A Mathematical Model for Predicting the Effects of the Steeping Programme on Water Uptake During Malting

Reinikainen³

et al. 2004

Self Cite

A dynamic model was developed that describes the formation of ␤-glucanase and the degradation of ␤-glucans at different temperatures and grain moistures during the germination of malting barley. The process was analysed by simulations and by solving an optimal control problem for maximising the ␤-glucanase activity. The results demonstrate the effects of controlling dynamically the germination process and improve the understanding of cytolysis in germination.

Section: Introductionmentioning

confidence: 99%

A Simulation Model for the Control of beta-Glucanase Activity and beta-Glucan Degradation During Germination in Malting

Kuusela

Reinikainen³

et al. 2004

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“…A simulation model for describing the water uptake has been published earlier. 2 The present paper focuses on modelling the effects of wet and dry periods in the steeping, the water sensitivity of the barley to be malted and the temperature on the homogeneity of germination, i.e., the proportion of grains that germinate during the first day, second day etc.…”

Section: -2863(9'8-32mentioning

confidence: 99%

“…During an air rest stage moisture content x is constant in the water uptake model 2 , and therefore l also is constant. During the wet steep, x is changed according to the water uptake model.…”

Section: %8)6-%07 %2( 1)83(7mentioning

confidence: 99%

“…In the model candidate (2)-(3), the intensity function is constant during both air rest and wet steep periods. Further, it should be noted that, even though the moisture content is ignored in the wet steep model, the moisture contents before and after a wet steep period affect the germination intensity through model (2).…”

Section: %8)6-%07 %2( 1)83(7mentioning

confidence: 99%

“…Thus, the germination intensity during the germination was described by (2). In fact, the grains were moistened in the experiments by spraying after the first day of germination and it is possible that they would have lost some moisture during the germination, but these facts were ignored in the model.…”

Section: %8)6-%07 %2( 1)83(7mentioning

confidence: 99%

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A Model for Predicting the Effects of a Steeping Program on the Germination of Barley with Different Water Sensitivities

Holmberg

Reinikainen³

et al. 2002

A method for modelling and simulation of malting barley during and after steeping was developed. The modelling was based on data from laboratory scale experiments with various steeping programs. The developed model takes into account the steeping program with different wet steep and air rest periods, the average moisture content of the grains, and the water sensitivity of the raw material, malting barley. The model can be used for the analysis of steeping and the subsequent germination process and for planning of the steeping programs for achieving homogeneous germination in malting.Key words: Germination, malting, mathematical model, steeping, water sensitivity. -2863(9'8-32Water is an important factor that controls the physical phenomena and chemical reactions in biological materials during processing. In malting, water is needed to start and maintain the germination of seeds in order to produce hydrolytic enzymes and the subsequent hydrolysis of biopolymers leading to endosperm modification. Correct moisture of the germinating seeds is essential for balanced modification. Homogeneity of the raw material, i.e., similarity of the kernels of malting barley both as to physical structure and germination properties, and control of the malting process determine the homogeneity and quality of the end product, malt.Barleys have different degrees of dormancy and water sensitivity as a result of the weather conditions during the grain filling and harvesting period. Dormant embryos are temporarily unable to germinate whereas water sensitive barleys can germinate and are ready to be malted if favourable steeping programs with sufficient air rest periods are used. Simultaneous chitting of the individual kernels enabling an even start of the germination process is needed for the production of homogeneous malt. The steeping program is important not only for the germination but also for the water uptake of the kernels determining the final steepout moisture. A simulation model for describing the water uptake has been published earlier.2 The present paper focuses on modelling the effects of wet and dry periods in the steeping, the water sensitivity of the barley to be malted and the temperature on the homogeneity of germination, i.e., the proportion of grains that germinate during the first day, second day etc. 1%8)6-%07 %2( 1)8,3(7Batches of eight 1 kg barley samples were steeped and germinated in a micromalting unit (Joe White Malting System, Australia). Crop 1993 Kustaa malting barley with 11.6% protein was used in the experiments that were carried out later in 1994. After harvesting, barley was dried to 11% moisture and stored at room temperature. Before steeping barley was screened and the over 2.5 mm fraction was used in the trials.Four sets (A, B, C, D) of eight steeping programs were applied using temperatures between 10 and 20°C. A, B, and C were applied at two temperatures and D at three temperatures (Table I). The experiments were also previously utilised for modelling the water uptake during steeping 2 . The germin...

A Simulation Model for Malt Enzyme Activities in Kilning

Reinikainen²

2007

Self Cite

The drying and survival of enzyme activities during the kilning of malt were modelled. A set of experiments at the micromalting scale was carried out for model identification and validation. The dynamic models predict the effects of the kilning programme, i.e. the temperature profile on grain moisture, activities of ␤-glucanase, ␣-amylase and limit-dextrinase, and diastatic power during kilning. The process behaviour was analysed by simulations. The predictions match the malting experience well. The models increase the general understanding of enzyme inactivation and can be used in planning the kilning programme.