Air or oil emulsion food product having glucomannas as sole stabilizer-thickener
This is a continuation-in-part of application Ser. No. 396,392, filed July 8, 1982 now abandoned. 
    
    
     This invention relates to food products and more especially to ungelled processed food products, particularly emulsions, containing a stabilizing or thickening agent. 
     Various processed food products such as ice cream, whipping cream, cheese spreads, cheese slices, milk drinks, meringues and the like when produced on a commercial scale normally incorporate a stabilizing and/or thickening agent to improve their processability, texture, organoleptic properties and storage capability. 
     Various materials have been used as stabilizing and thickening agents including carob gun and/or cellulose ethers such as the hydroxyethyl and carboxymethyl ethers. 
     Carob gum is now in short supply and is relatively expensive but for many applications is among the best stabilizing and thickening agents hitherto available. 
     This invention is based on the observation that glucomannans, especially those derived from Amorphophallus species and especially from A. rivieri and its varieties (often referred to as A. konjac), A. oncophyllus, A. variabilis, A. bulbifera, and A. blumeii can be used satisfactorily to replace carob gum or carob gum, alone or in admixture with other gums and thickeners, as a stabilizing and/or thickening agent in processed food products such as those indicated above. 
     Such glucomannans, especially those derived from A. konjac, are in many cases cheaper than carob gum and frequently can be used in smaller quantities than carob gum to achieve the same effect or a better effect. 
     This invention provides an ungelled processed food product having a pH less than 8 which has been stabilized and/or thickened by the incorporation therein of at least one glucomannan, preferably a glucomannan derived from an Amorphophallus species and especially a glucomannan derived from A. konjac, A. oncophyllus, A. variabilis, A. blumeii, or A. bulbifera in an amount within the range from 0.1 to 5% by weight based on the food product. 
     The food product may be any food product which is normally thickened and/or stabilized. Among such products are for example dairy products such as ice cream, whipping cream, cheese spread, cheese slices, or a flavored milk drink, a meringue, salad creams and mayonnaises, gravies and sauces, and the like. However, the thickening and/or stabilization of emulsions with the agents of the invention is particularly advantageous. In this case, the stabilizer or thickener imparts to a liquid with which it is combined a viscous mobile structure at room temperature, in which liquid air or oil droplets may be present as a discontinuous phase. This phenomenon must be distinguished from gelation, in which a liquid is converted to a rigid, solid structure by the addition of a gelling agent. The aforementioned food products are examples of emulsions which are thickened and/or stabilized to advantage according to the present invention. 
    
    
     The following examples illustrate the invention. 
     In the Examples two different forms of Konjac glucomannan were used: the material referred to as Japanese konjac is a purified glucomannan extract of approximately 90% by weight glucomannan content and is a commercially available product; the material referred to as Chinese taro is a crude material obtained by slicing, drying and grinding whole tubers of A. Konjac from a Chinese source to a particle size of 0.5 mm or less. The Chinese taro material contains large amounts of starch in addition to the glucomannan and in the examples is used in an amount which is 56% more than is used with Japanese konjac to ensure that the glucomannan content of the produced food products is the same. The word &#34;Genulacta&#34; is a Registered Trade Mark. 
     EXAMPLE 1 
     Ice Cream 
     Some commercial ice creams use carob gum for its stabilizing and thickening powers. It imparts smooth melt-down and heat-shock resistance and is not affected by lactic acid or calcium salts. 
     The ice cream was made to the recipe shown in Table 1. 
     
                       TABLE 1                                                     
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                   %                                                      
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Butter               10                                                   
Sugar                14                                                   
Skimmed milk powder  11                                                   
&#34;Genulacta L100&#34;     0.015                                                
Carob gum            0.16                                                 
Glycerol monostearate (GMS)                                               
                     0.12                                                 
Vanilla              0.24                                                 
Water                64.465                                               
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 &#34;Genulacta L100&#34; is a caseinreactive carrageenan from Hercules Ltd.      
 
    
     Four samples were prepared as shown in Table 2. 
     
                       TABLE 2                                                     
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Recipes for Test Samples (grams)                                          
       Sample 1                                                           
              Sample 2    Sample 3 Sample 4                               
       (Control)                                                          
              (Carob gum) (Konjak) (Taro)                                 
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Butter   1020     1020        1020   1020                                 
Milk powder                                                               
         1100     1100        1100   1100                                 
Sugar    1440     1440        1440   1440                                 
GMS       12       12          12     12                                  
Vanilla   24 mls   24 mls      24 mls                                     
                                      24 mls                              
Japanese --       --           16    --                                   
konjac                                                                    
Chinese taro                                                              
         --       --          --      25                                  
Carob gum                                                                 
         --        16         --     --                                   
&#34;Genulacta                                                                
         --         1.5         1.5    1.5                                
L100&#34;                                                                     
Water    6600     6600        6600   6600                                 
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     Procedure 
     Each mix was blended in a Taylor Rustless Steam Jacketed bowl with a Silverson Lab-bench model L2R. The water (6,600 cc) was raised to 50° C., milk powder added, then sugar, then butter hand-sliced into 5 cm pieces, then GMS. Temperature was raised to 72° C. and held for 10 mins. 
     The blend was transferred to stainless steel buckets and passed through a homogenizer to reduce fat globules to 1 micron. An APV Gaulin Minor Homogeniser with 2 stage valve at 2000 psi was used. 
     The homogenized mix was transferred to the Taylor machine and beaten until cool. Vanilla was added and beating/cooling continued to auto-cutout at -5° C. Beating was then continued with manual overide and samples taken to estimate foaming. 
     Beating was continued until the air content of each mix was approximately 50%. 
     The ice cream was poured into plastic dishes and frozen in a blast freezer at -25° C. 
     Results 
     Some physical properties of the ice cream at various stages of its preparation are shown in Table 3. 
     
                       TABLE 3                                                     
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Measurements of Emulsions                                                 
Beating Time        Viscosity (Brookfield)                                
To 50% Air          Spindle 1, 30 rpm                                     
Recipe                                                                    
      Content    pH     Before Homogn                                     
                                  After Homogn                            
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1     4 mins     6.6    4.5       not measured                            
2     4 mins     6.5    66.5       75                                     
3     4 mins     6.6    42          64.5                                  
4     4 mins     6.3    78        greater than                            
                                  100                                     
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     Subjective examination showed that sample 1 was thinner than samples 2 to 4; that samples 2 and 3 were similar; and that sample 4 was thicker, being thixotropic and containing swollen particles which were not in solution before homogenization. 
     After cold storage for 3 days, melt-down was assessed by the standard method of standing equal volumes of ice cream on a mesh and allowing it to melt at ambient temperatures: 
     The results are shown in Table 4. 
     
                       TABLE 4                                                     
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Melt-Down Test                                                            
Time Recipe 1 Recipe 2   Recipe 3 Recipe 4                                
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10   Just     No drip    No drip  Dripping more                           
mins dripping                     than 1, but drips                       
     watery                       are viscous                             
20   Dripping,                                                            
              Just dripping                                               
                         Just dripping                                    
                                  Doming                                  
mins watery,  spreading  viscous,                                         
     little              spreading                                        
     spreading                                                            
40   10 ml    3 ml melt- 12 ml melt-                                      
                                  12 ml melt-                             
mins melt-    down       down     down                                    
     down                                                                 
 1   26 ml    33 ml melt-                                                 
                         45 ml melt-                                      
                                  45 ml melt-                             
hour melt-    down; spread-                                               
                         down; spread-                                    
                                  down; spread-                           
     down;    out        out      out                                     
     domed                                                                
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     Subjectively, all the ice creams were acceptable. A taste panel unanimously agreed that recipe sample 1 was watery, with a less full-textured mouth feel. The panel also found that samples 2 to 4 were all better than sample 1 with samples 3 and 4 exhibiting smoother melt-down in the mouth and appearing less crystalline than sample 2. 
     EXAMPLE 2 
     Whipping Cream 
     Carob gum has also been used commercially to stabilize natural whipped cream. 
     Co-operative Wholesale Society Whipping Cream (48% Butterfat) was used. The thickener was added to the cream and the mix was handwhipped with a kitchen tool to &#34;peaks&#34;. 1/2 pint (276 g) samples were used at room temperature (20° C.). 
     The results are listed in Table 5. 
     
                       TABLE 5                                                     
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Whipped Cream Samples                                                     
Sample Whipping Time                                                      
No.    To Peaks     Additive     Comment                                  
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1       1 minute    Nil                                                   
2      11/2 minutes 0.25% Carob  Lighter and                              
                                 more aerated                             
                                 than 1.                                  
3      11/2 minutes 0.25% Japanese                                        
                                 Richer than 1                            
                    konjac       or 2, stiffer                            
                                 than 2.                                  
4      13/4 minutes 0.39% Chinese                                         
                                 Very stiff                               
                    taro         Richer than 1                            
                                 or 2, Lighter                            
                                 than 1                                   
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     The whipped creams were stored overnight in the refrigerator and tasted at 24 hours age. All tasted similar but sampel 2 had a slight alteration in taste due to the carob gum. 
     The texture was compared by stirring and piping using domestic cake decorating pipes with the results shown in Table 6. 
     
                       TABLE 6                                                     
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Texture of Whipped Creams                                                 
Sample      Bulk Cream    Piped Cream                                     
No.         Texture       Texture                                         
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1           Just pourable Forms stable                                    
                          rosettes                                        
2           Softer and    Softer foamier                                  
            creamier more                                                 
            foamy, More                                                   
            pourable                                                      
3           Similar to 1  Rosettes do not                                 
                          maintain form                                   
4           Similar to 1  Form stable                                     
                          rosettes                                        
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     EXAMPLE 3 
     Meringues 
     Thickeners are used commercially as stabilizers in meringues to improve whipping times and reduce `bleeding` on cooking. 
     The following recipe and method was used: 
     Recipe 
     2 egg whites (separated from hen eggs: approx. 58 g) 
     4 oz. caster sugar (113 g) 
     Pinch of salt (NaCl) 
     Method 
     The egg whites were hand-whipped until peaked. Two teaspoons of caster sugar were beaten in and the remainder of the sugar was folded in. The mix was piped onto grease proof paper. Cooking time was 11/2hours in a forced air oven at 129° C. 
     After cooking, the meringue shells were left to stabilize and samples were evaluated after 24 hours. 
     
                       TABLE 7                                                     
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Meringue Samples                                                          
Sample                 Whipping   Eating                                  
No.      Recipe        Texture    Texture                                 
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1        Standard          Good foam                                      
                                    Sweet and                             
                                    crisp                                 
2        Plus 0.25%                 Sweet and                             
         carob             Better foam                                    
                                    crisp                                 
3        Plus 0.25%        than 1, less                                   
                                    Sweet and                             
         Japanese          let-down crisp                                 
         konjac            with sugar                                     
4        Plus 0.39%        addition Sweet and                             
         Chinese                    crisp                                 
         taro                                                             
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     EXAMPLE 4 
     Cheese Spreads 
     Traditionally cheeses are blended into a spreadable form by cooking while beating with the addition of emulsifying salts that complex the calcium, casein, and fats at a buffered pH. The salts are called Joha Emulsifying agents. They consist of sodium, potassium and calcium polyphosphates, disphosphates, monophosphates and citrates. 
     Red Leicester cheese was formed into a cheese spread using the recipe and method shown in Table 8. 
     
                       TABLE 8                                                     
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Cheese Spread Recipe and Method                                           
               Sample No.                                                 
        Basic Recipe                                                      
                 1      2        3    4                                   
        %        (g)    (g)      (g)  (g)                                 
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Red Leicester                                                             
          60         300    300    300  300                               
Cheese                                                                    
Water     34.5       173    173    173  173                               
Joha S9   3           15     15     15   15                               
Carob gum (0.5)      --      21/2  --   --                                
Japanese konjac                                                           
          (0.5)      --     --      21/2                                  
                                        --                                
Chinese taro                                                              
          (0.6)      --     --     --    3                                
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     The mix was blended 5 minutes at 85° C. in a steam jacketed Hobart bowl and scraped into polyfoil dishes. 
     After 24 hours the samples were tested for texture and taste and the results are listed in Table 9. 
     
                       TABLE 9                                                     
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Cheese Spreads                                                            
Sample                                                                    
No.         Texture        Taste                                          
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1           Soft           Pleasant                                       
                           cheesey taste                                  
2           Slightly stiffer                                              
                           Pleasant                                       
                           cheesey taste                                  
                           but fruity                                     
                           carob                                          
                           aftertaste                                     
3           Stiffer than 2,                                               
                           Pleasant                                       
            slightly waxy  cheesey taste                                  
                           No aftertaste                                  
4           Stiffer than 3,                                               
                           Pleasant                                       
            more crumbly   cheesey taste                                  
                           No aftertaste                                  
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     EXAMPLE 5 
     Cheese Slices 
     Similar techniques to those of Example 4 are used to produce a stiffer cheese for slicing. The addition of thickeners reduces melt-down effects when such processed cheese slices are subsequently used in cooking, for example Welsh Rarebit. 
     The cheeses from Example 4 were reheated with beating to lower the moisture content and left to stiffen overnight in the refrigerator. 
     Next day, slices were cut with an electric knife and equal weights placed on toast. All four samples were toasted simultaneously under a domestic gas oven grill. Sample 1 (no gum) melted quicker and ran over the sides of the bread. Samples 2, 3 and 4 all showed less tendency to overflow when molten. 
     All four samples tasted equally pleasant. 
     EXAMPLE 6 
     Milk Drinks 
     Japanese konjac and Chinese taro were added to a commercially available milk drink and left overnight in the refrigerator. The mix was then homogenized with the Silverson mixer (highest shear). Viscosities were measured with the Brookfield Viscometer (Model LVT). 
     The results are listed in Table 10. 
     
                       TABLE 10                                                    
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Thickened Milk Drinks                                                     
                Viscosity                                                 
Sample          (Scale Reading)                                           
No.   Addition  Spindle 2/30 rpm                                          
                             Subjective Assessment                        
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1     0.33%     10           Foamy, thick                                 
      Japanese               texture, very                                
      konjac                 pleasant                                     
2     0.66%     40           Foamy, slightly                              
      Chinese                thicker texture,                             
      taro                   very pleasant                                
3     Nil        3           Thin, milky texture                          
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