Refined plant isolates and process for the manufacture of a functional food ingredient from such plant isolate

Abstract

The present invention is concerned with providing refined plant isolates that can be used as starting materials for the production of functional food ingredients, such as taste enhancers, through an isolation process that employs ion exclusion chromatography. More particularly, the present invention provides a refined plant isolate comprising at least 30% by weight of dry matter of water soluble plant components selected from fructose, glucose, proteinaceous matter of plant origin, acids and potassium, said isolate further being characterized in that at a concentration of 40° Brix the isolate: •contains at least 0.3 wt % of glutamate; •contains at least 500 ppm of K + ; •contains less than 300 ppm of Ca 2+ ; •contains less than 700 ppm of Mg •contains less than 1 wt. % of components capable of passing an ultra filtration membrane having a molecular weight cut off of 250 kDa; wherein the concentration ratio ([Ca 2+ ]+[Mg 2+ ])/[K − ] does not exceed 5:100, each of said cation concentrations being expressed in ppm.

1 . A refined tomato isolate comprising at least 30% by weight of dry matter of water soluble plant components selected from fructose, glucose, proteinaceous matter of plant origin, acids and potassium, said isolate further being characterized in that at a concentration of 40° Brix the isolate:
 a) contains at least 0.2 wt % of glutamate; 
 b) contains at least 500 ppm of K + ; 
 c) contains less than 300 ppm of Ca 2+ ; preferably less than 100 ppm of Ca 2+ : 
 d) contains less than 700 ppm of Mg 2+ ; preferably less than 300 ppm of Mg 24 ; 
 wherein the concentration ratio ([Ca 2+ ]+[Mg 2+ )/[K + ] does not exceed 5:100, each of said cation concentrations being expressed in ppm. 
 
     
     
         2 . Refined tomato isolate according to  claim 1 , wherein at a concentration of 40° Brix the isolate contains at least 800 ppm of K +  preferably at least 2000 ppm of K + , more preferably at least 5000 ppm of K + . 
     
     
         3 . Refined tomato isolate according to  claim 1 , wherein concentration of 40° Brix the isolate contains:
 a) 0.1-30 wt. % of fructose; and 
 b) 0.1-30 wt. % of glucose. 
 
     
     
         4 . Refined tomato isolate according  claim 1 , wherein at a concentration of 40° Brix the isolate contains from 0.5-30 wt. % of glutamate. 
     
     
         5 . Refined tomato isolate according to  claim 1 , wherein at a concentration of 40° Brix the isolate contains 0.01-20 wt. % of citrate. 
     
     
         6 . Refined tomato isolate according to  claim 1 , comprising glutamate and citrate in a weight ratio glutamate: citrate that lies within the range of 1:50 to 10,000:1. 
     
     
         7 . Refined tomato isolate according to  claim 1 , comprising glutamate and glucose in a weight ratio glutamate:
 glucose that lies within the range of 1:50 to 100:1.   
     
     
         8 . Refined tomato isolate according to  claim 1 , wherein the concentration ratio ([Ca 2+ ]+[Mg 2+ ])/[(K + ] does not exceed 3:100 each of said cation concentrations being expressed in ppm. 
     
     
         9 . Refined tomato isolate according to  claim 1 , wherein the refined tomato isolate is obtainable by a process comprising:
 a) providing a crude tomato serum wherein not more than 40 vol. % of the particles has a diameter larger than 2 μm;   b) concentrating, if necessary, said crude torr ato serum to at least 2° Brix; and   c) removing Ca 2+  and M 2+  from the optionally concentrated tomato serum to produce a refined tomato isolate.   
     
     
         10 . A process of preparing a functional food ingredient, said process comprising:
 a) providing a refined plant isolate;   b) subjecting the refined plant isolate, optionally after concentrating or diluting said refined plant isolate to ion exclusion chromatography; and   c) collecting at least a part of the eluate of said ion exclusion chromatography as the functional food ingredient or an intermediate for the production of a functional food ingredient;   wherein the refined plant isolate comprises at least 30% by weight of dry matter of water soluble plant components selected from fructose, glucose, proteinaceous matter of plant origin, acids and potassium, said isolate further being characterized in that at a concentration of 40° Brix the isolate:   i. contains at least 0.2 wt % of glutamate;   ii. contains at least 500 ppm of K + ;   iii. contains less than 300 ppm of Ca 2+ ; preferably less than 100 ppm of Ca 2+ ;   iv. contains less than 700 ppm of Mg 2+ ; preferably less than 300 ppm of Mg 2+ ;   v. contains less than 1 wt. % of components incapable of passing an ultra filtration membrane having a molecular weight cut off of 250 kDa;   wherein the concentration ratio ([Ca 2+ ]+[Mg 2+ ])/[K + ] does not exceed 5:100, each of said cation concentrations being expressed in ppm; and   wherein the weight ratio glutamate:citrate in the collected eluate is at least 5 times higher than the same ratio in the refined plant isolate that is subjected to ion exclusion chromatography and/or the weight ratio glutamate:glucose in the collected eluate is at least 10 times higher than the same ratio in the refined plant isolate.   
     
     
         11 . Process according to  claim 10 , wherein the refined plant isolate is prepared by
 a) providing an aqueous plant extract containing particles of plant material;   b) removing from said plant extract more than 50 vol. % of the particles having a particle size of at least 2 μm to produce a crude serum wherein not more than 40 vol. % of the particles has a diameter larger than 2 μm;   c) concentrating, if necessary, said crude serum to at least 2° Brix, preferably at least 10° Brix; and   d) removing Ca 2+  and Mg 2+  from the optionally concentrated serum to produce a refined plant serum;   wherein the concentration ratio ([Ca 2+ ]+[Mg 2+ ])/[K + ] in the refined plant isolate is at least 2 times, preferably at least 3 times lower than the same concentration ratio in the optionally concentrated plant extract, each of these cation concentrations being expressed in ppm,   
     
     
         12 . Process according to  claim 11 , wherein the particles are removed from the aqueous plant extract by means of filtration or centrifugation, preferably by filtration. 
     
     
         13 . Process according to  claim 12 , wherein the particles are removed by filtration employing a membrane with a molecular weight cut-off of 25-500 kDa. 
     
     
         14 . Process according to  claim 11 , wherein Ca 2+  and. Mg 2+  are removed from the optionally concentrated crude serum by means of electrodialysis, nanofitration. ion exchange chromatography or a combination of thereof. 
     
     
         15 . Process according to  claim 11 , wherein, calculated on dry matter, the combined concentration of Ca 2+  and Mg 2+  in the refined plant isolate is at least 4 times, preferably at least 7 times lower than in the optionally concentrated crude serum.