Changes in liquid phase and mechanical properties during osmodehydrofreezing of papaya (carica papaya L.)

Abstract

The aim of this study was to evaluate the influence of osmotic treatments on the freezing rate, drip loss (DL), elastic modulus (EM) and stress of yield limit (σL) of papaya (Carica papaya L.) samples stored under freezing conditions. Dehydration was performed using an osmotic sucrose solution with 55 and 45 ºBrix for 30 and 90 min. Osmotically dehydrated papaya samples were frozen at -40°C and stored for 10, 20, 30 and 60 days. Fresh fruit was used as a control sample during freezing storage. The results showed the treated samples exhibited lower drip loss with respect to control samples. It was observed that elastic modulus in treated samples showed higher values compared to control samples. Conversely, σL had achieved a decreasing for all treatments during freezing storage and treated samples exhibited higher σL values with respect to control samples.Keywords: Osmotic treatment; freezing; tropical fruits; osmotic solution Cambios en fase líquida y propiedades mecánicas de papaya (carica papaya L.) osmodeshidratada durante la congelacion Resumen El objetivo de este trabajo fue evaluar la influencia de tratamientos osmóticos sobre la velocidad de congelación, pérdida de fase líquida (PFL), módulo elástico (ME) y esfuerzo del límite de fluencia (σL) en muestras de papaya (Carica papaya L.) almacenadas en congelación. La deshidratación se realizó con soluciones osmóticas de sacarosa de 45 y 55°Brix durante 30 y 90 min. Las muestras osmo-deshidratadas fueron congeladas a -40°C y almacenadas durante 10, 20, 30 y 60 días. Fruta fresca fue empleada como muestra control (No tratada). Los resultados mostraron que las muestras tratadas presentaron menores pérdidas de fase líquida respecto a las muestras control. El módulo elástico en las muestras tratadas presentó mayores valores en comparación con las muestras control. El esfuerzo del límite de fluencia disminuyó para todos los tratamientos durante el almacenamiento y las muestras tratadas mostraron valores superiores de σL respecto a las muestras no tratadas.

Osmodehydrofreezing: An Integrated Process for Food Preservation during Frozen Storage

“…As partial removal of water, especially from plant tissues, induces the concentration of cytoplasmatic components, the depression of the freezing point, the increase of supercooling, and microcrystallization, as well as a significantly lower proportion of ice crystals to the unfrozen phase, damage of cellular integrity as well as drip loss, caused by freezing, is expected to be substantially decreased. In [ 101 ], it was found that papaya samples, pretreated with 45 and 55% sucrose for 90 min (at room temperature) exhibited lower drip loss with respect to control samples, when stored at −40 °C for a period of up to 60 days. The beneficial effect of OD pretreatment on thawed broccoli and radish drip loss was also confirmed in [ 66 ] and [ 80 ], respectively, especially when ultrasound was additionally applied.…”

“…As partial removal of water, especially from plant tissues, induces the concentration of cytoplasmatic components, the depression of the freezing point, the increase of supercooling, and microcrystallization, as well as a significantly lower proportion of ice crystals to the unfrozen phase, damage of cellular integrity as well as drip loss, caused by freezing, is expected to be substantially decreased. In [101], it was found that papaya samples, pretreated with 45 and 55% sucrose for 90 min Regarding texture retention during frozen storage, the shelf life study showed that osmodehydrofrozen compared with conventionally frozen sliced cucumbers, strawberries retained their firmness for prolonged storage period [33,60]. In [40], it was demonstrated that, after a year of storage, the firmness of samples pretreated with high dextrose equivalent maltodextrin (HDM), oligofructose, and the mixture of oligofructose/trehalose was about 18-75% higher than the corresponding values of the untreated tomato samples, although, in all cases, texture was observed to rapidly degradate.…”