Effect of freezing with oscillating magnetic fields on the physical and sensorial characteristics of mango (Mangifera indica L. cv. ‘Kent’)

Efeito de congelamento usando campos magnéticos oscilantes nas características físicas e sensoriais de manga (Mangifera indica L. cv. ‘Kent’)

Abstract

Freezing using oscillating magnetic fields (OMF), was developed and is marketed to overcome drawbacks that normally occur in conventional freezing, which affect firmness, colour, taste, and drip loss in frozen-thawed foods. In order to verify the aforementioned advantages, the effect of freezing using OMF on cubes of mango (Mangifera indica L. cv. ‘Kent’) was evaluated. The cubes were frozen at -30 °C for 35 min with OMF set at 0, 30%, 50%, 75% and 100%, and then immediately thawed at room temperature (25 °C) for 70 min. The frozen-thawed mango cubes showed cell wall breakage, presumably due to the formation of ice crystals. Likewise, the frozen-thawed cubes were less firm (p < 0.05) than fresh mango cubes (with both cubes having come from the same specimen), as determined using a texturometer and sensory evaluation. Drip loss ranged from 2.45% to 4.15% in the frozen-thawed mango. Freezing using OMF with a Cells Alive System (CAS) freezer caused negative changes to the thawed mango, mainly a decrease in firmness, with results similar to those reported elsewhere using conventional freezing.

Keywords:
Fruit; Freezing; Oscillating magnetic fields; Firmness; Histology