65A-38

A. QUINTERO-RAMOS¹, M. Bourne², J. Barnard², R. González-Laredo³, A. Anzaldúa-Morales⁴, M. Pensaben-Esquivel³, and R. Márquez-Meléndez⁴. (1) Faculty of Chemistry, Universidad Autónoma de Chihuahua and Instituto Tecnológico de Durango, PO BOX 1542-C, Chihuahua, Chihuahua, 31320, Mexico, (2) Institute of Food Science, Cornell University, (3) Centro de Graduados e Investigación, Instituto Tecnológico de Durango, (4) Faculty of Chemistry, Universidad Autónoma de Chihuahua

In order to attend the growing demand on frozen vegetables; texture, as a major quality parameter has to be improved. Low temperature blanching represents a viable technology to achieve this. An additive effect on firmness of processed fruits and vegetables have been observed when calcium ions were used in combination with low temperature blanch. The objective of this study was to evaluate the effect of low temperature blanching in calcium chloride solutions to increase firmness retention in frozen carrot slices and to determine optimum conditions to provide a final product with the maximum firmness. Low temperature (65ºC) blanching in CaCl2 solutions (0.05, 0.13, 0.33,0.52 and 0.6 molar) for holding times (5, 17.45, 47.5, 77.55 and 90 min.) was performed on carrots and the uptake of calcium ions and firmness in frozen carrots was measured. The study was optimized using a second order rotatable central composite design and results were analyzed using response surface methodology. The calcium absorption was significantly affected (p*0.05) by the CaCl2 concentration. The behavior of this variable was adjusted adequately to a second order model (R²=0.99). The firmness showed as maximum extrusion force was affected ((p*0.05) by the CaCl2 solutions and holding times. The second order model explains adequately (R²=0.86) the variability in the data. The optimum conditions were obtained in a CaCl2 concentration range (0.04-0.258 molar) with holding times (0-60 minutes); getting an extrusion force of 1693-2095 N and calcium content levels of 69-144 mg/100 g. The optimum conditions were verified experimentally, and the obtained values agreed closely with those predicted in calcium absorption and firmness values. Adoption of this technology will permit processors to obtain high firmness products.