ABSTRACT
I. Introduction ......................................................................................................................... 494 II. Effects of Processing on Fatty Acids ................................................................................... 494 A. Oilseed Processing ......................................................................................................... 495 a. Seed Selection and Cleaning .................................................................................... 495 b. Drying and Storage of Raw Materials ...................................................................... 495 c. Dehulling and Grinding, Rolling, or Flaking ........................................................... 495 d. Cooking .................................................................................................................... 496 e. Extraction ................................................................................................................. 496 f. Miscella Stripping .................................................................................................... 497 g. Degumming .............................................................................................................. 497 h. Caustic Re+ ning ....................................................................................................... 498 i. Bleaching .................................................................................................................. 499 j. Physical Re+ ning ..................................................................................................... 499 k. Hydrogenation .......................................................................................................... 499 l. Deodorization ........................................................................................................... 501 B. Animal Fat Processing ................................................................................................... 501 a. Rendering ................................................................................................................. 501 b. Caustic Re+ ning ....................................................................................................... 501 c. Bleaching .................................................................................................................. 501 d. Physical Re+ ning ..................................................................................................... 501 e. Hydrogenation .......................................................................................................... 501 f. Oil Modi+ cations ..................................................................................................... 502 C. Fish Oil Processing ........................................................................................................ 502 III. Effects of Storage on Fatty Acids ........................................................................................ 502 IV. Undesirable Changes in Fatty Acids that Occur during Processing and Storage ................ 503 A. Oxidation ........................................................................................................................ 503 a. Autoxidation ............................................................................................................. 503 b. Photooxidation ......................................................................................................... 504 B. Hydrolysis ...................................................................................................................... 505 C. Isomerization .................................................................................................................. 505 V. Antioxidants and Metal Chelators in Fat and Oil Processing ............................................. 505 VI. Summary and Conclusion ................................................................................................... 506 References ................................................................................................................................... 507
The goal of commercial oil or fat processing is to obtain the maximum possible yield of oil or fat from the oil-bearing material while maintaining high quality and nutritive value eliminating undesirable impurities, and retaining desirable components (e.g., tocopherols) that may be present (Carr, 1989). The + nished product normally consists of 98%–99% triacylglycerols and is odorless, bland, and oxidatively stable (Carr, 1989; Jung et al., 1989).
