THE EFFECT OF HEAT AND MICROWAVE TREATMENTS ON ORANGE JUICE QUALITY DURING STORAGE

Thamer A Khalil Khalil

doi:10.33899/magrj.2019.161323

Abstract

The effect of heat and microwave (MW) treatments on quality related parameters as ascorbic acid (AA), browning index (BI), reducing sugar (RS), total soluble solid percentage (TSS %), and pH of orange juice (OJ) were investigated directly after the treatments and after storage at 4 and 20°C for 2 months. Microwave treatment induced little reduction in AA compared to heat treatment. Microwave treatment ensured the quality stability of orange juice stored for 2 months under refrigeration (4°C) but inferior orange juice quality was detected after 2 month storage at 20°C. Using MW exposure above 60 sec gave better studied parameters than heat treatments. However, microwave exposure for more than 60 sec. was sufficient to preserve the OJ quality. Accordingly, the use of microwave energy may be proposed as an alternative to traditional heat treatment in order to preserve the OJ quality.

Highlights

Orange juice is one of the most popular beverages in Iraq as well as in the worldwide
The decomposition of ascorbic acid (AA) which leads to nonenzymatic browning, is the main deteriorative phenomena that occurs during storage of orange juice (OJ)
The objective of the present study is to examine the effect of MW treatment on OJ preservation in comparison with heat treatment

Summary

Introduction

Orange juice is one of the most popular beverages in Iraq as well as in the worldwide. When OJ is stored, it gradually turns brown. Two of the major changes during storage of OJ are development of off-flavour and browning (Handwerk and Coleman, 1988). AA is known to contribute to browning of some foods because it is oxidized and decomposed. The decomposition of AA which leads to nonenzymatic browning, is the main deteriorative phenomena that occurs during storage of OJ. It was reported that AA most contributes to browning within two weeks of storage (Shinoda et al, 2004). It has been shown that the browning occurred in acidic fruit juices during storage was attributed mainly to nonenzymatic reactions (Burdurlu and Karadeniz, 2003, Khalil and Al-Zubaidy, 2010)

Objectives

Methods

Results