The melting point of a fat also affects the ability of manufacturers to work with the fat during the production process. In a transfat-free world, you get a mixture of high melting point fractions and liquid oil, giving a higher melting point and a tendency toward softer products. Perhaps the most important phenomenon, however, is the slower crystallization speed of trans fat alternatives. sistency by varying temperatures from, for example, 21 degrees for the first 5 days then reducing to 16 degrees thereafter. For some, new pre-storage facilities that can enable the required temperature control may be required. CRYSTALLIZERS AND EMULSIFIERS SLOWER CRYSTALLIZATION, LOWER CAPACITY Generally, manufacturers simply cannot produce as much margarine from the same production lines as before. Process parameters require adjustment to handle slower crystallization, and most often, investments in new tube chillers are demanded or, for example, the combination of two machines where only one was needed before. Whichever route is chosen, final product quality just won’t be the same. Lower production capacity is one effect of slower crystallization. Another is that crystallization continues to develop for longer than the usual 24 or so hours during pre-storage, changing its structure over an extended period of time and resulting in a more brittle product. Storage, therefore, and storage temperature variations, have a much greater effect. In pre-storage, an attempt might be made to to reduce brittleness and ensure con- Manufacturers now need to come up with trans-fat-free recipes that give margarine’s batch-by-batch quality the best possible chance of success. Our research and experience indicates that crystallizers can do much to ease the production process. To discover how they can help, we examined how various process parameters affect the speed and nature of crystallization for puff pastry margarine. When chilling begins in the margarine production process, the first crystals appear, creating a ‘seat’ for more to build upon, finally arriving at a much firmer mass that must be broken down somewhat, restoring plasticity. To tackle this problem, we used one of our pilot plants to start the seating earlier in the process, allowing more time in the machine to reduce post-crystallization. Longer time in the equipment, however, means greater effect from the pin machine and the following tube chillers, resulting in a quite different product. Our trials compared hydrogenated, interesterified fat, and non-hydrogenated fat in puff pastry margarine. Hydrogenated fat performed best, crystallizing quickly. Far slower to crystallize, non-hydrogenated fats such as palm oil performed worst. In fact, both before and after the pin machine the latter was hopelessly overworked, and would be impossible to pack or, for that matter, to eat. The interesterified fat medium crystallized well, but again was all too easy to overwork. THE SOLUTION OF CHOICE A key aim is to determine a crystallizer whose melting point makes it easy to use in production. We found this can be achieved with steric acid (18), combined with behenic acids. Tribehenic and monobehenics have the most extreme melting points for crystallizers. Other triglyceride compositions, on the other hand, with behenic acids can produce a lower melting point, making them easier to handle in production. Any of these acids can easily be purchased, but constructing such triglycerides is no walk in the park. Locating the behenic acids in the right place on the chain requires more than a little expertise! The melting points of various fatty acids, triglycerides and crystallizers can be seen in Table 1. Table 1: Melting points of fatty acids, triglycerides and crystallizers TRIVIAL NAME C12:0 C14:0 C16:0 C18:0 C22:0 C18:1 n-9 cis C18,1 trans C18:2 n-6 cis C18:3 n-3 cis Lauric acid Myristic acid Palmitic acids Stearic acids Bebenic acids Oleic acid Elaidic acid Linoleic acid Linolenic acid MELTING POINT 44.4°C (112°F) 54.4°C (130°F) 62.7°C (145°F) 69.4°C (157°F) 80°C (176°F) 16.1°C (61°F) 43.8°C (111°F) -6.6°C (20°F) -12.7°C (9°F) TRIVIAL NAME Trilaurin Trimyristin Tripalmetin Tristearin Tribehenic Crystallizer : C22 –C18 Crystallizer : C16 –C18 Crystallizer : C16 –C18-C22 Crystallizer : C18 MELTING POINT 46.1°C (115°F) 55°C (131°F) 65°C (149°F) 72.2°C (162°F) 82.2°C (180°F) 61.1°C (142°F) 57.2°C (135°F) 58.8°C (138°F) 72.2°C (162°F)
Del
Print
Download PDF fil
