this study, pH values of treated mango nectars decreased and TA increased
significantly during storage,which could benefit the acid hydrolysis
of pectin in mango nectars.
Another common problem associated with cloudy juices or nectars
is the loss of cloud, and the absorbance at 660 nm of cloudy juices can
be used to predict its cloud stability (Chandler & Robertson, 1983). As
shown in Table 4, the cloud of mango nectars increased significantly
after HHP or HTST treatment, while it decreased gradually during 16-
week storage. Decreases in the cloud during storage were possibly due
to the loss of the viscosity, as well as the reduction in stability of nectar
system caused by the precipitation of bigger pulp particles and polymerization
of phenolic compounds and protein (Cao et al., 2012). Cao
et al. (2012) reported that the decrease in the cloudwas highly correlated
to the viscosity during storage of strawberry juice at 4 °C
(R = 0.962) and 25 °C (R = 0.788). However, in this study, high correlations
between the cloud and viscositywere only found in HHP-treated
mango nectars stored at 25 °C. Moreover, HTST-treated mango nectars
exhibited higher cloud stability than HHP-treated ones.