Microwave pasteurization of pre-packaged carrots

In this study, organic intermediate moisture raisin was pasteurized with microwave and conventional pasteurization methods. The thermal resistance (D and z values) of the target yeast, Zygosaccharomyces rouxii, was determined for both methods at different temperatures 60°C, 70°C, and 80°C and at different time intervals. The effect of pasteurization methods on the quality properties of raisin samples was investigated. The D values of Z. rouxii were found as 6.50 ± 0.49, 2.96 ± 0.02, 1.91 ± 0.01 min for conventional treatment and 3.46 ± 0.31, 2.02 ± 0.14 and 1 ± 0.01 min for microwave treatment at 60℃, 70℃, and 80℃, respectively. F8537 values for 5‐log reduction and come‐up time significantly decreased after microwave pasteurization. Brix, acidity, and color values were preserved better by microwave treatment. Hydroxymethylfurfural content of the microwave pasteurized samples was found 42% less than the samples pasteurized conventionally. Microwave pasteurization can be alternatively used for the conventional method for raisin improving quality with less heating time. Practical applications Microwave heating needs less come‐up time rather than conventional pasteurization. Decreasing process time provides advantageous via the costs and energy saving so organic intermediate moisture fruits that are perishable can be safely pasteurized by a microwave method for longer shelf life in the industry. Z. rouxii, which may be found in high sugar content foods, can be inactivated to the target log that provides the fruit safe by using this method. In addition, quality properties, such as color, which is effective on the consumer preference also, protected better by the effect of volumetric heating.

Section: Resultsmentioning

confidence: 99%

Effects of microwave pasteurization on the thermal resistance of Zygosaccharomyces rouxii and on the physicochemical properties of organic intermediate moisture raisin

Çağlar

Ergün

Baysal

2021

“…It can be seen from Figure 6a1,b1 that apart from the fresh samples, various hot and cold spots were formed on the thermal processed samples. The cold spots were the areas that received the least thermal energy and the hot spots were the parts that absorbed higher microwave energy (Peng et al., 2017) during the drying periods. These variations are mainly due to the configuration of the microwave sending out both low and high electromagnetic fields in the drying cabinet (Therdthai & Zhou, 2009).…”

Section: Resultsmentioning

confidence: 99%

Quantitative analysis and visualization of moisture and anthocyanins content in purple sweet potato by Vis–NIR hyperspectral imaging

Tian

Aheto

Bai

et al. 2020

Total anthocyanin (TA) and moisture content (MC) are critical indexes of processed purple sweet potatoes (PSPs). The current study examined the feasibility of hyperspectral imaging to investigate how MC and TA contents of PSPs change during processing under two different drying methods namely convective hot‐air drying (CHD) and microwave drying (MD). Models based on spectral data and the integration of spectral and one or three gray‐level co‐occurrence matrix features were established with partial least square regression. The best prediction outcome based on Spectra + HOMOGENEITY + CONTRAST + ENTROPY combinations were (Rp2 = 0.862, 0.847; RMSEP = 0.079, 0.303), respectively, for MC and TA for the CHD samples. Similarly, for the MD samples, the best prediction outcomes were (Rp2 = 0.867, 0.859; RMSEP = 0.088, 0.241), respectively, for MC and TA. Image algorithms were also developed to generate distribution of MC and TA in some representative samples. Practical applications Anthocyanins have been reported as having the potential to lower blood pressure, improve eyesight, reduce cancer cell multiplication, impede tumor formation, and prevent diabetes. Studies have, however, shown that cooking modes including boiling, baking, and steaming decreased the contents of anthocyanins. This study assessed the impact of convective hot‐air and microwave drying (MD) process of purple sweet potato (PSP) on total anthocyanin (TA) content as a function of moisture loss. Hyperspectral Imaging (HSI) was useful in estimating not only the contents of TA and moisture, but also in generating a visual map of their distribution pattern in the processed PSPs. The TA content of PSPs processed by MD was higher than that by convective hot‐air drying, but the distribution uniformity of TA in microwave dried PSPs was worse than that in convective hot‐air dried samples. Finally, to guarantee consistency in drying processes of food products, the HSI could be used to obtain visual images of their chemical parameters.

“…Consumer demand for nutritious foods, which are minimally and naturally processed, has led to processor interest in nonthermal or mild thermal technologies. Microwave heating as a promising alternative to conventional pasteurization has been reported in different studies (Contreras, Benlloch‐Tinoco, Rodrigo, & Martínez‐Navarrete, 2017; Matsui, Granado, De Oliveira, & Tadini, 2007; Peng et al., 2017). Microwaves have the capacity to penetrate and dissipate energy into the food with the interaction of water molecules inside the food, and this property of microwave helps in heating the food rapidly.…”

Section: Introductionmentioning

confidence: 96%

mentioning

confidence: 99%

Effects of microwave combined with ultrasound treatment on the pasteurization and nutritional properties of bottle gourd (Lagenaria siceraria) juice

Das

Chakraborty

et al. 2020