黔江肾豆碳水化合物组成及淀粉营养特性研究

以黔江肾豆为材料,对其碳水化合物组成和淀粉营养特性进行了研究。结果显示,肾豆富含碳水化合物(57.25±0.41)%,其中淀粉和粗纤维质量分数分别为(48.16±0.59)%和(3.59±0.11)%,表明肾豆是食物能量和膳食纤维的重要来源。淀粉直/支比0.63,较豌豆和部分绿豆高;肾豆淀粉消化特性分析显示慢消化淀粉(SDS)和抗性淀粉(RS)占比60.24%,可在混合膳食中起降低膳食整体碳水化合物消化速率的作用,对于慢性疾病如心血管等疾病和糖尿病的预防有益。体外血糖指数(GI)分析显示肾豆淀粉GI=88.5,为高GI;肾豆全粉GI=67.2,为中GI食品,肾豆全粉GI值低于肾豆淀粉,与其含蛋白质、纤维素、单宁、植酸和脂肪等成分有关。因此,食用全豆可减慢消化。黔江肾豆淀粉是制备粉丝、粉皮等深加工淀粉食品的良好淀粉来源。     

肾豆粉丝加工及粉丝特性的研究

以黔江肾豆淀粉为原料,研究了肾豆粉丝制备工艺及食用品质。以"滞后面积"为粉丝加工关键工艺"调粉团"评判指标,以"粉丝断条率和汤液透明度"为"冷冻"优化评判指标,得到肾豆粉丝制备优化工艺为:调芡糊[m(淀粉)∶m(水)=1∶10混合,在100℃沸水中糊化80 s]→调粉团(含水量40%,含芡量4%,加水温度50℃,保温温度50℃)→漏粉(沸水煮制8~13 s)→冷冻(4℃老化6 h,-2℃冷冻6 h)→干燥(40℃烘至水分含量约10%)→成品。以绿豆粉丝为对照,进一步研究了肾豆粉丝感官品质、蒸煮品质和质构特性,结果显示:肾豆粉丝光洁透明、弹韧性好、煮沸损失小(断条率和煮沸损失率分别为(3.33±2.89)%和(1.94±0.20)%),蒸煮品质佳,与绿豆粉丝相似,但硬度偏大、弹性和剪切形变较绿豆粉丝高,感官评定总体可接受性不如绿豆粉丝,但肾豆淀粉仍然具有应用于粉丝生产的潜在价值。     

基于主成分分析的豆粕物理特性评价

为对豆粕的物理特性进行分析及量化评价,本文以42个豆粕样品为试验材料,测定分析其水分、容重、热物理特性、摩擦特性及粉碎特性指标参数,并运用主成分分析法简化物理特性指标,构架评价体系,得到每种样品的综合得分。结果表明,样品各物理特性指标之间存在不同程度的相关性,其中比热与水分和热传导系数呈显著正相关,与热扩散系数、休止角和摩擦系数呈极显著负相关;热传导系数与热扩散系数呈显著正相关,与休止角和摩擦系数呈极显著负相关;热扩散系数与容重呈显著负相关;摩擦系数与水分呈显著正相关,与容重和休止角呈极显著正相关;平均粒径与水分呈显著正相关,与休止角呈显著负相关。通过主成分分析提取了前4个主成分,累积方差贡献率达到88.898%(85%),能够代表原来8个物理特性指标中的绝大部分的信息,并得到评价公式Z=0.363Z_1+0.234Z_2+0.150Z_3+0.142Z_4,计算出豆粕物理特性指标综合得分。     

小麦摩擦特性的试验研究

主要利用直剪仪对小麦(湿基含水量为13.55%、15.28%、16.60%、17.90%)的内摩擦角、小麦与不锈钢板的摩擦系数、小麦与混凝土板的摩擦系数进行了试验测定与比较。结果表明:小麦的内摩擦角变化范围是21.21～37.94°,小麦与不锈钢板的摩擦系数变化范围是0.25～0.63,小麦与混凝土板的摩擦系数变化范围是0.46～0.95,且均随法向压应力的增加而减小,随含水量的增加而增加。根据试验结果,分别拟合出内摩擦角、摩擦系数与法向压应力、含水量的关系方程。     

玉米霉变程度与敏感品质变化关系研究

玉米收获时含水量较高,若无烘干设施,需要短期堆存或运输至烘干场地,在此过程中极易霉变。本研究将含水量为26%、23%、20%和17%的玉米分别在高温环境(25～35℃)和低温环境(15～25℃)条件下存储,检测其在存储过程中霉菌菌落总数、色泽、糊化特性、脂肪酸值和容重等品质指标的变化,并找出品质与玉米霉变程度之间的关系。结果表明,玉米霉变过程中,带菌量急剧上升;色泽指标L~*值和b~*值有所下降;玉米容重也呈现下降趋势;脂肪酸值发生显著变化,26%、23%、20%和17%含水量的玉米分别在初期、16、20、24、40 d就达到国标的重度不宜存状态;峰值黏度、最低黏度、最终黏度、衰减值和回升值也出现不同程度的下降。     

肾豆分离蛋白酶解液抗氧化性能研究

以肾豆分离蛋白为原料,采用酶法工艺水解,对酶解液的抗氧化性能进行研究,为黔江肾豆的开发利用提供思路和方法。选用木瓜蛋白酶、中性蛋白酶和碱性蛋白酶,分别在各种酶的最适pH和温度下,以相同的酶量对提取的肾豆蛋白进行不同程度的酶解,测定蛋白及其酶解物的还原能力、超氧阴离子自由基清除能力、过氧化氢清除能力。结果表明,木瓜蛋白酶、中性蛋白酶、碱性蛋白酶对肾豆分离蛋白的酶解作用均能显著提高抗氧化活性,以中性蛋白酶水解1h条件下获得最大活性的抗超氧阴离子自由基酶解产物,同时有较高还原性和过氧化氢清除能力,对应水解程度(DH)2.46。     

基于含水率的无患子物理性质的测定

为了给无患子加工机械的研发提供设计依据和理论基础,需要对无患子的物理特性及机械特性进行研究,如无患子的三维尺寸、含水率、千粒重、密度、孔隙率、静摩擦系数等,并研究一些物理性质随含水率的变化关系。结果表明:无患子果及无患子种子的三维尺寸、粒子密度、体积密度、无患子果皮及无患子种子与其他材料的静摩擦系数随含水率的升高而增大;无患子果及无患子种子的孔隙率、无患子种子(除长度方向)的压缩破坏载荷随含水率的升高而减小。     

不同用量腐植酸钾对果蔗产量和品质的影响

以果蔗为研究对象,通过施用不同用量腐植酸钾,研究其对果蔗产量、品质及土壤特性的影响。结果表明,施用以木本泥炭为主要成分的腐植酸钾,可显著改善土壤的特性;随着腐植酸钾施用量的增加,土壤pH升高,土壤容重下降,土壤含水量提高,土壤碱解氮、速效磷含量升高。在与常规施肥等量钾的腐植酸钾施用量下,土壤容重比常规施肥处理下降11.0%,土壤含水量增加5.4%,碱解氮和速效磷含量分别提高16.8%和16.1%。结果也表明,施用以木本泥炭为主要成分的腐植酸钾,可提高果蔗的产量和品质,与常规施肥对照相比,当量常规施肥150%钾的腐植酸钾处理果蔗增产8.9%,糖分提高7.7%,效果显著。因此,以木本泥炭为主要成分的腐植酸钾的合理施用对酸性土壤质量改善及果蔗产量、品质的提升具有重要作用。     

豆粕热物理特性的试验研究

为研究豆粕热物理特性的测定方法及不同湿基含水率、温度下的相关规律,以5种湿基含水率(分别为4.85%、8.94%、12.81%、16.72%、20.87%)的豆粕为试验材料,在5种温度梯度下(分别为30、45、60、75、90℃),对其比热、热导率、热扩散系数等热物理特性进行了测定。结果表明:豆粕的比热在2.073~5.170 J/(g·K)之间,其热导率在0.066~0.097 W/(m·K)之间,其热扩散系数在0.416×10~(-7)~0.787×10~(-7)m~2/s之间;含水量和温度对其热物理特性影响显著;其比热、热导率均随湿基含水量和温度的升高而增大;热扩散系数随温度的升高而增大,随湿基含水量的增加而减小。根据试验结果,分别拟合出比热、热导率、热扩散系数与湿基含水量、温度的回归方程。     

基于主成分分析的玉米DDGS物理特性评价

为对玉米DDGS的物理特性进行分析及量化评价,以国内外8个玉米DDGS为试验材料,测定分析其容重、热物理特性、摩擦特性、粉碎特性及色差指标参数,并运用主成分分析法简化物理特性指标,构架评价体系,得到每种样品的综合得分。结果表明:样品各物理特性指标间存在不同程度的差异;各物理特性指标之间存在不同程度的相关性,比热与热导率呈极显著正相关,与导温系数呈极显著负相关;热导率与平均粒径呈显著正相关;导温系数与容重呈极显著负相关;摩擦系数与休止角呈极显著正相关,与平均粒径呈极显著负相关;L*、b*与平均粒径呈极显著正相关;L*与b*呈极显著正相关。通过主成分分析提取了3个主成分,累积方差贡献率达到87.415%;主成分分析的结果表明进口玉米DDGS的物理特性较好。     

Moisture Dependent Physical Properties of Dry Sweet Corn Kernels

Physical properties of sweet corn kernels have been evaluated as a function of kernel moisture content, varying from 9.12 to 17.06% (db). In the moisture range, kernel length, width, thickness, and geometric mean diameter increased linearly from 9.87 to11.09 mm, 7.41 to 9.25 mm, 3.25 to 4.37 mm, and 6.18 to 7.62 mm, respectively, with increase in moisture content from 9.12–17.06%. The sphericity index, kernel volume, kernel surface area, and thousand seed weight increased linearly from 62.6 to 68.8, 93.8 to 194.3 mm³, 120.1 to 182.9 mm², and 220 to 268 gr, respectively. Apparent density and bulk density decreased linearly from 1.315 to 1.232 g/cm³ and 0.765 to 0.698 g/cm³, respectively, while bulk porosity increased from 41.8 to 43.3%. The highest static coefficient of friction was found on the plywood surface. The static coefficient of friction increased from 0.680 to 0.891, 0.605 to 0.741, and 0.530 to 0.644 for plywood, galvanized iron, and aluminum surfaces, respectively. The angle of repose increased linearly from 30.2 to 35.2° with the increase of moisture content.     

Physical Properties of Guar Seeds

A study on the guar seeds (Cyamopsis tetragonoloba) was performed to investigate the effect of moisture content on the selected physical properties. Moisture contents of seeds were varied from 5.2% to 25.0%, dry basis (d.b.). Seed geometric parameters, such as average length, width, thickness, geometric-mean diameter, surface area, volume, increased but sphericity decreased with increase in moisture content. The 1,000-seed mass increased linearly with moisture content. Bulk density of guar seeds decreased linearly when moisture content was raised from 5.2% to 25.0% d.b. On the other hand, true density decreased till moisture content was increased up to 20%. Further increase in seed moisture resulted in increased true density, which has not been observed in other food grains. The porosity decreased till seed 15.3% moisture and then increased with further addition of moisture. Angle of repose, coefficients of static friction on three different surfaces (plywood, mild steel, and galvanized iron), and terminal velocity increased linearly with seed moisture content.     

Mass-Volume-Area Related and Mechanical Properties of Soybean as a Function of Moisture and Variety

Selected physical properties of three varieties of soybean were determined within a moisture content range of 6.25 to 11.60% dry basis. The seed length, width and thickness for the three varieties increased with the increase in moisture content while the sphericity and roundness of the three varieties increased within the range of 43.0 to 72.3% and 45.5 to 75.9% respectively. True density, bulk density and porosity decreased with increase in moisture content within the range of 1203 to 964 kgm^?3, 809 to 740 kgm^?3 and 0.35 to 0.22. The coefficient of friction also decreased with increase in moisture and the highest and lowest value was 23.7 and 17.3 on plywood while that on glass was 19.8 and 11.6, respectively. The angle of repose and terminal velocity increased within the range of 10.2° to 15.3° and 10.10° to 12.60 m/s for the varieties. The compressive force however decreased and the highest and lowest value was 12.85 and 3.5 N respectively for the three varieties.     

Selected Geometric Characteristics,Density, and Mechanical Properties of Unsplit Pistachio Nut

In this study, several physical properties of unsplit pistachio nut were determined as functions of moisture content. By increasing moisture content from 5 to 20% all geometric characteristics increased linearly. Also, apparent and bulk density increased from 803 to 872 kg/m3 and from 458 to 575 kg/m3, respectively, while porosity decreased from 43% to 34%. Coefficient of static friction of the sample nuts on galvanized iron, plywood, and rubber surfaces increased linearly with moisture content. Nut splitting force decreased from 142 to 21 N and energy increased from 20 to 52 mJ with increasing moisture content from 5 to 20%.     

Moisture-dependent physical properties of dried pomegranate arils

Physical properties of dried pomegranate arils and its variation with moisture content play an important role in designing of equipment for storage, conveying and handling. Physical properties of dried pomegranate arils in the moisture content range of 7–28 % (d.b.) were investigated. Size (GMD), sphericity, weight of the thousand dried arils, true density, bulk density, angle of repose and coefficient of friction at different surfaces (wood, galvanized iron and aluminum) increased, whereas porosity, hardness and toughness decreased with increase in the moisture content. All physical properties except porosity and angle of repose were significantly affected by the change in moisture content at probability level p ≤ 0.01.     

PHYSICAL AND AERODYNAMIC PROPERTIES OF MAKHANA

Makhana is a popped kernel of gorgon nut (Euryale ferox) and is considered a delicious food item in India. It is, presently, sorted, graded and processed manually. To develop any kind of mechanized system for these purposes, physical data are required and thus, test weight, bulk density, true density, porosity, angle of repose and coefficient of friction of different grades of makhana were determined using standard techniques at moisture contents ranging from 5 to 20% (dry basis). The data were used to develop correlation equations that predict these physical properties as a function of moisture content of makhana. The spatial dimensions and aerodynamic properties were also determined. The average diameter of makhana varied between 18.4 mm to 12.4 mm with the sphericity between 0.581 to 0.967; and other physical properties varied quadratically with moisture content. The terminal velocity and drag coefficient of makhana at 8% moisture content (dry basis) varied between 4.48 to 6.10 m/s and 0.62 to 1.06, respectively.     

Some physical properties of sugarbeet seed

Various physical properties of sugarbeet seed were determined as a function of moisture content. The lengths of the major, medium and minor axes varied from 4.61 to 5.30, 3.82 to 4.36 and 2.20 to 2.38 mm, respectively, as the moisture content increased from 8.4 to 14.0% d.b. In the same moisture range, the arithmetic and geometric mean diameters increased from 3.54 to 4.02 and 3.38 to 3.80 mm, respectively. Studies on rewetted sugarbeet seed showed that the sphericity decreased from 0.734 to 0.717, whereas thousand seed mass and projected area increased from 12.60 to 13.41 g and 12.1 to 15.6 mm², respectively, with increase in moisture content from 8.4 to 14.0% d.b. The bulk density, true density and porosity decreased from 447 to 418 kg m⁻³, 962 to 851 kg m⁻³ and 53.6 to 50.9%, whereas terminal velocity and angle of repose increased from 5.6 to 6.6 ms⁻¹ and 17.6 to 25.0°, respectively, as the moisture content increased from 8.39 to 14.00% d.b. The static coefficient of friction increased on four structural surfaces namely, rubber (0.687-0.790), plywood (0.480-0.608), galvanised metal (0.392-0.434) and aluminium (0.279-0.388) in the moisture range from 8.4 to 14.0% d.b.     

Moisture-Dependent Physical Properties of Kola Nut (Cola nitida) Seed

This study was carried out to determine the effect of moisture content on some physical properties of kola nut seed. Four moisture levels ranging from 47.48 to 61.4 % wet basis (w.b.) was considered. Results showed that there was linear increase in the mean length, width, thickness, geometric mean diameter, surface area, volume, sphericity, aspect ratio, 1,000 nut mass, bulk and true densities, and static coefficient of friction at different surfaces (mild steel and wood) by 3.58, 3.96, 6.29, 4.98, 10.72, 16.87, 1.54, 1.50, 26.23, 11.50, 7.27, and 17.86 to 23.53 %, respectively, with increase in moisture content from 47.48 to 61.4 % (w.b.). Furthermore, the angle of repose increased by 17.45 % while the porosity decreased by 3.85 % with increase in moisture content.     

The moisture dependent physical and mechanical properties of whole lentil pulse and split cotyledon

Some physical and mechanical properties of lentil whole grain/pulse and dhal (dehusked split pulse), at different moisture contents were determined. Among the physical properties, size, sphericity, roundness, average surface area, bulk density and void fraction were determined. Bulk densities of whole pulse were between 785 and 831 kg m^?3, whereas for dhal they were between 741 and 840 kg m^?3 and bulk density decreased as moisture content was increased for both the whole grain and the dhal. The compression behaviour was judged by determining the firmness and the linear elastic limit, of which the former decreased with moisture content but the linear elastic limit increased. A method is proposed to calculate the total surface area of dhal and whole pulse. Photomicrographs showed the thickness of the outer seed coat to be between 25 and 65 microns.     

PHYSICAL PROPERTIES OF GRAM AS A FUNCTION OF MOISTURE CONTENT

This study was carried out to determine the effect of moisture content on some physical properties of gram. Six levels of moisture content ranging from 10.83 to 31.20 percent (dry basis) were considered for this study. Length, width, thickness, diameter of equivalent sphere, mass of 1000 grains and porosity increased linearly from 7.968 to 8.758 mm, 5.864 to 6.554 mm, 5.713 to 6.359 mm, 6.770 to 8.795 mm, 137.97 to 172.73 g, and 33.17 to 35.85% respectively with the increase of moisture content from 10.83 to 31.20%. The angle of repose increased from 27.03 to 33.27° with the increase of moisture content. Bulk density and true density decreased linearly from 787.31 kg/m³ to 712.61 kg/m³ and 1398 kg/m³ to 1250 kg/m³, respectively. Static coefficient of friction was determined over plywood, galvanized steel, celluloid sheet, and glass sheet. Static coefficient of friction varied from material to material and depended on the roughness and wetness of the true. The highest coefficient of static friction was found over plywood and lowest for glass sheet among the materials tested.