Preservation of tempoyak

This research project is to determine the effect of pressure treatment process and the effects of natural and synthetic additives in the fermentation of tempoyak, a Malaysian condiment made from bad or spoiled fruit called Durian. Several knowledges need to be established in molecular techniques in food fermentation especially in its principles and applications. The ecosystem that occurs in molecular level in food is not static. Due to changes in the surroundings and the shifting of the environment’s parameters such as temperature, pressure, light intensity and pH changes cause stress reactions on the dynamics of growth and biochemical activity of the bacterias present in the food, thus affecting its shelf life are the main concern. Quality changes including overall sensory analysis, colour and absorbance of O-H and primary alcohol were monitored for every 3 days of testing for a total 30 testing days. In order to pass the overall sensory evaluation, a set of tempoyak samples must pass a minimum of 6 points on a 9-points scale by at least 15 panelists. Due to concern of altering the taste and texture of the tempoyak sample during the study, only non-taste altering ingredients such as turmeric oil, rosemary extracts, vitamin C and butylated hydroxytoluene (BHT) will be used. 0.1g of each additives are added to every 10g of tempoyak and compared to standard, stored at 4⁰C and 25⁰C (ambient temperature). Some of the samples are exposed to light while some will be kept in the cupboard with very limited light exposure. Since heat treatment is not the focus in the inactivation of microorganisms in tempoyak , potential alternative such as Ultrahigh pressure (UHP) processing is studied on tempoyak to detemine its effects on the textural changes, flavor and retention of nutrients ovetime, thus its overall shelf life prolongation. Pressure of 600 MPa offers a good stress in the inactivation of bacterias and high food spoilage pathogens while leaving many flavour and vitamins intact. Currently, there are very limited reasearch done on the shelf life of tempoyak while if there is, some mentioned that without refrigeration, adequate seasoned tempoyak with salt or sugar can only lasts up to 4 months. With the addition of natural additives mentioned above, it is expected that the shelf life of tempoyak could be of at least 5-6 months. UHP may offer a significant improvement in the shelf life prologation, possibly up to 1 year before it is rotten and must be discarded or turn it into compost.