麦麸酚基木聚糖对发酵面团特性和馒头品质的影响

为了提高麦麸的附加值、馒头的品质以及增强馒头的营养价值,该试验以小麦粉为原料,采用2个分子量的麦麸酚基木聚糖（820、581 kD）,研究不同添加量（0.25%、0.5%、1.0%、2.0%）对发酵面团特性以及馒头品质的影响。结果表明：随着麦麸酚基木聚糖添加量的增加,发酵面团的弹性模量、质子密度A22先增加后下降,黏性模量、质子密度A23增加,弛豫时间T22下降;馒头的亮度下降,红度和黄度增加,比容、黏聚性、回复性先增加后下降,硬度、咀嚼性先下降后上升,黏附性下降,馒头的感官得分先上升后下降。高分子量的麦麸酚基木聚糖,其发酵面团的弹性模量和黏性模量变幅较大,弛豫时间T22、T23较大、质子密度A21较小,低分子量的麦麸酚基木聚糖,其馒头比容和弹性较大,但馒头硬度和咀嚼性相对也较大。麦麸酚基木聚糖添加量在0.5%时,对发酵面团以及馒头品质改善效果最好。添加量在1.0%内,发酵面团特性以及馒头品质均可接受。高分子量的酚基木聚糖对发酵面团以及馒头品质改善效果高于低分子量的酚基木聚糖。研究结果为麦麸酚基木聚糖广泛应用于馒头中,提高馒头品质及营养价值提供理论依据。     

适量燕麦β-葡聚糖改善面团流变学特性

为探讨燕麦β-葡聚糖在强化面粉中应用的可行性,该文利用粉质仪、拉伸仪和糊化仪分析质量分数为0.5%~5.0%燕麦β-葡聚糖的添加对低筋面粉、中筋面粉、高筋面粉及馒头专用粉的流变学特性的影响。结果表明,随着β-葡聚糖添加量的增加,4种面粉面团的的吸水率、形成时间和稳定时间均增大;0.5%~2.0%添加量增强了4种面粉面团的最大拉伸阻力,0.5%~1.0%添加量能够使低筋面粉的拉伸特性接近馒头专用面粉的拉伸特性;燕麦β-葡聚糖能够使中筋面粉的糊化温度稍有升高,但亦能降低馒头专用粉的糊化温度及4种面粉(2.0%~4.0%添加量的低筋面粉及4.0%添加量的高筋面粉除外)的最高黏度、保持黏度、最终黏度、衰减值和回生值。研究表明适量的燕麦β-葡聚糖能够改善面团的流变学特性,研究结果为燕麦β-葡聚糖在强化面粉中的应用提供参考。     

复合改良剂对后发酵馒头冷冻面团冻藏品质的影响

冷冻面团加工技术作为一种面食生产新工艺,是目前较先进的面制品保鲜技术。冷冻处理会对酵母活力、面团品质、面团面筋结构等产生不良影响。为了提高冷冻面团品质,明确不同食品改良剂对后发酵冷冻面团馒头品质的影响,该研究优化了复配增稠剂（卡拉胶、瓜尔豆胶、海藻酸钠）、复配乳化剂（双乙酰酒石酸单双甘油酯、羧甲基纤维素）、复配酶制剂（谷氨酰胺转氨酶、葡萄糖氧化酶）和海藻糖对后发酵冷冻面团馒头品质的作用,通过单因素和响应面试验设计,考察了不同复合改良剂对冷冻面团馒头比容、质构和感官品质的影响。研究表明：海藻糖、酶制剂对冷冻面团馒头比容的影响极其显著（p<0.01）。在添加量为0.4%乳化剂、0.8%增稠剂、45 mg/kg酶制剂、2%海藻糖的复配工艺下,冷冻面团馒头的比容达到最佳水3.15 mL/g,其硬度和弹性也达到较优值,分别为926.832 g、0.912 8。同时对未添加和添加复合改良剂冻藏0～2.5个月的冷冻面团进行扫描电镜观察,发现未添加复配改良剂的冷冻面团中大多数小淀粉颗粒裸露在外,颗粒分明,内部组织结构不均匀,而添加复合改良剂的冷冻面团淀粉颗粒镶嵌在面筋网络之间,蛋白网络结构清晰完整,冷冻面团内部组织结构均匀紧密,面团的抗冻性较强。     

依据面筋蛋白质构变化划分馒头面团调制阶段研究

为了研究依据面筋蛋白变化划分馒头面团调制阶段,特一粉为原料,用小型和面机调制馒头面团。研究和面搅拌过程面团的面筋含量和面筋指数、二硫键和游离巯基含量、氢键和疏水作用力,以及面团的蠕动-恢复情况和硬度变化。结果表明:面团面筋含量及面筋指数、二硫键含量、氢键和面团硬度呈先上升后下降的规律,而游离巯基、疏水作用力和面团蠕动-恢复量呈先下降后上升趋势。根据面团变化规律,可将馒头面团调制过程分为4个阶段:物料混合面粉吸水阶段、面筋形成阶段、面筋扩展阶段和面筋打断阶段。该研究结果可为面食的加工做参考。     

酵母对冷冻面团发酵特性及馒头品质的影响

为了找出使冷冻面团和馒头综合品质较稳定的酵母产品,采用动态流变仪和F3发酵仪对低糖型国光高活性干酵母(1#)、英联马利苹果即发高活性干酵母(2#)、品一高活性干酵母(3#)、高糖型马利即发高活性干酵母(4#)、高糖型丹宝利即发高活性干酵母(5#)和耐高糖安琪高活性干酵母(6#)冷冻面团冻藏35 d过程中的流变学特性和发酵特性进行研究,并对由此面团制作馒头的质构、色泽、比容和感官品质进行分析。结果表明:不同市售酵母冷冻面团在不同冻藏时间下的流变学特性和发酵特性不同。不同酵母冷冻面团制作馒头后硬度、弹性、回复性、咀嚼性、亮度、红度、黄度、比容和感官品质分别差异显著,不同冻藏时间下同种酵母冷冻面团馒头的质构、色泽、比容和感官品质也分别差异显著。6种酵母在冻藏35 d内,1#和2#酵母冷冻面团的发酵活力始终较大,6#酵母冷冻面团的发酵特性参数始终最稳定;1#、5#和6#酵母冷冻面团的弹性模量与黏性模量较大,其中面团流变学特性最稳定的是5#;1#和6#酵母冷冻面团制作馒头的感官品质较好的同时,比容较高,色泽品质较好,质构品质也较好。因此整个冻藏期间,使冷冻面团和馒头综合品质较好较稳定的是1#,其次是6#。研究结果为冷冻面团馒头工业化生产中酵母的选择提供参考。     

高量秸秆不同深度还田对黑土有机质组成和酶活性的影响

在田间耕作条件下黑土3个土层(0~20、20~40、40~60cm)添加4%和8%高量玉米秸秆于尼龙袋中原位培养近4年后,研究不同层次土壤秸秆转化与有机碳积累特征,以及腐殖质各组分和土壤酶活性的变化。结果表明,添加4%的秸秆量0~20、20~40和40~60cm土层有机碳分别增加31.8%、96.4%和171.1%,8%秸秆添加量分别增加了86.2%、193.5%和265.9%,增加秸秆还田深度有利于土壤有机碳的积累。0~20 cm土层在无秸秆还田情况下有机碳下降了29.3%,而20~40 cm土层仅下降了1.8%。土壤有机碳含量和酶活性均随秸秆添加量的增加而提高,腐殖质胡敏酸/富里酸(HA/FA)比值发生较大变化,改善了腐殖质品质。各处理腐殖酸碳(HS-C)和胡敏酸碳(HA-C)的大小为20~40 cm土层0~20 cm土层40~60 cm土层,而40~60 cm土层则更有利于富里酸碳(FA-C)的积累。土壤过氧化氢酶活性、脲酶和蔗糖酶活性分别与HA-C、FA-C含量呈极显著正相关、显著正相关。研究结果为深层秸秆还田促进土壤有机质的积累提供了理论依据。     

提高大豆渣膳食纤维中可溶性成分的方法研究

以大豆渣为原料,采用微生物发酵、微射流均质机高压均质处理和高温蒸煮的方法来提高大豆膳食纤维中可溶性成分含量,研究不同发酵时间、不同处理压力和蒸煮温度以及蒸煮时间对提高豆渣可溶性膳食纤维（SDF）含量的影响。结果表明：利用发酵法可提高可溶性膳食纤维的含量达15%之多,并且在发酵的前6天,SDF含量增长很快,6 d后SDF的含量变化较少;而高压均质处理法提高可溶性膳食纤维含量的幅度在10%～28%之间,并随着处理压力的升高而增大;高温蒸煮法能提高可溶性膳食纤维的含量20%,121℃,20 min为较理想的蒸煮条件。     

麸皮面粉面团的粉质和拉伸特性

为了探讨麸皮对小麦面粉品质的影响,将微粉碎后的燕麦麸细粉、小麦麸细粉与小麦粉按混料配方均匀设计制备麸皮面粉,用粉质仪和拉伸仪测定了麸皮面粉的面团流变学特性,并对麸皮面粉各组分含量与流变学参数间的相关性进行分析。结果表明,随着麸皮含量的增加,麸皮面粉面团的吸水率增大,形成时间变化不大,稳定时间不断减少;弱化度和粉质指数在不同样品变化较大,以样品3粉质特性(即小麦粉88.5%,燕麦麸细粉10.20%,小麦麸1.39%)最优;相同醒发时间下,随着麸皮总含量的增加,面团的拉伸曲线面积、延伸度、拉伸阻力及最大拉伸阻力均呈下降趋势;拉伸参数均随醒发时间而呈上升趋势。与面团粉质特性相关性最显著的是小麦粉含量,其次是小麦麸和燕麦麸细粉含量;小麦粉含量与拉伸特性呈显著正相关,与燕麦麸含量呈显著负相关,与小麦麸含量的相关性不显著。这些研究表明麸皮添加比例能够显著影响面团的流变学特性。     

稻壳-鸡粪好氧高温堆肥体系中磷石膏消纳能力的研究

为探究堆肥体系中磷石膏的消纳能力,增加磷石膏资源化利用强度,该研究以稻壳作为主要原料,以鸡粪为辅料,添加基于堆肥有机物料(干质量)的0、10%、20%、30%和40%磷石膏(CK、P10、P20、P30和P40)作为堆肥调理剂,研究其对高温堆肥过程中堆肥的物理、化学、生物指标以及堆肥腐熟后堆料品质性状的影响,从肥料化的角度,探究稻壳-鸡粪堆肥体系中磷石膏的消纳能力。结果表明,相比于CK而言,磷石膏添加量在10%~30%明显促进了堆料温度的快速上升和高温时间,增加堆肥的发酵强度。当磷石膏的添加量超过20%以后,随着磷石膏添加量的增加,堆肥持续高温期的时间有明显减少。添加40%磷石膏处理稀释效应太明显,堆肥结束以后,堆肥的总有机碳的绝对含量较低,导致堆肥产物的有机质含量(34.3%)不达标。添加磷石膏可以提高堆体的种子发芽指数,到堆肥结束时,CK、P10、P20、P30和P40的种子发芽指数分别为65.43%、86.54%、97.52%、81.35%和71.40%。但P40处理到堆肥结束时,水溶性铵态氮含量还高达528.2 mg/kg。与CK处理相比,P10、P20和P30处理的养分含量增加显著,且均符合NY525-2012标准要求。各处理重金属含量均未超过NY525-2012标准的要求,但磷石膏的添加仍有增加堆肥重金属的风险。综合添加磷石膏对堆肥腐熟度的影响和堆肥品质的影响来看,在稻壳为主要原料的堆肥体系中,添加有机物料干质量的30%的磷石膏,是本堆肥体系磷石膏最大的消纳量。     

有机肥添加对镉污染稻田土壤养分及镉有效性的影响

通过田间小区定位试验,一次性添加不同量的有机肥(0、10、20、30 t hm~(-2)和40 t hm~(-2)),于水稻不同生育期(分蘖期、扬花期和收获期)采集各处理耕作层和犁底层的土壤样品,研究其土壤理化性质、有效态Cd含量及Cd迁移状况的变化。结果表明:随着有机肥添加量的增加,各水稻生育期的耕作层土壤中pH、铵态氮和有效磷含量均呈先增大后减小的趋势,有机质和硝态氮含量呈上升趋势。添加适量(≤20 t hm~(-2))的有机肥可以降低土壤中有效态Cd的含量,在有机肥添加量为20 t hm~(-2)时耕作层和犁底层中有效态Cd含量达到最小值,降幅分别为31.26%(扬花期)和65.99%(收获期);但当有机肥添加过多时(≥30 t hm~(-2)),土壤中有效态Cd含量反而会增加。相关分析表明,耕作层中土壤的有效态Cd含量与该土层土壤的pH和有效磷含量呈显著负相关关系,与犁底层中土壤有效态Cd含量呈显著正相关关系。添加适量的有机肥可以抑制土壤中Cd向下层土壤的迁移,在有机肥添加量为20 t hm-2时这种抑制作用最为显著。因此,添加适量的有机肥可以改善Cd污染土壤的养分状况,减小稻田土壤中的有效态Cd含量,抑制土壤中Cd的迁移;20 t hm~(-2)的有机肥添加量可作为研究区周边Cd污染稻田修复的参考标准。     

Impact of Sodium Alginate and Xanthan Gum on the Quality of Steamed Bread Made from Frozen Dough

The impact of freezing on dough rheology, fermentation performance, and final steamed bread quality was investigated in this study. Also, the incorporation of sodium alginate and xanthan gum into the frozen dough formulation, in comparison with 0.1% salt, was studied to test their suitability as frozen dough improvers. Incorporating these hydrocolloids into steamed bread revealed their totally different characteristics from those in baked bread. Freezing of dough led to diminished specific volumes of proofed dough and steamed bread, and it also caused higher crumb firmness for steamed bread. The incorporation of sodium alginate and xanthan gum did not improve the quality of the steamed bread but led to further reduction in specific volume and increase in crumb firmness at the higher levels of 0.3, 0.5, and 1.0% and 0.07 and 0.1%, respectively. Xanthan gum and sodium alginate showed dough strengthening effects by increasing resistance to uniaxial deformation, bubble burst stress, and declining dough weakening coefficients at these levels, but decreased dough extensibility and bubble burst strain were revealed at these concentrations tested.     

Effect of Wheat Bran on Dough Rheology and Final Quality of Chinese Steamed Bread

Wheat bran is a low‐cost by‐product abundantly produced by the wheat flour industry. As a staple food of China, Chinese steamed bread (CSB) represents about 40% of China's wheat consumption. This study investigated the effects of incorporating wheat bran into the CSB at different levels (5, 10, and 15%). The dough behavior was measured by analyzing rheological properties. Quality of CSB was analyzed from two perspectives: physical properties and nutritional quality. For physical properties, specific volume, loaf height, moisture, and texture were measured by 1 . The predicted glycemic response of the bread was analyzed by using an in vitro digestion method. The results illustrated that the incorporation of wheat bran into wheat flour reduced the extensibility of the dough, decreased specific volume, and increased bread hardness, gumminess, and chewiness. However, this study also showed that addition of wheat bran can decrease the predicted glycemic response of steamed bread by up to 39%.     

Application of Polished‐Graded Wheat Grains for Sourdough Bread

Flours obtained by a specific polishing process were used to prepare sourdough and bread. Three fractions designated C‐1 (100–90%), C‐5 (60–50%), and C‐8 (30–0%) were studied. The pH, total titratable acidity levels, and buffering capacity of sourdoughs made from polished flours were significantly different from those of the control sourdough with No. 1 Canada Western Red Spring (CW), and they provided sourdough breads with better qualities than that of CW. The growth of lactic acid bacteria and yeast in polished flour sourdoughs were significantly accelerated during fermentation over that in CW sourdough. Higher maturation of polished flour sourdoughs softened the hardness of mixed dough. The intricate network of honeycomb structure gluten and uneven surface of starch granules were distinctly observed in SEM images. Substitutions of C‐5 or C‐8 sourdoughs for CW significantly increased the loaf volume and softened breadcrumbs more than CW sourdough. Flour qualities of polished flours such as suitable acidity and good buffering capacity caused by the bran fraction were effective for better growth and longer life of yeast in the dough during fermentation. Therefore, application of polished flours in sourdough bread would improve rheological properties of dough and bread as compared with CW sourdough.     

Effects of DATEM on Dough Rheological Characteristics and Qualities of CSB and Bread

Diacetyl tartaric acid ester of monoglycerides (DATEM) is a kind of anionic emulsifier. To date, the positive effect of DATEM on the volume of bread has been reported, but the effects on Chinese steamed bread (CSB) quality and other parameters for bread quality are still unclear. The effects of DATEM on the characteristics of dough and the qualities of CSB and bread were investigated. The results showed that, the effects of DATEM on the rheological properties of dough were complex. Water absorption ratio of CSB dough decreased slightly, while that of bread dough increased slightly. But gas retention and structure improved and gluten strength increased for both CSB and bread doughs after DATEM was added. The studies also showed that structure, elasticity, tenacity, and whiteness of CSB were improved, but specific volume was almost unchanged. The structure, color, and smoothness were significantly improved for bread, and specific volume increased compared with the control. The optimal quantities of DATEM for CSB and bread were both ≈0.10% (on flour mass basis).     

南方馒头专用小麦粉原料选择研究

为生产高品质南方馒头,确定优质南方馒头专用小麦粉原料特性的取值范围,本研究以20种小麦粉为原料制备南方馒头,探究小麦粉的理化特性、糊化特性、拉伸特性、粉质特性对南方馒头品质的影响,通过逐步回归分析法筛选出影响南方馒头综合品质的小麦粉关联性指标,结合聚类分析得到适宜加工南方馒头的小麦粉原料关联性指标范围。结果表明,小麦粉原料的灰分、降落数值、峰值黏度、形成时间、稳定时间、弱化值、延伸度、拉伸面积、拉伸比、最大拉伸比与南方馒头品质综合得分存在显著(P < 0.05)相关性。影响南方馒头综合品质的关键指标为延伸度、形成时间和峰值黏度,适宜加工南方馒头的小麦粉参考关键指标范围为:延伸度126.00~158.00 mm、形成时间1.70~5.00 min、峰值黏度 1 027.00~1 326.00 Pa·s。小麦粉原料选择模型的建立和关键性指标范围的确定可预测南方馒头品质。本研究为南方馒头原料选择提供了依据,并可用于进一步改善南方馒头的综合品质。     

Effect of RS4 Resistant Starch on Dietary Fiber Content of White Pan Bread

Bread flour was replaced with 5, 10, 15, 20, or 25% phosphorylated cross‐linked RS4 resistant wheat starch and augmented with vital wheat gluten to maintain original flour protein content. Effect on dough and bread characteristics, total dietary fiber content, and consumer acceptability were evaluated. Mixograph water absorption was not affected by addition of 5, 10, and 15% RS4; however, a significant 2% increase in absorption occurred with 20 and 25% RS4 addition. Mixograph mix time was increased by 15 s with the addition of 5, 10, and 15% RS4, by 30 s with 20% added RS4, and by 45 s with 25% added RS4. There was not a difference in farinograph absorption of doughs containing all levels of added RS4. Farinograph mixing time increased as addition level increased up to 15% and then decreased at higher addition levels. In general, dough strength and extensibility were not affected by RS4 addition. Levels of added RS4 up to 20% did not affect bread volume. Loaves with 15, 20, and 25% added RS4 contained sufficient fiber to meet the “good source of fiber” claim. A consumer sensory panel reported no difference in liking of flavor, texture, or overall liking of bread containing 15, 20, and 25% RS4.     

Qualitative Effect of Added Gluten on Dough Properties and Quality of Chinese Steamed Bread

Glutens isolated from 15 soft red winter (SRW) wheat flours were added into a SRW wheat flour to obtain protein levels of 9.6 and 11.3% for determination of the qualitative effect of added gluten on the dough properties and quality of northern‐style Chinese steamed bread (CSB). Sodium dodecyl sulfate sedimentation (SDSS) volume of the gluten source flour exhibited positive relationships with mixograph absorption, midline peak time (MPT), and midline peak value (MPV) of the gluten‐added flours and with surface smoothness, crumb structure, and total score of CSB prepared from the gluten‐added flours regardless of protein content. Positive correlations were also observed between SDSS volume of the gluten source flour and specific volume and stress relaxation score of CSB prepared from the gluten‐added flours of 11.3% protein. The increase in protein content from 9.6 to 11.3% by gluten addition raised mixograph absorption, MPT, and MPV but had no apparent effect on resistance breakdown, dough maximum force for extension, and extensibility, and it increased CSB specific volume and crumb structure score without affecting surface smoothness, stress relaxation, and total score. Mixograph parameters exhibited significant relationships with CSB total score, indicating that they could be effective predictors of the CSB‐making quality of flours.     

Fortification of Bread with Hulls and Cotyledon Fibers Isolated from Peas,Lentils, and Chickpeas

Bread was prepared from wheat flour and wheat flour fortified with either 3, 5, and 7% legume hulls or insoluble cotyledon fibers, or with 1, 3, and 5% soluble cotyledon fibers isolated from pea, lentil, and chickpea flours. Incorporation of hulls or insoluble fibers resulted in increases in dough water absorption by 2–16% and increases in mixing time of dough by 22–147 sec. Addition of soluble fiber resulted in decreases in water absorption as the substitution rate increased and similar mixing times to the control dough. Loaf weights of breads containing hulls or insoluble fibers were generally higher than that of control bread at 149.4–166.5 g. However, the loaf volume of breads fortified with legume hulls and fibers (685–1,010 mL) was lower than that of the control bread (1,021 mL). Breads containing soluble fibers were more attractive in terms of crumb uniformity and color than breads containing either hulls or insoluble fibers. Breads fortified with legume hulls and fibers were higher in moisture content than control bread regardless of the type, source, or fortification rate. Bread fortified with up to 7% hulls or insoluble cotyledon fibers or up to 3% soluble cotyledon fibers, with the exception of 7% insoluble pea fiber, exhibited similar firmness after seven days of storage compared with the control bread, despite their smaller loaf volume. Breads containing hull fibers exhibited the lowest starch transition enthalpies as determined by DSC after seven days of storage, while the starch transition enthalpies of breads containing added soluble or insoluble fiber were not significantly different from the control bread.