Moisture sorption isotherm and shelf-life prediction of anticaking agent incorporated spray-dried soursop (Annona muricata L.) powder

The moisture sorption isotherm (MSI) and shelf lives of soursop powders that had been incorporated with two commercial anticaking agents, calcium silicate (CS) and tricalcium phosphate (TCP), and inserted into aluminum laminated polyethylene pouches under room (RT, 25 +/- 1 degrees C) and elevated (ET, 38 +/- 1 degrees C) temperature, maintained at 93 +/- 1% RH, were investigated. The powder possessed a Type III Brunauer's classification isotherm curve. The monolayer moisture content (M-o) was 0.023 +/- 0.001 g H2O/g ds. A combination of low mean relative percent deviation modulus, E (2.18-3.75%), small sum of square residual, SSR (1.03 x 10(-5)-8.51 x 10(-6)), and high coefficient of determination (R-2 > .99) indicating the moisture sorption data was sufficiently good fit using GAB model. Powder without anticaking agent stored at ET has the shortest estimated shelf life (~86 days) while 1.0 g/100 g TCP stored at RT exhibited the longest shelf life (~316 days). This study demonstrated that the incorporation of anticaking agents is effective to maintain the quality of powder by extending the shelf life by lowering moisture adsorption. The acceptability of reconstituted soursop powder based on hedonic test showed the scores for all attributes were higher than six. Practical applications Up to date, limited information describes the preservative effect of anticaking agents throughout the storage period. Hence, this work provides an insight to look into detail of how the incorporation of anticaking agents improve or retain the quality of the dried powder especially the moisture sorption isotherm (MSI) behavior. To achieve this, enzymatic pre-treated spray-dried powder was incorporated with anticaking agent. MSI was carried out and the behavior was determined by fitting the data into Guggenheim-Anderson-de Boer (GAB) model. Prediction of shelf life was studied by considering the critical moisture content (X-c), which is the moisture content of powder that undergoes transition changed. The outcome of this work was expected to be beneficial to food powder industry to comprehend the protective effect of anticaking agents as a functional additive. Production of anticaking agent treated spray-dried soursop powder was expected to broaden its potential applications as functional ingredient.