Study of the application of edible coatings and different osmotic dehydration conditions on pear cubes

SOTERAS, E.M.,; RODRIGUEZ, ANABEL; CAMPAÑONE, L.A.

Congreso; 11th World Congress of Chemical Engineering; 2023

The objective of the present work is to evaluate the effect of different coating materials and osmotic dehydration process conditions on mass transfer and quality of pear cubes. The fruits were treated with edible coatings of alginate (sodium alginate 2 % w/w - calcium lactate 5 % w/w) and pectin (low methoxyl pectin 3 % w/w- calcium lactate 5 % w/w). They were subjected to different osmotic dehydration conditions (temperature: 20 °C and 40 °C and time: 1, 2, 4, 8 and 16 h) in glucose syrup solutions and sucrose solutions (40 °Brix and 60 °Brix). In order to evaluate the barrier property of the edible coatings against solid ultake, the dehydration performance (WL/SG) at the end of the process was calculated and the physicochemical parameters of the final product (weight loss (WR), water loss (WL), solids gain (SG), color difference (DC) and firmness (N)) were evaluated. The results showed that the application of the coatings significantly improved weight loss and water loss under all conditions studied. Besides, it could be observed that at low temperature (20°C) and concentration of the solutions (40 Brix) and during at least 16 h of processing, the edible coatings did not act as a barrier to solids. However, when high temperature (40°C) and concentration (60 Brix) were used, it was observed that the coated samples showed better dehydration performance (DR) compared to the uncoated samples, with the pectin coating showing the best barrier behavior against solids uptake (Table 1). On the other hand, the best dehydration yields were obtained when the lowest molecular weight osmotic agent was applied, which shows a clear barrier property of the coatings, knowing that the lower the molecular weight of the osmotic agent, the easier it is for the molecules to penetrate into the fruit. Based on these results, it was possible to define those conditions (glucose syrup 60 °Brix at 40 °C and pectin coating) that allowed a high yield of dehydrated pear cubes without excessive absorption of solids, with a smaller difference in color compared to fresh fruit and a good preservation of firmness.