Freeze–thawing damage evaluation of vegetables with two cutting orientations

Abstract

This work aimed to evaluate how cut orientation of squash, eggplant, and turnip affects the damage of tissues due to freeze/thawing process. For that, cylinders of 2 cm diameter and 0.5 cm height were cut in two orientations according to vascular tissues: longitudinal and transversal. Then, they were frozen at À20 C for 53 hr and thawed at 6.1 C for 12 hr. After that, two indirect methods to measure tissue damage were analyzed: by electrical conductivity of drip loss and by mass transfer during drying of samples before and after freeze/thawing process. As results, cut orientation showed significant effect on eggplant damage, finding approximately 143% more drip loss using transversal cut, than longitudinal cut. Regarding, turnip and squash, they did not show damage differences by freeze/thawing process using different cut orientations. In addition, measuring drip loss electrical conductivity demonstrated to be a more suitable method to assess freeze damage than mass transfer evaluation. This work concludes that cut orientation is an approach that cannot be ignored during freeze/thawing processes evaluation. Practical ApplicationsThis work demonstrated that the orientation how vegetables are cut can affect the freeze-thawing process. This simple consideration should be considered to avoid obtaining low quality vegetables after thawed them. Despite this could not be observed during industrial process, consumers, who are not used to apply controlled conditions, can note food damages after product thawing.

Evaluating cold damage on blueberries (Vaccinium corymbosum) caused by different thawing methods

“…2) Conductimetría: La conductividad eléctrica se midió tal como lo describe Silva, et al [13] tanto en fresco, como después de descongelado. Para ello se tomaron 3 muestras de arándano por cada método.…”

Effects of ultrasonication and freeze–thaw pretreatments on the vacuum freeze-drying process and quality characteristics of apricot (Prunus armeniaca L. cv. Diaoganxing)

“…For instance, Fan et al (2021) reported that high-power US destroys the cell walls of carrots, forming pore structures and reducing the VFD time by 15%; while Xu, Chen, Sylvain Tiliwa, et al (2021) reported that sequential pretreatment with dual frequency US significantly improves the color, flavor, and nutrient characteristics of freeze-dried strawberry slices. FT is another effective non-thermal pretreatment method that has been widely used for meat products ( Jiang, Nakazawa, Hu, Osako, & Okazaki, 2019 ), fruits and vegetables ( Bassey, Cheng, & Sun, 2022 ; Silva, Ramirez, Gavidia, & Miano, 2021 ). During the FT pretreatment process, the material is cooled, converting the water in the cells to ice crystals, which are then melted upon warming, resulting in more intracellular space and cavities in the cell structure ( Silva et al, 2021 ).…”

“…FT is another effective non-thermal pretreatment method that has been widely used for meat products ( Jiang, Nakazawa, Hu, Osako, & Okazaki, 2019 ), fruits and vegetables ( Bassey, Cheng, & Sun, 2022 ; Silva, Ramirez, Gavidia, & Miano, 2021 ). During the FT pretreatment process, the material is cooled, converting the water in the cells to ice crystals, which are then melted upon warming, resulting in more intracellular space and cavities in the cell structure ( Silva et al, 2021 ). Xu, Zhang, Feng, et al (2021) reported that FT pretreatment before VFD changes the microstructure of okra and shortens its drying time by 62.5%, and the dry-matter-content loss is only ∼5.6%.…”

Structure–process interaction in mass transfer processes: Application of ethanol and ultrasound in a vascular structure

“…In relation to food structure, the tissues orientation, sample size and tissue distribution should be also considered when those approaches are studied. For instance, cut orientation has been demonstrated to be important in food with complex structures (formed by different tissues), as affecting drying (Ren et al, 2021), shrinkage (Lin et al, 2020;Rojas & Augusto, 2018c), rehydration (De Los Santos et al, 2021) and freezethawing process (Silva et al, 2021). This demonstrates that food material is anisotropic, which means that food properties depend on the orientation of the food when analyzed.…”