Abstract:
The present invention relates to the instant coffee or coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content and production method thereof which comprises the steps of roasting the input material, grinding the roasted material, extracting the ground material, yeasting the extract, fermentation, filtration, drying the filtrate; and wherein carcinogenic and cytotoxic process components, which are found in heat treated foods especially in instant coffees, are minimized.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to instant coffee and coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content wherein the carcinogenic and cytotoxic process components found in heat treated roasted foodstuffs especially such as coffee are minimized, and production method thereof. 
       BACKGROUND OF THE INVENTION 
       [0002]    The method used in production of instant coffee in today&#39;s technology comprises a series of processes such as roasting of raw coffee beans, grinding, aroma separation, extraction, concentration and drying. During roasting of coffee beans, acrylamide and HMF are formed at varying concentrations depending on the intensity of the heat treatment that is applied. After the Swedish scientists (Tareke et al, 2002) determined presence of acrylamide, which is announced to be a potential carcinogen (International Agency for Research on Cancer, IARC, 1994), in heat treated foods; determination of the amount of acrylamide in various foods has gained importance. Taking into consideration the incidence of consumption of foods which contain a high concentration of acrylamide such as french fries, many bakery products and coffee, it is obviously necessary to reduce the amount of acrylamide in these foods. In addition to acrylamide, since HMF is also cytotoxic and mutagen, its amount should also be limited. Maximum limit specified for HMF is 40 ppm in honey and 20 ppm in fruit juices. 
         [0003]    Studies are intensively carried out for reducing concentrations of acrylamide and HMF in various products. It has been concluded that reduction of heat treatment time and temperature (Surdyk et al., 2004; Taubert et al., 2004) and reduction of pH value (Jung et al., 2003; Rydberg et al., 2003) reduce formation of acrylamide. Use of asparaginase enzyme (Zyzak et al., 2003; Ciesarova et al., 2006) was also developed as another strategy. By using asparaginase, the asparagine amino acid playing a key role in acrylamide formation is converted to aspartic acid. There is a United States patent document numbered US20040081724 which discloses that roasted coffee beans having reduced amount of acrylamide can be obtained by using the said method. 
         [0004]    United States patent document no. US20070178219, which is another patent document in the state of the art, discloses that acrylamide can be reduced by a method which eliminates asparagine by weakening the cell wall of asparagine-containing plants by microwave energy, ultrasonic energy, pressure force or an enzyme. The principle of this technique is the prevention of asparagine from entering into Maillard reaction. Asparagine is decomposed by asparaginase enzyme or a competitive medium is created to inhibit Maillard reaction of asparagine by using cysteine, lysine or glycine amino acids. It is disclosed that this method was tried for french fries and that it is also applicable for coffee beans. 
         [0005]    In another related study conducted (Gökmen and Senyuva 2007a,b; Park et al., 2005), results are obtained demonstrating that divalent cations reduce acrylamide formation. Making use of this information, European patent document no. EP2160948 discloses that acrylamide formation is reduced by soaking chicory beans into solutions containing Ca 2+  and Mg 2+  before roasting. 
         [0006]    In the Japanese patent document no. JP2007282537, superheated steam was used for roasting and it is mentioned that by means of this method while acrylamide content decreases, chlorogenic acid content increases. 
         [0007]    In the International patent document no. WO2005094591, acrylamide content can also be reduced by 48% by fermenting the coffee beans with lactic acid bacteria before roasting. By means of this process, pH of the medium decreases and thus Maillard reaction slows down. When the coffee beans are roasted after fermentation, less color formation is observed. 
         [0008]    In addition to all of these, in a research (Quarta and Anese, 2012) conducted, vacuum application for reducing furfural and HMF content in coffee is tried and it is determined that it is not very effective in reduction of HMF in soluble coffee. When coffee sample was hydrated before vacuum application, furfural content could be reduced by 100% and HMF content by 20%. However it is reported that serious losses occurred in the volatile smell and aroma components of coffee in this technique. 
         [0009]    Upon consideration of practiced techniques today; firstly decreasing the heat treatment load was tried for reducing acrylamide and HMF, however this was not found to be very useful since it also reduced the benefits provided by heat treatment. Reducing the thermal load also reduces the rate of Maillard reaction and thus concentrations of Maillard reaction products, which are responsible for development of the taste and smell desired in the product. This is the most significant disadvantage of changing the heat treatment parameters. 
         [0010]    Since asparagine amino acid in food plays a key role in production of acrylamide, asparagine removal is used as an alternative technique for limiting acrylamide amount. Asparagine in the food is converted into aspartic acid by using asparaginase enzyme and it is prevented from entering into Maillard reaction. This method is applied in production of biscuits and it is stated that it can be applied in foods, which include dough production in their process such as cakes, breads. However it is stated that its applicability in french fries is difficult. Additionally, when it is used in production of coffee beans with reduced asparagine and thus acrylamide content, since Maillard reaction is again limited, loss of taste, smell and aroma occurs in instant coffee production. 
         [0011]    Strategy of reducing acrylamide by immersing the raw material in solutions containing divalent cations (Ca 2+  etc.) may cause taste defects when used in production of instant coffee. Additionally, cations such as Ca 2+ , Mg 2+  promote glucose dehydration, and thus accelerate HMF formation. 
         [0012]    It is observed that generally mitigation strategies for acrylamide and HMF content in foods is based on limiting Maillard reaction. As Maillard reaction is responsible for formation of the desired taste-smell in the product, use of these techniques especially in considerably aromatic products such as coffee is disadvantageous. 
       SUMMARY OF THE INVENTION 
       [0013]    The objective of the present invention is to provide instant coffee or coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content and production method thereof which is performed without requiring any change in heat treatment (such as roasting). 
         [0014]    Another objective of the present invention is to provide instant coffee or coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content and production method thereof without any loss of taste, smell or aroma. 
         [0015]    A further objective of the present invention is to provide instant coffee or coffee substitute whose harms on human health are reduced or completely eliminated and acrylamide and hydroxymethyl furfural (HMF) contents are reduced, and production method thereof. 
         [0016]    Another objective of the present invention is to provide instant coffee or coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content and production method thereof wherein extracts obtained from grains or grainlike roasted foodstuffs are fermented. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    The inventive instant coffee or coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content and production method thereof is illustrated in the accompanying figure wherein 
         [0018]      FIG. 1  is the flow chart of the production method. 
         [0019]    Instant coffee or coffee substitute with reduced acrylamide and hydroxymethyl furfural (HMF) content and production method thereof ( 100 ) developed to fulfill the objective of the present invention comprises the steps of
       roasting the input material ( 101 ),   grinding the roasted material ( 102 ),   extraction of the ground material ( 103 ),   yeasting the extract ( 104 ),   fermentation ( 105 ),   filtration ( 106 ),   drying the filtrate ( 107 ).       
 
         [0027]    In the inventive instant coffee or coffee substitute production method ( 100 ) firstly roasting ( 101 ) is performed. Seeds, beans and/or fruits obtained from different plants and trees can be used as the input materials. In the preferred embodiment of the invention, coffee beans that are obtained from the seeds of the fruits of coffee trees are used. After the mature coffee beans are collected, they are cleaned by being processed according to wet or dry processing technique. The roasting ( 101 ) process is required for the said cleaned coffee beans to give taste, smell and aroma to the final product. Roasting ( 101 ) can be carried out at different temperature and time conditions. In the preferred embodiment of the invention, temperatures in the range of 200-250° C. are used to obtain the taste and smell specific to the material. Formation of the taste and smell specific to coffee is provided by Maillard reaction. Maillard reaction takes place between free amino groups and carbonyl groups and accelerates as the temperature rises. While enabling formation of the features desired in the product, these reactions also cause formation of various carcinogenic compounds. Acrylamide and hydroxymethyl furfural (HMF) are the most known among these compounds. 
         [0028]    The roasted material is then ground by the help of a grinder ( 102 ) and broken up into smaller particles. 
         [0029]    The ground material is subjected to extraction ( 103 ) under a certain pressure and temperature, and then all soluble components of the coffee are taken into a liquid medium, whereas the insoluble components are removed. In the preferred embodiment of the invention, extraction ( 103 ) is carried out by using water at 10-15 bar pressure and 90-150° C. temperature. The final concentration of the extract is adjusted so that it will contain 10-20% soluble solid. 
         [0030]    The extract containing 10-20% soluble solid obtained after extraction ( 103 ) is taken to the step of yeasting ( 104 ). In this step ( 104 ), mixtures are prepared by adding sucrose and yeast to the extracts. In the preferred embodiment of the invention, baker&#39;s yeast ( Saccharomyces cerevisiae ), which does not have any harm on human health and which is used in production of many fermented products, is used as the yeast. Baker&#39;s yeast basically needs carbon and nitrogen source and is easily active at such mediums. In the preferred embodiment of the invention, the extract containing 10-20% soluble solid is mixed with % 0.5-1 yeast (w/v) and 1-10% sucrose (w/v) and thereby fermentation takes place. 
         [0031]    The mixtures that are prepared are fermented ( 105 ) with the impact of the step of yeasting ( 104 ), and at the same time acrylamide and HMF formed after roasting ( 102 ) are reduced by being metabolized by the yeast. In the preferred embodiment of the invention, fermentation ( 105 ) continues for 12-48 hours at temperatures 25-30° C. 
         [0032]    After fermentation ( 105 ) ceases, filtration ( 106 ) is carried out in order to separate and remove the yeast cells from the product. 
         [0033]    The filtrate which is cleaned from the yeast cells is finally dried ( 107 ). Drying can be applied in two different ways, namely spray drying or freeze drying. 
         [0034]    Following drying ( 107 ), the final product is obtained such that there is no loss of taste-smell and aroma and that it is mostly cleared of the undesirable carcinogenic and cytotoxic substances. 
         [0035]    Acrylamide and HMF concentration in the final product can be adjusted by changing the percentages of extract, yeast and sucrose in the mixtures prepared during the step of yeasting ( 104 ). Examples and results pertaining to the mixtures wherein the extracts obtained from the coffee beans are used are given below. 
       EXAMPLE 1 
       [0036]    A mixture is prepared by 20% coffee extract (w/v), 10% sucrose (w/v) and 1% baker&#39;s yeast (w/v); and is allowed to ferment for 12 hours. The HMF content in the final product, which is thus produced, is observed to decrease by 94% relative to the HMF content in the roasted coffee. 
       EXAMPLE 2 
       [0037]    A mixture is prepared by 20% coffee extract (w/v), 10% sucrose (w/v) and 1% baker&#39;s yeast (w/v); and the extract is allowed to ferment for 24 hours. The acrylamide content in the final product, which is thus produced, is observed to decrease by 52% relative to the acrylamide content in the roasted coffee. HMF content decreased by 98.6%. 
       EXAMPLE 3 
       [0038]    A mixture is prepared by 20% coffee extract (w/v), 10% sucrose (w/v) and 1% baker&#39;s yeast (w/v); and the extract is allowed to ferment for 48 hours. The acrylamide content in the final product, which is thus produced, is observed to decrease by 72.7% relative to the acrylamide content in the roasted coffee. HMF content decreased by 100%. 
         [0039]    As it is seen from the above given examples, fermentation time plays a significant role in reducing acrylamide and HMF content in the product.