Effect of Voltage and Frequency in Pasteurization Pulsed Electric Field (PEF) Continous System of Pineapple (Ananas comosus [L.] Merr) Juice

Abstract

Pineapple which is one of the perishable commodities with high water content about 90.73% in 100 gr of fresh material. Thermal pasteurization has a weakness that can degrade the quality of fruit juice products. In contrast, non thermal processes have expectations which is don’t make decreasing quality of the product. One of the non-thermal pasteurization type called Pulsed Electric Field (PEF). Nowadays, PEF system have two type batch and continous, which respectively used in this research is PEF continous system. This study uses research methods group random design (GRD) with two factorial that voltage (20, 30 and 40 kV) and frequency (10, 20, 30 and 40 kHz). Based on these studies it is known that the voltage and frequency is significantly different to the value of Total Plate Count (TPC), and absorbance. However there aren’t significantly different with the pH, vitamin C, viscosity, total dissolved solid (TDS), total sugar and color. The treatment based on the microbial test are at a voltage of 40 kV and a frequency of 40 kHz which can reduce bacteria significantly 1.01x103 cfu/mL or 0.94 by log cycle with the effectiveness of microbial death by 88.5%. The treatment based on the microbial test are at a voltage of 40 kV and a frequency of 30 kHz which The result indicates that physical and chemical characteristic of pineapple juice become 3.98 of pH, total dissolved solid (TDS) of 6.25 °brix, total sugar of 14.75 % viscosity of 3 cp, vitamin C of 7.6 mg/100ml, absorbance of 0.67, color on the brightness (L*) value of 24.05, redness (a*) of 6.35, and yellowish (b*) of 7.5. This result shows that PEF continuous respectively work system to pasteurize the pineapple juice.