Thermal Inactivation Kinetics of Kudzu (Pueraria lobata) Polyphenol Oxidase and the Influence of Food Constituents.

Junping Liu,Jiayan Zhang,Liqiang Zou,Lei Zhou,Li Zhang,Tao Liao,Wei Liu,Yafei Liu

doi:10.3390/foods10061320

Abstract

The thermal inactivation kinetics of kudzu (Pueraria lobata) polyphenol oxidase (PPO) were investigated in model and food systems. PPO in kudzu tissue (tPPO) showed a higher thermostability than that of PPO in crude extract (cPPO) and purification fractions (pPPO). The PPO inactivation rate constant (k) increased with an increase in temperature, and tPPO showed the lowest k value, followed by that of cPPO and pPPO at the same temperature, indicating that PPO in the food system was more resistant to thermal treatment. Food constituents (pectin, starch, sucrose, and bovine serum albumin) in the food system decreased the activity of PPO but increased the thermostability of PPO, among which pectin exhibited the strongest protective effect against thermal inactivation, and the influence of sucrose was much slighter than that of other macromolecules. Fluorescence emission spectra indicated that pPPO exhibited stronger interactions with pectin than sucrose, and pPPO with pectin showed a more stable conformation under thermal treatment.

Highlights

Kudzu (Pueraria lobata) is a herbaceous, perennial plant native to East Asia and belongs to the Leguminosae family
Polyphenol oxidase (PPO) from kudzu was purified by ammonium sulfate fractionation together with
The results showed that different food constituents have different effects on PPO

Summary

Introduction

Kudzu (Pueraria lobata) is a herbaceous, perennial plant native to East Asia and belongs to the Leguminosae family. It is a rich source of starch, dietary fiber, minerals, and isoflavonoids and possesses many nutritional and pharmacological activities [1,2,3], such as antioxidant, anticancer, anti-inflammation, and neuroprotective properties. Kudzu is used as a vegetable and edible ingredient in the preparation of various foods [4]. Kudzu starch is used in the production of noodles, beverages, oral liquids, and various dishes, and it serves as a sauce thickener [5]. Food products containing components of kudzu have begun to attract interest from both consumers and researchers due to their health benefits.

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