绵毛嗜热丝菌(Thermomyces lanuginosus)木聚糖酶对面包品质的改善

研究了绵毛嗜热丝菌（Thermomyces lanuginosus）W205耐热木聚糖酶的添加量对面包品质及老化的影响。结果表明,添加2．5～5mg／kg纯酶为较适酶添加量。在此添加量下,面包比容增加17％,面包瓤硬度与高径比略为下降,面包内部质构明显提高,老化速率放缓。     

嗜热真菌耐热木聚糖酶对面包品质的改善

研究了纯化的耐热木聚糖酶对面包品质及老化的影响，探讨了耐热木聚糖酶影响面包发酵及烘烤过程的作用机理。适量添加木聚糖酶的面包体积显著增加且面包芯的组织结构优良，同时老化变缓：本试验条件下，添加纯酶1．5mg／kg为最适酶添加量，体积增加43％，硬度减小44％，老化速度放缓近一半。     

外源戊聚糖酶对国产小麦面包粉品质的影响

通过流变学试验、面包烘焙试验和面包芯质构测试,探讨了戊聚糖酶对国产小麦面包粉品质的影响。试验表明,与对照组相比较,在添加适量戊聚糖酶后,面团的流变学性质、面包品质都得到明显改善。质构测试显示,戊聚糖酶可以有效地延缓面包制品的老化现象。试验条件下,添加戊聚糖酶60μg/g(酶/小麦粉)为最适添加量。     

响应面优化复配型面包改良剂工艺研究

以面包的比容、硬度和弹性为指标,以面包专用粉为原料,分别采用正交设计试验和响应面设计试验优化复配型面包改良剂的配方.实验结果表明复配型面包改良剂的最适配比:复配胶添加量0.28 g/100 g面粉,复配酶添加量41.33 mg/kg面粉,抗坏血酸添加量42.96 mg/kg面粉,预测的面包比容达到7.23.面包中复配型改良剂的最适添加量为0.21 g/100 g面粉,添加复配型改良剂面包的老化速率明显下降,且抗老化的效果好于市售改良剂.     

溶血磷脂在面包中应用的探讨

磷脂酶A1催化酶解大豆磷脂获得溶血磷脂。采用单因素试验研究溶血磷脂在面包中的应用,发现溶血磷脂在面包中添加量在0.65%～0.9%范围内能有效增大面包的体积。利用质构仪对添加溶血磷脂面包和浓缩大豆磷脂面包储存期间的物性参数进行了测定,硬度值变化表明,溶血磷脂能有效延缓面包的老化。     

马铃薯全粉在面包中的应用研究

研究了马铃薯全粉对面包的水分、酸度、比体积和感观品质的影响,并进行了面包的贮藏试验。结果表明,提高马铃薯全粉添加量,可使面包成品的含水量相应增大,对面包酸度影响不大。当马铃薯全粉的添加量在5%~15%时,对面包的体积不产生抑制作用;当添加量高于15%后,面包的比体积随着马铃薯全粉添加量的增大而明显减小。适量添加马铃薯全粉制作面包,能提高面包的感观品质。添加马铃薯全粉降低了面包的老化速度,延长了面包的保质期。     

α-淀粉酶对绿豆面包品质的影响

比较研究了添加α-淀粉酶的绿豆粉与绿豆浆酶解液对绿豆面包高度、比容、感官特性、质构特性和抗老化特性的影响。结果表明,在2种绿豆处理方式下添加α-淀粉酶均可增加面包的高度、比容、感官评分,改善面包的质构和抗老化特性,其中添加绿豆浆酶解液的面包各项指标更好。经综合考虑确定当绿豆浆酶解液中α-淀粉酶加酶量为0.5%时,面包高度和感官评分最大,面包芯内部气孔均匀,硬度和咀嚼性小,老化速度慢。     

几种改良剂对板栗面包焙烤品质及老化指标的影响

采用单因素实验,研究了黄原胶、α-淀粉酶、单甘酯三种面包改良剂对板栗面包焙烤品质及老化指标的影响。实验结果表明：黄原胶的添加对板栗面包的感官品质及老化指标均产生了显著影响,当添加量为板栗粉及面包粉总重的1%时,板栗面包具有良好的焙烤品质,贮存7天后,其硬度比对照组下降了9%;不同添加量的单甘酯对板栗面包的老化均有延缓作用,但对面包的焙烤品质均产生负面影响;当α-淀粉酶添加量为0.01%或0.005%时,板栗面包的抗老化效果及焙烤性能均好于对照组,但当添加量较高时,面包焙烤品质骤然下降。     

复配型面包品质改良剂在板栗面包中的应用

首次利用面包品质改良剂对板栗面包的焙烤品质及延缓老化的作用效果进行了研究。依据各种改良剂对面包防老化效果的不同,确定出试验用改良剂为黄原胶、α-淀粉酶、单甘酯。分别以三种面包品质改良剂做单因素实验,实验结果表明:当黄原胶以板栗粉与面包粉总重量的0.5%、1%、1.5%、2%的比例添加到板栗面包中时,对板栗面包的感官品质及老化指标均产生了显著影响,当添加量为1%时,不但板栗面包具有良好的焙烤品质而且延缓了面包的老化;当α-淀粉酶按不同的比例添加时,在添加量为0.01%或0.005%时,板栗面包的抗老化效果及焙烤性能均较对照组好,但当添加量为0.03%、0.06%时,致使板栗面包芯发粘,面包醒发性能受阻;在单甘酯的单因素实验中,不同添加量的单甘酯对板栗面包的老化均有延缓作用,但对面包的焙烤品质均产生负面影响。选择几种改良剂的较优添加量做正交实验,实验结果表明:在板栗面包制作过程中按板栗粉及面包粉总重用量添加1.5%黄原胶、0%α-淀粉酶、0.3%单甘酯时,板栗面包具有良好的焙烤品质,且在贮存7d后,面包芯硬度比对照组下降44%,延缓了面包老化,延长了其货架期。     

荞麦无麸质面包研究进展

对荞麦无麸质面包配方、工艺及品质改良研究进展进行综述。荞麦粉作为优质无麸质原料,常与其他谷物粉或淀粉复配制作面包,添加量主要为10%～50%,多采用温水和面,发酵时间短;添加纤维或多糖可通过模拟面筋蛋白黏弹性和控制水分子移动来增加面团黏度、提高荞麦面团发酵性能和持气性,降低面包硬度,增加面包体积;酸面团发酵技术可降低荞麦面团和面包的pH,增加面包体积,延缓面包老化;酶处理技术可帮助形成蛋白质网络,增加荞麦面包咀嚼性;添加蛋白质可强化荞麦面团网络结构,增加面包体积;营养学评价显示添加荞麦粉可提高无麸质面包抗氧化能力和矿物质含量。但荞麦无麸质面包依然存在面团持气性差、操作性不佳,面包体积小、硬化快等问题。未来研究应关注原料预处理、多种酶或胶体协作、老化改善及产品免疫学验证。     

INFLUENCE OF ENZYMES ON THE TEXTURE OF BROWN PAN BREAD

Enzymes are commonly used to improve the textural quality of bread and to extend its shelf life. To study the effect of enzymes on the texture of brown pan bread, four types of bread were industrially manufactured using amylase, xylanase, a mixture of amylase : xylanase (1:1) and control (no enzyme). After baking, the bread samples were stored for 1, 4, 7, 10, 13, 15 and 17 days. At each storage time, bread texture was evaluated by sensory and instrumental methods, and the overall acceptability was determined. Instrumental and sensory texture data showed that the addition of amylase or amylase : xylanase decreased the staling rate of breads. Furthermore, the use of a mixture of amylase and xylanase provided better results than the addition of amylase alone. Therefore, the results suggest that the addition of a mixture of amylase and xylanase is recommended to extend the shelf life of brown pan bread. On the other hand, the addition of xylanase resulted in an increase of the staling rate. The results suggest that when xylanase is used to improve dough machinability, the addition of amylase along with it should be considered in order to prevent an increase of staling rate.     

毛壳霉CQ31低分子质量木聚糖酶对馒头品质的改善

研究了毛壳霉CQ31低分子质量木聚糖酶对馒头品质及老化的影响。木聚糖酶的添加对馒头的比容、高径比、白度、硬度等几个方面均可产生明显的影响。不同加酶量的试验结果表明,添加该木聚糖酶能明显改善馒头的品质和延缓馒头的老化。当木聚糖酶的添加量为2.5 mg/kg时,馒头的比容、高径比及白度分别增加了20%、1.2%和0.4%,组织结构有明显的改善。同时,对照组与加木聚糖酶组馒头的硬度大小都随着贮存时间的延长而增加,但加木聚糖酶组馒头老化速率明显减缓。因此,毛壳霉CQ31低分子质量木聚糖酶能高效改善馒头品质和延缓馒头老化,在馒头加工中具有广阔的应用前景。     

耐热木聚糖酶对面包老化作用探讨

研究了纯化的耐热木聚糖酶对面包老化的影响作用,探讨了耐热木聚糖酶影响面包老化的动力学。研究证明,适量添加耐热木聚糖酶的面包品质得到了明显改善,并且老化速度变缓,老化速率常数相比对照组下降幅度高达48%。耐热木聚糖酶对面包老化的影响作用显著。     

橄榄绿链霉菌木聚糖酶组对面包品质的改善

本文研究了橄榄绿链霉菌(Streptomyces olivaceovirdis)E-86产生的分子量约1200kDa木聚糖酶组对面包品质的影响。焙烤试验结果表明，添加20ppm木聚糖酶组的面包比容增加了38．8％，新鲜面包芯硬度降低了1／3，面包老化速率也明显减小。该木聚糖酶组具有内切酶和切枝酶的活性，在面粉中水溶性和水不溶性阿拉伯木聚糖组成比例范围内，对水不溶性阿拉伯木聚糖的降解作用比水溶性阿拉伯木聚糖快。因此，该酶组能够改善面包的品质。     

Impact of microbial transglutaminase on the staling behaviour of enzyme-supplemented pan breads

The effects of microbial transglutaminase (TGM) when added singly and in combination with amylolytic (-amylase, NMYL) and non-amylolytic (xylanase) enzymes on the textural profile of fresh pan beads and pan breads stored for up to 20 days have been investigated in samples made with low and high extraction rate wheat flours following a sponge-dough process. White and whole-wheat enzyme-supplemented bread samples evidenced a similar sensory firming profile but a different quantitative instrumental staling pattern during storage. Two groups of samples with different staling behaviour can be defined according to the absence (faster staling kinetics) or the presence (slower kinetics) of NMYL in the bread formula, the separation being particularly clear for hardness, cohesiveness and resilience in white bread samples. TGM when added to NMYL-supplemented doughs induced synergistic beneficial effects on fresh bread quality and staling kinetics retardation. The binary combination led to breads with softer and less chewy fresh crumbs, increased initial crumb cohesiveness and resilience, and slower crumb staling kinetics and sensory deterioration during storage, particularly for samples made with white flour.     

Improvement of the breadmaking quality of wheat flour by the hyperthermophilic xylanase B from Thermotoga maritima

The study was carried out to investigate the effect of hyperthermophilic xylanase B (XynB) from Thermotoga maritima on the properties of wheat bread and its staling during storage. The presence of XynB in the dough led to improvements in the breadmaking quality (i.e. specific volume and crumb structure) and provided an anti-staling effect on breads compared to the control. Addition of XynB could cause ≈60% increase in specific volume in comparison with the control. By fitting the crumb firming kinetics during storage to the Avrami equation, it showed that XynB retarded the bread staling by reducing the initial crumb firmness and the firming process during storage. XynB hydrolyzed the isolated WU-AX faster than WE-AX under the ratio of wheat AX in wheat flour. Improvement of bread quality by XynB can partly be ascribed to the enzyme specificity.     

Effects of sourdough and enzymes on staling of high-fibre wheat bread

The effects of sourdough and enzyme mixture (α-amylase, xylanase and lipase) on the specific volume, staling and microstructure of wheat pan bread supplemented with wheat bran were studied. Staling of bread was followed for 6 days by measuring the crumb firmness, changes in crystallization of amylopectin (DSC), increase in signal from the solid phase (NMR) and by light microscopy. The most effective treatment in improvement of quality was the combination of bran sourdough and enzyme mixture. During storage the rate of changes in crumb firmness, amylopectin crystallinity and rigidity of polymers were greatest for the white wheat bread. The most pronounced microstructural changes were swelling of starch granules and separation of amylose and amylopectin in the starch granules. Least changes in crumb firmness, amylopectin crystallinity and rigidity of polymers were observed in bran sourdough bread with enzymes. In contrast to white wheat bread, the starch granules were very much swollen in bran sourdough bread with enzyme mixture. This was hypothesized to be due to the higher water content of bran bread, and degradation of cell wall components leading to altered distribution of water among starch, gluten and bran particles during storage.     

Effect of different carbohydrases on fresh bread texture and bread staling

The effect of cellulase, xylanase and #-glucanase on the properties of wheat bread and its staling during storage was studied. The presence of the carbohydrases tested led to breads with high specific volume compared to the control. The texture profile analysis was greatly modified in that the firmness of bread crumb was reduced by all the carbohydrases. A kinetic study of the firmness along with the storage by the Avrami equation showed that the presence of carbohydrases produced softer crumbs and also reduced the rate of bread firming, although no great differences were found between enzymes. Since retrogradation of starch is one of most important factors related to bread staling, the modification of the amylopectin retrogradation was measured by scanning calorimetry. Those studies showed that all the carbohydrases decrease the starch retrogradation, and that the xylanases had the greatest effect. The simultaneous analysis of the firming and starch retrogradation results revealed that the anti-staling effect of xylanase might be due to the retardation in the starch retrogradation, while in the case of cellulase and #-glucanase some other mechanism should be implied in their anti-staling action.     

The application of dextran compared to other hydrocolloids as a novel food ingredient to compensate for low protein in biscuit and wholemeal wheat flour

Wheat is primarily used for bread-making. However, fungal diseases, grain moisture at harvest and low-protein contents strongly influence the quality of the wheat flour, thus creating challenges for traders, millers and commercial bakers who struggle to produce consistently high-quality products. This paper address the replacement of low-protein/wholemeal flour functionality for bread-making purposes. Three hydrocolloids, xanthan gum, dextran and hydroxypropyl methylcellulose, were incorporated into bread recipes based on high-protein flours, low-protein flours and coarse wholemeal flour. Hydrocolloid levels of 0–5 % (flour basis) were used in bread recipes to test the water absorption. The quality parameters of dough (farinograph, extensograph, rheofermentometre) and bread (specific volume, crumb structure and staling profile) were determined. Results showed that xanthan had negative impact on the dough and bread quality characteristics. HPMC and dextran generally improved dough and bread quality and showed dosage dependence. Volume of low-protein flour breads were significantly improved by incorporation of 0.5 % of the latter two hydrocolloids. However, dextran outperformed HPMC regarding initial bread hardness and staling shelf life regardless the flour applied in the formulation.