THE EFFECT OF ACIDIFICATION AND PASTEURIZATION ON SHELF-LIFE OF VACUUM-PACKAGED TEMPE AT ROOM TEMPERATURE

Abstract

Tempe is a traditional Indonesian fermented soybean product characterized by its high protein content and relatively low production cost. Despite its notable nutritional value, fresh tempe has a very limited shelf life of approximately two days at room temperature, which poses a significant challenge to its wider distribution and commercialization. This study aimed to extend the shelf life of tempe through the application of hurdle technology, combining three preservation methods, which were acidification, vacuum packaging, and pasteurization. The study was divided into three stages: tempe acidification (immersion in a 6% glucono delta lactone solution for 90 and 105 minutes), pasteurization of the acidified and vacuum-packaged tempe (80°C for 20 and 25 minutes), and storage of the pasteurized tempe at room temperature for 8 days. During storage, observations were conducted at 2-day intervals to measure pH, hardness, total plate count (TPC), and sensory attributes by hedonic testing. Acidification decreased the tempe pH to 4.47 ± 0.07 (90-minute immersion) and 4.67± 0.32 (105-minute immersion). No significant differences were found between the two immersion durations. The acidified tempe remained sensorially acceptable; therefore, the shortest immersion was selected to proceed to the next stage. Pasteurization for 20 and 25 minutes yielded pasteurization values of 3.8 minutes and 9.4 minutes, equivalent to a reduction in Bacillus subtilis counts of 1.2log and 3.1log cycles, respectively. During storage, the pasteurized tempe showed no significant changes in pH, hardness, or TPC, indicating that both pasteurized tempe remained stable throughout the storage period. Based on the hedonic test, tempe that underwent acidification and pasteurization treatment had a shelf life up to 6 days, compared to only 2 days for the control tempe, at room temperature.