CJFST.2019.11.2.06

Original scientific paper                                                                                                                                                       DOI: 10.17508/CJFST.2019.11.2.06

Response surface methodology assessment of osmotic pre-drying and convective dehydration processes on the anti-oxidant property of Hausa variety of tomato

OBAFEMI IBITAYO OBAJEMIHI 1*, JOSHUA OLANREWAJU OLAOYE 1, MAYOWA SAHEED SANUSI 1, TIMOTHY DENEN AKPENPUUN 2, KAYODE MURITALA SALAWU 3 ADEOLA AKOREDE ASIPA 2 AND DANIEL OLUWASEGUN DIKKO 2

1Department of Food Engineering, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria
2Department of Agricultural and Biosystems Engineering, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria
3Department of Pharmacognosy and Drug Development, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria

ARTICLE INFO ABSTRACT
Article history:
Received: November 21, 2018
Accepted: July 18, 2019
This study was conducted to determine the effect of osmotic pre-drying treatment on the vitamin C content of Hausa variety of tomato. The tomatoes used were sliced to a uniform diameter of 10 mm, deseeded and then osmotically pre-treated with sugar and honey solution at different osmotic concentrations (20, 30, 40, 50, 60 °Bx), osmotic time (10, 20, 30, 40 and 50 min) and osmotic temperature (10, 20, 30, 40, 50 °C). Experimental design was done using the Central Composite Design (CCD) methodology of Design Expert software version 6.0.6. Drying of the samples was done at 65 °C in a cabinet dryer operating mainly on convectional heat transfer.  Drying process was completed and terminated when the samples reached their equilibrium moisture content between 3-5% after total drying time of 10 hours.  The data obtained were analysed statistically using analysis of variance (ANOVA) and regression analysis at p≤0.05 significance level. The developed model was significant and has goodness of fit with an R2 value of 71.29% and lack of fit test was insignificant at p≤ 0.05. Optimized process conditions for producing the best quality of tomato product with vitamin C content of 22 mg/100 g were 35.43 °Bx osmotic concentration, 11.10 min osmotic time and 23.86 °C osmotic temperature having a desirability function of 1. These conditions were considered to be advantageous as they were more economical, time and energy saving.
Keywors:
Hausa tomato variety
drying
vitamin C
sugar and honey solution