Comparative impacts of different post-processing treatments (pasteurization, microwave, retort) on quality, texture, and aroma of vacuum-packed potato cakes.

Abstract

This study evaluated the effectiveness of four post-processing treatments-pasteurization at 65 °C (P65, 10 min) and 85 °C (P85, 10 min), microwave heating (MS, 750 W, 30 s), and retort treatment (RTS, 121 °C, 10 min)-for microbial reduction and quality maintenance of vacuum-packed potato cakes. No statistically significant differences (p > 0.05) were observed in proximate composition (moisture, ash, protein, total starch). However, starch fractions appeared process-sensitive, with P65 increasing resistant starch and RTS/MS increasing apparent amylose. Color shifts were detected with L* and a* increasing. Meanwhile, b* decreased in P65/P85/MS but not in RTS. Texture and small-amplitude rheology were maintained across groups, consistent with the pre-formed dense, continuous matrix observed on SEM. Using SPME-GC-MS, 21 volatiles were identified, and hydrocarbons and aldehydes dominated after all treatments. On multivariate analyses, P65/P85/MS clustered close to the control, while RTS diverged and exhibited the lowest aldehyde diversity/abundance. Subsequently, odor-activity values suggested that aldehydes were likely the principal aroma contributors. In sensory tests, only RTS reduced the overall acceptability, while P65/P85/MS largely preserved color and favorable odors. Critically, all treatments required subsequent continuous refrigeration at 4 °C to maintain microbial counts below 105 CFU/g over 14 days. Storage under temperature abuse conditions (25-37 °C) led to microbial exceedance of this limit within 6-8 days, underscoring that these temperatures constitute spoilage risks, not viable storage options. Overall, microwave or mild thermal pasteurization best balanced microbial control with color, aroma, and texture preservation, supporting their potential applicability for preparing refrigerated ready-to-eat potato cakes.