Changes of Limiting Dextrinase in Germinating Process of Malting Barley

Based on five different species of barley, the foot layer analytic method was used to examine the activity and heat-resistance of the limiting dextrinase. The study was conducted on the dynamic changes of several types of the dextrinase in barley germinating process, the effect of temperature on the dextrinase and the divergence of dextrinase in different barley variety. The probability of the dextrinase that as reference index is

Classification of Barley according to Harvest Year and Species by Using Mid-infrared Spectroscopy and Multivariate Analysis

In order to monitor malt quality in the malting industry, despite yearly variations in the barley quality, 394 barley samples were analysed using conventional （moisture, protein and B-glucan content） and mid-infrared Fourier transform spectroscopy FT-IR. The experimental dataset included barley from three harvest years, two barley species, 77 barley varieties, and two-row and six-row barley, from 16 cultivation sites. For each sample, the malt quality indices were also assessed according to European Brewing Convention （EBC） standards. Principal component analysis （PCA） was carried out on mean-centred, normalized and derivative spectra using 200/cm width spectral bands. The most informative spectral bands were observed in the 800-1,000/cm and 1,000-1,200/cm ranges. PCA revealed that barley harvested in 2010 and in 2011 had bands that were very close together, while 2009 harvest clearly displayed a difference in its quality. PCA made it possible to distinguish two species and confirmed that two-row winter barley quality was closer to two-row spring barley quality than to six-row winter barley. Results indicate that mid-infrared spectrometry （MIR） could be a very useful and rapid analytical tool to assess barley qualitative quality.

The Antioxidant Activity of Barley Malt Rootlet Extracts in Heated Corn Oil at Frying Temperature

In this study the antioxidant activity of barley malt rootlet (BMR) extracts was evaluated in heat treated corn oil up to 5 hours at 185°C frying temperature. The antioxidant activity of BMR extracts was measured at 25, 50, 100 and 150 ppm concentrations. The free and bound antioxidant phenolics were extracted from BMR using three different extraction methods. Conventional solvent extraction (CSE), microwave assisted extraction (MAE) and autoclave assisted pretreated solvent extraction (APSE). In the present experiment, the total phenolic content and antioxidant activity of the various extracts were measured. Thiobarbituric acid reactive substances (TBARS) assay was used to evaluate the ability of the BMR to protect lipid peroxidation in corn oil at 185°C frying temperature. The formation of TBARS at 5 hours of heat treated corn oil has shown similar antioxidant levels in 150 ppm butylated hydroxytoluene (BHT) or MAE free phenolic extract added to corn oil. TBARS value for BHT was 1.896 ± 0.013 μg/mL of corn oil and for MAE was 1.896 ± 0.034 μg/mL of corn oil. The highest level of antioxidant activity was found for the free phenolic extracts. The order of inhibition of oxidation was found to be for free phenolics as follows: BHT (100 ppm) > APSE (50 ppm) > MAE (100 ppm) > CSE (100 ppm).

Thin-layer Drying Characteristics and Modeling of Two Varieties Green Malt

Malting process includes steeping, germination and kilning of cereal grains in controlled conditions. The Kilning process is the most expensive stage of malting industry. In the present study, drying behavior of green malt of two different barley varieties （Sahra and Dasht） were evaluated at air temperatures ranging from 40 to 85 ℃, at constant air velocity of 6 m/s. The main objective of this research was to select the best drying equations, in order to use them for the calculation of drying time and energy consumption. For that the experimental data was fitted to five thin layer drying equations （Lewis, Henderson and Pabis, Page, Modified page and Two-term）. The coefficients of the equations were compared by three statistical parameters as residual sum of squares, standard error of estimate and mean relative deviation. The effect of temperature on the coefficients of the five selected equations was evaluated by linear regression. The results show that The Page model was found to be most suitable in describing the drying characteristics of green barley malt because of that has the lowest statistical parameters. The color of green barley malt was determined after drying using a spectro-colorimeter （Hunter Lab） in terms of Hunter L, a, and b values. Color measurement indicated that the AE index increased with an increase in drying air temperature.