chocolate must undergo a conching process if one wants to produce a ( quality ) chocolate with the desired rheological properties and flavour . the present invention relates in particular to this conching process and modifications thereto . when submitting a chocolate mass to a conventional conching process , the antioxidant activity decreases after conching . in particular , the antioxidant activity decreases during a conching process as used in the art . the present invention relates to the changes the inventors made to the conventional conching process with the aim of avoiding this decrease in antioxidant activity . to their surprise , the inventors discovered that the antioxidant activity of chocolate was not only conserved , but most often increased with their method . the examples below show that by using a conching process according to the invention , the antioxidant level of the chocolate can be significantly improved . the newly developed conching process consists of two successive phases or steps : in the first phase , the so called “ dry conching step ”, the chocolate with a low fat content ( typically between 25 and 30 %) is subjected to an intense kneading at elevated temperatures . temperatures applied during the dry conching step in the method of the invention may vary from about 50 ° c . to about 70 ° c ., and the duration of this dry conching step may vary from a few hours ( about 1 to 2 hours ) up to about 12 hours . preferably , dry conching according to the invention takes place at about 55 ° c . to about 65 ° c . and lasts for about 6 to about 10 to 12 hours . most preferably the dry conching step lasts for about 6 hours at about 60 ° c . advantageously , in a method of the invention the chocolate mass is cooled to maintain these temperatures . if not , the temperature may rise up to e . g . 90 ° c . because of friction heat generated during the dry conching step . ( immediately ) after the dry conching step , and before the wet conching step , an emulsifier and / or some fat is advantageously added . typical emulsifiers are lecithin , polyglycerol polyricinoleate , ammonium phosphatide or any mixture of these . typical fats are cocoa butter , milk fat and / or some allowed vegetable fats . preferred emulsifiers / fats are traditionally lecithin and / or cocoa butter . in an embodiment of the invention cocoa butter was added . in an even more preferred embodiment of the invention lecithin was added . in the method of the invention , a “ wet conching step ” ( immediately ) follows , is subsequent to , the dry conching step . the wet conching step of the invention may last from a few hours ( 1 to 2 hours ) up to about 12 hours with temperatures in the range of about 60 till about 110 ° c . preferably “ wet conching ” according to the invention is performed at about 60 ° c . to about 105 ° c ., at about 65 ° c . to about 100 ° c ., and lasts for about 6 to about 10 to 12 hours . most preferably the wet conching step of the invention lasts for about 6 hours at about 90 ° c . however , also at 60 ° c . an increase in antioxidant activity could be observed . according to another preferred embodiment , the wet conching step of the invention therefore lasts for about 6 hours at 60 ° c . advantageously , the chocolate mass is heated to maintain these temperatures . as mentioned above , conventional wet conching steps are performed at temperatures of about 40 ° c . to about 60 ° c . after conching , the chocolate viscosity can still be adjusted by adding fat and / or cocoa mass in the conche itself or in any mixing unit . when cocoa mass is added , it has preferably undergone a heating step for a prolonged time at an elevated temperature , most preferably it has undergone a heating step for about 12 hours at about 90 ° c . using the particular combinations of conching process steps as described above , a level of about 20 % above the typical antioxidant activity can be obtained ( fig5 and 11 ). even a level of about 40 % above the typical antioxidant activity can be obtained with a method of the invention ( fig6 ). the typical antioxidant activity is hereby the antioxidant activity just before conching ( t = 0 ). excellent results were obtained with a dark chocolate ( increases of up to 40 %). a method of the invention can also be used for milk chocolate , in particular when a dry conching at 60 ° c . is followed by a wet conching at 90 ° c . in said case an increase in antioxidant activity of about 7 % was noted at the end of the conching process compared to t = 0 . as demonstrated below ( see the examples ), the typical combination of low and high temperatures , specifically linked to the respective textures of the product during the two phases of the conching process (“ dry ” and “ wet ” conching ), results in the formation of highly antioxidative compounds ( e . g . antioxidative polymers ) in the chocolate . as further demonstrated , the method of the invention results in a higher effectively measured antioxidant activity . where the traditional processes cause a degradation of the antioxidant components , the processes described in the present invention “ naturally ” increase the antioxidant activity of the chocolate . by “ naturally ” is meant that in order to conserve and / or increase the antioxidant activity , no antioxidative molecules need to be added ( as additive ) to the chocolate mass . where adapted ( manufacturing ) processes previously described only claim to preserve the amount of antioxidant components , the process of the present invention boosts ( increases ) the antioxidant activity . as shown the level of “ beneficial ” antioxidants can be ( further ) improved by using a wet conching step at a higher temperature ( preferred temperature ranges for methods of the invention given above ). preferably , this temperature in a method according to the invention lies around 90 ° c . at this temperature the increase in antioxidant activity was the highest , yet also a wet conching step at ( about ) 60 ° c . proved beneficial . the inventors observed that a ( chocolate ) composition which was submitted to a method of the invention , with a “ wet conching ” at about 60 ° c . ( preceded by a “ dry ” conching at 60 ° c .)) did not undergo any significant changes in procyanidin content , and not even in the repartition of the procyanidins in small oligomers ( p2 - p6 ) and in polymers ( p +). however , the antioxidant activity was increased with about 20 % ( compared to the activity just before (“ dry ”) conching , t = 0 ). the composition which was submitted to a “ wet ” conching at 90 ° c . ( preceded by a “ dry ” conching at 60 ° c .) contains significantly less procyanidin polymers ( p +) whereas the antioxidant activity increased with about 40 % ( compared to the activity just before (“ dry ”) conching , t = 0 ). although in the literature it is reported that the antioxidant activity of procyanidin oligomers was found to increase significantly with the degree of polymerisation , in both compositions the antioxidant activity of the chocolate was significantly increased with an equal or lower procyanidin polymer content . it therefore appears that part ( s ) of the chocolate extract that remain ( s ) unidentified contributes greatly to the antioxidant activity . the method of the invention most probably also extracts melanoidins and perhaps higher - order tannins ( counet , c . & amp ; collin , s ., 2003 ). a process temperature of about 90 ° c . is ideal to promote the development of these melanoidins and tannins . this may explain the higher increase in antioxidant activity at ( about ) 90 ° c . during the “ wet ” conching phase of the method of the invention . the data below demonstrate that a high natural antioxidant activity of antioxidants in chocolate can be obtained , without the “ addition ” of any antioxidant molecules . the invention will be described in further details in the following examples by reference to the enclosed drawings , which are not in any way intended to limit the scope of the invention as claimed . mixing : in this step all the sugar , cocoa mass and part of the cocoa butter ( 48 . 8 % of the cocoa butter ) were mixed together . refining : the chocolate paste was refined on a three roll refiner with a grinding length of the rolls of 280 mm × 600 mm . the fineness of the powder was between 15 and 20 μm . filling : the conche was slowly filled with chocolate powder over a time period of 70 minutes . immediately after this period another 3 . 3 % of the cocoa butter amount was added . conching : the chocolate was dry - conched for 6 h at 90 ° c . in a frisse conche . lecithin and the rest of the cocoa butter were added immediately after the dry conching step . the liquid step , following the conching step at dry texture , was operated for one hour at 60 ° c . the antioxidant activity was measured by measuring the protective degree of the chocolate extract against a forced oxidation of linoleic acid according to a method described by liégois , c . et al . ( 2000 ). for the extraction protocol , see example 2 . the oxidation of linoleic acid was induced by 2 , 2 ′- azobis ( 2 - amidinopropane ) dihydrochlorure ( aaph ) in an aqueous dispersion in the absence or presence of antioxidant ( chocolate extract ). aaph generates free radicals by spontaneous thermal decomposition . the rate of oxidation at 37 ° c . was monitored by recording the increase in absorption at 234 nm caused by conjugated diene hydroperoxides . from these data the inhibition time of the oxidative reaction of linoleic acid can be calculated ( fig3 ) which is a measure for the antioxidant activity . the longer the inhibition time ( tinh ), the higher the antioxidant activity . the antioxidant activity was evaluated at various intervals during the process and finally expressed in the form of a percentage of the antioxidant activity at the beginning of the conching ( point at 0 hours ), as this allows to compare the effect of different conching processes for different chocolates . the antioxidant activity in this case corresponds to the following : [ tinh ( t = x ) / tinh ( t = 0 ) ]* 100 . fig4 clearly shows that after 6 hours the antioxidant activity decreases round and about 40 % ( compared to the initial value at t = 0 ) in a chocolate produced by a traditional conching process . two chocolates were prepared as described in example 1 with the exception that the conching process includes first a dry conching step at 60 ° c . instead of 90 ° c . and secondly , after the addition of only the lecithin , a wet conching step either at 60 ° c . ( for the first chocolate ) or at 90 ° c . ( for the second chocolate ). each conching step (“ dry ” and “ wet ”) lasted for about 6 hours . the remaining part of the cocoa butter was added after conching . the antioxidant activity was once more evaluated at various intervals during the conching process . results are presented in fig5 & amp ; 6 . in both cases the antioxidant activity ( at the end of the conching process ) is increased , with about 20 % at 60 ° c . and about 40 % at 90 ° c . ( compared to the start point at t = 0 ). dry conching lasted for 6 hours and was followed by a wet conching according to the invention . after 1 hour of wet ( or liquid ) conching there was already an increase in oxidant activity ( compared to the start point ). said increase was most pronounced if the wet conching step also lasted for about 6 hours . the procyanidin content has been evaluated in both chocolates by np - hplc - uv . briefly , the chocolate was transformed in powder with a mixer and introduced into a soxhlet filtration cartridge to remove the lipids . the defatted chocolate ( 1 g ) was then extracted two times with 5 ml of solvent ( 2 × 10 min , 25 ° c . to avoid any thermal degradation of procyanidins ). three organic solvents are frequently used for procyanidin extraction mixed with water and acetic acid : acetone , ethanol or methanol ( e . g . acetone / water / acetic acid : 70 / 28 / 2 % ( v / v )). after each extraction , the suspension was centrifuged ( 3000 g , 10 min ). the combined supernatants were concentrated by rotary evaporation under partial vacuum ( 40 ° c .) ten milligrams of procyanidin extract were then diluted in 1 ml of methanol and finally 20 μl of this solution was injected in a np - hplc ( normal phase - hplc ). procyanidins were separated on a phenomenex 5 μm normal - phase luna silica column , 250 mm × 4 . 6 mm ( inside diameter ) ( bester ) at 25 ° c . separations were carried out at a flow rate of 1 ml / min with a linear gradient from a ( dichloromethane ) to b ( methanol ) and a constant level of c ( acetic acid and water , 1 : 1 , v / v ). the np - hplc was coupled to a uv detector ( 280 nm ) in order to determine the concentration of the different procyanidins present in the extract according to the method of counet , c . & amp ; collin , s . ( 2003 ). in fig7 , the repartition profile of the procyanidins is shown with p1 to p6 being the monomers to hexamers and p + being the polymers . this graph shows that the composition which was submitted to a wet conching at 60 ° c . did not undergo any significant changes in procyanidin content , and not even in the repartition of the procyanidins in monomers ( p 1 ), in small oligomers ( p 2 - p 6 ) and in polymers ( p +). the composition which was submitted to a wet conching at 90 ° c . clearly contains significantly less procyanidin polymers ( p +). the first chocolate was conched by applying only a dry conching phase . only step 1 of the method of the invention was thus performed . the dry conching step lasted for 12 hours and was performed at 60 ° c . the fat content was 29 % ( w / w % on the chocolate mass submitted to dry conching ) and no emulsifier was added . the second chocolate was conched by applying only a wet conching phase . only step 2 of the method of the invention was thus performed . the wet conching step lasted for 12 hours and was performed at 90 ° c . the chocolate contained 0 . 5 % w / w of lecithin as emulsifier ( percentage on the total chocolate mass ). in both cases , the antioxidant activity remained more or less stable during the conching process . there is no ( consistent ) decrease or increase of the antioxidant activity over the whole period of the conching process . the data presented here — when compared with those of fig6 — show that it is the combination of the 2 types of conching ( a dry conching followed by a wet conching according to the invention ) that results in an increase in antioxidant activity . in the present example , the antioxidant activity of a commercial sample (“ new tree , chocolat noir , eternity ”) claiming a high antioxidant content in polyphenols was compared with that of a chocolate prepared by a method of the invention ( see example 2 ). the chocolate prepared according to a method of the invention was submitted to a dry conching step at 60 ° c . ( step 1 ), followed by a wet conching step at 90 ° c . ( step 2 ). the antioxidant activity of each sample was measured as described in example 1 . results , calculated for the same amount of non - fat dry cocoa content , are presented in fig1 and are expressed as the inhibition time of the oxidative reaction of linoleic acid . the process according to the present invention produced a chocolate having an antioxidant activity equivalent to that of the commercial chocolate claiming to have an increased content in antioxidant components . the commercial sample is an example of a chocolate to which antioxidant components are added . by following a method of the invention an increased antioxidant activity can be obtained through a simple adaptation of the conching process . no antioxidants need to be added during ( at the end of ) the production process to achieve this effect . this is what is meant when saying that the antioxidant activity is conserved and preferentially increased in a “ natural way ”. advantageously the taste ( and other properties ) of chocolate is not influenced by the adapted production process ( conching process ) according to the invention . two chocolates were prepared as described in example 2 with the exception that a cocoa mass of the type madagascar was used instead of one of the type côte d &# 39 ; ivoire . the chocolate was conched according to a method of the invention . the conching process includes first a dry conching step at 60 ° c . and secondly , after the addition of lecithin , a wet conching step either at 60 ° c . ( for the first chocolate ) or at 90 ° c . ( for the second chocolate ). each conching step (“ dry ” and “ wet ”) lasted for about 6 hours . the antioxidant activity was once more evaluated at various intervals during the conching process . results are presented in fig1 & amp ; 12 . in the case of a wet conching at 60 ° c . the antioxidant activity at the end of the conching period was about 20 % higher than at t = 0 . in the case of a wet conching at 90 ° c . an increase of about 15 % was noted . the way of preparing is in fact as indicated in example 2 , except that instead of lecithin there was an addition of cocoa butter after 6 hours of conching ( before starting wet conching ). the texture ( fluidity ) of the mass submitted to wet conching is comparable to that of example 2 . mixing : in this step all the sugar , cocoa mass and part of the cocoa butter ( 28 . 2 % of the cocoa butter ) were mixed together . refining : the chocolate paste was refined on a three roll refiner with a grinding length of the rolls of 280 mm × 600 mm . the fineness of the powder was between 15 and 20 μm . filling : the conche was slowly filled with chocolate powder over a time period of 70 minutes . immediately after this period another 1 . 9 % of the cocoa butter amount was added . conching : the chocolate was dry - conched for 6 h at 60 ° c . in a frisse conche . 42 . 3 % of the cocoa butter was added immediately after the dry conching step ( or the conching step at dry texture ). the liquid phase ( wet conching ) was operated for 6 h at 90 ° c . the remaining part of the cocoa butter was added after conching . at t = 12 the antioxidant activity was increased by about 7 % compared to the antioxidant activity at t = 0 . in the table below some examples are given of antioxidant activity for dry and wet conching temperature combinations applied in a method of the invention . suitable temperatures (° c .) for dry and wet conching : results in bold italic . preferred combinations for dry and wet conching : results in bold . for the chocolate recipe , see example 1 . values of antioxidant activity (%) are those after 12 hours : 6 hours dry conching followed by 6 hours wet conching , see example 2 . the value at t = 0 was set at 100 % ( value at the start of conching ). similar results were obtained for other dark chocolates . best results were obtained when a dry conching step at a temperature between about 50 ° c . and about 70 ° c ., more preferably between about 55 ° c . and about 65 ° c ., was followed by a wet conching step near 60 ° c . or near 90 ° c . antioxidant activity (% compared to t = 0 ) for dry and wet conching temperature beckett , s . t . industrial chocolate manufacture and use . second edition . blackie academic & amp ; professional . 1994 : 118 - 121 . ziegleder , g . conching . information on the britanniafood web site , accessible via http :// www . britanniafood . com / download /? mode = dynamic & amp ; id = 21 , july 2006 . van sant , g . vrije radicalen en antioxidanten : basisprincipes . symposium — antioxidanten en voeding — instituut danone . 2004 . information on ‘ free radicals ’ on the wikipedia web site , accessible via http :// www . wikipedia . org / wiki / free radicals , july 2006 . roura , e . ; andrés - lacueva , c . ; jauregui , o . ; badia , e . ; estruch , r . ; izquierdo - pulido , m . ; lamuela - raventos , r . m . rapid liquid chromatography tandem mass spectrometry assay to quantify plasma (−)- epicatechin metabolites after ingestion of a standard portion of cocoa beverage in humans . j . agric food chem . 2005 , 53 : 6190 - 6194 . mursu , j . ; voutilainen , s . ; nurmi , t . ; rissanen , t . h . ; virtanen , j . k . ; kaikkonen , j . ; nyyssönen , k . ; salonen , j . dark chocolate consumption increases hdl cholesterol concentration and chocolate fatty acids may inhibit lipid peroxidation in healthy humans . free radical biology & amp ; medicine , 2004 , vol 37 , no . 9 : 1351 - 1359 . lee , k . w . ; kim , y . j . ; lee , h . j . ; lee , c . y . cocoa has more phenolic phytochemicals and a higher antioxidant capacity than teas and red wine . j . agric . food chem ., 2003 , 51 : 792 - 7295 . usda ( us department of agriculture )- mc bride , j . high - orac foods may slow aging . 1999 , 47 : 15 - 17 . counet , c . ; collin , s . effect of the number of flavanol units on the antioxidant activity of procyanidin fractions isolated from chocolate . j . agric . food chem . 2003 , 51 : 6816 - 6822 . wan , y . ; vinson , j . a . ; etherton , t . d . ; proch , j . ; lazarus , s . a . ; kris - etherton , p . m . effects of cocoa powder and dark chocolate in ldl oxidative susceptibility and prostaglandin concentrations in humans . american journal of clinical nutrition , 2001 , vol . 74 , no . 5 : 596 - 602 . kondo , k . ; hirano , r . ; matsumoto , a ., igarashi , o . ; itakura , h . inhibition of ldl oxidation by cocoa . lancet , 1996 , 348 : 1514 . waterhouse , a . l . ; shirley , j . r . ; donovan , j . l . antioxidants in chocolate . lancet , 1996 , 348 : 834 . sanbongi , c . ; suzuki , n . ; sakane , t . polyphenols in chocolate , which have antioxidant activity , modulate immune functions in humans in vitro . cell immunol , 1997 , 177 ( 2 ): 129 - 36 . engler , m . b . ; engler , m . m . ; chen , c . y . ; malloy , m . j . ; browne , a . ; chiu , e . y . ; kwak , h . k . ; milbury , p . ; paul , s . m . ; blumber , j . ; mietus - snyder , m . l . flavonoid - rich dark chocolate improves endothelial function and increases plasma epicatechin concentrations in healthy adults . j . am . coll . nutr , 2004 , 23 : 197 - 204 . hemann , f . ; spieker , l . e . ; ruschitzka , r . ; sudano , i . ; hermann , m ; binggeli , c . ; luscher , t . f . ; riesen , w . ; noll , g . ; corti , r . dark chocolate improves endothelial and platelet function . heart , 2006 , 166 : 411 - 417 . grassi , d . ; lippi , c . ; necozione , s . ; desideri , g . ferri , c . short - term administration of dark chocolate is followed by a significant increase in insulin sensitivity and a decrease in blood pressure in healthy persons . am . j . clin . nutr . 2005 , 81 : 611 - 614 . buijsse , b . ; feskens , e . j . m . ; kok , f . j . ; kromhout , d . cocoa intake , blood pressure , and cardiovascular mortality . arch . intern . med ., 2006 , 166 : 411 - 417 . liégeois , c . ; lermusieau , g . ; collin , s . measuring antioxidant efficiency of wort , malt and hops against the 2 , 2 ′- azobist ( 2 - amidinopropane ) dihydrochloride - induced oxidation of an aqueous dispersion of linoleic acid . j . agric . food chem ., 2000 , 48 : 1129 - 1134 .
the present invention relates to a novel method for conching chocolate , whereby a chocolate mass is submitted to a conching method that comprises the following steps : — a dry conching step performed at a temperature of between 50 ° c . and 70 ° c ., — and subsequent a wet conching step performed at a temperature of between 60 ° c . and 110 ° c ., more in particular at a temperature between 60 ° c . and 90 ° c ., wherein the dry conching temperature and the wet conching temperature are comprised within the range defined by the graph of fig . 13 . most preferably the dry conching step is performed at about 60 ° c . and the wet conching step at about 60 ° c . or about 90 ° c . advantageously , this adapted conching process conserves and even increases the antioxidant activity of a chocolate , in particular a dark chocolate . consequently , the present invention further relates to a method of conserving and / or increasing the antioxidant activity of chocolate and to chocolates processed accordingly .