DETERMINATION OF THE MOISTURE CONTENT OF BARLEY

The method of the International Organization for Standardization, (ISO 712–1985) for the determination of moisture in cereals and cereal products, has been tested by members of the Analysis Committee of the European Brewery Convention on samples of barley. The method, which relies on loss in mass on drying at 130–133°C for 2 h, is recommended for use as a replacement for the current method, based on loss in mass on drying at 105–107°C for 3 h. It was judged that precision values were independent of concentration over the range 11 to 13% m/m. Repeatability (r₉₅) and Reproducibility R₉₅) values of 0.13 and 0.55 respectively were obtained over this range. At a mean level of 21.7% m/m, the r₉₅ and R₉₅ values were 0.27 and 2.6 respectively. This was probably due to errors associated with the double drying technique which is necessary for samples at this moisture content.     

蔷薇红景天中原花青素含量的测定方法

测定蔷薇红景天提取物中原花青素的含量.采用酸化香草醛比色法,最佳比色条件为:盐酸浓度为8%,香草醛浓度为2%,反应温度为30℃,时间为20min,检测波长500nm.结果表明:该方法的线性范围为10.5 μg/mL～420 μg/mL,相关系数r=0.999 8,平均加标回收率为97.98%,相对标准偏差(RSD)1.24%,检出限为1.32μg/mL.该法操作简便、准确、稳定,适用于原花青素含量的测定.     

DETERMINATION OF HOT WATER EXTRACT

The Analysis Committee of the European Brewery Convention has recommended that the Hot Water Extract procedure for malt, which relies on a coarse grind and single temperature mash (65°C), is included in Analytica-EBC, as an additional method to that of the EBC Extract procedure. The Committee accepted the precision values obtained by the Institute of Brewing on the 1984 Check Malt. Repeatability (r₉₅) and reproducibility (R₉₅) values in litre degrees/kg were 2.14 and 3.48 respectively, for mean value of 295.3 at a Miag 0.7 mm setting, and 1.93 and 2.90 respectively, for a mean value of 298.2 at a Miag 0.2 mm setting.     

THE NUTRITIVE CONTENT OF AFRICAN BEERS BREWED WITH MAIZE GRITS OR SORGHUM ADJUNCT

Sorghum beer samples were brewed in a pilot plant operation using either sorghum grain or maize grits as starchy adjunct in order that the nutritive content of the beers could be compared. Significantly higher ethanol, thiamin, nicotinic acid, ash, phytate, zinc, copper, manganese, iron, magnesium, potassium and phosphorus concentrations were found in beers brewed with sorghum adjunct. Sorghum adjunct beers can therefore make a greater contribution to the nutritional requirements of the Southern African beer drinker than beers brewed with maize grits. The results obtained suggest that the use of sorghum adjunct in the brewing of sorghum beer should be encouraged for economic and dietary reasons.     

NEW MASHING SYSTEM FOR DETERMINATION OF LABORATORY EXTRACT

The method of preparation of laboratory wort by the Tepral mashing system provides a clear improvement in the evaluation of industrial malts and in the optimization of malting procedures. The equipment required is simple and easy to operate. The use of the method has shown significant differences in terms of both wort viscosity and extract yield between malt from 2-row spring barley (variety Carina) and malt from 2-row winter barley (variety Sonja), produced under identical industrial conditions: the Sonja malt gave fewer good results for finely ground malt than did the Carina malt.     

THE INSTITUTE OF BREWING ANALYSIS COMMITTEE REVISED METHODS OF EXTRACT DETERMINATION

Following a Brewer's Society request to consider a change from a standard Miag Disc Mill setting of 0·5 mm to one of 0·7 mm the Analysis Committee has re-evaluated the determination of hot water extract. It is recommended that from 1st December 1979–1. A Miag Disc Mill setting of 0·7 mm be adopted for grinding malt for the determination of hot water extract. 2. Where an estimate of the fine/coarse grind hot water extract difference is required, mill settings of 0·2 mm and 0·7 mm respectively should be used. The reproducibility of this procedure is adequate to separate malts into classes with high and low values but analytical tolerances cannot be recommended for commercial transactions. Revised methods for setting the Miag Disc Mill and for determining the hot water extract of fine and coarse ground malts are given in Appendix I. It is proposed that all mashes should be made in stainless steel beakers, the use of the standard brewers' mash flask being limited to making the mash to the correct volume at the end of the determination. It is recommended that, from 1st December 1979, the 0·7 mm Miag Disc Mill setting should replace also the 0·5 mm setting in all Recommended Methods for coloured malts, dark malts, roasted barley and unmalted grain. It is further recommended that from 1st December 1979 all specific gravity determinations for laboratory extracts of malt, coloured malt, dark malt, roasted barley, unmalted grain, sugars, syrup, caramel and spent grains should be made at 20°C.     

灵芝不同部位多糖含量测定

采用苯酚-硫酸法对灵芝菌盖表皮层、木栓层、菌柄、孢子粉、发酵菌丝体等部位中的灵芝多糖进行了测定,结果发现,灵芝发酵菌丝体中的多糖含量明显高于灵芝的其它部位,其含量顺序分别为：发酵菌丝体〉菌盖表皮层〉孢子粉〉菌柄〉木栓层。     

THE DETERMINATION OF FERMENTABLE EXTRACT IN BREWING WORTS

A method for determining the real fermentability of a standard Institute of Brewing wort is proposed for use in the Brewing Industry. The method is based on a system currently operating in the Distilling Industry using standard Distillers Co. Ltd (D.C.L.) ‘M’ type yeast. To provide a safeguard against variability in the performance of the yeast used, it is recommended that a standard malt (e.g. Institute of Brewing check malt A) of known fermentable extract should be used to check the condition of the yeast.     

EXPRESSION OF EXTRACT OF DISTILLING MALTS ON A PERCENTAGE BASIS: CHANGES IN RELATIONAL FACTORS FOLLOWING THE 1979 REVISION OF THE IOB METHOD OF EXTRACT DETERMINATION

The derivation of the factor linking excess gravity with % soluble extract and also the factor relating the expression of hot water extract by either % soluble extract or litre degrees/kg is described. The effect of the 1979 revision to the temperature of the specific gravity determination on these factors is highlighted and a modified value for each is advanced.     

NEW METHOD FOR THE DETERMINATION OF HOT-WATER EXTRACT OF MALT

A new method for the measurement of hot-water extract of malt is described. In this method malt grist is continuously extracted in a Soxhlet apparatus under reduced pressure, the pressure being chosen such that the extraction is carried out at 65·5° C. In a comparison of malt extracts by the new method and by the Standard Institute of Brewing method the former gives lower extract values. The new method provides certain advantages: it requires a smaller malt sample, is rather quicker to carry out, requires less manipulation and avoids the problem of accounting for spent grain volumes.     

玉米浸泡液超滤提取菲汀

用中空式膜超滤和分步碱沉淀处理玉米浸泡液提取菲汀,纯度好,得率高,可充分利用原料,得到高质量的蛋白饲料,推广于工业生产,可大大提高企业经济效益,本文对此从理论和实践上进行了研究。     

DETERMINATION OF THE FILTERABILITY OF BEER

A method for the determination of the filterability of beer has been evaluated by members of the European Brewery Convention Analysis Committee. The method is based on the filtration of a beer sample, with a standard amount of diatomaceous earth (DE), under standardised conditions. Repeatability of the test was quite good, however the predictive value of the test is still questionable since no direct correlation could be established between the different filtercake values and industrial filtration problems. No collaborative test was performed as the filterability has to be determined on unfiltered beer; the test is easy to run, and as for the other filterability tests, day to day practice in a brewery will reveal its usefulness.     

DETERMINATION OF MOISTURE,TOTAL AVAILABLE EXTRACT AND SOLUBLE EXTRACT IN SPENT GRAINS

The methods for the determination of moisture⁴, total available^3,4 and soluble extracts⁴ in spent grains have been collaboratively tested by members of the Analysis Committee of the European Brewery Convention to obtain repeatability (r₉₅) and reproducibility (R₉₅) values . Repeatability and reproducibility values of 0.1 and 0.67 respectively were obtained for spent grain moisture's ranging between 4 and 8% m/m in pre-dried and pro-milled samples. In a pro-dried and unmilled sample containing 3.4% m/m moisture the values obtained were 0.3 and 1.5 respectively . For total available extract (MEBAK) these values were 0.5 and (2.2+0.045 m) respectively, with total available extract ranging from 9 to 42% m/m dry matter, where m refers to the actual value. The values for the pre-dried and unmilled sample containing an extract of 41.2% m/m were 0.5 and 4.6 respectively . The precision values for soluble extract were dependent on the extract level of the sample over the range 6 to 40% m/m dry matter. A repeatability value of 0.13+0.007 m and a reproducibility value of 0.2+0.06 m were obtained over this range. Values for the same pre-dried and unmilled sample with a soluble extract of 38.7% m/m were 1.3 and 3.8% m/m respectively .     

II. DETERMINATION OF EXTRACT AND COLD WATER EXTRACT IN MALT BY MEANS OF THE REFRACTOMETER

The refractometer is being successfully employed for the routine determination of hot and cold water extracts obtained by The Institute of Brewing Recommended Methods of Analysis and for hot water extracts derived from The E.B.C. Standard Methods of Analysis. In general, results have appeared to be more reliable than those obtained by using the specific gravity bottle and the method has proved to be more convenient.     

牛奶中尿素含量的测定

根据二乙酰-肟与在酸性条件下尿素的反应,建立了一种分光光度法快速测定牛奶中尿素含量的方法,该方法可以定性和定量测定牛奶中尿素含量.在0.125g/L～1g/L之间线性良好.平均回收率为99.4%.该方法在实际的原料奶质量控制中得到了很好的应用.     

DETERMINATION OF THE SOLUBLE IRON CONTENT OF FILTER AIDS: A COLLABORATIVE TRIAL

The international method for the determination of the soluble iron content of filter aids has been collaboratively tested by members of the Analysis Committee of the European Brewery Convention to obtain repeatability (r₉₈) and reproducibility (R₉₈) values. It was Judged that precision values were dependent on the quantity of the soluble iron content of the filter aids over the range 32 to 220 mg/kg. Repeatability (r₉₈) value of 0.050 m and reproducibility value (R₉₈) of 0.255 m were obtained over this range.     

THE DETERMINATION OF SULPHUR DIOXIDE IN MALT

The Institute of Brewing Recommended Method for the determination of sulphur dioxide in beer has been modified for determination in malt. Three inter-laboratory trials are reported and the resulting procedure is described. It has the advantages of being well tried in its general form and employing relatively cheap equipment. While the inter-laboratory reproducibility achieved was not particularly good the method is published for use in laboratories where it may fulfil a present need.     

A RAPID SMALL SCALE METHOD FOR THE DETERMINATION OF MALT EXTRACT

A rapid, small-scale method was developed using 1 g of ground malt mashed in 10 ml of water at 65°C. The extract was centrifuged and the specific gravity determined using a density meter. The method was compared with an earlier small-scale method and the Institute of Brewing method and was found to have good precision (CV 1.2%). Absolute malt extract values were not significantly different (P = 0.05) from those obtained by the IOB method.     

DETERMINATION OF THE VOLATILE COMPONENTS OF BEER

A method relying on headspace sampling and gas chromatography for the determination of the lower boiling point volatile compounds (fusel oils) in beer, has been approved by the Analysis Committee of the Institute of Brewing (IOB), for inclusion in Recommended Methods of Analysis. In view of the large values obtained for precision in terms of repeatability (r₉₅) and reproducibility (R₉₅) and the differences in gas chromatographic equipment used by individual brewing laboratories, the method is considered not to be ideal, but is given as a guideline only. The IOB Analysis Committee has recommended a method relying on gas chromatography and flame photometric detection for the determination of dimethyl sulphide in beer. Repeatability (r₉₅) and reproducibility (R₉₅) values of 3.3 μg/litre and 3.66+0.168 m μg/litre (where m is concentration), respectively, were obtained over the range 20–50 μg/litre. Methods currently used in brewing laboratories, for the measurement of vicinal diketones, are being surveyed with a view to obtaining a suitable method for collaborative testing by the Analysis Committee.     

纺织品中纤维含量检测结果的评定

分析了影响纺织品纤维含量准确测定的主要因素,并对检测结果的不确定度表述方式进行了评定,为更科学和准确地测定纺织品中纤维的实际含量提供参考和指导。