Accelerated shelf life testing of mocatilla chip using critical moisture content approach and models of sorption Isotherms

Abstract

Mocatilla is a tortilla chip made from composite flour consists of modified cassava, corn, and rice flour which is enriched by tempeh. This study aimed to estimate the shelf life of mocatilla chips when packed in polyethylene terephthalate (PET), polypropylene (PP), and aluminum foil (alufo) using the Accelerated Shelf Life Testing (ASLT) method by the critical moisture content approach. The study was conducted by determining the initial, critical, and equilibrium moisture content of the sample by thermogravimetry. Six models of moisture sorption isotherm were fitted to determine the equilibrium moisture content using six salts with relative humidity (RH) values at a range of 0.076-0.903. The result showed that the initial and critical moisture content of mocatilla chips (g H2O/g solid) was 0.0141 and 0.0532, respectively. Meanwhile the equilibrium moisture content at relative humidity 80% and temperature 30°C was 0.1471. The Guggenheim Anderson de Boer (GAB) equation was the most suitable model for describing the sorption isotherm phenomenon of mocatilla chips. Based on Labuza’s equation, the shelf life prediction of mocatilla chips (80% RH, 30°C) packed in PET, PP, and alufo was 3, 8, and 62 months, respectively.