Optimization of the osmotic dehydration of carrot cubes in sugar beet molasses

Abstract

A Response Surface Methodology approach (RSM) was used to determine optimum conditions for the osmotic dehydration of carrot cubes in sugar beet molasses. Treatment times were set to 1, 3 and 5 h, at temperatures of 45, 55 and 65°C and molasses concentrations were 40, 60 and 80% (w/w). The used responses variables were: final dry matter content (DM), water loss (WL), solid gain (Sg), and water activity (aw). A Box and Behnken’s fractional factorial design (2 level-3 parameter) with 15 runs (1 block) was used for design of the experiment. DM, WL, Sg were significantly affected by all process variables (at 90-95% confidence level). The optimum conditions were determined by superimposing the contour plots, with the following response limiting values: DM 50-60%, WL 0.7- 0.8, Sg 0.08-0.09, and aw 0.84-0.86. The optimum conditions generated were: treatment time of 4h, temperature of 60°C, sugar concentration of 66% (w/w)

Sugar beet molasses: Properties and applications in osmotic dehydration of fruits and vegetables

“…often cause decreasing in nutritional and sensory quality of treated fruits and vegetables (loss of vitamins, changes in colour, altered taste and texture, bad rehydration) (Mišljenović et al, 2011).…”

“…Adopted from Filipčev and Lević (2014) Considering the cell membrane is not perfectly selective, other solutes present in the cells can diffuse into the osmotic solution (Mišljenović et al, 2011). For fruits and vegetables dehydration, the most commonly used osmotic agents are sucrose and sodium chloride and their combinations.…”

“…The most commonly used hypertonic solutions in the processes of osmotic dehydratation are concentrated solutions of sucrose, NaCl or their combinations (Mišljenović et al, 2011). Recent research data have shown that use of sugar beet molasses as hypertonic solution improves osmotic dehydration processes.…”

“…Sugar beet molasses is an excellent medium for osmotic dehydration, primarily due to a high solid content (80%, w/w), liquid aggregate state, and specific nutrient content: 51% saccharose, 1% raffinose, 0.25% glucose and fructose, 5% proteins, 6% betaine, 1.5% nucleosides, purine and pyrimidine bases, organic acids and bases; which subsequently results in a high osmotic pressure of the solution. From nutrient point of view, an important advantage of sugar beet molasses as a hypertonic solution is its ability to enrich the treated food material with minerals and vitamins, which penetrate from molasses into the plant tissue (Mišljenović et al, 2011). From technological point of view, the main asset of molasses would be its liquid state and high solid content since this ensures advance in comparison to, for example, usage of high concentration sucrose solutions which is associated to numerous problems such as slow dissolution of sucrose and its continuous recrystallization during the process (Filipčev and Lević, 2014).…”

Drying of Gelidium sesquipedale (Rhodophyta) Under Microwave Irradiation: Study of Thermal and Kinetic Aspects of the Drying Process

“…Over the years, the drying is performed by various methods: by convection of preheated air (Karathanos & Belessiotis, 1997;Toǧrul & Pehlivan, 2004) direct solar drying (Yaldiz & Ertekin, 2001;Doymaz, 2005;Vijaya Venkata Raman et al, 2012), drying by irradiation (Rodríguez et al, 2005;Zhang et al, 2006;Bilbao-Sàinz et al, 2006;Giri & Prasad, 2007), by freeze-drying (Graciela et al, 1993;Burgschweiger & Tsotsas, 2002;Kettner et al, 2006), under fluidized bed (Soponronnarit et al, 1997;Kannan & Subramanian, 1998;Syahrul et al, 2002), by osmotic dehydration (Raoult-Wack, 1994;Simal et al, 1997;Della Rosa & Giroux, 2001;Ozen et al, 2002;Mišljenović et al, 2012), etc. Currently, through continuous improvement, the thermal drying is one of the industrial operations that consume the most energy and the dehydration process is significant in the worldwide energy industry.…”