcong Fan; Weijia Lian; Tingting Li; Zhiming Rao; Yan Li; Haifeng Qian; Hui Zhang; Xiguang Qi; Li Wang

doi:10.1016/j.foodchem.2020.126962

Characterization of promising natural blue pigment from Vaccinium bracteatum thunb. leaves: Insights of the stability and the inhibition of α-amylase

Food Chem. 2020 Oct 1:326:126962. doi: 10.1016/j.foodchem.2020.126962. Epub 2020 May 4.

Authors

Mingcong Fan¹, Weijia Lian¹, Tingting Li², Zhiming Rao³, Yan Li⁴, Haifeng Qian⁴, Hui Zhang⁴, Xiguang Qi⁴, Li Wang⁵

Affiliations

¹ School of Food Science and Technology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
² Department of Food Science and Engineering, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China.
³ School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
⁴ School of Food Science and Technology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
⁵ School of Food Science and Technology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China. Electronic address: wl0519@163.com.

PMID: 32413753
DOI: 10.1016/j.foodchem.2020.126962

Abstract

A concise method of natural blue pigment from Vaccinium bracteatum thunb. leaves (VBTL) was proposed firstly in this research. The potential properties of new pigment source needed to be assessed for further application. During the shelf life and thermal-accelerated storage, the blue pigment was prone to stable in the mildly acidic system, which was observed retention of 35.85% for storage of 12 weeks in pH 4.0. The 65% of blue pigment retained after the in vitro simulated digestion. The blue pigment exhibited inhibition effect on the pancreatic α-amylase (IC₅₀ = 2.915 mg/mL). The analysis of inhibition kinetics indicated the blue pigment was an uncompetitive inhibitor. Through fluorescence quenching and circular dichroism study, the blue pigment inhibited α-amylase activity via the structural unfolding of α-amylase molecule and changing the secondary structure. These findings provided the new evidence of the digestion resistibility of VBTL pigment and the functional food - "Wu mi".

Keywords: Blue pigment; Pancreatic α-amylase inhibition; Stability; Vaccinium bracteatum thunb. leaves.

MeSH terms

Enzyme Inhibitors / chemistry*
Pigments, Biological / chemistry*
Plant Extracts / chemistry*
Plant Leaves / chemistry
Vaccinium myrtillus / chemistry*
alpha-Amylases / antagonists & inhibitors*
alpha-Amylases / chemistry

Substances

Enzyme Inhibitors
Pigments, Biological
Plant Extracts
alpha-Amylases