Effect of High Pressure Homogenization on the Stability and Quality of Not-From-Concentrate Cloudy Honey Peach (Prunus persica L.) Juice

In order to determine the effect of high pressure homogenization (HPH) on the stability and quality of not-from-concentrate (NFC) cloudy honey peach juice, the samples were subjected to HPH processing with 20~40 MPa for 1~2 successive passes. The changes in turbidity, centrifugation precipitating rate, particle size distribution, Zeta potential, water soluble pectin content, pectin methylesterase (PME) activity, pH, total soluble solids (TSS), total acidity (TA), TSS/TA, reducing sugar content, color, total phenol and V_C content were evaluated. The results showed that HPH could effectively improve the stability of NFC cloudy honey peach juice. With the treatment of 30~40 MPa/1 and 20~40 MPa/2, the centrifugation precipitating rates significantly decreased by 13.49%~24.22% (P<0.05), while the mean particle diameter decreased from 1853.67 nm to 501.10~665.27 nm, as compared to that in untreated samples. Moreover, the absolute Zeta potential significantly increased (P<0.05). As the pressure and successive pass increased, the water soluble pectin content tended to increase, while the PME activity gradually decreased. HPH observably increased the L^* value of cloudy peach juice, and reduced its browning index (P<0.05), indicating the color of NFC cloudy peach juice was markedly improved. Juice homogenized at 30 MPa/1 showed the best quality. The contents of total phenol and V_C were significantly enhanced (P<0.05), whereas no change was found for pH, TSS, TA and TSS/TA levels (P>0.05). HPH decreased the pH, TSS, TA, total phenol and V_C content with increasing pass number (P<0.05), leading a decline in juice quality. HPH treatment could dramatically improve the stability of NFC cloudy peach juice, and inhibit browning and improve its total phenol and V_C levels.