浅谈以国产赤霉酸替代进口赤霉酸

赤霉酸是植物本身所固有的生长素。当植物生长不够旺盛时,可以通过添加适量的赤霉酸,以促进其生长和分解。对于麦芽制造业来说,添加赤霉酸的主要作用是:①克服大麦的休眠期,提高发芽;②促进麦芽的分解,提高麦芽的α—氨基氮含量;③增加酶活力;④缩短发芽时间等。正确掌握赤霉酸的使用方法和用量是确保其使用效果的关键。添加赤霉酸的最佳时间是大麦刚开始萌发时,即浸麦后期或发芽初期。但在浸麦后期添加其用量是在发芽初期添加的四倍,故一般采用在发芽初期添加较为经济可行。添加方法或用量不当时,会有     

赤霉酸的添加对成品麦芽中残留量的影响

作为植物生长调节剂,赤霉酸添加到制麦过程中,可以加速大麦发芽,提高麦芽质量。但是若使用不当,会引起麦汁煮沸色度增加、赤霉酸残留量增加等问题。本文选取澳麦、法麦和国产苏北大麦为主要研究对象,考察了制麦过程添加赤霉酸对成品麦芽品质的影响。研究结果显示:赤霉酸对三个不同地区的大麦麦芽质量指标及其赤霉酸残留量的影响趋势基本一致,即添加量在0～0.3mg/kg范围内,对麦芽质量有明显提高,超过0.3mg/kg后趋于平缓。添加赤霉酸对麦汁色度的影响与大麦产地相关,法麦煮沸色度受影响最大,澳大利亚大麦受影响程度最小。成品麦芽中赤霉酸的残留量与制麦时的添加量具有非常明显的正相关性(R~2>0.99))。所以合理使用赤霉酸对麦芽品质的改善和控制具有重要意义。     

制麦过程中过氧化物酶活性可能影响绿麦芽的生根和制麦损失

过氧化物酶（POD）在植物生长过程中起着重要的调节作用。研究了制麦过程中POD活性对大麦根芽生长和制麦损失的影响。结果表明：制麦添加剂GA3促进根芽的生长、POD活性的升高和制麦损失的增大,而KBrO4反之,而且随着KBrO4浓度的增大,这种抑制也增大;对20种大麦样品的微型制麦试验表明,绿麦芽和干麦芽的POD活性与根芽长度和制麦损失均呈现高度显著的正相关性（P〈0．01）。研究认为,制麦过程中POD活性与绿麦芽根芽的生长和制麦损失有密切关系,POD活性可能对根芽生长和制麦损失有促进作用。     

制麦工艺中添加剂的筛选研究

通过培养皿小试对影响大麦发芽的添加剂进行单因素筛选,来确定添加剂的最佳浓度.试验结果表明:添加剂赤霉素GA对大麦的发芽率有显著性影响,最佳浓度为0.2 mg/kg;甲醛HCHO可以显著抑制大麦根叶芽的生长,最佳浓度为0.05%;溴酸钾KBrO3可抑制大麦根叶芽的生长,最佳浓度为100 mg/kg;氢氧化钠NaOH可以抑制大麦的根叶芽影响显著,最佳浓度为为O.2 g/L.     

使用赤霉酸缩短制麦周期的工艺研究

通过几年来运用赤霉酸制麦实践，作者总结了先低温，后高温的浸麦、发芽工艺，从而制麦周期缩短2～3天，各项麦芽指标优于不加赤霉酸的麦芽。因此，有显著的经济效益。（陆月雪）     

赤霉酸对大麦制麦特性和氨基酸组成影响的研究

研究了制麦过程中,添加不同浓度的赤霉酸(GA3)时Azurel大麦制麦特性、麦芽质量参数和氨基酸组成的影响.结果表明,当赤霉酸添加量为0.2mg/kg时,库尔巴哈值为55%、游离氨基氮达到最大值190.1 mg/100mg干麦芽,麦芽中的氨基酸含量最高.当赤霉酸添加量低于0.2mg/kg时,麦芽的酿造品质可得到不同程度的提高.     

小麦制麦工艺初探

探讨了小麦制麦工艺的特性、制麦方法及培烤工艺。提出了适合小麦制麦的短浸长断、间歇喷淋的浸麦方法,浸麦度控制在41％－43％。先低后高变温发芽6天,干燥分3个阶段进行。发芽过程中生 石灰、甲醛的使用对杀菌、促进发芽、 抑制根芽生长起到重要作用,所制麦芽比较适合做小麦啤酒。     

小宗粮食加工(十)——大麦制备麦芽

4 7　发芽发芽的目的 :通过大麦发芽 ,根芽和叶芽得到适当生长 ,使麦粒中形成大量的各种酶。一部分非活化酶 (酶原 )得到活化和增长 ,同时使麦粒的部分淀粉、蛋白质和半纤维素等高分子物质得到分解 ,达到一定的溶解度 ,以满足酿造啤酒中糖化工艺的需要。发芽是一种生理生化变化过程[3 ] 。4.7.1　发芽机理和发芽过程4.7.1 .1　发芽机理[2 ]大麦开始发芽时 ,麦粒的胚利用自身原有的糖类和氨基酸等物质生长合成新的组织 ,即根芽和叶芽。同时分泌出生长素赤霉酸渗至糊粉层 ,诱发生成淀粉酶、蛋白酶等酶类。其中蛋白酶先溶解了连结胚乳细胞的蛋…     

添加不同发芽时间的小麦芽粉对面团及馒头品质的影响

以潍麦8号小麦为原料,采用常规制麦工艺分别制得不同发芽时间的小麦芽,后经125℃焙烤2 h磨粉,探究添加5%小麦芽粉对面粉糊化特性、面团粉质特性、拉伸特性及馒头品质的影响。结果表明,小麦芽经125℃焙烤2 h后,其α-淀粉酶的灭活率为82.2%~90.0%。添加小麦芽粉对面粉的峰值黏度、最低黏度、最终黏度、回生值和峰值时间均有显著影响(p≤0.05)。添加发芽第2~5天的小麦芽粉能显著降低面团的稳定时间,粉质指数,拉伸能量,拉伸比,拉伸阻力,升高面团的弱化度和延展度(p≤0.05)。添加发芽第2、4、5天的小麦芽粉制成馒头比容较大。添加发芽第2天的小麦芽粉制成馒头的感官评分最高。与空白对照组和添加其他发芽时间的小麦芽粉制成的馒头品质相比,添加发芽第2天的小麦芽粉制成的馒头外观呈咖啡色,比容较大,表面光滑,带有浓郁的焙烤麦芽香气。     

如何提高啤酒的非生物稳定性

为了提高啤酒的非生物稳定性,必须从原料和工艺方面着手,着重点应放在不影响风味和酒体的情况下,尽量减少啤酒中的高分子蛋白质和多酚物质的含量。大麦:采用含氮量低的大麦品种(12％以下)。制麦:浸麦水中加碱,以降低麦芽中的花色苷含量;最后一次浸麦水中,适当添加甲醛或绿麦芽干燥前喷洒甲醛(100-200ppm),均可降低成品啤酒中的花色苷含量。提高麦     

MICROMALTING TRITICALE

A sample of ‘Lasko’ triticale, a wheat × rye hybrid cereal, was micro-malted in a variety of ways. The grain was adequately steeped in under 24 h, and was relatively unaffected by high steeping temperatures, or the use of air-rests. Malts with exceptionally high extracts (about 340 1°/kg dry) and diastatic powers were obtained with malting losses of about 8% after 4 days germination. However, levels of soluble nitrogen were also high, even when potassium bromate had been employed. Malts made from this cereal could be of value in mixed brewing grists and in the manufacture of some malt extracts.     

MALTING TECHNOLOGY AND THE PROPERTIES OF MALT: A CLUSTER ANALYSIS STUDY

A cluster analysis study of 72 malts produced from four varieties of barley malted under varying conditions has demonstrated the relative importance of the degree of steeping, germination time and temperature and kilning on the chemical and physical analysis of the malt. Seventy-two malt samples were produced from four barley varieties malted at two different degrees of steeping, two germination temperatures, two germination times, and two kilning temperatures. The malt samples were divided into 2 or 3 groups (clusters) by means of the Fuzzy Cluster Variety family of algorithms, applied to nine chemical or physical malt analyses. Each cluster could be characterized by certain mean values for the laboratory analyses and also by a particular set of technological parameters. The degree of steeping was the most important of these parameters. Laboratory analyses such as fine/coarse difference and friability were able to discriminate between a high or low degree of steeping. The cluster with a high degree of steeping could be further divided into two subclusters, with different kilning temperature. The DMS-precursor discriminated between these two kilning temperatures.     

EFFECT OF GERMINATION CONDITIONS,WITH OPTIMISED STEEPING,ON SORGHUM MALT QUALITY—WITH PARTICULAR REFERENCE TO FREE AMINO NITROGEN

Using optimised steeping conditions for sorghum, the effect of various germination parameters (time, temperature and moisture) on the quality of sorghum malt for brewing purposes (in terms of diastatic power, free amino nitrogen and hot water extract) and on the associated malting losses, was investigated. Over the range studied (2, 4 and 6 days), the quality of the malt and the losses incurred during malting increased with increasing germination time. In general, the optimum germination temperature was between 25 and 30°C, and 18°C was found to be sub-optimal for the development of malt diastatic power. The quality of the finished malt and the associated malting losses were significantly correlated with the moisture content of the green malt. The root and shoot portion of the malt was found to be rich in free amino nitrogen (more than four times richer than the berry portion). Although a relatively small proportion of the total weight of the whole malt, the roots and shoots were found to contribute a substantial amount (as much as 61% under certain circumstances) to the whole-malt free amino nitrogen.     

Malting of Triticum dicoccum (Khapli) Wheat: Response to Gibberellic Acid and Use in Baking

T. dicoccum malt developed high amylolytic and proteolytic activity by applying 0.25 and 0.50 ppm gibberellic acid (GA) and germination for 5 and 7 days at 20°C. The 5- and 7-day malts without GA showed an alpha-amylase activity (SKB/g) of 73.7 and 99.2, respectively, which was increased to 183.5 and 193.1 by 0.5 ppm of GA treatment. Kolbach Index values of 61.7 and 65.2% of GA malts indicated high modification with conversion times of >1 min. Phytic P decreased from 80.5% in wheat to 41.2–53.4% in malts. Increased volume and softer crumb were characteristic of loaves made with 10 SKB of malt per 100g flour without sugar in the formula.     

Effect of ozone treatment on the safety and quality of malting barley

Molds and their mycotoxins are an expensive problem for the malting and brewing industries. Deoxynivalenol (DON) is a mycotoxin that is associated with Fusarium spp. These fungi frequently cause Fusarium head blight in wheat and barley in the midwestern region of the United States; Manitoba, Canada; Europe; and China. Barley growers and malt producers would benefit from a postharvest control method for mold growth and DON production. We evaluated the use of gaseous ozone (O(3)) for preventing Fusarium growth and mycotoxin production while maintaining malt quality characteristics. Micromalting was performed in three replications under standard conditions. Ozone treatment was applied to malting barley during steeping via a submerged gas sparger. Ozone treatment conditions were 26 mg/cm(3) for 120 min after 2 and 6 h of steeping. The effects of gaseous ozone on DON, aerobic plate counts, Fusarium infection, and mold and yeast counts of barley throughout the malting process were measured. Various quality parameters of the malt were measured after kilning. Statistical tools were used to determine the significance of all results. Ozonation of malting barley during steeping did not lead to significant reductions in aerobic plate counts but did lead to a 1.5-log reduction in mold and yeast counts in the final malt. The influence of gaseous ozone on DON concentration was inconclusive because of the low initial concentrations of DON in the barley. Ozone significantly reduced Fusarium infection in germinated barley. Gaseous ozone did not negatively influence any aspect of malt quality and may have subtle beneficial effects on diastatic power and β-glucan concentrations.     

CHANGES IN ORGANIC ACID LEVELS DURING MALTING

A method, based on HPLC, was developed for analysis of organic acids in germinating barley and finished malt. Levels of the major respiratory organic acids were examined daily during steeping, germination and kilning in a commercial maltings. The major acids detected were citrate, malate, succinate and lactate. L-lactate but not D-lactate was produced in the grain during steeping but was rapidly lost during subsequent germination. Both L- and D-lactate were accumulated in the grain during late germination and kilning. Final levels of lactate and malate in malt were determined primarily by their rate of accumulation during kilning. A comparison of two maltings revealed that kilning time is important for final lactate levels in the malt, with long kilning times leading to high levels of both lactate isomers. It is postulated that lactate is produced during steeping by anaerobic respiration of barley whereas during late germination and kilning it is produced by proliferation of grain microbes.     

Malting of Hulless Barley Cultivars and Glenlea (T. aestivum) Utility Wheat

Malting of hulless barley cultivar, Scout, and Utility wheat, Glenlea, was compared with the hulled barley, Harrington. Hulless barley showed faster steeping rate than either Harrington or wheat cultivars. Gibberellic acid, applied by steeping in 1 ppm solution, and germination for 2-8 days significantly increased cr-amylase activity of Scout and Glenlea cultivars and their extract yields were 46% higher than Harrington malts. The 2-day Scout malts produced highly viscous extracts. Desirable viscosity (5500 cPs) was obtained from 5-day malts.     

Control of Superoxide Dismutase Activity during Malting Using Plackett‐Burman and Box‐Behnken Experimental Design and Its Effect on Reducing Power of Wort

The Plackett‐Burman multifactorial design was employed to screen the important malting parameters for superoxide dismutase (SOD) in final malt of Ganpi‐3. The eight factors screened for SOD were steeping temperature, steeping time, peroxide hydrogen concentration in steeping water, germination temperature, germination time, withering temperature, drying temperature and kilning temperature. Variance analysis showed that steeping time, germination temperature and kilning temperature were significant for SOD activity. Box‐Behnken experimental design was further used to optimize the levels of the above three factors. By response surface methodology and canonical analysis, the optimal malting factors for higher SOD activity in final malt were: steeping time 42.2 h, germination temperature 16.9°C and kilning temperature 82.9°C. Under these conditions, the model predicted a SOD activity of 2234 U/g of dry weight malt. Verification of the optimization showed that a SOD activity of 2220 U/g was observed under optimal conditions. It showed that the experimental data could be reliably predicted by the polynomial model. Besides Ganpi‐3, three other barley varieties including Ganpi‐4, Ken‐2 and Hamelin were malted under optimal and common conditions under laboratory conditions. To some extent, SOD activities were higher in malts from the optimal malting process than those from the common malting process. Especially, SOD activities in Ganpi‐3 and Hamelin increased by 18.8% and 15.3%, respectively. Furthermore, twenty‐nine samples of malts, including eleven imported malts and eighteen domestic malts, were used. Relationships between SOD activity in malt and the reducing power of wort were examined. There was significant correlation between SOD activity and the reducing power of wort (R² = 0.8069).     

The Influences of Steeping Duration and Temperature on the α‐ and β‐Amylase Activities of Six Thai Rice Malt Cultivars (Oryza sativa L. Indica)

A preliminary study of malting conditions for six Thai rice cultivars was conducted. Three non‐glutinous rice cultivars (KDML105, PT60, and WR) and three glutinous rice cultivars (SPT, RD6, and KND) were selected. The steeping durations (24, 48, and 72 h) and temperatures (20, 25 and 30°C) were investigated for their effect on α‐ and β‐amylase, the key enzymes for malt quality evaluation. During steeping, the production of both enzymes was lower than at the germination process. The longer the steeping duration, the lower the maximum β‐amylase activity obtained. The contradictory effect was observed for α‐amylase activity, near the end of the germination time. Additionally, temperature influenced the water absorption content as well as the amylolytic enzyme activity. Particularly at 30°C, the maximum β‐amylase activity (6.7 unit/mg protein) was found in KND malt steeped for 24 h, and maximum α‐amylase activity (20 unit/mg protein) was found in PT60 malt steeped for 72 h. The amount of enzyme production depended on the variety rather than the amylose content in the rice. The optimal condition for malting rice regarding β‐amylase activity and α‐amylase activity was analyzed at 30°C, with steeping for 24 h and germination for 4–5 days.