Quality Changes of Orange Juice after DPCD Treatment

Liying Niu,Dajing Li,Xiaojun Liao,Wuyang Huang,Chunquan Liu

doi:10.1155/2019/6897583

Abstract

Dense phase carbon dioxide (DPCD) offers advantages of enhanced physical and nutritional qualities during the processing of juices. Here, freshly squeezed orange juice was treated with DPCD, and changes of physical properties and volatile components were investigated and compared with the original untreated and thermally treated samples. The correlations among physiochemical properties were also examined based on Pearson correlation, cluster analysis (CA), and principal component analysis (PCA). Significant correlations were found among the particle size, color parameters, and volatile compounds in the DPCD-treated samples. The 12 parameters were clustered into three groups using CA and PCA, and the eight volatile compounds were separated within the three groups. Nonanal and citronellol were clustered in group I, and they increased for a longer duration of more than 40 min with higher levels than the control. Parameters in group II included D (4,3), L∗, a∗, ethyl butyrate, and trans-2-hexenol, and they linearly decreased after 10–60 min DPCD treatment. The parameters of b∗ and monoterpenes were clustered in group III, and they decreased within 40 min of DPCD treatment and then increased to an intermediate level. In addition, PCA clearly showed that the orange juice samples under DPCD for 10–60 min formed a “U” shape on the two-dimensional plot and that the samples treated by DPCD for 10 min and 20 min were closer to freshly squeezed orange juice than the heat-treated orange juice. This indicated that the nonthermal DPCD process offers the potential to be used more extensively in juice products.

Highlights

As a nonthermal process, the use of dense phase carbon dioxide (DPCD) is attractive because it causes less degradation to the quality of juices and beverages than thermal processes. e e ects of DPCD on the nutrient content, stability, color, and sensory quality of foods have been widely studied
Changes of Particle and Color Parameters. e effects of DPCD treatment on the physical parameters of orange juice are shown in Figure 1. e particle size of samples treated by DPCD for 10 min was not significantly different (p > 0.05) from the untreated sample but was reduced significantly—approximately 20%—by the 20 min treatment
E changes in particle size of the orange juice remained insignificant until the DPCD treatment time reached 50 or 60 min

Summary

Introduction

The use of dense phase carbon dioxide (DPCD) is attractive because it causes less degradation to the quality of juices and beverages than thermal processes. e e ects of DPCD on the nutrient content, stability, color, and sensory quality of foods have been widely studied. Many results have shown that DPCD does not modify the chemical, physical, and organoleptic qualities such as pH, °Brix, and turbidity of fresh liquid foods [1,2,3]. Most results on the volatile components have shown negative conclusions: in most cases, the content of volatile components was reduced signi cantly. Gasperi et al [4] reported that the contents of esters and aldehydes in fresh apple juice were reduced by more than half after DPCD treatment. A few reports showed no signi cant change [6] or even an increase of some volatile components [7] after DPCD treatment. When juice is immersed in dense CO2, the particle size, solubility of volatile substances, and the distribution of pigments could change under certain pressure and temperature conditions [11,12,13]. The b∗ value (yellowness/blueness) decreased in grapefruit juice [1] and mandarin juice [16] after DPCD treatment

Methods

Results

Discussion

Conclusion