Comparison of the Changes in Seed Germination Vigour with Prolonged Postharvest Storage for Hordeum vulgare Varieties, Hope and Sierra Malting Barley Varieties, in Zimbabwe

To ensure production of quality malt that conforms to brewing requirements, the barley used should have minimal postharvest dormancy and be able to germinate rapidly and uniformly. The objective of the study was to compare the changes in seed germination, vigour trends, and storage stability of two-row Zimbabwean commercially grown malting barley varieties (Hope and Sierra), as the postharvest storage time increased. The two varieties were stored for 12 months, and at monthly intervals, germination index, capacity, and energy were determined. In addition, other quality parameters (protein content, screening, moisture content, water sensitivity, and insect damage index) were also assessed. Hope’s germination index improved with an increase in storage time from 8.67 at the beginning of the study to 9.18 at the end of the study, while that for Sierra diminished with storage from 9.35 to 6.71. Generally, water sensitivity improved with postharvest storage for both varieties. However, the germination energy for Hope diminished with increased postharvest storage compared to Sierra. Hope variety is the more suitable variety for extended postharvest storage than Sierra. However, Sierra variety is more suitable for early malting postharvest storage

Comparison of the Changes in Seed Germination Vigour with Prolonged Postharvest Storage for Hordeum vulgare Varieties, Hope and Sierra Malting Barley Varieties, in Zimbabwe

To ensure production of quality malt that conforms to brewing requirements, the barley used should have minimal postharvest dormancy and be able to germinate rapidly and uniformly. The objective of the study was to compare the changes in seed germination, vigour trends, and storage stability of two-row Zimbabwean commercially grown malting barley varieties (Hope and Sierra), as the postharvest storage time increased. The two varieties were stored for 12 months, and at monthly intervals, germination index, capacity, and energy were determined. In addition, other quality parameters (protein content, screening, moisture content, water sensitivity, and insect damage index) were also assessed. Hope’s germination index improved with an increase in storage time from 8.67 at the beginning of the study to 9.18 at the end of the study, while that for Sierra diminished with storage from 9.35 to 6.71. Generally, water sensitivity improved with postharvest storage for both varieties. However, the germination energy for Hope diminished with increased postharvest storage compared to Sierra. Hope variety is the more suitable variety for extended postharvest storage than Sierra. However, Sierra variety is more suitable for early malting postharvest storage.</jats:p

Optimisation of Malting Parameters for Quinoa and Barley: Application of Response Surface Methodology

Quinoa (Chenopodium quinoa Willd) is a nutritious pseudocereal that is more stress-tolerant compared with traditional cereals. It is an excellent example of a climate-smart crop that is more resilient to climate change compared with barley. The purpose of the study was to investigate the optimum malting conditions required to produce quinoa malt using barley as a control. Response surface methodology (RSM) was used to investigate the influence of the two malting parameters steeping time and germination time on Brix (wort extract), diastatic power (DP), and free amino nitrogen (FAN) of the malt. The temperature was set at 15°C during the steeping process. Steeping time ranging from 12 to 48 hours and germination time ranging from 24 to 96 hours were designed using a central composite design (CCD). The kilning temperature for all malts was 65°C. For quinoa malt, there was a notable weak positive correlation between germination time and Brix (r = +0.119). However, there was a strong positive correlation between steeping time and diastatic power (r = +0.893). A similar trend was noted for barley with a weak positive correlation between germination time and Brix (r = +0.142). A strong positive correlation was also recorded between steeping time and diastatic power (r = +0.897) during the malting of barley. There was a relatively stronger correlation between steeping time and FAN (r = +0.895) than germination time and FAN (r = +0.275) in quinoa malt. The optimum values for the malting of barley were 47.68 hrs steeping time and 82.55 hrs germination time with a desirability value of 1.00. The responses for the optimised barley malt were 8.25°Bx, 162.28 mg/L, and 271.69°L for Brix, FAN, and diastatic power, respectively. To produce quinoa malt with Brix, FAN, and diastatic power of 8.37°Bx, 165.60 mg/L, and 275.86°L, respectively, malting conditions of 47.69 hrs steeping time and 95.81 hrs germination time are required. It was noted that quinoa is a very good candidate for producing high-quality malt for the brewing process.</jats:p

Optimisation of Malting Parameters for Quinoa and Barley: Application of Response Surface Methodology

Quinoa (Chenopodium quinoa Willd) is a nutritious pseudocereal that is more stress-tolerant compared with traditional cereals. It is an excellent example of a climate-smart crop that is more resilient to climate change compared with barley. The purpose of the study was to investigate the optimum malting conditions required to produce quinoa malt using barley as a control. Response surface methodology (RSM) was used to investigate the influence of the two malting parameters steeping time and germination time on Brix (wort extract), diastatic power (DP), and free amino nitrogen (FAN) of the malt. The temperature was set at 15°C during the steeping process. Steeping time ranging from 12 to 48 hours and germination time ranging from 24 to 96 hours were designed using a central composite design (CCD). The kilning temperature for all malts was 65°C. For quinoa malt, there was a notable weak positive correlation between germination time and Brix (r = +0.119). However, there was a strong positive correlation between steeping time and diastatic power (r = +0.893). A similar trend was noted for barley with a weak positive correlation between germination time and Brix (r = +0.142). A strong positive correlation was also recorded between steeping time and diastatic power (r = +0.897) during the malting of barley. There was a relatively stronger correlation between steeping time and FAN (r = +0.895) than germination time and FAN (r = +0.275) in quinoa malt. The optimum values for the malting of barley were 47.68 hrs steeping time and 82.55 hrs germination time with a desirability value of 1.00. The responses for the optimised barley malt were 8.25°Bx, 162.28 mg/L, and 271.69°L for Brix, FAN, and diastatic power, respectively. To produce quinoa malt with Brix, FAN, and diastatic power of 8.37°Bx, 165.60 mg/L, and 275.86°L, respectively, malting conditions of 47.69 hrs steeping time and 95.81 hrs germination time are required. It was noted that quinoa is a very good candidate for producing high-quality malt for the brewing process