Quality changes of frozen mango with regard to water mobility and ice crystals during frozen storage

Abstract

Quality changes of mango with regard to water mobility and ice crystals were studied at different storage temperatures for 6 months. Mangoes were stored in the glassy state (T [−80 and − 60 C] < T g 0 and T g 0 < T [−49 C] < T g 00), partially freezeconcentrated state (T g 00 < T [−38 C] < T m 0), and rubbery state (T [−18 C] > T m 0). Results indicated that the most samples stored at −80 and − 60 C had no significant difference in the water mobility, freezable water, drip loss, and vitamin C after the same storage period. The T g 0 and T g 00 showed a different effect on the quality stability of frozen mangoes. In the glassy state, changes in water state, freezable water, and ice crystal size of frozen samples were slower, resulting in lower rate of quality changing (L* value, hardness, and vitamin C) than other conditions from 0 to 6 months. Practical applications: This study demonstrated the correlation between the water mobility and ice crystals of mango revealing the mechanism of physical and chemical changes in samples stored at different states during frozen storage. Compared to the partially freeze-concentrated and rubbery state storages, the glassy state storage reduced the rate of the quality change in mangoes over time. Therefore, glassy state storage (below T g 00) has great potential for the food processing industry because it can improve frozen storage strategies and extend the shelf life of frozen mango during long-term storage. 1 | INTRODUCTION Mango is a tropical fruit and a rich source of vitamins, carotenoids, polyphenols, and other bioactive compounds (Zhao, Liu, Wen, Xiao, & Ni, 2015). However, mangoes are perishable and have a relatively short storage life. Freezing is a suitable method to preserve the quality attributes of mango and extend its shelf life (Zhao et al., 2017). It is well documented that at temperatures below the glass transition temperature, the molecular diffusion and the rates of deteriorative reactions are significantly reduced, and thus foods are relatively stable in the glassy sate (Aktaş & Akköse, 2011; Roos, 1998). For frozen foods (high water content foods), their maximum stability can be obtained when the freezable water transforms into ice crystals and the temperatures are maintained below their characteristic glass transition temperatures (Fabra, Talens, Moraga, & Martínez-Navarrete,-2009). The stability of frozen foods depends on characteristic glass transition temperatures of the maximal-freeze-concentration condition (T g 0 , T g 00) and characteristic end point of freezing temperature (T m 0) (Rahman, 2010; Zhang et al., 2018). The temperatures below T g 0 are recommended as safe storage temperatures for foods containing freezable water (frozen food systems) (Syamaladevi, Sablani, Tang, Powers, & Swanson, 2011). However, when the storage temperatures are above T m 0 , the mangoes become lower viscosity and higher molecular mobility because the frozen matrices are plasticized by melting of † Xian-Xian Li and Jin-Hong Zhao equally contributed to this paper.

Osmotic Dehydration, Drying Kinetics, and Quality Attributes of Osmotic Hot Air-Dried Mango as Affected by Initial Frozen Storage

“…However, at the same drying time, frozen storage for 1 and 2 months resulted in slightly lower (p < 0.05) water activities and moisture contents compared to the 0-month sample. This agreed with the fact that ice crystal growth can occur during frozen storage [14] and therefore slightly increased the cell damage. Nevertheless, all samples showed water activities in the range 0.55-0.61 and moisture content of 18.68-20.68% (w.b.…”

“…This suggested that for a relatively short time (2 months), frozen storage did not significantly increase the cell structure damage in the mangoes. As shown by Li, Zhao, Zhang, Xiao, Sablani, Qu, and Tang [14], mango frozen at −18 • C, which was in its rubbery state, showed only a slight ice crystal growth during the first two months of storage from the mean size of 120 to 136 µm.…”

“…Generally, the formation of ice crystals increases the porosity of structure and therefore enhances moisture removal during drying. Li et al [14] reported an approximately 5-13% drip loss in mango after frozen storage at different temperatures for 6 months. However, a study on the effect of freezing and frozen storage on both mass transfer kinetics during the osmotic dehydration and drying kinetics during the hot air dying of mango has never been published.…”

Simple and efficient approach for shelf-life test on frozen spinach and parsley

“…Accordingly, ice crystals became bigger over the storage time, mainly at the highest frozen temperature. The thermodynamics of the ice crystal tends to create a bigger and more stable crystal more stable, but this causes damages to the food structure, which is generally recognized after thawing process (Fu and Labuza, 1997;George and Gormley, 2000;Roos, 2012;Li et al, 2020). Mechanical and thermal data describe physical properties of the products in different way, but they are connected and converge in the same thermodynamic modifications.…”

“…Storage temperature is the most widely used environmental factor in most research works carried out to estimate food shelflife. Indeed, tests are performed by studying a deterioration process at different temperatures (higher than real storage temperature), therefore, the measurement of the rate of quality depletion at higher temperatures makes it possible to extrapolate the reaction rate at a desired storage temperature and consequently to predict the shelf-life (Fu and Labuza, 1997;Martins et al, 2005;Correa et al, 2015;Li et al, 2020). Concerning the frozen foods, reported common temperatures for accelerated shelf-life testing are -5, -10, -15 and -18°C (Labuza and Fu, 1993;Fu and Labuza, 1997).…”