Sweetpotato (SP-30) Flakes: Process Optimization and Moisture Adsorption Isotherm Studies

Julie  D. Tan,; Daniel Leslie  S. Tan,; Adrian  C. Alumbro,

Sweetpotato (SP-30) Flakes: Process Optimization and Moisture Adsorption Isotherm Studies

Julie D. Tan | Daniel Leslie S. Tan | Adrian C. Alumbro

Abstract:

Sweetpotato is one of the predominant crops grown by local farmers in the marginal uplands of Brgy. Linao, Sitio Batuan, Inopacan, Leyte. The need to produce quality food products from sweetpotato is a continuing challenge to open new opportunities for farmers and entrepreneurs alike. This study aimed to determine the potential of sweetpotato var.SP30 for flake production and conduct moisture adsorption isotherm studies.Two screening processesweremadeusing the 7-variable 8-run Plackett-Burman design while a face centered Central Composite Design (CCD) was employed during optimization. Sensory evaluation results were subjected to response surface regression (RSREG) analyses to generate optimum processing condition(s). Moisture adsorption studieswere carried out to determine the nature of the product isotherm based on Brunauer-Deming-Deming-Teller (BDDT) classifications. Fitting of datawas done using the Bruanauer-Emmett and Teller (BET) and Guggenheim-Anderson de Boer (GAB) models to determine the amount of adsorbedmoisture inthe product during storage at different temperature levels. Screening results identified Drying time (Dt), Drying Temperature (DT) and Oven Toasting time (OTt) as the critical processing variables. A set of combinations of Dt (min.), DT ( C), and OTt (min.) were generated as a result of the optimization. These o combinationswere 75-50-20, 80-50-20, 80-50-18, 85-50-20 and 90-50-20. Calculated values for the mass fraction of adsorbedwater in the monolayer (W andW ) at 30 C, mB mG o 40 C and 50 C are 0.0971, 0.1311, 0.0591 and 0.1046, 0.2447 and 0.2224 respectively o o (expressed in g/100gH O) 2 Sweetpotato (var. SP30) was found suitable for flake production. Moisture adsorption isotherm of sweetpotato flakeswas sigmoid in shape and classified as type II in the BDDT classification.W values for both BET and GABwere found to followthe m relationshipW

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