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Chocolate Bloom a thing of the past?Geoff Talbot, The Fat Consultant, Kevin Smith, Unilever Research,Loek Favre, Loders Croklaan, Imro t Zand, Loders Croklaan

erhaps its too much to claim that fatbloom on chocolate is completely a thingof the past but the Prestine range of

filling fats from Loders Croklaan shouldensure that fat bloom caused by migration of

centre fats into chocolate is history.Much has been written (for example,

Lonchampt and Hartel, 2004) about themechanism of fat bloom formation in chocolateand the consensus is that it is linked to a change

in polymorphic form in the cocoa butter from theV form produced during tempering to the morestable VI form. When this happens there is acrystallisation or, some would say, a recrystallisa-tion of cocoa butter on the surface of thechocolate this is fat bloom.

It is by no means the case thatevery chocolate product will bloom sowhat makes some more susceptiblethan others? There are a number offactors which come into play butthree are perhaps of greatest impor-tance. Firstly, the composition of thechocolate can affect its propensity tobloom. Milk fat has been observed(Pajin and Jovanovic, 2005) to have aninhibiting effect on bloom and so milkchocolate will be less likely to bloom

than dark chocolate under the sameconditions. Secondly, storage temper-ature plays a role. The higher thetemperature at which the chocolate isstored, the more likely it is to bloomand the quicker that bloom will form.Of course, if the chocolate is storedat a very high temperature it willmelt and effectively de-temper.Subsequent cooling will very quicklyresult in bloom but this is not thekind of bloom we are discussing here.Thirdly, the structure of the productcan play a big part in whether or notthe chocolate will bloom. If it is achocolate-coated product with softerfats in the centre then, on storage,these fats can start to migrate into thechocolate coating. As they do so, theyincrease the amount of liquid oil inthe chocolate. This increases themobility of triglycerides andincreases the rate at which the choco-late will bloom.

We have studied migration in atwo-phase product (filling andcoating) and have shown that there isan exponential decrease in filling fat inthe chocolate coating the fartheraway from the filling-chocolate inter-face you go (Talbot et al, 2007). Wehave also looked at the degree ofpolymorphic change at various pointswithin the chocolate coating and havefound a direct correlation between the

amount of filling fat present and the ratio of V toVI at that point. We have also shown that evenvery low levels (1%) of liquid oil in the filling canhave a significant effect on the rate of this poly-morphic change.

The question then arises how can we usethis knowledge to reduce the tendency for choco-late to bloom under these conditions? We eitherneed to add something to the chocolate to makeit more stable in the V form or we need to add

something to the filling to prevent migration orminimise its effects in terms of bloom formation.Various materials have been added in the past tochocolate to improve its stability and thesefunction to varying extents. The introduction ofthe 2003 EU Chocolate Regulations, however,

meant that many of these additives were nolonger permitted. This has meant that to inhibitbloom caused by migration then something needsto be added to the migrating fat phase. As a result,Loders Croklaan developed a range of Prestinefilling fats. These are fats that can be used either asthe complete fat phase in fillings or as part of thefat phase (with the remainder being, for example,hazelnut paste). They are all based on vegetableoils and contain triglycerides of a very specific

structure which possess the ability to greatlyretard the transformation of V cocoa butter intoVI cocoa butter. These triglycerides are referredto here as AB (anti-bloom) triglycerides.

To show the effect of these AB triglycerideswe made three different filling compositions.

Each filling contained 60% icing sugarand 25% hazelnut oil. The remaining15% was a blend of AB with a Couvatype of cocoa butter replacer. Levels ofAB in the three fillings were 0%, 5%and 15%. Each of these fillings weredeposited into small steel washers2.5mm deep. On top of this fivethinner washers (0.5mm each) werefilled with tempered cocoa butter. Thisarrangement, known as the washertest has become a standard method

of studying migration in confectioneryproducts (Talbot, 1996). Samples werestored at 20C, 25C and 28C. Atintervals, the amount of filling fatappearing in the cocoa butter layerwas analysed by both GC (to deter-mine actual degrees of migration) andX-ray diffraction (to determine thepolymorphic form of the cocoabutter). By having the cocoa butterwithin five thin washers it was possibleto analyse the cocoa butter at each ofthe five depths.

As we had found in previousstudies the concentration of filling fatin the cocoa butter layer decreasedfrom the interface towards the surface.Although the actual concentrations offilling fat at any particular depth of thecocoa butter layer increased with bothstorage time and temperature thegeneral profile of higher concentra-tions at the interface than at thesurface was maintained.

Previously, we had found thathigher levels of liquid oil migrating intothe cocoa butter produced a greaterdegree of transformation from V intoVI. This was also seen in the samplecontaining no AB (Figure 1a) where thesample closest to the interface (depth0.0-0.5mm) contained the highestamount of VI. The effect of storagetemperature is seen in Figure 1b transformation to VI is almost

Chocolate Bloom

Figure 1: Formation of VI in cocoa butter for a filling containing noanti-bloom fat(a) at 25C and various distances from the filling(b) for the layer at 0-0.5mm from the filling at 20C, 25Cand 28C

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complete after 6 weeks at 28C buthas not yet reached equilibrium evenafter twice that time at 20C.

The effect of adding AB trigly-cerides is, however, marked. Figure 2shows the amount of VI in the layerof cocoa butter immediately adjacentto the interface with the filling whendifferent levels of AB are used at a

storage temperature of 25C. With noAB present, transformation is 90%complete after 5 weeks; with 5% AB inthe filling, only 50% transformationhas occurred in this time; with 15%AB in the filling only 30% transforma-tion has taken place. Indeed, the fillingcontaining 5% AB showed a similardegree of transformation at 25C asdid one containing no AB at 20Csuggesting that even low levels of ABcan improve the heat tolerance of thesystem with regard to polymorphictransformation.

So, what does this mean forinhibiting bloom formation in filledchocolates? Firstly it should be noted that thesewere model studies in which migration took place

into cocoa butter itself, not into chocolate. In a realsituation the amount of cocoa butter presentwould be about one-third that present in thesestudies. That, in itself, would mean that migrationwould be slower. When combined with the effectsof tortuosity provided by the non-fat componentsin the chocolate the result should be to slow downmigration and thus slow down polymorphicchange making the results described here a worst-case scenario.

Secondly, because we were using cocoa

butter instead of a chocolate as the coating wewere unable to make any observations about

whether or not surface bloom was formed. All wecould do was to measure the degree of formationof VI and make the link that previous researchershave made between VI formation and bloomformation and say that because the presence of ananti-bloom fat in the filling reduces the degree oftransformation from V to VI then it is also likelyto reduce the degree of bloom formation. Usingchocolate in place of cocoa butter would haveallowed us to see whether or not bloom formationwas inhibited by the presence of an anti-bloom fat

but it would have prevented us frommaking fundamental measurementsof the degree of transformation fromone form into the other. This isbecause the presence of non-fatcomponents in chocolate, especiallysugar, interfere with the X-raydiffraction pattern in the area we areinterested in.

However, despite these com-ments the results do show that anti-bloom fats in a migrating filling reducethe rate of transformation of V cocoabutter into VI cocoa butter and, byimplication, reduce the rate of bloomformation on the surface of a choco-late containing that cocoa butter.Furthermore the types of triglyceridewhich have been studied here formthe functional base of the Prestinerange of anti-bloom fats from LodersCroklaan demonstrating the scientificfoundations upon which this range offats is built.

ReferencesLonchampt P, Hartel RW (2004) Fat bloom inchocolate and compound coatings Eur. J. Lipid Sci.Technol. 106 241-274Pajin B, Jovanovic O (2005) Influence of high-melting milk fat fraction on quality and fat bloomstability of chocolate Eur. Food Res. Technol. 220(3-4), 389-394Talbot G (1996) The Washer Test A Methodfor Monitoring Fat Migration ManufacturingConfectioner, 76(9) 87-90Talbot G, Smith K, t Zand I (2007) Effect of liquidoil in chocolate on polymorphic changes Innovationsin Food Technology, August 2007, 20-21

Figure 2: Formation of VI in cocoa butter in the layer 0-0.5mm fromthe filling at 25C for levels of anti-bloom fat in the filling of0%, 5% and 15%

Geoff Talbot is The Fat Consultant, based in Bedford, United Kingdom Email: thefatconsultant@btinternet.comKevin Smith is Lead Lipid Scientist at Unilever Research, Sharnbrook, United Kingdom

Email: kevin.w.smith@unilever.comLoek Favre is Director of Product Management, Palm at Loders Croklaan Email: loek.favre@croklaan.com

Imro t Zand is Product Development Manager at Loders Croklaan, Pasir Gudang, MalaysiaEmail: Imro-'t.Zand@croklaan.com)

Geoff Talbot and Kevin Smith both act as consultants to Loders Croklaan, The Netherlands

Not all Trans fatty acids are equal!he effects of natural and industrially-

produced sources of trans fatty acids oncardiovascular disease markers in healthy men

and women were examined by a multidisciplinaryresearch team from worldwide research institutes(TRANSFACT project). This study shows that transfatty acids derived from natural sourcesversus industrially-produced sources yielddifferent effects on cardiovascular disease (CVD)factors. Furthermore, results revealed that womenare more sensitive than men to the effects ofcertain TFA.

The TRANSFACT study, a collaborationbetween the French National Institute forAgricultural Research (INRA), Clermont-Ferrand,France, the Nestl Research Center (NRC),Lausanne, Switzerland and the French DairyCouncil (CNIEL), Paris, France, found that naturalTFA - from milk, do not have the same impact onCVD risk factors as industrially-produced TFA.Results suggest that the deleterious HDL-Clowering property of TFA is specific to industrially-produced sources. Additionally, the biologicalresponses to TFA were more significant in women

than in men; the mechanism underlying theseeffects warrants further investigation.

Research on trans fatty acids (TFA) and theirpotential effects on human health is of widespreadinterest to scientists and public health officials.Restrictions on the use of TFA are based onsignificant scientific evidence that industrially-produced TFA are detrimental to human health.Consumption of these TFA results in decreasedlevels of good cholesterol (HDL-C) and increasedlevels of bad cholesterol (LDL-C), markedlyenhancing the risk of CVD.

Interestingly, a similar study was recentlyperformed by researchers at Laval University,Canada, evaluating the consequences ofnaturally-occurring vs. industrially-produced TFAon LDL and HDL cholesterol levels. Resultsrevealed that consumption of moderate amountsof natural TFA do not alter CVD risk, whereas TFAfrom industrial sources did elevate LDL-C levels.

These new findings suggest that consumptionof TFA from natural sources, even at levels wellabove current human consumption, does notimpact CVD risk. As indicated in the American

Journal of Clinical Nutrition editorial by WC.Willett and D. Mozaffarian, the critical publichealth question remains - to find healthful ways toreduce intake of industrially-produced TFA. Thiscomes as no surprise to Nestl, who has had apolicy since 2003 to reduce the industriallyproduced TFA content in Nestls products.

Nestl, CNIEL and INRA are independentlyperforming more in-depth studies to better under-stand the differential effects of trans fatty acidsand their underlying biological mechanisms,to assist food safety agencies and regulatoryauthorities in providing recommendations foroptimal CVD health.

Web version of the paper available at:http://www.nutrition.org/media/publications/ajcnMarch6.pdf

American Journal of Clinical Nutrition, vol 87,Number 3, Mach 2008, pp 558-566 J.-M. Chardigny, F.Destaillats, C. Malpuech-Brugre, J. Moulin, D. E.Bauman, A. L. Lock, D. M. Barbano, R. P. Mensink, J.-B.Bezelgues, P. Chaumont, N. Combe, I. Cristiani, F. Joffre, J.B. German, F. Dionisi, Y. Boirie and Jean-Louis Sbdio.

www.research.nestle.com

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