Effects of different freezing methods on calcium enriched papaya (Carica papaya L.)

LOVERA, NANCY N.; RAMALLO, LAURA; SALVADORI, VIVIANA O.

JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE

ASSOC FOOD SCIENT TECHN INDIA

Año: 2018

0022-1155

The effect of calcium impregnation on drip loss,colour, mechanical properties, sensory perception andfreezing time on frozen-thawed papaya was studied, evaluatingdifferent freezing methods: cryogenic, tunnel andhousehold freezer freezing. Osmotic dehydration as pretreatmentwas also evaluated. Freezing in liquid nitrogenwas considered an inappropriate method for papayapreservation due to cracking. Calcium impregnation andosmotic dehydration increased tissue firmness anddecreased freezing time (freezing time for fresh, calciumimpregnated and osmo-dehydrated fruit was 23, 17 and5 min in a tunnel and 118, 83 and 60 min in a householdfreezer, respectively). Calcium lactate was the mosteffective way to protect tissue?s firmness before and after afreeze-thaw cycle (maximum stress values approx.300?400% of the raw tissue for tunnel freezing and 260%for household freezer). Microstructure analysis showedbetter tissue integrity retention in papaya samplesimpregnated with calcium lactate than in those with calciumgluconate, after a freezing?thawing cycle, in agreementwith the drip loss results. In spite of these results,consumers preferred frozen papaya without pre-treatmentor impregnated with calcium gluconate.