Investigation of the Germination of Barley and Wheat Grains with a Design of Experiments for the Production of Hydrolases.

Bertolt Kranz,Milena Koch,Lutz Fischer,Matthias Schapfl

doi:10.17113/ftb.53.02.15.3718

Abstract

The production of hydrolases from cereals has been examined in order to investigate food-derived enzymes as an alternative source to microbial enzymes for the use in food processes. For that, the influence of temperature on the pretreatment, imbibition and germination of barley and wheat grains was determined by measuring the β-glucosidase, β-galactosidase and lipase activities using a design of experiments. The evaluation of the statistical model showed an increase of the β-glucosidase activity with low imbibition and low germination temperature for barley grains and low imbibition and high germination temperature for wheat grains. The maximum β-glucosidase activity in wheat extracts was (585±151) nkat per g of dry mass (dm), while in barley extracts it was (109±15) nkat per g of dm. The maximum β-galactosidase activities in barley and wheat extracts were (34±12) and (63±23) nkat per g of dm, respectively. The maximum lipase activities of (6.7±0.1) and (4.6±4.4) nkat per g of dm in barley and wheat extracts, respectively, were rather low compared to the glycosidase activities. The extracts were also tested for other hydrolase activities (e.g. peptidase and α-amylase activities). The insights obtained enable the basis for the potential use of cereal hydrolases in food processing, which might be attractive to consumers.

Highlights

Many enzymes from different classes used for food processing [1,2,3,4,5] originate from genetically modified microorganisms [6]
The influence of temperature on the pretreatment, imbibition and germination of barley and wheat grains was determined by measuring the β-glucosidase, β-galactosidase and lipase activities using a design of experiments
The evaluation of the statistical model showed an increase of the β-glucosidase activity with low imbibition and low germination temperature for barley grains and low imbibition and high germination temperature for wheat grains

Summary

Introduction

Many enzymes from different classes used for food processing [1,2,3,4,5] originate from genetically modified microorganisms [6]. People in Finland, Italy and Germany show the most positive attitude towards the use of endogenic enzymes from plants (without genetic modification) and most negative towards the use of genetically modified enzymes, regardless of whether they are of microbial or plant origin, as shown by a study about consumers’ attitudes to enzymes in food production [7]. In a study about the degradation of gliadin peptides with peptidases from germinated wheat, barley and rye grains, the authors stated that peptidases derived from germinated grains have a higher acceptance by coeliac patients [8] It seems that non-genetically modified enzymes and enzymes from natural origins (e.g. plants) and not from microorganisms are of high interest for certain consumers. The grain-associated peptidases are more suitable for the hydrolysis of some food ingredients, e.g. gluten [9]

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