Asian Food Science Journal

Background: Retort processing is a thermal food preservation technique that involves heating hermetically sealed containers to achieve commercial sterility and microbiological safety. This method can be applied to various food products, including canned foods, ready-to-eat meals, and health drinks.

Aim: The present study was carried out to assess the microbiological quality and physico-chemical properties of the ready-to-eat (RTE) Thai dessert, namely Cha Bang Ang.

Material and Methods: This Cha Bang Ang was subjected to retort processing at different temperatures, 114 °C, 118 °C, and 121 °C, with a Fo value of 3 (sterilisation unit). Before retorting processing, all ingredients, including caramel milk, grass jelly, and basil seeds, were mixed to produce the dessert. The filled and sealed pouches were then subjected to retort processing to optimise the process temperature at a Fo value of 3. A control sample of the Cha Bang Ang without retort processing was also prepared. The total soluble solids (TSS) were measured using a handheld refractometer and expressed as Brix. Viscosity was determined by using a viscometer at a temperature of 25 ± 2 °C. The colour changes of Cha Bang Ang before and after the retort process were determined using a chromameter (by measuring the L*, a* and b* parameters. All data were expressed as means ± standard deviations (SD). Results were compared using one-way analysis of variance (ANOVA) using Tukey’s HSD post hoc test with 95% confidence using Minitab 19.

Results: The effects of the different temperatures on microbiological properties (total plate count, E. coli, coliform, and yeast & mould), sensory evaluation, and physicochemical properties were evaluated. Microbial analysis results indicated no bacterial growth at any of the temperatures tested. Viscosity and total soluble solids increased with rising temperatures, while the colour (lightness) of the caramel milk darkened after the retort process. The panellist prefers retorted Cha Bang Ang samples, except for the texture of the grass jelly. The sensory score given by the panel for colour of the product was found to be 5.83, 5.89, 5.97 and 5.97 for non-retort and retorted samples at 114 °C, 118 °C and 121 °C, respectively. The overall acceptability of the Cha Bang Ang sample retorted at 121 °C was the most preferred by the panellists, with a score given of 6.11 ± 0.98 when compared to the other samples.

Conclusion: The Cha Bang Ang retorted to achieve a Fo value of 3 at all temperatures studied (114 °C, 118 °C, and 121 °C) met acceptable microbiological limits and exhibited acceptable physicochemical characteristics. These findings suggest the feasibility of using retort processing to improve the shelf stability and safety of traditional Thai desserts without compromising quality.