Reuse of Sucrose Syrup in the Osmotic Dehydration of Peaches

Abstract

The objective of this work was to determine the technical feasibility of reusing sucrose syrup during the osmotic dehydration of peaches combined with hot air drying (OD/HD). Two trials using different reconditioning methods were carried out over 15 OD/HD cycles, using new syrup in the first cycle and reconditioned syrup in the following ones. The first method consisted of sieving, vacuum concentration, and syrup replacement. The second included filtration through diatomaceous earth. After OD (65°Brix/50°C/4 h), the fruits were dried using a forced air dryer (65°C). The OD parameters of water loss and solids incorporation were evaluated, and physical, chemical, and microbiological analyzes were carried-out on the raw material, syrup, and products. Sensory tests were carried-out using the difference from control method. For both methods, the syrup showed increases in titratable acidity, electrical conductivity, and reducing sugar content over the cycles, but the pH decreased. The syrup turbidity increased without filtration, but for both methods the reconditioning process had no effect on the OD parameters or microbiological load. Both reuse methods favored maintenance of the yellow color of the dried peach and did not influence the flavor and sensory texture.

Keywords:

• Microbial stability
• Osmotic solution
• Prunus persica (L.) batsch
• Reconditioning
• Sensory analysis

ACKNOWLEDGMENTS

The authors are grateful to the Brazilian Agricultural Research Corporation (EMBRAPA) for the scholarship and support and to Sigmagropesquisa and the Holambra Agro-industrial Cooperative for their collaboration and support.

Notes

^a  F =raw fruit; PD₁ = predried fruit from trial 1; PD₂ = predried fruit from trial 2.

^b S _{i 1} = initial syrup of trial 1; S _{i 2} = initial syrup of trial 2.

Means for the same parameters followed by the same letters in the same column (comparison between cycles) do not differ significantly (p > 0.05) according to ANOVA.ns = not significantly different.

^a Estimated count quantification limit of the method.

Means followed by the same letter in the same line (same trial) do not differ significantly (p > 0.05) according to ANOVA.

Means corresponding to “similar to the standard” according to the attributes: appearance (3), color (4), texture (4), flavor (5). ns = not significantly different.