Characterization of the sensory, chemical, and microbial quality of microwave‐assisted, thermally pasteurized fried rice during storage

Abstract

Companies producing ready‐to‐eat (RTE) meals are looking for processing alternatives that allow them to gain presence in the supermarket chill section. Microwave‐assisted pasteurization systems (MAPS) offer the potential to produce safe, high‐quality foods. This research examined sensory, physical, chemical, and microbial changes in fried rice processed with MAPS and stored at 7 °C over a 6‐week storage period. Additional fried rice samples (cooked but not MAPS‐processed) were stored at –31 °C and were used as the control. Randomly selected trays of each type of rice were analyzed at 1, 4, and 6 weeks of storage. Aroma, appearance, taste/flavor, texture, mouthfeel, and aftertaste were evaluated by a semitrained sensory panel with rate‐all‐that‐apply questions. The type of rice treatment (MAPS or control) significantly influenced sensory attributes (P < 0.05), with firm texture attribute of the egg being more intense in the MAPS‐rice compared to the control. In addition, storage time affected the sensory modalities of both rice samples, including aroma, appearance, and taste/flavor (P < 0.05). No spoilage‐associated sensory attributes were detected in the MAPS‐rice during storage. At each examination point, various physical, chemical, and microbial analyses were conducted for the MAPS‐ and control rice. From the physical and chemical perspective, the MAPS‐rice did not present relevant changes over the period tested. Microbial growth was the main cause of spoilage of the MAPS‐rice; however, MAPS was able to extend the regular 5‐day shelf life of a chilled fried rice meal to 6 weeks, demonstrating the potential of this technology for the RTE industry. Practical Application The findings of this study indicate that, by applying microwave technology to RTE fried rice, the shelf life can be extended from 5 to 7 days up to 42 days (6 weeks) when stored at 7 °C. This temperature closely mimics that of consumers’ refrigerators in the United States. This study also shows the potential of working with a semitrained panel and RATA questions when characterizing sensory changes during storage.

Consumer Acceptance of a Ready-to-Eat Meal during Storage as Evaluated with a Home-Use Test

“…A detailed description of MAPS can be found in Tang et al (2018) [ 19 ]. The specific processing conditions used to produce jambalaya in the MAPS are described in the methods section of Montero et al, (2020) [ 22 ]. At the time the study was conducted, the MAPS could process 16 trays in one run; thus, there were 12 total runs.…”

“…Participant Selection and Orientation: A semi-trained panel ( n = 10; 8 females, 2 males, ages 23–46) also evaluated the sensory profile of the MAPS-jambalaya and the control with rate-all-that-apply (RATA) questions. All the members of the semi-trained panel had previous experience in conducting sensory evaluation and had participated in multiple descriptive panels conducted at the WSU Sensory Science Center [ 22 ].…”

“…These evaluations were also done at Weeks 2, 8, and 12 of storage. RATA methodology has been reported to be a valid and reliable sensory profiling tool suitable for semi-trained panels [ 22 , 27 ]. For each session, the control trays were thawed in water at room temperature for 1.5 h. Next, each jambalaya tray (250 g) was warmed at 45–50 °C for 30 min (15 min on each side, top and bottom) with a food warmer (Glo-Ray HATCO Corporation, Milwaukee, WI, USA).…”

“…RATA Data: RATA results were analyzed by treating the RATA scores as continuous data and expanding the scale to four points (0, 1, 2, 3 for absent, low, medium, and high, respectively) [ 22 , 28 , 29 ]. A repeated measures ANOVA with mixed models was conducted.…”

“…Thus, MAPS is particularly suitable for pasteurization of pre-packaged, heat-sensitive, multi-component meals that are highly viscous, semisolid, or solid [ 19 ]. Montero, Sablani, Tang and Ross (2020) [ 22 ] investigated the potential of MAPS to extend the shelf life of RTE fried rice. The authors found that MAPS processing was able to extend the shelf life of a chilled fried rice meal up to 6 weeks when stored at 7 °C, demonstrating the potential of this technology for the RTE industry.…”