Effect of Retort Pressure on Sterilization of Rembiga Satay in Flexible Packaging Using Overpressure Retorts

Abstract

Background: Flexible packaging, such as retort pouches, is widely used for sterilized food products, since it can preserve product quality and improve distribution efficiency. However, flexible packaging is susceptible to deformation and leakage during thermal processing. This study aimed to evaluate the effects of retort pressure and packaging type on heat penetration characteristics, process lethality (F₀), packaging integrity, and physicochemical properties of Rembiga satay processed using an overpressure retort.

Methods: The study consisted of four stages: heat distribution testing, preparation of Rembiga satay, heat penetration testing, and physicochemical analysis. Rembiga satay was packaged in aluminum and plastic retort pouches and sterilized at 116 °C using different retort pressures. Process optimization was performed using the Ball method. Data were analyzed using analysis of variance (ANOVA) followed by Duncan’s multiple range test at a 95% confidence level using SPSS software.

Result: Heat distribution testing produced Come Up Time (CUT) values of 21 min for aluminum packaging and 23 min for plastic packaging. Initial heat penetration trials resulted in F₀ values ranging from 1.06 to 3.66 min, indicating insufficient lethality in several treatments. After process redesign using the Ball method, estimated F₀ values increased to 3.28 min for aluminum packaging and 6.55 min for plastic packaging. The highest tensile strength of the sealing area was observed in aluminum retort pouches processed at 0.8 bar, with a value of 19.4 N/mm². Sterilization also significantly affected the physicochemical properties of Rembiga satay, including texture profile parameters, color values, and proximate composition.

Conclusion: Retort pressure and packaging type significantly affected packaging integrity and thermal processing characteristics of Rembiga satay. Although several initial sterilization treatments resulted in insufficient F₀ values, process redesign using the Ball method successfully achieved F₀ values exceeding the minimum commercial sterility requirement.