Effects of low molecular sugars on the retrogradation of tapioca starch gels during storage.

Xiaoyu Zhang,Jinling Fan,Huaibin Kang,Xinfang Liu,Wenxue Zhu,Denglin Luo,Qunyi Tong,Rongfang Li,Zonghua Wang

doi:10.1371/journal.pone.0190180

Abstract

The effects of low molecular sugars (sucrose, glucose and trehalose) on the retrogradation of tapioca starch (TS) gels stored at 4°C for different periods were examined with different methods. Decrease in melting enthalpy (ΔHmelt) were obtained through differential scanning calorimetry analysis. Analysis of decrease in crystallization rate constant (k) and increase in semi-crystallization time (τ1/2) results obtained from retrogradation kinetics indicated that low molecular sugars could retard the retrogradation of TS gels and further revealed trehalose as the best inhibitor among the sugars used in this study. Fourier transform infrared (FTIR) analysis indicated that the intensity ratio of 1047 to 1022 cm−1 was increased with the addition of sugars in the order of trehalose > sucrose > glucose. Decrease in hardness parameters and increase in springiness parameters obtained from texture profile analysis (TPA) analysis also indicated that low molecular sugars could retard the retrogradation of TS gels. The results of FTIR and TPA showed a consistent sugar effect on starch retrogradation with those of DSC and retrogradation kinetics analysis.

Highlights

Tapioca starch (TS) is one of the basic raw materials in food industry
Differential scanning calorimetry (DSC) analysis is widely adopted to investigate the effect of low molecular sugars on starch retrogradation compared with rarely used Fourier transform infrared (FTIR) and Texture profile analysis (TPA) methods [9, 10, 11]
We studied the effects of different low molecular sugars on TS retrogradation using DSC, FTIR and TPA methods under refrigeration

Summary

Introduction

Tapioca starch (TS) is one of the basic raw materials in food industry. It has been widely used as thickener, stabilizer or food matrix in food due to its physical properties of texture and stability, as well as its bland flavor [1]. It was found that the addition of low molecular sugars could influence gelatinization and retrogradation properties of starchy food [2]. There are many kinds of starch and sugars used in food engineering, and large amount of experiments will be made to develop various starchy food formula, so it’s necessary to find more common or effective methods to evaluate the sugar effect on starch retrogradation. DSC analysis is widely adopted to investigate the effect of low molecular sugars on starch retrogradation compared with rarely used FTIR and TPA methods [9, 10, 11]. We studied the effects of different low molecular sugars (sucrose, glucose and trehalose) on TS retrogradation using DSC, FTIR and TPA methods under refrigeration. This study will be conductive to our understanding of the interaction of starch and sugar during storage, as well as provide new evidence and effective methods for the development of starchy food

Materials and methods

Findings

Conclusion