The overall objective of this research was to evaluate the effect of pretreatment, chemicals during preparation, frying condition (frying temperature: 90, 100 and 110 {u00BA}C and frying time: 30, 45 and 60 minute) and frying method (vacuum frying and induction heating) for the production of pineapple chips. The quality of pineapple chips were investigated by determining their physiochemical properties (moisture cont ent, oil content, color and texture) and performing a sensory evaluation. In the pretreatment study, it was found that moisture content of pineapple without pretreatment and freezing at - 10 {u00BA}C before frying were not significantly difference but differ fr om pineapple with drying at 60 {u00BA}C . The product from pineapple without pretreatment had the highest oil content . Color of pineapple chips in term of L, a and b value were significantly difference (P<0.05) at every pretreatment before frying. Pineapple chips from pineapple without pretreatment had the highest hardness but pineapple with drying at 60 {u00BA}C had the lowest hardness value from all pretreatment. Frying condition of pineapple chips affected the quality of the products. Increasing frying temperature and frying time reduced moisture content, L value and hardness. When frying temperature decreased and frying time increased, oil content increased. a value and b value increased as frying temperature and frying time increased. Sensory evaluation showed tha t the best pretreatment and condition of vacuum fried pineapple was pineapple with drying at 60 {u00BA}C before frying and then frying at 60 {u00BA}C for 45 minute because it obtained the highest value of overall acceptability . The effect of different chemicals duri ng preparation and frying in the best preparative condition were not significantly difference in the properties such as moisture content, oil content and color (L, a and b value) . Pineapple treated with Na 2 SO 3 during preparation also had the highest score of overall acceptability from sensory test. The effect of deep frying and induction assisted frying at 2, 3 and 4 minute showed result that all properties of pineapple chips were not significantly difference (P<0.05) but it known that induction heating a ssisted frying needed less preheat time for oil than deep fryer containing 500 ml of palm oil (3 and 6 minute, respectively). The panelists accepted the pineapple chips at 3 minute of frying time at the same temperature (160 {u00BA}C) of two frying methods . A study of the polarity of the oils showed that all frying oil could be reused about five times after which the polarity exceeded acceptable levels.

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineeri ng and Bioprocess Technology, School of Environment, Resources and Development

Thesis (M. Sc.) - Asian Institute of Technology, 2010