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A computer-controlled micro-malting apparatus
Journal a/Cereal Science 4 (1986) 71-78
A Computer-controlled Micro-malting Apparatus PETER G. GOTHARD and DEREK B. SMITH Plant Breeding Institute, Maris Lane, Trumpington, Cambridge eB22LQ, U.K. Received 30 May 1985
An automated, computer-controlled malting apparatus suitable for assessing the small samples produced by barley breeders is described. This apparatus enables one operator to malt and analyse more than 100 samples per week. Results showed that the discriminating ability ofthe automated system compared favourably with the more complex and slower manual malting method currently used in this laboratory. These results suggest that the system is well suited for screening breeding material and the increased efficiency enables more crosses to be analysed or more selections to be made from earlier generations.
Introduction Large numbers of samples are generated in plant breeding programmes and selections are made for appropriate agronomic and quality criteria. In breeding new varieties of barley, malting quality is an important character, and several rapid, small-scale tests have been proposed to select for malting quality amongst large numbers of genotypes>", However, none of the tests has gained widespread acceptance, and many barley breeders still rely on micro-malting tests conducted on material from the later generations of a programme. Many micro-malting systems have been designed since that reported by Whitmore and Sparrow" in 1957, and several automated systems have been described'
© 1986 Academic Press Inc. (London) Limited
P. G. GOTHARD AND D. B. SMITH
72
B
w T
t·~----_......J w
c
t
T
A
_Ij:~t
11
-;..
I
-- '0
I
FIGURE 1. Diagram of automated malting apparatus. Key: A = water circulator and temperature controller; B = malting tank; C = reservoir tank; D = rollers; E = filter; F = secondary reservoir; G = emergency overflow; H = inlet manifold; I = malt container; PI = main circulating pump; P 2 = reservoir drain pump; P 3 = malt tank drain pump; V I := water level control valve; V 2 = mains water inlet valve; T = temperature probe; W = water level sensor. The reservoir tank measures 90 x 60 x 40 em internally and is mounted with the temperaturecontrolling water circulator (A) on a wheeled trolley. This trolley fits under a laboratory bench but can be pulled out for servicing and cleaning as the plumbing to the malting tank is of reinforced flexible piping. The circulator collects and returns water' from the reservoir tank via a small secondary reservoir (F) to ensure that the circulator pump remains primed when the main reservoir is emptied. The other pumps are all mounted below the tank from which they receive water, so they too are always primed. Water is fed into the reservoir tank through a motorised valve (V2) and an emergency overflow (G) is fitted. Another outlet and pump (P2) are used to drain the tank. A temperature probe (T) is located below the water level in this tank and float switches (W) detect whether it is full or empty. A high-capacity pump (P I) takes water from the reservoir to the malting tank and distributes the water throughout the tank by means of a perforated manifold (H). The malting tank (122 x 66 x 15 ern internally) fits on the bench above the reservoir tank. An outlet and pump (P 3) are provided to drain the tank. The samples, in containers (I), are placed on a set of nine stainless steel rollers (D) that are turned via gearing by a 0·25 h.p. electric motor fitted with a reduction gearbox. Final speed adjustment between O' 5 and 10 rjmin is controlled by a thyristor. The roller system is easily removable for servicing. Two outlets control the water level in the malting tank, one being below the rollers and fitted with a rnotorised valve (V 1). When this valve is open the water level remains below the rollers to provide the conditions for air rests and endosperm modification; when the valve is closed water rises to the other outlet to provide conditions for steeping. The level and temperature of the water in the malting tank are monitored as for the reservoir tank. The outflow from the malting tank is fed back into the reservoir tank through a filter (E). The samples are weighed and placed in containers, which are 75 mm lengths of plastic piping
COMPUTER-CONTROLLED MALTING APPARATUS
73
(42 mm i.d.) with three groups of five slots (35 x 2 mm) cut round the circumference (I). One end is closed permanently with a 39 mm dia. neoprene bung and the other is sealed by a cut-down 43 mm dia. bung after the grain has been added. A rubber O-ring is partially recessed into each end of the container to ensure traction on the rollers. A total of 104 containers, each capable of holding up to 20 g of grain, can be fitted on to the roller system.
Control system The variable functions of the apparatus are controlled by a BBC model B micro-computer. The user and printer ports are utilised to collect analogue signals from the temperature probes and water-level detectors and to send appropriate signals to the pumps, valves and the water circulator, which also controls the temperature. The computer driyes the equipment through a series of relays. The thermistor probes are routed through a variable resistor to enable accurate calibration of temperature. Data derived from the sensors are displayed on an elapsed-time graph together with details of the current stage of the malting regime. The contents of the visual display unit (VDU) screen are transferred to a printer every 20 h to form a continuous record of the malting conditions throughout the process.
The program" A flow diagram of the program used to control the malting process is shown in Fig. 2. The program contains a facilityto set the conditions of the regime to be used or to use a set of standard conditions if required. Options to change or correct details are included and constraints are set on the number of wet steeps, air rests and temperatures requested to prevent the entry of impractical parameters. The samples are weighed, placed into containers and loaded on to the rollers, and an appropriate roller speed is selected (usually 0·5 r/rnin), The program is RUN and initially requests details of the material to be malted and the regime to be used. The reservoir tank is then filled automatically and the temperature adjusted for the first steep. This temperature is held until the MALT command is entered. The program then controls the temperatures and water levels to give wet steeps, air rests and modification conditions. At the end of each steep some of the liquor is discharged to waste and is replaced automatically by fresh water. The small head space above the rollers ensures that the air is always very humid and that it is maintained at the temperature of the water. At the end of the modification period the data on the VDU screen are transferred to the printer, an end of run message is displayed and the two tanks are emptied. The sample containers (with closing bung removed) are transferred to a forced-draught oven and kilned at 50°C for 7'5 hand 65°C for 22 h before the shoots and roots are removed.
Assessment ofperformance Experiments were conducted to observe the effect of steep, air rest and modification conditions on the malting performance of four barley samples of different malting qualities and to select regimes suitable for screening breeding material. The barleys chosen were samples of the varieties Triumph and Egmont from the 1983 harvest and Triumph and Koru from the 1984 harvest, all grown at Cambridge, U.K. For these experiments, ten replicates of each sample were distributed randomly on the rollers. When provisional optimal conditions had been determined an experiment using replicated samples from a breeder's trial was conducted using the automated apparatus described here and the standard manual system used in this laboratory!". Details of the regimes used in each experiment are given in Table I.
*
Copies of the complete control program arr available on request from the authors.
74
P. G. GOTHARD AND D. B. SMITH
Convert times to minutes and calculate elapsed time before each operation
Plot temperature and water level
No
Set and maintain temperatures, water level s and time for each stage of the regime
FIGURE 2. Simplified flowchart of control program. Procedures used in program: PROCchange, uses required temperature to determine whether to use PROCon or PROCoff. PROCcheck, displays regime entered to allow details to be changed. PROCcorrect, enables any part of regime to be corrected or changed. PROCdump, copies contents of VDU screen to printer. PROCempty, stops circulation pumps, closes all valves and runs drain pumps until tanks are empty. PROCheat, uses required temperature to turn on heater for a period proportional to temperature increase required. PROClower, lowers water level in malt tank for air rests and germination. PROCoff, turns cooler motor off. PROCon, turns cooler motor on. PROCplot, plots temperature and water level in VDU graphics window. PROCprint, prints details of trial and regime from VDU text window. PROCquest, issues audible signal when tank is up to temperature and looks for start command. PROCraise, raises water level in malt tank for steeping.
TABLE I. Malting conditions and hot-water extract (HWE) data from five malting regimes with four samples of barley
Regime
Code number
Steep
Air rest
(h)
(h)
Within-replicate statistical analysis (dJ= 9)
Mean HWE (%) (n = 10) Modifi- Temperacation ture Triumph (h) 1983
eq
Egmont 1983
Triumph 1984
Koru 1984
S.E.D. a
C.V. (%)b
V.R. C
o 0
5
"51
19 5 19 5 64
2
0·257
0·30
0·466 N •S •
75
75
12 12 12 12 12 15
5 IS
5 15 5
~
o
}
0
72-4
70·7
76·1
73·4
0·319
0·40
1·597 N •s.
15 5
15 5
5 15
5 15 5
= Standard error of differences.
= Coefficient of variation. = Varianceratio.
r-
t'"' ttl
tl
~ ;J> t-
j
}
61·6
55-3
68·6
62·1
0·571
0·90
0·g03 N •S •
1
a ~ ~
~..,
5
= Not significant.
c:::: >-l
ttl
:;c
12 12 13 } 12 14 10
64
N.S.
75·8
Z
72
5
a S.Il.D. b C.V. e V.R.
77-2
>-l
19
5
72·0
0
17 17 17 17 17 17 12 12 12 12 12 10
5
4
."
73-1
5 19
3
15·5 15·5 15·5 15·5 15·5
~
64·7
55·0
68·2
61·7
0·531
0·80
0·643 N . S •
70·6
65·3
73·6
70·4
0·352
0·50
1·163N •s.
c: tf}
..., u.
76
P. G. GOTHARD AND D. B. SMITH
TABLE II. Ranges of differences in hot-water extract values within replicates and within overall data Range of differences in hot-water extract values (%) Within replicates Regime code-
1 2 3 4 5
Triumph 1983
Egmont 1983
Triumph 1984
Koru 1984
Overall data
2'2 2·0 2·4
5·2 5·4 13·3
2-2
13·2
1·8
1-8
1·6 1·1 2·5 5·5 1'5
1·4 1·9 3·7
2'3
3·2 1·1 6·4 4·7
3'3
10·1
" See Table I for details.
Results Five regimes were used to malt the four barley samples in the automated apparatus. The steeping and germination (growth) conditions are given in Table I, and malt analyses were carried out as described by Gothard et al.13 Malt moisture at the end of kilning was between 4 and 5 %. Regimes 1 and 2 produced over-modified malt, 3 and 4 under-modified malt and 5 gave more acceptable results. Despite differences of up to 17 % in hot-water extract (HWE) between the different regimes within one variety, each regime consistently separated the best and worst varieties. These results show that any regime within the conditions we tested would separate the samples successfully into good, intermediate and poor categories; this is all that is required of a screening test. The overall range (Table II), which includes varietal effects, showed that the less modified samples gave greater separation between varieties. This result indicated that a regime that stresses the samples during malting is more suitable for selection purposes as it emphasises variations, confirming previous observations to this effect". However, the extracts from regimes 3 and 4 were particularly low and may not have reflected how the material would behave under commercial conditions. Statistical analyses within the ten replicates suggested that greater precision was achieved when modification was greater (regimes 1 and 2). However, this was due to the more restricted range of variation under these regimes; replicate variance ratios were all non-significant, and coefficients of variation were all < 1%. Regime 5 gave results that combined a good range in extracts, and hence easy separation of cultivars, with good precision. Regime 5, therefore, seemed the most promising and was tested more rigorously. Thirty-three samples, each of 20 g from a barley trial were malted using this regime and the standard manual malt regime": The results, summarised in Table III, show that the automated method produced malts with near ideal cold-water extracts (CWE)16 but with rather high Kohlbach Index (KI) values-". The malts produced by the manual system are somewhat under-modified as judged by CWE, but they have reasonable KI values.
77
COMPUTER-CONTROLLED MALTING APPARATUS
TABLE III. Comparison of some malt characters in samples processed by the manual and the automated micro-malting systems (n = 33, replicates = 3)
V.R.a
Correlation coefficient between methods (r)
7·76
1·128N •s.
0'514**
43·17
11·72
3·018N .s.
0,724***
71·46
6·87
1·150N .s.
0,811***
Manual malting
Automated malting
Character
Mean
Range
V.R. a
Mean
Range
Cold-water . extract (%) Kohlbach index Hot-water extract (%)
14·98
4·10
1·445N .s.
18'57
34·13
11·73
1·451N .s.
73-16
6·97
0·133N •s.
a V.R. N.S. =
= Variance ratio (within replicates).
Not significant.
"'" p < 0·01. P < 0·001.
"'"*
Both methods produced acceptable HWEs, the most important quality criterion, with similar varietal differences. The variance ratio within replicates was not significant for any of the characters examined by either method. There were significant correlations between the two methods for the three parameters measured, with HWE having the highest correlation coefficient. A comparison of the same number of samples processed in duplicate by the manual system was carried out at the same time to assess variation within this system. A correlation coefficient of 0·842 (P < 0'001) was obtained between the duplicate HWE measurements, a value only slightly greater than that found between the two methods. Since these results were obtained the automated system has been used successfully to test many hundreds of samples, which can now be processed at the rate of 104 per week. The time required to produce and analyse these samples on a routine basis is less than that of one full-time operator. Conclusion
The microcomputer-controlled apparatus enables one operator to malt and analyse about twice the number of samples that is possible using the manual system. Grain protein content can be measured by near-IR reflectance spectrometry" and this is rapid and simple enough to complement the increased level of malt production. The automatic method has proved well suited to the rapid screening of barley lines for quality at the F 4 or Fij stage of breeding programmes. Other advantages of the computer-controlled process are (a) that the system provides a print-out of the conditions throughout each run, (b) it is easier to change malting regimes, and (c) such regimes are now no longer restricted by the working day of operators. Accurate control by computer also results in better reproducibility from run to run.
78
P. G. GOTHARD AND D. B. SMITH
The authors thank Mr B. Williams for the design and construction of the interface between the computer and the malting apparatus and for help with the programming. Thanks are also due to Mr P. Gurner, Mr P. Bavister and Mr F. Head for much of the design and construction work. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.
Allison, M. J., Cowe, I. A., Borzucki, R., Bruce, F. and McHale, R. J. Inst. Brew. 85 (1979) 262-264. Ellis, R. P., Swanston, J. S. and Bruce, F. M. J. Inst. Brew. 85 (1979) 282-285. Morgan, A. G. and Gothard, P. G. J. Inst. Brew. 85 (1979) 339-341. Morgan, A. G. and Gothard, P. G. J. Sci. Food Agrtc. 32 (1981) 333-338. Reeves, S. G., Baxter, E. D., Martin H. L. and Wainwright, T. J. Inst, Brew. 8S (1979) 141-143. Whitmore, E. T. and Sparrow, D. H. B. J. Inst. Brew. 63 (1957) 397-398. Anderson, J. A. Can. J. Res. CIS (1937) 204-216. Atkinson, J. M. and Bendelow, V. M. Can. J. Plant Sci. 56 (1976) 1007-1010. Banasik, O. J., Myhre, D. V. and Harris, R. H. Brew. Dig. 31 (1956) 50--55, 63-67. Davis, A. D. and Pollock, J. R. A. J. Inst. Brew. 62 (1956) 383-389. Haslemore, R. M., Tunnic1iffe, C. G., Slack, C. R. and Shaw, S. Jt Inst. Brew. 91 (1985) 101-105. Meredith, W. O. S., Anderson, J. A. and Hudson. L. E. in 'Barley and Malt Biology, Biochemistry and Technology' (A. H. Cook, ed.), Academic Press, London (1962) pp 231-241. Gothard, P. G., Morgan, A. G. and Smith, D. B. J. Inst. Brew. 86 (1980) 69-73. Gothard, P. G. in 'Barley Genetics IV. Proceedings of the Fourth International Barley Genetics Symposium', Edinburgh University Press, Edinburgh (1981) pp 242-248. Wainwright, T. Brewer 65 (1979) 314-317. Hudson, J. R. in 'Development of Brewing Analysis. A Historical Review', The Institute of Brewing, London (1960) p 22. Kent-Jones, D. W. and Amos, A. J. in 'Modern Cereal Chemistry', Northern Publishing Co., Liverpool (1957) p 95. Starr, C., Morgan, A. G. and Smith, D. B. J. Agric. Sci. Comb. 97 (1981) 107-118.
A Computer-controlled Micro-malting Apparatus PETER G. GOTHARD and DEREK B. SMITH Plant Breeding Institute, Maris Lane, Trumpington, Cambridge eB22LQ, U.K. Received 30 May 1985
An automated, computer-controlled malting apparatus suitable for assessing the small samples produced by barley breeders is described. This apparatus enables one operator to malt and analyse more than 100 samples per week. Results showed that the discriminating ability ofthe automated system compared favourably with the more complex and slower manual malting method currently used in this laboratory. These results suggest that the system is well suited for screening breeding material and the increased efficiency enables more crosses to be analysed or more selections to be made from earlier generations.
Introduction Large numbers of samples are generated in plant breeding programmes and selections are made for appropriate agronomic and quality criteria. In breeding new varieties of barley, malting quality is an important character, and several rapid, small-scale tests have been proposed to select for malting quality amongst large numbers of genotypes>", However, none of the tests has gained widespread acceptance, and many barley breeders still rely on micro-malting tests conducted on material from the later generations of a programme. Many micro-malting systems have been designed since that reported by Whitmore and Sparrow" in 1957, and several automated systems have been described'
© 1986 Academic Press Inc. (London) Limited
P. G. GOTHARD AND D. B. SMITH
72
B
w T
t·~----_......J w
c
t
T
A
_Ij:~t
11
-;..
I
-- '0
I
FIGURE 1. Diagram of automated malting apparatus. Key: A = water circulator and temperature controller; B = malting tank; C = reservoir tank; D = rollers; E = filter; F = secondary reservoir; G = emergency overflow; H = inlet manifold; I = malt container; PI = main circulating pump; P 2 = reservoir drain pump; P 3 = malt tank drain pump; V I := water level control valve; V 2 = mains water inlet valve; T = temperature probe; W = water level sensor. The reservoir tank measures 90 x 60 x 40 em internally and is mounted with the temperaturecontrolling water circulator (A) on a wheeled trolley. This trolley fits under a laboratory bench but can be pulled out for servicing and cleaning as the plumbing to the malting tank is of reinforced flexible piping. The circulator collects and returns water' from the reservoir tank via a small secondary reservoir (F) to ensure that the circulator pump remains primed when the main reservoir is emptied. The other pumps are all mounted below the tank from which they receive water, so they too are always primed. Water is fed into the reservoir tank through a motorised valve (V2) and an emergency overflow (G) is fitted. Another outlet and pump (P2) are used to drain the tank. A temperature probe (T) is located below the water level in this tank and float switches (W) detect whether it is full or empty. A high-capacity pump (P I) takes water from the reservoir to the malting tank and distributes the water throughout the tank by means of a perforated manifold (H). The malting tank (122 x 66 x 15 ern internally) fits on the bench above the reservoir tank. An outlet and pump (P 3) are provided to drain the tank. The samples, in containers (I), are placed on a set of nine stainless steel rollers (D) that are turned via gearing by a 0·25 h.p. electric motor fitted with a reduction gearbox. Final speed adjustment between O' 5 and 10 rjmin is controlled by a thyristor. The roller system is easily removable for servicing. Two outlets control the water level in the malting tank, one being below the rollers and fitted with a rnotorised valve (V 1). When this valve is open the water level remains below the rollers to provide the conditions for air rests and endosperm modification; when the valve is closed water rises to the other outlet to provide conditions for steeping. The level and temperature of the water in the malting tank are monitored as for the reservoir tank. The outflow from the malting tank is fed back into the reservoir tank through a filter (E). The samples are weighed and placed in containers, which are 75 mm lengths of plastic piping
COMPUTER-CONTROLLED MALTING APPARATUS
73
(42 mm i.d.) with three groups of five slots (35 x 2 mm) cut round the circumference (I). One end is closed permanently with a 39 mm dia. neoprene bung and the other is sealed by a cut-down 43 mm dia. bung after the grain has been added. A rubber O-ring is partially recessed into each end of the container to ensure traction on the rollers. A total of 104 containers, each capable of holding up to 20 g of grain, can be fitted on to the roller system.
Control system The variable functions of the apparatus are controlled by a BBC model B micro-computer. The user and printer ports are utilised to collect analogue signals from the temperature probes and water-level detectors and to send appropriate signals to the pumps, valves and the water circulator, which also controls the temperature. The computer driyes the equipment through a series of relays. The thermistor probes are routed through a variable resistor to enable accurate calibration of temperature. Data derived from the sensors are displayed on an elapsed-time graph together with details of the current stage of the malting regime. The contents of the visual display unit (VDU) screen are transferred to a printer every 20 h to form a continuous record of the malting conditions throughout the process.
The program" A flow diagram of the program used to control the malting process is shown in Fig. 2. The program contains a facilityto set the conditions of the regime to be used or to use a set of standard conditions if required. Options to change or correct details are included and constraints are set on the number of wet steeps, air rests and temperatures requested to prevent the entry of impractical parameters. The samples are weighed, placed into containers and loaded on to the rollers, and an appropriate roller speed is selected (usually 0·5 r/rnin), The program is RUN and initially requests details of the material to be malted and the regime to be used. The reservoir tank is then filled automatically and the temperature adjusted for the first steep. This temperature is held until the MALT command is entered. The program then controls the temperatures and water levels to give wet steeps, air rests and modification conditions. At the end of each steep some of the liquor is discharged to waste and is replaced automatically by fresh water. The small head space above the rollers ensures that the air is always very humid and that it is maintained at the temperature of the water. At the end of the modification period the data on the VDU screen are transferred to the printer, an end of run message is displayed and the two tanks are emptied. The sample containers (with closing bung removed) are transferred to a forced-draught oven and kilned at 50°C for 7'5 hand 65°C for 22 h before the shoots and roots are removed.
Assessment ofperformance Experiments were conducted to observe the effect of steep, air rest and modification conditions on the malting performance of four barley samples of different malting qualities and to select regimes suitable for screening breeding material. The barleys chosen were samples of the varieties Triumph and Egmont from the 1983 harvest and Triumph and Koru from the 1984 harvest, all grown at Cambridge, U.K. For these experiments, ten replicates of each sample were distributed randomly on the rollers. When provisional optimal conditions had been determined an experiment using replicated samples from a breeder's trial was conducted using the automated apparatus described here and the standard manual system used in this laboratory!". Details of the regimes used in each experiment are given in Table I.
*
Copies of the complete control program arr available on request from the authors.
74
P. G. GOTHARD AND D. B. SMITH
Convert times to minutes and calculate elapsed time before each operation
Plot temperature and water level
No
Set and maintain temperatures, water level s and time for each stage of the regime
FIGURE 2. Simplified flowchart of control program. Procedures used in program: PROCchange, uses required temperature to determine whether to use PROCon or PROCoff. PROCcheck, displays regime entered to allow details to be changed. PROCcorrect, enables any part of regime to be corrected or changed. PROCdump, copies contents of VDU screen to printer. PROCempty, stops circulation pumps, closes all valves and runs drain pumps until tanks are empty. PROCheat, uses required temperature to turn on heater for a period proportional to temperature increase required. PROClower, lowers water level in malt tank for air rests and germination. PROCoff, turns cooler motor off. PROCon, turns cooler motor on. PROCplot, plots temperature and water level in VDU graphics window. PROCprint, prints details of trial and regime from VDU text window. PROCquest, issues audible signal when tank is up to temperature and looks for start command. PROCraise, raises water level in malt tank for steeping.
TABLE I. Malting conditions and hot-water extract (HWE) data from five malting regimes with four samples of barley
Regime
Code number
Steep
Air rest
(h)
(h)
Within-replicate statistical analysis (dJ= 9)
Mean HWE (%) (n = 10) Modifi- Temperacation ture Triumph (h) 1983
eq
Egmont 1983
Triumph 1984
Koru 1984
S.E.D. a
C.V. (%)b
V.R. C
o 0
5
"51
19 5 19 5 64
2
0·257
0·30
0·466 N •S •
75
75
12 12 12 12 12 15
5 IS
5 15 5
~
o
}
0
72-4
70·7
76·1
73·4
0·319
0·40
1·597 N •s.
15 5
15 5
5 15
5 15 5
= Standard error of differences.
= Coefficient of variation. = Varianceratio.
r-
t'"' ttl
tl
~ ;J> t-
j
}
61·6
55-3
68·6
62·1
0·571
0·90
0·g03 N •S •
1
a ~ ~
~..,
5
= Not significant.
c:::: >-l
ttl
:;c
12 12 13 } 12 14 10
64
N.S.
75·8
Z
72
5
a S.Il.D. b C.V. e V.R.
77-2
>-l
19
5
72·0
0
17 17 17 17 17 17 12 12 12 12 12 10
5
4
."
73-1
5 19
3
15·5 15·5 15·5 15·5 15·5
~
64·7
55·0
68·2
61·7
0·531
0·80
0·643 N . S •
70·6
65·3
73·6
70·4
0·352
0·50
1·163N •s.
c: tf}
..., u.
76
P. G. GOTHARD AND D. B. SMITH
TABLE II. Ranges of differences in hot-water extract values within replicates and within overall data Range of differences in hot-water extract values (%) Within replicates Regime code-
1 2 3 4 5
Triumph 1983
Egmont 1983
Triumph 1984
Koru 1984
Overall data
2'2 2·0 2·4
5·2 5·4 13·3
2-2
13·2
1·8
1-8
1·6 1·1 2·5 5·5 1'5
1·4 1·9 3·7
2'3
3·2 1·1 6·4 4·7
3'3
10·1
" See Table I for details.
Results Five regimes were used to malt the four barley samples in the automated apparatus. The steeping and germination (growth) conditions are given in Table I, and malt analyses were carried out as described by Gothard et al.13 Malt moisture at the end of kilning was between 4 and 5 %. Regimes 1 and 2 produced over-modified malt, 3 and 4 under-modified malt and 5 gave more acceptable results. Despite differences of up to 17 % in hot-water extract (HWE) between the different regimes within one variety, each regime consistently separated the best and worst varieties. These results show that any regime within the conditions we tested would separate the samples successfully into good, intermediate and poor categories; this is all that is required of a screening test. The overall range (Table II), which includes varietal effects, showed that the less modified samples gave greater separation between varieties. This result indicated that a regime that stresses the samples during malting is more suitable for selection purposes as it emphasises variations, confirming previous observations to this effect". However, the extracts from regimes 3 and 4 were particularly low and may not have reflected how the material would behave under commercial conditions. Statistical analyses within the ten replicates suggested that greater precision was achieved when modification was greater (regimes 1 and 2). However, this was due to the more restricted range of variation under these regimes; replicate variance ratios were all non-significant, and coefficients of variation were all < 1%. Regime 5 gave results that combined a good range in extracts, and hence easy separation of cultivars, with good precision. Regime 5, therefore, seemed the most promising and was tested more rigorously. Thirty-three samples, each of 20 g from a barley trial were malted using this regime and the standard manual malt regime": The results, summarised in Table III, show that the automated method produced malts with near ideal cold-water extracts (CWE)16 but with rather high Kohlbach Index (KI) values-". The malts produced by the manual system are somewhat under-modified as judged by CWE, but they have reasonable KI values.
77
COMPUTER-CONTROLLED MALTING APPARATUS
TABLE III. Comparison of some malt characters in samples processed by the manual and the automated micro-malting systems (n = 33, replicates = 3)
V.R.a
Correlation coefficient between methods (r)
7·76
1·128N •s.
0'514**
43·17
11·72
3·018N .s.
0,724***
71·46
6·87
1·150N .s.
0,811***
Manual malting
Automated malting
Character
Mean
Range
V.R. a
Mean
Range
Cold-water . extract (%) Kohlbach index Hot-water extract (%)
14·98
4·10
1·445N .s.
18'57
34·13
11·73
1·451N .s.
73-16
6·97
0·133N •s.
a V.R. N.S. =
= Variance ratio (within replicates).
Not significant.
"'" p < 0·01. P < 0·001.
"'"*
Both methods produced acceptable HWEs, the most important quality criterion, with similar varietal differences. The variance ratio within replicates was not significant for any of the characters examined by either method. There were significant correlations between the two methods for the three parameters measured, with HWE having the highest correlation coefficient. A comparison of the same number of samples processed in duplicate by the manual system was carried out at the same time to assess variation within this system. A correlation coefficient of 0·842 (P < 0'001) was obtained between the duplicate HWE measurements, a value only slightly greater than that found between the two methods. Since these results were obtained the automated system has been used successfully to test many hundreds of samples, which can now be processed at the rate of 104 per week. The time required to produce and analyse these samples on a routine basis is less than that of one full-time operator. Conclusion
The microcomputer-controlled apparatus enables one operator to malt and analyse about twice the number of samples that is possible using the manual system. Grain protein content can be measured by near-IR reflectance spectrometry" and this is rapid and simple enough to complement the increased level of malt production. The automatic method has proved well suited to the rapid screening of barley lines for quality at the F 4 or Fij stage of breeding programmes. Other advantages of the computer-controlled process are (a) that the system provides a print-out of the conditions throughout each run, (b) it is easier to change malting regimes, and (c) such regimes are now no longer restricted by the working day of operators. Accurate control by computer also results in better reproducibility from run to run.
78
P. G. GOTHARD AND D. B. SMITH
The authors thank Mr B. Williams for the design and construction of the interface between the computer and the malting apparatus and for help with the programming. Thanks are also due to Mr P. Gurner, Mr P. Bavister and Mr F. Head for much of the design and construction work. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.
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