Multiple-optimization of the impregnation and dehydration of stone fruits

RODRÍGUEZ M.M.; ARBALLO J.R.; CAMPAÑONE L.A; MASCHERONI R.H.

Stellenbosch

Simposio; 7th CIGR International Technical Symposium "INNOVATING THE FOOD VALUE CHAIN" y 2nd International Conference on Postharvest Technology & Quality Management; 2012

Stellenbosch University

The objective of the present work was to optimize the osmotic dehydration of stone fruits using regressional-desirability function methodology. Each nectarine or plum was cut into 16 pieces and immersed into hypertonic solution with different osmotic agents (sorbitol and glucose). The experimental conditions were process time (15-120min), sugar concentration (40-60ºBrix), temperature (25-40ºC) and solution/fruit ratio (4-10); and the kinetic responses were water loss (WL), solid gain (SG) and weight reduction (WR). Modified second-order polynomial models for each response were obtained by multiple linear regressions from experimental data. Individual analyses were conducted for each osmotic agent and solution/fruit ratio. A complete solution algorithm for desirability function method was coded in Matlab® 7.2 (Mathworks, Natick, MA) with the purpose of maximize WL and WR and minimize SG. Applying the multiple optimization methodology the optimum conditions for nectarines were: process time of 120min, sugar concentration of 40ºBrix and depending the osmotic agent used temperature of 25ºC or 40ºC for sorbitol or glucose, respectively; and for plums: process time of 120min, sugar concentration of 40ºBrix and temperature of 40ºC; no differences were found in optimal conditions between treatments with different solution/fruit ratio.