谷朊粉对糙米粉面团性质影响研究

研究了谷朊粉添加量对糙米粉面团性质的影响,主要包括粉质特性、热机械性质、流变学性质、微观结构等。结果表明:随着谷朊粉添加量增大,面团的吸水率、形成时间、稳定时间、淀粉衰减值和回生程度均在逐渐增长,蛋白弱化度在逐渐降低。糙米粉面团的弹性模量和粘性模量均在增大,且弹性模量大于粘性模量。扫描电镜结果显示:随着谷朊粉添加量增大,面团的网络结构越来越明显,淀粉颗粒镶嵌在蛋白形成的网络结构中,增加了面团的弹性及变形的阻力。

发芽对糙米粉性质及糙米鲜湿米线品质的影响

比较了发芽和未发芽糙米米粉直链和支链淀粉含量、水合特性、糊化特性差异,并探究了发芽对糙米鲜湿米线蒸煮品质、质构特性、微观结构、营养成分及感官品质的影响。结果表明:与未发芽糙米粉相比,发芽糙米粉的直链、支链淀粉含量分别下降了11.19%和15.49%;水合特性提高,在100℃下溶水率和溶胀率分别提高了1.75倍和1.15倍,糊化特性中黏度的降低与发芽糙米鲜湿米线蒸煮损失率提高、质构硬度和弹性降低、微观结构松散均密切相关;发芽糙米制备的鲜湿米线口感更加柔软顺滑,营养价值更高。

面包改良剂对红薯面包面团流变特性的影响及改良剂的优化分析

以高筋粉∶红薯全粉=3∶1为基料制作面包,为了改善红薯面包的品质,利用各种面包改良剂如谷朊粉、乳化剂、亲水凝胶、酶制剂和抗坏血酸,研究其对面团发酵和粉质性质的影响。结果表明,在单因素实验中得到谷朊粉对面团发酵特性有一定的改善,添加量4.5%与5.5%的改善效果最明显且相当。对于其它改良剂选择,乳化剂-二乙酰酒石酸单甘脂(DATEM)、硬脂酰乳酸钠(SSL)、羟丙基纤维素(HPC),亲水凝胶-卡拉胶,酶制剂-葡萄糖氧化酶(GOX)、木聚糖酶(XYL)、脂肪酶(LYP)和抗氧化剂-抗坏血酸(VC)对面团发酵均有不同程度的改善,但羟丙基纤维素(HPC)和脂肪酶(LYP)对混合粉的粉质特性影响不显著。采用两两复合和响应面设计实验,以面包硬度和比容作为指标,确定了复合型改良剂的配方:复配乳化剂0.47%,卡拉胶0.58%,复配酶制剂0.0221%,VC0.00225%,理论得到的面包比容为5.01 cm3/g,硬度为166.3 g。为了检验模型预测的准确性,在最适添加量条件下进行验证实验,面包比容实测为5.08 cm3/g,硬度为171.5 g,明显优于空白组的比容(4.12 cm3/g)和硬度(271.1 g)。

Correlation between Milling Flour Quality of Xinjiang Spring Wheat and Processing Quality of Xinjiang Hand-stretched Noodle

In the research,36 spring wheat cultivars from Xinjiang were used to investigate flour yield,ash content,color,granularity,flour quality,paste quality and gelatinization property and to evaluate processing quality and characters of stretched noodle,in order to explore relationship of milling flour quality with quality property of Xinjiang spring wheat and with processing quality of Xinjiang hand-stretched noodle,which provides theoretical references for improvement of Xinjiang spring wheat cultivars,breeding of specific cultivars（for Xinjiang stretched noodles）,and advancement of stretched noodles.The results indicated that flour color is dominant among flour quality properties of Xinjiang spring wheat,which is of significant correlation with processing quality of stretched noodles.Therefore,in quality improvement of Xinjiang stretched noodles,flour yield of Xinjiang wheat should be enhanced and ash content and damaged starch should be reduced in order to improve quality of flour and stretched noodles from Xinjiang spring wheat.The indices of milling flours for Xinjiang stretched noodles are as follows：flour yield ≥60.77%,ash content ≤ 0.45%,damaged starch≤3.77%,granularity ≤108.14%,brightness（L^＊）≥ 90.86,redness（a^＊）≥-0.82,and yellowness（b^＊） ≤9.00.

Application of near-infrared spectroscopy to predict sweetpotato starch thermal properties and noodle quality

Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy （NIRS）. This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature （To） （standard error of prediction SEP=2.014 ℃, coefficient of determination RSQ=0.85）, gelatinization peak temperature （Tp） （SEP=-1.371 ℃, RSQ=0.89）, gelatinization temperature range （Tr） （SEP=2.234 ℃, RSQ=0.86）, and cooling resistance （CR） （SEP=0.528, RSQ=0.89）. Gelatinization completion temperature （To）, enthalpy of gelatinization （△H）, cooling loss （CL） and swelling degree （SWD）, were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality.

Effect of Gluten-Free Flours on Physical Properties of Cakes

In this study, the effect of lupin flour （LF） and whole buckwheat flour （BF） on the physical properties of gluten-free cake was studied. LF up to 40% and BF flour up to 20% level were partially replaced with corn starch and rice flour mix in the gluten free cake recipe. Cake dough properties （specific gravity and pH）, cake properties （weight, volume, symmetry and uniformity index, hardness）, crust and crumb color values were investigated. High addition levels of LF decreased the pH values of the dough. Compared to control, volume index of the cakes improved with BF at 5% addition level or LF up to 20% level. While minimum level of the LF/BF gave softer cake texture, high substitution levels of LF （30%-40%） and BF （15%-20%） had detrimental effect on softness of the samples. All addition level of the LF increased the darkness and yellowness of the cake＇s crust and crumb, whereas BF above 5% level decreased lightness and yellowness of the samples. The high levels of LF （30%-40%） and BF （15%-20%） had reducing effect all physical properties of gluten-free cake samples.

Influence of Aloe Gel Enrichment on the Physicochemical, Textural and Sensory Characteristics of Dahi

Aloe gel, derived from Aloe vera plant is well known for its nutraceutical potential, It is available commercially as a juice with poor sensory quality. The therapeutic benefits of Aloe gel could be extended to food products concomitantly improving its acceptability. Dahi/curd is an Asian fermented dairy product that enjoys tremendous mass appeal. The objective of the present study was to formulate dahi enriched with Aloe gel （AG） as a functional ingredient and to study its effect on the quality of dahi. Plain dahi was prepared by addition of 2.5% skimmed milk powder （SMP） and suitable starter to milk. For the preparation of AG enriched dahi, SMP was replaced by AG at different levels （0.1-0.25%）. The products were evaluated for moisture, pH, titrable acidity （TA）, whey syneresis （WS）, total solid content （TS）, water holding capacity （WHC）, total yield （TY）, whiteness index （WI）, and viscosity. Microbial analysis and sensory evaluation were also carried out. Enrichment of dahi with AG was found to improve its quality characteristics by causing a significant reduction in WS and an increase in TA, TS, WHC, TY, WI and viscosity. AG dahi recorded good sensory acceptability. Storage study also indicated AG dahi to perform better in terms of the various parameters studied. The present investigation suggests the feasibility of adding Aloe gel powder as a functional ingredient to dahi to enhance product quality as well as its nutritional and therapeutic potency. It could be commercially exploited as a novel product.

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.