Crystallizers: The crystalclear answer to trans fat-free

Transcription

1 Crystallizers: The crystalclear answer to trans fat-free margarine production Palsgaard has examined how crystallizers can step in to fill the production performance gap left by slowly crystallizing, trans fatty acid-free margarines. By Anders Mølbak Jensen, Product & Application Manager, Lipid & Fine Foods Palsgaard A/S. PUBLIC ENEMY: TRANS FATS For the origins of the fight against partially hydrogenated fats and the trans fatty acids they produce, we have to go back to the early nineties. That s when a famed Harvard Medical School paper was released, reporting the results of a long-term epidemiological study that tracked, among other factors, the dietary habits of almost 8, female nurses. The study was considered by many to be a landmark in the fight against coronary disease. The Harvard research team, led by Dr. Walter Willett, arrived at a number of eye-opening conclusions, one of which is that trans fats present a significant health risk, with higher risks of cardiovascular disease already registered at daily trans fatty acid intake levels of just 5 to grams. Further research has pointed to an ability of saturated fat and trans fats to raise the level of Low Density Lipoprotein Cholesterol (LDL) in the blood. Excess LDL particles are deposited in the arteries, lead- ing to hardening of the arteries and heart disease over time. Simultaneously, trans fats appear to decrease High Density Lipoprotein Cholesterol (HDL), further increasing the risk of heart disease. Other studies have indicated that a high intake of saturated fats and trans fats promotes insulin resistance, too, threatening consumers with Type diabetes. INSTANT EFFECT ON THE INDUSTRY The impact of the Harvard study, and follow-up research, on the food

2 industry was powerful and, at least in Europe, instantaneous. Danish consumers, for example, reacted quickly, slashing their purchases of margarine by around 5% almost overnight, and butter grabbed new market share. Legislators moved almost as quickly, and since in Denmark, for example, oils and fats used in food products have been permitted a maximum of % trans fat content (excepting oils and fats of animal origin). For European margarine manufacturers, the message was clear: something needed to be done to reduce their recipes content of hydrogenated fats and restore consumer confidence. The US, on the other hand, has been somewhat slower to react, though it introduced mandatory labelling for trans fats in. Most recently however, in June 5, the FDA has finalised a determination that trans fats are not generally recognized as safe, and set a three-year time limit for their removal from all processed foods. Of course, the ban needs to be seen in the light of an 85% reduction that has been gradually achieved by the industry over the past years, mainly due to the mandatory labelling, but the writing is clearly on the wall for US manufacturers: It s simply not enough. So, while the industry is pushing to have very low amounts of trans fats allowable in, for example, the sprinkles on cupcakes or cookies, manufacturer focus is now on tuning recipes to deliver unaltered product quality in an uncompromising new, trans fat-free landscape. LIFE WITHOUT TRANS FATS No trans fats on your new ingredients list? Congratulations: life as a production manager at a margarine manufacturer is about to get much more interesting. Partially hydrogenated oils have long enabled margarine to step up to the plate, forming more stable products and supporting mouthfeel to deliver an eating experience not far from that of butter. And their positive effect on shelf-life is well documented, too. Without trans fats, it s much more difficult to consistently produce high-quality margarine. In fact, every part of the production process becomes more sensitive to a variety of factors that were comfortably, even transparently, handled by partially hydrogenated oils in the past. HIGHER MELTING POINT One such factor is the higher melting point of other fat types. For optimum flavour release, it s best to use fats that melt at approximately mouth temperature: around 35 o C (95 o F). In the old world, trans fats fitted the bill perfectly. In the new one, the only economically feasible, readily available fat type is palm oil, fractions of palm oil, or interestified fat types. That said, the melting point of palm oil is still a little higher than that of trans fats, and it lacks comparable functionality. Not only that, but in the US, and for reasons that may be difficult to pin down, the use of tropical oils has long been given the cold shoulder. So palm oil isn t a viable option in that part of the world. The melting point of a fat isn t just important for the consumer s eating experience, it also affects the ability of manufacturers to work with the fat during the production process. In a trans fat-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, for margarine manufacturers to think about is the slower crystallization speed of trans fat alternatives and this brings us to the particular focus of this paper. FACT BOX: The effect of trans fatty acid reduction Higher melting point Slow crystallization of the fat types Easier to overwork the fat product Post crystallization Change structure over time Storage: more sensitive to temperature variations THE EFFECTS OF SLOWER CRYSTALLIZATION A lot has been done to address slow crystallization issues, but generally, manufacturers are simply unable to produce as much margarine from the same production lines as before. Process parameters, including machine settings, need to be adjusted to cope with the slower crystallization, and most often, investments in new tube chillers are demanded or, for example, the combination two machines where only one was needed before. Whichever route was chosen, final product quality just isn t the same as that of trans fat-containing recipes. Without trans fats, for example, margarine begins to crystallize on the tube chiller shaft, reducing production capacity by perhaps % from morning to afternoon, as there is gradually less volume to work with. Flushing the tube with heat to restore capacity is one way to fix the problem, but has its own set of drawbacks and can t be recommended. Lower production capacity is one effect of crystallization. Another is that, due to the slower crystallization speed of alternative fats, crystallization continues to develop for longer than the usual or so hours during pre-storage, changing its structure over an ex-

3 tended period of time. So you re likely to end up with a more brittle product than you re used to. Storage, therefore, has a much greater effect on the final product and storage temperature variations introduce further sensitivity to recrystallization. Pre-storage, therefore, seldom the focus of a margarine production process in the good old trans fat days, has suddenly taken on new significance for the final product s quality. Now manufacturers need to focus on pre-storage during the first 5 to 7 days following production, making this aspect part of the overall production process. For example, an attempt might be made to to reduce brittleness and ensure consistency by varying pre-storage temperatures from, for example, degrees for the first 5 days then reducing to degrees thereafter. One implication for many manufacturers is the need to invest in pre-storage facilities that can enable the required temperature control. Slower crystallization, therefore, is a manufacturer s nightmare, imposing both immediate limitations on total production capacity and gradually reduced capacity during production days due to crystallization buildup on chiller shafts. Non-hydrogenated products will have a slower crystallization speed, and interestified products have a tendency to become overworked and very soft. IN STEP CRYSTALLIZERS AND EMULSIFIERS With widespread attention on the ill effects of trans fats, US food manufacturers and their European counterparts now need to come up with trans fat-free recipes that give margarine s batch-by-batch quality the best possible chance of success. likely to be carefully concocted combinations of crystallizers and emulsifiers. Crystallizers, in particular, can do much to ease the production process. And we ll take a thorough look at exactly how shortly. That said, crystallizers will not have significant influence on the longer-term storage phase, during which polymorph structure will make for a firmer margarine over time, an aspect that manufacturers will still need to give special attention to in their trans fat-free strategies. EXPLORING TRANS FAT-FREE PRODUCTION STRATEGIES To get to the bottom of the case for these ingredients as the toolbox of choice for food manufacturers facing the trans fat ban, we first needed to gain a better understanding of crystallization processes in margarine oils and fats. We were particularly keen to find out how various process parameters affected the speed and nature of crystallization. Equipped with this knowledge, we would then be able to properly examine the role played by emulsifiers in relation to crystallization, and to make recommendations to margarine manufacturers based on our findings. And we set the bar high: our tests would be conducted with one of the most difficult beasts in the business: puff pastry margarine. WHAT AFFECTS CRYSTALLI- ZATION IN MARGARINE AND SHORTENING? When chilling begins in the margarine production process, there are, at first, no crystals. Then the first crystals appear, creating a seat for more to build upon, finally arriving at a much firmer mass. This firmness needs to 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 time. Longer time in the equipment, however, means greater effect from the pin machine and the following tube chillers, resulting in a quite different product. In our trials, we compared hydrogenated, interesterified fat, and unhydrogenated fat in puff pastry margarine. Hydrogenated fat, as might be expected, performed best, crystallizing quickly. Far slower to crystallize, unhydrogenated fats such as palm oil clearly perform worst. In fact, both before and after the pin machine it 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. According to Palsgaard s application center research into the area, and our lengthy experience in the first-to-move European market, that particular something is most Liquid margarine with Palsgaard crystallizer Liquid margarine without Palsgaard crystallizer 3

4 CRYSTALLIZERS: THE SOLUTION OF CHOICE At Palsgaard, we ve determined the most effective strategy is to use crystallizers as a trans fat-free remedy. Tribehenate Mp o F Crystallizer Mp o F 3 5 These can be, for example: High in behenic acid (C) and steric acid (C8) High in steric acid (C8) and palmitic acid (C) Very high in steric acid (C8) Mixture of behenic acid (C), steric acid (C8) and palmitic acid (C) Reference 5 5 η in Cp The melting points of various fatty acids, triglycerides and crystallizers can be seen in Table. A key aim is to determine a crystallizer whose melting point makes it easy to use in production. This can be achieved with steric acid (8), combined with behneic acids. Tribehenic and monobehenics have the most extreme melting points for crystallizers. At 8 o F (8. o C), they cannot be handled in a normal production environment. If a pipe were to become blocked, for example, things would become very problematic. Despite this, and in the name of thorough research, we did attempt to use this acid in various recipes, but achieved the same or better results with other products. Other triglyceride compositions, on the other hand, with behenic acids can produce a lower melting point, making them easier to handle in production Figure : Crystallizing effect of crystallizer compared with tribehenate Any of these acids can easily purchased, but constructing these triglycerides using high melting point behenic acids yet ending up with something that has a significantly lower melting point is no walk in the park. Locating the behenic acids in the right place on the chain requires more than a little expertise! With these acid in the right positions, however, the melting point can be brought down to as little as degrees C instead of, for example, 8. CRYSTALLIZING EFFECT OF CRYSTALLIZER COMPARED WITH TRIBEHENATE Using Tribehenate Mp, with its 8 o C (8 o F) melting point, speeds up crystallization greatly in comparison with our reference (% palm oil, % palm stearin and % liquid soya oil without crystallizer), as can be seen in Figure. The Mp crystallizer we tested almost matches Tribehenate Mp s speed, but with a lower melting point of o C ( o F). Both solutions far outstrip the performance of the reference. The tests also revealed that using crystallizers forms more beta prime crystals, which have a better absorbing effect than other crystal types. The tests also revealed that using crystallizers forms more beta prime crystals, which have a better absorbing effect than other crystal types. Table : Melting points of fatty acids, triglycerides and crystallizers TRIVIAL NAME MELTING POINT TRIVIAL NAME MELTING POINT C: Lauric acid. C ( F) Trilaurin. C (5 F) C: Myristic acid 5. C (3 F) Trimyristin 55 C (3 F) C: Palmitic acids.7 C (5 F) Tripalmetin 5 C (9 F) C8: Stearic acids 9. C (57 F) Tristearin 7. C ( F) C: Bebenic acids 8 C (7 F) Tribehenic 8. C (8 F) C8: n-9 cis Oleic acid. C ( F) Crystallizer : C C8. C ( F) C8, trans Elaidic acid 3.8 C ( F) Crystallizer : C C8 57. C (35 F) C8: n- cis Linoleic acid -. C ( F) Crystallizer : C C8-C 58.8 C (38 F) C8:3 n-3 cis Linolenic acid -.7 C (9 F) Crystallizer : C8 7. C ( F)

5 TRIAL 3 TRIAL TRIAL 5 TRIAL 8 TRIAL 9 TRIAL Oil blend: Palsgaard.7%.7%.7%.%.%.% Palm stearin.%.% 5.%.%.% 5.% RBD. palm oil.%.% 5.%.%.% 5.% Liquid soya oil C 8.3%.3% 8.3%.%.%.% % % % % % % Melting point: 5.% 5.9% 5.% 5.7% 5.8% 5.8% Avr. SFC % C/5 F.9% 3.% 7.% 5.% 55.% 59.8% Avr. SFC % C/8 F 5.% 5.7% 5.8%.%.% 3.9% Avr. SFC % 3 C/8 F 3.7% 3.% 3.%.%.%.8% Avr. SFC % C/ F.%.8%.7%.% 3.% 3.9% Table : SFC values in puff pastry margarine blends with and without crystallizer SFC VALUES WITH AND WITHOUT CRYSTALLIZER Moving on with our exploration, we examined more or less the same puff pastry margarine recipe as in the previous trials, this time adding.7 grams of crystallizer. We were keen to determine the Solid Fat Content (SFC) values that resulted from this addition. These are depicted in Table. The trials demonstrated a somewhat surprising result: While.7% crystallizer is not a large portion of the recipe, its effect on crystallization was strong, quickly getting the seating in place upon which to build further crystals. Judging by the SFC values in Table, crystallizers have a strong effect on fat crystallization because they activate some of the fats to crystallize more quickly than would otherwise be the case. With other test methods, to 8 hours at o C ( o F) would have been required to do this. CRYSTALLIZERS AND PRO- DUCTION CAPACITY Next up, we took a closer look at the effect of crystallizers on production capacity. Figure shows the results of testing a similar puff pastry margarine recipe to that used in our other trials. We tested two production capacity levels, each with and without crystallizers added. In Figure, the pilot plant s bar pressure indicates that crystallization is occurring. When producing at low capacity (%), the fat has time to crystallize by itself. But at higher capacity (above 7%), low bar pressure shows the fat is more liquid and crystallization is less effective. At low capacity, fast-crystallizing fat types can produce crystallization, but it requires crystallizers to be added to increase contact and result in sufficient crystallization both at higher and lower capacities. As a general conclusion, it seems that the more crystallizers you add, the higher the bar pressure and therefore the better you are able Figure : The effect of crystallizer doses on production capacity bar bar to maintain or increase capacity. Without adding crystallizers, you would need to reduce capacity, allowing the blend to remain in the tube chillers for longer. So, while adding crystallizers will increase recipe costs, there s a worthwhile trade-off in better utilisation of production equipment. Still in our experimental corner, we decided to look more closely at the effect of different crystallizer dosages on production capacity, moving from zero to.5%, %,.5% and, finally, right up to %. To make things more interesting, we simultaneously tested the effect of two different rotation speeds: and 8 RPM..5.% crystallizer %.5% crystallizer %.% crystallizer 7%.5% crystallizer 7%.% crystallizer %.5% crystallizer %.% crystallizer 7%.5% crystallizer 7% 5

6 In Figures 3 and, the coloured bars represent the four tube chillers in our pilot lab production setup. It came as no surprise, of course, that the viscosity needed for margarine required more energy toward the end of the production line. We also confirmed that applying crystallizers does indeed increase viscosity by the end of the process, but the difference they make is nothing extraordinary. CRYSTALLIZERS AND PRODUCTION CAPACITY Margarine produced for incorporation into puff pastry is very thin when first made, expanding in the oven to arrive at the mouth-feel loved by consumers all over the world. Seen from a puff pastry expansion point of view, trials with Palsgaard s crystallizers produce a very stable margarine. No matter how hard we work the product, it still performs well in this vital regard. But we were curious to learn what might happen if we were to conduct a baking test on the final product itself. So we measured the effect on ten such pastries of increasing crystallizer dosages from zero to %, switching between three different rotation speeds. Normally, rotation speed isn t a parameter most production staff can work with. Often, that s because most production machinery has a fixed speed or enables switching only between one or two levels. Now however, in a trans fat-free landscape, the ability to adjust rotation speed in combination with various dosages of crystallizers has become a key factor for achieving the right result. In Figure 5, rotation speed strongly affects expansion results, performing best at around RPM. Introducing crystallizers smooths out the effects of rotation speeds, enabling a good expansion result not only with different process parameters but also on different machines expansion simply becomes less sensitive to process parameter variations. There is, of course, production machinery that Exspansion (x) Amp Tube chiller Pin machine Tube chiller Tube chiller rpm in all tube chillers rpm in all tube chillers 8 rpm in all tube chillers % crystallizer.5% crystallizer.% crystallizer,5% crystallizer,% crystallizer Figure 5: The effect of different process parameters on puff pastry expansion % Crystallizer.5% Crystallizer.% Crystallizer.5% Crystallizer.% Crystallizer Figure 3: The effect of crystallizer doses at RPM Figure : The effect of crystallizer doses at 8 RPM

7 can arrive at comparable results without any addition of crystallizers, but few manufacturers have invested in the up-to-date equipment that can do it. ARE CRYSTALLIZERS AWAYS NECESSARY? Let s stop for a moment and ask an important question: Have we all too narrowly pursued crystallizers as the only feasible solution to the problem of slower crystallization? Are they, in fact, always necessary? The answer is no. It is possible to create recipes that perform just as well as, or at least comparably to the performance of a trans fat-containing formulation. Cake margarines, for example, that use fast-crystallizing fat types such as palm oil or coconut oil fat, have nothing to be gained by adding crystallizers. But with cheaper fat types, small amounts of crystallizers can make a significant difference. There is, however, no way to avoid spending some amount of additional funds to cope with a trans fat-free world and for most, the costs will be high. Manufacturers will need to take a look at their equipment line-up. Most likely, older machinery won t be enough to maintain current capacity and product quality on the new, trans fat-free playing field at least, not without applying crystallizer dosages as high as %. Upgrading brings new and better technologies with it enabling, for example, the use of CO as a more efficient and effective cooling medium. But even after an upgrade to more modern equipment, manufacturers should still expect to incorporate from.5 to % crystallizer content in their recipes. A TOUGH JOURNEY For European manufacturers, who have been battling the effects of low or no trans fat recipes for quite some years now, it s been a tough journey. The only comfort, perhaps, was the fact that everyone was in the same boat product quality decreased across the entire industry and everyone needed to come up with their own answer to the problems. In the US, things are about to heat up but there s much to be learned from the journey already embarked upon by their European competitors. In a nutshell, to cope with a trans free future, production managers need to realize that the days of pouring in ingredients, setting the machines and retreating to the comfort of the control room are most likely over. Instead, even a minor fluctuation in production requires active and proactive efforts. And most affected are those whose job it is to produce puff pastry. WE RE HERE TO HELP Margarine manufacturers need to develop new production strategies, understanding the new realities described above, experimenting with crystallizers and emulsifiers in their recipes, and preparing for significant capital investments in equipment. Palsgaard is here to help its customers work their way through the hurdles, helping to arrive at a roadmap for process, recipe and equipment adaptations. We have all the equipment needed to play with every production parameter, taking samples at many different points and conducting trials that simply wouldn t be feasible in a live production environment. Manufacturers have a variety of other avenues to turn to for advice, too, including concentrated efforts being made by oil refineries (developing new oils and fat types), universities, in-house R&D centers and machinery/storage suppliers. The sooner the industry faces up to the issues discussed in this article, the better. Failure to move quickly enough is likely to result in a rollercoaster ride through reduced capacity, zig-zagging product quality and costly re-runs. The sooner the effort is made, therefore, the lower the overall cost of the necessary transition to trans free products and the smoother the journey for both manufacturers and their customers. American Journal of Epidemiology. 5 Apr ;(7):7-9. Dietary fat intake and risk of coronary heart disease in women: years of follow-up of the nurses health study.. Oh K, Hu FB, Manson JE, Stampfer MJ, Willett WC. ABOUT THE AUTHOR Anders Mølbak Jensen, is Product & Application Manager, Lipid & Fine Foods Palsgaard A/S. He can be reached at am@palsgaard. dk or Before joining the company years ago, he held various roles as a laboratory, quality control and R&D manager at a large margarine producer for years. He holds an M.Sc in food science and technology from the University of Copenhagen and a Bachelor of Commerce, IT. His is am@palsgaard.dk. Get more info at www. palsgaard.com. 7