Effect of Some Processing Variables on the Quality Attributes of Yam Flour

The effect of varied processing variables （yam slice thickness, drying temperatures and type of drying） were investigated to determine their effects on the proximate and some functional properties of yam flour. The yam flour was produced with different slice thickness of 1, 1.5, 2.0, 2.5 and 5 cm using both conventional sun drying method and oven drying at temperatures; 40 ~C, 50 ~C, 60 ~C and 70 ~C. The moisture content of all the yam flour samples increased with increasing yam slice thickness, with the samples sun dried having the lowest values （6.20%-6.87%） followed by those dried at 70 ~C and then 60 ~C. The protein content of the yam flour samples increased with increase in slice thickness and decreased with increase in drying temperatures while the fat and the crude fibre of all the yam flour samples decreased with increase in slice thickness. The water absorption capacity of the sun dried yam flour samples decreased with increase in slice thickness while the syneresis value, bulk density and the gel strength increased with increase in slice thickness for all drying temperatures and for sun dried yam flour samples but smaller slice thickness had higher swelling capacity.

Composition and Functional Properties of Yam Bean (<i>Pachyrhizus</i>spp.) Seed Flour

Yam bean (Pachyrhizus spp.) is legume crop that not only produces edible roots but also has a high yield of unutilized seeds. Although the yam bean seeds are rich in protein, they are not used due to a high content of toxic rotenone. In this study, yam bean seeds were detoxified and the nutritional and functional properties of their protein determined to assess the proteins’ potential for applications. Seeds of 10 accessions (2 accessions of P. erosus, 4 accessions of P. ahipa and 4 accessions of P. tuberosus) were analyzed for proximate composition, pasting and functional properties (bulk density, least gelation concentration, water absorption capacity, oil absorption capacity, emulsifying capacity, emulsion stability, foaming capacity, foam stability and protein solubility). The results showed that yam bean seeds contained: 29.2 - 32.1 g/100g proteins, 31.3 - 33.0 g/100 g carbohydrates, 24.1 - 25.6 g/100g total fat, 7.5 - 8.1 g/100g crude fiber and 3.4 - 4.1 g/100g ash. The defatted P. erosus seed flour contained 45.6 - 48.8 g/100g protein, 32.6 - 36.5 g/100g total carbohydrate, 6.7 - 7.1 g/100g crude fiber, 6.0 - 6.4 g/100g ash and 5.2/100 g crude fat. The defatted yam bean seed flour exhibited relatively high protein solubility (68.0% - 70.4%), least gelation concentration (14%), water absorption capacity (2.8% - 2.9%) and oil absorption capacity (1.5%). The defatted flour exhibited emulsifying capacity of 35.7% - 36.0%, emulsion stability of 33.2% - 33.5%, foaming capacities of 42% and foam stability of 25.1% - 25.8%. With respect to pasting properties, the defatted yam bean seed flours exhibited pasting temperature of 80.0?C - 81.3?C, peak viscosity of 145.5 - 146.7 RVU, trough viscosity of 95.1 - 102.0 RVU, break down of 43.5 - 51.6 RVU, set back of 252.9 - 258.1 RVU and final viscosity of 348 - 360 RVU. The results show that yam bean seed has potential for use in both food and non-food applications.

Quality and Storage Characteristics of Hot Press Tortilla Prepared from Yam-Wheat Composite Flour

Mixtures of refined wheat flour (RWF) with flours from different sources could impact the functional qualities and shelf life of wheat-based products. Storage stability is one of the most critical factors for tortilla quality. Tortillas made from yam (Dioscorea sp.) wheat composite flours were characterized. RWF was substituted with 5%, 10%, 15%, and 20% of fermented yam flour-brown (FYF) and unfermented yam flour-white (UYF). Farinograph water absorptions of UYF-composite flours (65.5% - 77.1%) were significantly (P < 0.05) higher than FYF-composite flour absorptions (60.5% - 61.5%). During storage, moisture contents of composite flour tortillas increased while the RWF-tortilla decreased. Tortilla from FYF-composite flour exhibited greater strength (3.1 N at day zero on average) compared to UYF-composite tortillas (2.1 N at day zero on average), while UYF-composite flour tortillas had good extensibility and rollability properties. The properties and composition type and ratios of flour blends affected tortilla quality during the storage period. The substitution of RWF with 15% or 20% UYF would be more suitable for making tortilla with improved properties compared to that of FYF.

Assessment of Microbial Changes and Nutritional Qualities of Extruded White Yam (<i>Dioscorea rotundata</i>) and Bambara Groundnut (<i>Vigna subterranean</i>) Blends

Two flavoured extruded products were developed by co-extruding yam grits (750 μm) obtained from white yam (Dioscorea rotundata) and bambara groundnut flour (250 μm) in 160:40 respectively obtained from white bambara groundnut with added flavouring agents of salt (1% - 3%) and sugar (4% - 6%) in the feed blends at screw speed of 70 rpm, 17.5%, feed moisture and at the barrel temperature of 145℃. The extruded products were packaged in low density polyethylene bag (0.02 μm gauge size) and stored at room temperature (28℃ ± 2℃) and at refrigeration temperature (9℃ ± 2℃) for a period of twenty weeks. The microbiological changes in the extruded products as determined by the total plate under both storage conditions showed that maximum total plate counts were 0.5 × 104 and 5.4 × 104 cfu/g at 9℃ ± 2℃ and 28℃ ± 2℃ respectively. Nutritional evaluation studies of extrudates were comparable (p ≥ 0.05) with standard casein diet with minimum crude protein content of 13.51% providing 1707.2 KJ energy per 100gof diet and supported weight gain and growth of laboratory animals.

山药对蒸煮、焙烤面制品品质的影响研究进展

山药是一种常见的药食同源植物,其含有大量多糖、皂苷、黄酮等活性成分,具有提高免疫力、抗氧化、抗肿瘤、降血糖、降血脂等功效。随着人们对健康、营养食品的迫切需求,山药在面制品中的应用越来越广泛,已开发了山药挂面、山药饼干、山药面包等多种面制品。诸多研究表明,山药加入面制品后会改变面团的结构和特性,影响蛋白质、淀粉等化学组分之间的相互作用,致使面制品的感官品质、营养成分、质构特性等发生变化,而目前尚未见有关山药对蒸煮、焙烤面制品品质影响的系统论述。因此,本文从山药对面团品质的影响入手,系统综述了山药对蒸煮类面制品(如面条、馒头)、焙烤类面制品(如面包、饼干)品质的影响,以期为山药资源的开发和利用、山药面制品的深度研究提供理论参考。

热处理对淮山熟全粉理化特性的影响

为探讨常压蒸(steaming at atmospheric pressure,SAP)和常压煮(boiling at atmospheric pressure,BAP)两种热处理方式对淮山熟全粉理化性质的影响,采用快速黏度分析仪、流变仪、傅里叶变换红外光谱仪和扫描电子显微镜研究不同热处理方法对淮山熟全粉理化性质的影响。结果表明:两种热处理均改善了淮山熟全粉的润湿性和分散性,经SAP处理30 min后分别从7.77、4.68 min降低到了2.17 min和0.52 min;经热处理后,淮山熟全粉的糊化温度、峰值黏度、最低黏度、衰减值和最终黏度均降低,碘蓝值则随着热处理时间的延长而增大;经热处理后淮山糊的表观黏度随剪切速率增大先急剧降低,再趋于平稳,呈现剪切稀化现象;热处理可破坏淮山熟全粉的结构,使其内部有序程度降低,外观形貌变得不规则。研究还发现,经BAP处理所得淮山熟全粉的色差值小于SAP处理组;经SAP处理后,熟全粉的溶解度提高,从16.05 g/100 g(0 min)提高到了17.89 g/100 g(15 min),在相同处理时间下,SAP处理组溶解度高于BAP处理组;经BAP处理后,功能成分整体流失较多,多糖、总多酚、总黄酮和尿囊素的含量分别从2.67、0.076、0.084、0.445 g/100 g(0 min)下降至1.75、0.070、0.071、0.288 g/100 g(30 min),而经SAP处理后,则主要表现为总多酚和总黄酮含量的降低,分别从0.076、0.084 g/100 g(0 min)降至0.055、0.061 g/100 g(30 min);相比BAP处理,SAP是一种较好的淮山熟全粉加工方式。

干燥方式对淮山全粉品质的影响

通过对热风干燥、变温压差干燥、喷雾干燥和真空冷冻干燥4种干燥方式所得淮山全粉的物理特性和营养成分进行分析测定,研究了不同干燥方式对淮山全粉品质的影响。结果表明:在物理特性方面:变温压差干燥、喷雾干燥和真空冷冻干燥淮山全粉色泽好,而热风干燥褐变严重;真空冷冻干燥淮山全粉的堆积密度显著低于其他干燥方式;喷雾干燥淮山全粉的吸水性显著低于其他干燥方式,溶解度显著高于其他干燥方式,且颗粒特征较好。在营养成分方面:4种淮山全粉的营养成分均有不同程度的差异,热风干燥淮山全粉的维生素B1含量显著低于其他干燥方式;喷雾干燥淮山全粉的蛋白质、氨基酸和尿囊素含量均较高;说明喷雾干燥淮山全粉的营养成分损失较小。喷雾干燥法干燥淮山全粉品质较好,且所需干燥时间短,生产效率高、成本低。

干燥方法对山药粉性质的影响

通过真空干燥、冷冻真空干燥和喷雾干燥制备山药生/熟粉,研究其流变特性、糊化特性和消化性质,初步探究其变化机制。结果表明,山药生粉具有较高的成糊温度,山药熟粉中冷冻真空干燥山药熟粉的峰值黏度最高(3619.50 c P)。不同干燥方法干燥的山药粉均呈非牛顿流体特性,冷冻真空干燥的山药熟粉的粘弹性最高;山药生粉呈现完整的淀粉颗粒形态,山药熟粉的颗粒形貌差异较大。熟化处理使山药粉抗性淀粉含量显著降低(P<0.05)。熟粉中真空干燥山药熟粉的抗性淀粉含量最高(56.11%)。三种干燥方法中,冷冻真空干燥能较好的保留山药粉的原有理化特性。

淮山全粉-小麦粉混粉特性及其对饼干品质的影响

为拓宽淮山全粉的应用渠道,对不同配比淮山全粉-小麦粉混粉的粉质特性、吹泡特性以及面团粘性等流变学特性进行研究,并分析了淮山全粉对酥性饼干烘焙品质的影响。结果表明,淮山全粉的添加显著改变了面团流变特性,添加淮山全粉后,面团的形成时间延长,吸水率、弱化度增大,稳定时间缩短,其总体评价值下降;随着淮山全粉添加量的增加,酥性饼干面团的P值呈先增大后减小的趋势,L值、P/L值变小,其黏着性和附着功增大,饼干感官评分呈先下降后上升的趋势。当淮山-小麦粉配比为2∶8时,满足了作为酥性饼干原料粉的要求,制作的饼干感官品质较好。本研究结果为淮山全粉的应用提供了一定的理论参考。

紫淮山与燕麦粉对酥性饼干品质及营养特性的影响

为研制一种高纤饼干,以低筋粉、紫淮山泥、燕麦粉为主要原料,制作紫淮山燕麦无糖饼干。以感官评分和最大剪切力为指标,考察紫淮山泥、燕麦粉、油脂、奶粉及木糖醇添加量对饼干品质的影响,通过正交试验确定制作饼干的最佳配方和工艺。结果表明:最佳工艺条件为以混合粉(低筋粉和燕麦粉)添加量100%计,低筋粉添加量60%、燕麦粉添加量40%、紫淮山泥添加量50%、木糖醇添加量40%、油脂添加量40%、奶粉添加量4%、鸡蛋液添加量4%、食盐添加量0.3%、小苏打添加量1.5%、单甘酯添加量0.8%、柠檬酸添加量0.2%,在上下火均为160℃条件下,烘烤12 min。此条件下制作的饼干与空白对照饼干相比,紫淮山燕麦饼干具有高蛋白、低脂肪、高纤维的特点,营养价值更优。饼干淀粉水解指数(hydrolysis index,HI)和预估血糖生成指数(estimated glycemic index,EGI)分别为52.76、68.67,属于中等血糖生成指数食品。饼干中添加紫淮山和燕麦粉能够起到延缓淀粉消化速度的效果。

紫淮山全粉喷雾冷冻干燥工艺及其特性研究

制备高品质的紫淮山全粉,有利于拓宽紫淮山的消费途径和提升产品价值。本文考察了固液比、进料流量和冻结温度对紫淮山全粉水分含量、溶解度和花色苷含量的影响,通过四因素三水平正交试验,优化了紫淮山全粉喷雾冷冻干燥工艺,并对热风干燥、真空冷冻干燥、喷雾干燥、喷雾冷冻干燥这4种干燥方式制备的紫淮山全粉理化特性和抗氧化能力进行了比较。结果表明,紫淮山冷冻喷雾干燥的最佳工艺条件为进料流量25 mL/min、固液比1∶1、冻结温度-30℃,在此条件下得到的紫淮山全粉水分含量为3. 89%、溶解度为23. 12%、花色苷含量为13. 28 mg/100 g。干燥方式对紫淮山全粉的物理性质、营养成分、活性成分和抗氧化能力的影响显著。

淮山全粉喷雾干燥工艺优化研究

为了改善淮山全粉的喷雾干燥效果,优化喷雾干燥工艺,采用响应面法优化喷雾干燥条件,分析了不同进风温度、进料流量和固液比对产品品质的影响规律。结果表明:当进风温度为170℃,进料流量为15m L/min,固液比为1∶1.5,在此优化条件下得到的淮山粉水分含量为3.89%、吸水性为0.78g/g、溶解度为27.34%、堆积密度为0.87g/m L,产品综合评价得分最高,通过响应面优化得到的喷雾干燥工艺能有效应用于淮山全粉加工。

复合益生菌发酵凝固型山药香蕉酸奶的研制

以山药浆、香蕉粉和鲜牛奶为主要原料,利用保加利亚乳杆菌、嗜热链球菌和益生菌(Lactobacillus casei Zhang)按1∶1∶1混合作为复合益生菌菌种,研制出一种集山药、香蕉和益生菌于一体的兼具营养保健功能新型乳品。通过单因素和正交实验确定了复合益生菌发酵山药香蕉酸奶的最佳工艺条件。结果表明:在鲜牛奶中添加1.8%复合益生菌、15%山药浆、0.3%香蕉粉,发酵8h。在此工艺条件下制得的酸奶风味独特、质地均匀、营养丰富,而且在储藏期内,该酸奶的活菌数表现稳定,优于同类产品。

山药固体饮料喷雾干燥工艺优化

以山药为原料,在单因素试验的基础上,通过正交试验优化山药固体饮料喷雾干燥工艺。研究助干剂含量、进风温度、物料固液比和雾化器转速对喷雾干燥山药固体饮料出粉率和品质的影响。结果表明,山药固体饮料喷雾干燥最佳工艺条件为:助干剂含量8%,进风温度180℃,物料固液比1∶4(g/mL),雾化器转速20000 r/min,在此条件下喷雾干燥效果较好,得到的山药固体饮料质地光滑,山药气味浓郁,其出粉率为20.15%,堆积密度0.5746 g/mL,水分含量4.89%,色泽L*值95.37。

紫山药粉在曲奇饼干中的应用

以紫山药粉、低筋面粉为主要原料生产紫山药曲奇饼干。以感官评分作为评价指标,通过单因素试验和正交试验确定最优配方:以紫山药低筋粉质量为基准(紫山药粉15%+低筋面粉85%)、鸡蛋液25%、黄油70%、白砂糖35%、奶粉12%。在180℃/160℃下烘烤15 min得到的紫山药曲奇饼干品质优良,曲奇饼干的硬度、胶着性和咀嚼性均较好。

山药粉对小麦粉加工特性及挂面品质的影响

采用降落值仪、面筋仪、粉质仪、拉伸仪、质构仪等,研究山药粉对小麦粉加工特性及挂面品质的影响。结果表明,山药粉影响小麦粉的加工特性,改善挂面的品质。添加山药粉混合粉的理化指标和面团特性均有不同程度的变化,表现为面团吸水率、弱化度、降落值、沉淀值、拉伸比升高,面团形成时间、稳定时间、评价值、拉伸阻力、拉伸能量和延伸度降低,粗蛋白含量略有下降,淀粉和灰分含量增大,添加山药粉可改善挂面的品质,表现为提高挂面的蒸煮时间、损失率、硬度,降低挂面的吸水率、拉伸力和黏性。综合分析,建议山药粉的添加量不宜超过9%。

山药发糕的配方优化

以山药粉、小麦粉为主要原料生产发糕,采用感官鉴评和质构分析两种方法对配方进行优化。结果发现,山药发糕的最佳配方为山药粉与小麦粉比例5∶1,白砂糖14%,发酵剂0.25%,山药粉小麦粉比例对山药发糕的品质影响最大。山药发糕最佳保水剂为0.1%单甘酯,0.1%蔗糖酯,0.05%β-环状糊精和0.2%的乳酸钙,此条件下生产的山药发糕品质最优。

山药蛋糕预混粉的研制

山药蛋糕预混粉是指按配方将烘焙所用的部分原辅料预先混合好的复配半成品,蛋糕制作时只需要加水,简化了蛋糕制作工艺。通过对蛋清粉、粉末油脂、山药粉、单甘脂四因素的正交试验研究,以蛋糕制品的感官评值进行正交分析,得出山药蛋糕预混粉的最佳配方为:蛋清粉18%、山药粉8%、单甘酯0.4%、绵白糖20%、食盐0.5%、塔塔粉0.2%、泡打粉0.3%、面粉45%、粉末油脂4%、脱脂奶粉3.5%、香精0.1%。

降血糖营养强化面包的研制及其对血糖值的影响

降血糖营养强化面包是以面包专用粉、山药粉、茯苓粉、蛋白糖为原料 ,加入高铬酵母 ,经过调粉、发酵烘烤精制而成。经过正交试验确定了产品的最佳配方 ,并通过临床实验证明了此种面包具有一定的降糖效果 。

紫淮山全粉对面团流变特性及面条质构特性的影响

研究不同紫淮山全粉添加量对面粉粉质特性、糊化特性、面团拉伸特性和面条品质的影响。结果表明,随着紫淮山全粉添加量的增加,面粉的吸水率上升。面团的形成时间在添加量为15%时达到最大值,为5.3 min,增加了39.5%。面团稳定时间在添加量为10%时达到最小值,为3.5 min,减少了40.7%。紫淮山全粉的添加使拉伸能量、延伸度下降。面团在45、90、135 min醒发时间下的延伸度均在添加量为25%时达到最小值。添加紫淮山全粉能降低糊化温度、面粉黏度和回生值,且最终黏度和回生值均在添加量为25%时达到最小值,但崩解值在添加量为25%时达到最大值。面条的硬度、胶黏性、咀嚼性、回复性均在紫淮山全粉的添加量为15%时达到最大值,但紫淮山全粉的添加对面条的弹性无显著性(p> 0.05)影响。面条的L*值随紫淮山全粉添加量的增加呈显著(p <0.05)下降趋势,添加量低于15%时,紫淮山面条的感官评分较高。紫淮山全粉对面粉粉质特性、糊化特性、面团拉伸特性和面条感官品质均有较大影响,紫淮山全粉的最高添加量以15%为宜。本研究结果可为紫淮山全粉的应用提供理论参考。