Effects of Radio Frequency Tempering on the Texture of Frozen Tilapia Fillets.

Jiwei Jiang,Fen Zhou,Yuyao Shi,Xichang Wang,Caining Xian

doi:10.3390/foods10112663

Abstract

Radio frequency (RF) tempering has been proposed as a new alternative method for tempering frozen products because of its advantages of rapid and volumetric heating. In this study, the texture of RF-tempered frozen tilapia fillets was determined under different RF conditions, the effects of related factors on the texture were analyzed, and the mechanisms by which RF tempering affected the texture of the tempered fillets were evaluated. The results show that the springiness (from 0.84 mm to 0.79 mm), cohesiveness (from 0.64 mm to 0.57 mm), and resilience (from 0.33 mm to 0.25 mm) decreased as the electrode gap was increased and the power remained at 600 W, while the shear force increased as the power was increased for the 12 cm electrode gap (from 15.18 N to 16.98 N), and the myofibril fragmentation index (MFI) values were markedly higher at 600 W than at 300 W or 900 W (p < 0.05). In addition, the tempering uniformity had a positive effect on hardness and chewiness. The statistical analysis showed that the texture after RF tempering under different RF conditions correlated relatively strongly with the free water content, cooking loss, and migration of bound water to immobilized water. The decrease in free water and bound water migration to immobilized water resulted in a significant increase in cohesiveness and resilience.

Highlights

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The purposes of this study were to analyze the texture of frozen tilapia fillets under different radio frequency (RF) tempering conditions and to explore the mechanism of the changes in texture for different RF treatments based on tempering uniformity, water loss, and moisture migration, which will provide a useful reference for exploring quality improvements in RF-tempered products
The hardness, shear force, and Myofibril Fragmentation Index (MFI) showed a negative correlations with cooking loss. These results indicate that the contents of immobilized water and free water and the cooking loss may have a certain effect on the texture, and that a close correlation exists between textural properties, water migration and water loss during RF tempering, which requires further analysis and confirmation

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Traditional tempering methods affect the quality, water and juice loss, texture, and organizational structure of fillets by causing varying degrees of damage due to changes in physical properties, chemical reactions, and microorganisms [4], which lead to increased resource consumption due to longer tempering times. The emerging tempering technologies have advantages such as shorter tempering times, low energy consumption, high energy utilization rates, effective inhibition of the growth of microorganisms and lipid oxidation during the tempering process, reduced production of spoilage substances, improved freshness, and extended storage time. The purposes of this study were to analyze the texture of frozen tilapia fillets under different RF tempering conditions (power and electrode gaps) and to explore the mechanism of the changes in texture for different RF treatments based on tempering uniformity, water loss, and moisture migration, which will provide a useful reference for exploring quality improvements in RF-tempered products

Methods

Results

Conclusion