Effect of Different Sugars on Mass Transfer and Cell Integrity of Osmo-Dehydrofrozen Garden Egg

Abstract

Fast freezing methods like osmotic dehydrofreezing (ODF) have gained tremendous research interest worldwide. Meanwhile, plant cell structures are often altered when exposed to hypertonic sugar solutions during the ODF process. This study investigated the effect of different sugars on mass transfer, and cell integrity of garden eggs that were frozen using ODF. Garden egg slices, with dimensions of 1 × 1 × 1 cm, were pretreated with sucrose and glucose solutions in a water bath at osmotic solution concentrations and temperatures of 55 and 65oBrixand 30 and 35°C, respectively for 10 minutes. The treated and untreated (control) samples were frozen at -12 oC. The effects of the pretreatment on mass transfer indices, including water loss, solid gain, and drip loss, were observed using standard methods. A scanning electron microscope (SEM) was employed to study the effect of sugar-induced ice crystal imprints on the microstructure of optimized osmo-dehydrated frozen samples. The results showed that sucrose solution at 65 oBrix and solution temperature of 35oC significantly (P ≤ 0.05) decreases drip loss by 91%, whereas glucose solution at the same premixes decreases drip loss by 28% when compared with the untreated samples. In addition, samples treated with sucrose solution showed lower water loss and higher solid gain and exhibited stable cells when compared with the samples treated with glucose solution and untreated ones. In conclusion, sucrose solution is the most suitable for the osmodehydrofreezing of garden egg for the food industry.