Effect of process variables on the osmotic dehydration of star-fruit slices

Abstract

The objective of this work was to study the effect of blanching and the influence of temperature, solution concentration, and the initial fruit:solution ratio on the osmotic dehydration of star-fruit slices. For blanching, different concentrations of citric and ascorbic acids were studied. The samples immersed in 0.75% citric acid presented little variation in color in relation to the fresh star-fruit. Osmotic dehydration was carried out in an incubator with orbital shaking, controlled temperature, and constant shaking at 120 rpm. The influence of process variables was studied in trials defined by a complete 23 central composite design. In general, water loss and solids gain were positively influenced by temperature and by solution concentration. Nevertheless, lower temperatures reduced water loss throughout the osmotic dehydration process. An increase in the amount of dehydrating solution (initial fruit:solution ratio) slightly influenced the evaluated responses. The process carried out at 50 ºC with a solution concentration of 50% resulted in a product with lower solids gain and greater water loss. Under these conditions, blanching minimized the effect of the osmotic treatment on star-fruit browning, and therefore the blanched fruits showed little variation in color in relation to the fresh fruit.

Ultrasonic modulated osmotic dehydration of Aonla ( Phyllanthus emblica L.) slices: An integrated modeling through ANN, GPR, and RSM

“…When the concentration of osmotic solution increases, the concentration gradient between the solution and the fruit, which drives the osmotic dehydration process, increases thus causing an increase in water loss and solid gain (Islam et al., 2019). The similar effect of concentration on WL and SG on different fruits has also been reported by Alam and Singh (2010), Campos et al (2012). The detrimental effect of US time and temperature on water loss could be possible because of high intensity of ultrasonication which might have caused excessive moisture intake in the aonla slices during the pretreatment.…”

Osmodehydration assisted by ohmic heating/pulse vacuum in apples (cv. Fuji): retention of polyphenols during refrigerated storage

“…The results show a slight increase in luminosity values for OD and OD/OH treatments compared to fresh samples. This increase can be explained due to sugars that increase the brightness in fruits (Campos et al ., ). However, luminosity was significantly ( P < 0.05) reduced in the vacuum‐pulsed samples (PVOD and PVOD/OH) compared to fresh and treated samples at atmospheric pressure, which were associated with the transparency achieved due to air loss in the vacuum pulse in which the air in the intercellular spaces was totally or partially substituted by osmotic solution (Castello et al ., ).…”

Influence of osmotic dehydration pre-treatment on oven drying and freeze drying performance

“…Total solids content (SS) was determined by direct reading using an automatic refractometer (Model J357, Rudolph Research Analytical, Hackettstown, NJ, USA). The solids gain (SG %) was calculated using the following equation (Campos, Sato, Tonon, Hubinger, & Cunha, 2012):…”