重组米品质特性影响因素研究

通过分析不同挤压参数制得的13种挤压重组米样品和普通籼米,探讨挤压样品的糊化度、质构特性、膨化度、水溶性、吸水性等挤压特性之间的相关性。结果表明,膨化度与弹性(r=—0.583)、回复性(r=—0.757)呈显著负相关;吸水性与回复性呈显著正相关(r=0.613);容重与胶黏性呈显著正相关(r=0.657);糊化度与膨化度、吸水性、容重也有一定相关性;黏度与水分含量呈明显正相关(r=0.920),与碘蓝值也有一定的负相关(r=—0.303)。雷达图显示出重组米样品相比普通籼米的糊化度、硬度、内聚性、胶黏性、回复性和耐咀性均升高。     

谷物组成对挤压膨化产品品质的影响

该实验以6种谷物(粳米、小麦、玉米、糯米、小米、燕麦)为原料,考察不同谷物原料组成成分与产品膨化特性之间的相关性。结果表明,挤压后谷物膨化制品的一些指标得到很大提高,如吸水性指数、水溶性指数;蛋白质含量及脂肪含量与膨胀度呈负相关,淀粉含量与膨胀度呈正相关,膨化制品中蛋白质及脂肪含量要控制在合理范围内;水溶性指数与蛋白质含量呈极显著正相关,与总淀粉含量呈极显著负相关;糊化度与总淀粉含量呈极显著正相关,与蛋白质、粗脂肪含量呈极显著负相关。粳米、小麦以及糯米的膨化特性要优于玉米、小米以及燕麦,其中糯米在膨胀度、体积密度、水溶性指数、糊化度、硬度以及脆度方面都表现较为优异,膨化性能最好。综上所述,6种谷物原料中,糯米、小麦和粳米的挤压特性较好,可作为挤压膨化的主要原料,玉米、小米以及燕麦可根据成本适量添加。     

双螺杆挤压对玉米重组米理化特性及品质特性的影响

为研究双螺杆挤压技术对玉米粉挤压前后理化特性及品质特性的影响,采用SLG-30双螺杆挤压机对吉林省17?个品种玉米进行挤压膨化,对双螺杆挤压处理前后重组米理化特性及品质特性进行分析。结果表明,挤压处理后不同品种玉米粉的蛋白质量分数平均降低11.32%,脂肪质量分数平均降低29.88%,直链淀粉质量分数平均降低5.11%,冻融稳定性平均提高58.90%,糊化度平均提高88.62%,吸水性平均提高77.03%,水溶性平均提高73.57%,膨润力平均提高87.51%。相关性分析表明,挤压处理后糊化度与脂肪、直链淀粉、蛋白质量分数均呈负相关,与吸水性和水溶性均呈极显著正相关（P＜0.01）;直链淀粉、脂肪质量分数与冻融稳定性、糊化度、吸水性和水溶性均呈极显著负相关（P＜0.01）。挤压处理对玉米的理化特性指标有负面影响,但能明显提高产品加工性能和食用特性。     

复合米粉挤压膨化制品配方的研究

以大米为基料,面粉、糯米粉、玉米淀粉、马铃薯淀粉为辅料,采用挤压膨化工艺制作膨化制品,研究了大米粉进料颗粒度、各辅料添加量对膨化制品L值、b值、吸水性、水溶性、容重、硬度等品质指标的影响,筛选出了大米粉最佳进料颗粒度为60目。在此基础上设计正交试验,优选出最佳配方为以大米粉为基准(计为100),辅料配比为面粉25%、糯米粉20%、玉米淀粉15%、马铃薯淀粉15%;利用该配方制得产品的L值为59.69、b值为12.96、水溶性指数为30.95%、吸水性指数为5.08g/g、容重为126.72g/L、硬度为617.3g,产品感官品质优良。     

小米挤压膨化特性的差异及相关性分析

以四种不同产地的小米为原料,采用小型单螺杆谷物挤压膨化机挤压膨化,分析小米籽粒性状及理化性质对小米膨化后品质特性的影响.结果表明,在相同处理条件下,不同产地小米膨化度及感官品质差异显著,其中胶州小米膨化度最大为1.752,山西和德州小米膨化度分别为1.668和1.556,济南小米最小为1.427;胶州小米感官品质评价最高为44.432,济南小米最低29.519.不同产地的小米淀粉含量及直链淀粉含量与膨化度及膨化小米感官指标存在显著的相关性,淀粉含量与之呈正相关(r =0.945 7,r=0.973 9),直链淀粉含量与之呈负相关(r=-0.915 8,r=-0.988 6).     

荞麦挤压膨化产品的理化特性研究

为明确操作参数对荞麦挤压膨化产品特性的影响,确定产品理化特性间的关系,从淀粉分子结构角度解释产品理化特性的变化,本文以荞麦粉为原料,利用德国布拉本德DSE-25型双螺杆挤压机,通过响应面试验设计,系统研究物料含水量、加工温度、螺杆转速及其交互作用对膨化产品截面膨化率、水溶性指数、吸水性指数、色泽等理化特性以及挤压膨化产品淀粉分子结构的影响。结果表明,加工温度、螺杆转速是影响截面膨化率、水溶性指数、吸水性指数的重要因素;水分含量、螺杆转速是影响黏度、淀粉平均分子半径、重均分子质量的重要因素。淀粉平均分子半径与水溶性指数、色差呈显著负相关,与吸水性指数、黏度呈显著正相关。截面膨化率与其它产品特性无显著相关性。剪切效应加剧,淀粉降解程度加大,平均分子半径减小。在水分含量较高、温度较低、螺杆转速较小条件下,单位机械能耗较小,荞麦挤压膨化物中淀粉平均分子半径较大,吸水性指数和黏度较大,水溶性指数和色差较小。通过挤压处理可改善荞麦淀粉的水溶性、吸水性、黏度等理化特性。     

速食小米粉膨化特性研究

选取6种不同直链淀粉含量的小米作为研究对象,采用气流膨化技术对小米进行膨化,并将膨化小米粉碎后制作速食小米粉。对不同品种小米的膨化度、速食小米粉的糊化特性和消化性进行测定,并将小米淀粉特性与小米膨化特性和速食小米粉消化性进行相关性分析,结果表明：济12、济13、保18的膨化度较高,其中膨化度与回生黏度呈显著正相关（r=0．862）;市2、复1速食粉RDS含量高,与淀粉中直链淀粉含量呈显著负相关;市1、济13速食粉SDS含量高,且与淀粉中直链淀粉含量呈显著正相关,而RS含量与淀粉特性无显著相关性。     

甘薯块根膨大过程中质构特性和淀粉直/支比的研究

甘薯块根膨大过程中质构特性和淀粉组分的变化对甘薯的品质和用途有着重要影响。本研究选取3种甘薯类型和4个时期,通过质地多面分析法(TPA)和双波长碘比色法,分析其质构特性和淀粉直链淀粉和支链淀粉比值(淀粉直/支比)随块根膨大的变化规律。结果表明,甘薯淀粉直/支比在扦插后80天开始下降,至扦插后110天达到谷值,之后小幅回升;整体上,甘薯扦插后的天数与淀粉直/支比、内聚性和弹性呈显著负相关(r =-0.390, r= -0.367, P <0.05;r= -0.634, P <0.01);与硬度呈显著正相关(r= 0.590, P <0.01)。淀粉直/支比与块根的内聚性、弹性和咀嚼性呈显著正相关(r =0.368, P <0.05; r= 0.463, r= 0.642, P <0.01);综合分析发现,扦插后80~110天（块根膨大高峰期至膨大后期）收获的甘薯适合水果型(生食型)甘薯的开发。     

挤压膨化对谷物营养成分的影响

采用挤压膨化技术处理大米、玉米、小麦、燕麦和荞麦,分析这些谷物在处理前后的淀粉、直链淀粉、粗蛋白质、粗脂肪、还原糖、膳食纤维和矿物元素等营养成分含量影响。结果显示,挤压膨化后大米、玉米、小麦、燕麦和荞麦的淀粉、粗蛋白质、粗脂肪和矿物元素含量降低(P0.05),还原糖含量显著增加(P0.05),直链淀粉和膳食纤维含量提高(P0.05)。     

人参山药挤压膨化工艺优化及其理化性质研究

采用双螺杆挤压膨化工艺制备人参、山药膨化制品,并研究其最佳工艺条件及其膨化前后理化性质的变化。以生晒参、山药饮片为实验材料,将生晒参粉与山药饮片粉按1:1比例混合,在单因素的基础上,以膨化制品的径向膨化率为考察指标,根据L₉(34)正交表进行正交试验,确定人参、山药复合粉挤压膨化的最佳工艺参数,并对膨化前后的营养品质、物理化特性、有效成分进行比较分析。结果显示:人参、山药复合挤压膨化的最佳工艺参数为:螺杆转速为250 r/min,Ⅲ区温度160 ℃,物料水分含量24%,在此条件下得到疏松多孔的膨化制品,产品径向膨化率达到最大值为2.43。人参、山药复合粉挤膨化后与膨化前营养化学成分相比,粗灰分含量差异不大(P>0.05),粗脂肪、TDF、IDF、粗蛋白质、可溶性蛋白质、总淀粉、支链淀粉含量均降低(P<0.05);可溶性膳食纤维、直链淀粉均有提高(P<0.05),分别提高了12.96%、18.03%。膨化后与膨化前物理特性比较,糊化度、WSI、WAI均有提高;人参、山药复合粉基本营养化学成分与物理特性相关性分析表明,膨化前后的糊化度变化率与淀粉含量变化率、支链淀粉含量变化率呈显著负相关(P<0.05),WAI值的变化率与IDF呈极显著正相关(P<0.01),WSI值与支链淀粉、脂肪、TDF、IDF含量变化率呈显著负相关(P<0.05)。膨化前后人参总皂苷由5.50%下降到5.15%,差异显著(P<0.05)。结论:通过挤压膨化技术的应用,使人参、山药复合粉的理化性质得到了改善,为进一步研究奠定理论基础。     

Extrusion of Rice,Bean and Corn Starches: Extrudate Structure and Molecular Changes in Amylose and Amylopectin

The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V^® corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V^® corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion.     

HARDNESS OF COOKED MILLED RICE BY INSTRUMENTAL AND SENSORY METHODS

Fifteen milled rice varieties covering the usual range of amylose content and cooked rice hardness were used in a collaborative study to verify the sensitivity of the present objective method for measuring cooked rice hardness. The grains were cooked either in a rice cooker using a fixed water:rice ratio of 2:1, or by boiling in excess water for the predetermined optimum cooking time for each sample followed by draining. Hardness of cooked rice was measured in an Instron Universal Testing Machine (UTM) using two methods: (1) puncture of 100 individual grains and (2) extrusion through a 30 cm² Ottawa Texture Measuring System (OTMS) cell with either a 3.2- or 4.8-mm-diam. holes plate. Hardness values were compared with sensory scores by a trained panel composed of 11 members. Sensory hardness of the rices cooked in a fixed amount of water showed very good correlation with puncture force (r = 0.94, P < 0.01) and with extrusion force through a 3.2-mm-diam. holes plate (r = 0.94). The correlation coefficient between puncture force and extrusion force was 0.97. Paired comparison test by the sensory panel on three pairs of rices verified consumers' claims with respect to preference between members of each pair and agreed with results of ranking test.     

不同品种马铃薯淀粉功能性质的相关性及主成分分析

分析黑龙江、甘肃、北京3个地区的11个马铃薯品种制备得到淀粉的水分含量、色泽、直链淀粉含量、透光率、碘蓝值、溶解度、膨胀度、胶稠度、质构特性。结果显示,不同品种各指标差异显著,直链淀粉质量分数的变化范围是10.96%～16.64%;相关性分析发现不同品种的各品质指标间存在显著的相关性,直链淀粉与淀粉提取率(r=0.468 3)、膨胀度(r=0.520 9)、硬度(r=-0.472 1)、咀嚼性(r=-0.449 6)分别呈显著的相关性。主成分分析结果显示,前4个主成分的特征根大于1,可以解释原有数据的信息,综合主成分得分,陇薯9号的综合值排名第一,荷兰薯的综合值最低。     

Effects of Wheat Starch Contents on Malt Qualities

The relationships between wheat starch content and wheat malt qualities were studied in the present work. Six wheat varieties that were typical in starch, protein content and amylopectin/amylose ratio were selected from 12 wheat varieties and germinated under the same conditions. The decreased degree of total starch content after malting had a positive correlation (r = 0.8020, P < 0.1) with the amylopectin/amylose ratio of the raw wheat. Extracts of wheat malts were influenced by starch content and the amylopectin/amylose ratio of the raw wheat. When the amylopectin/amylose ratio was in the range 3.65:1?3.93:1, extracts of the malts had significant positive correlation (r = 0.967, P = 0.002) with the starch content of the raw wheat. In this investigation a suitable amylopectin/amylose ratio (3.65:1 to 3.93:1), a high starch content and a low protein content were the characteristics of a wheat variety suitable for malting.     

不同物理方法处理对碎米中淀粉特性的影响

采用挤压、微波、超声波三种物理方法对水分含量18%的碎米淀粉进行处理,研究分析碎米淀粉经物理方法处理前后的理化性质和结构变化。结果表明,碎米淀粉经微波和超声处理后酶解力增加,糊化黏度下降,而溶解度、膨胀力、糊化温度和直链淀粉含量变化不显著;两种淀粉颗粒表面棱角减少,淀粉颗粒晶型基本没有发生变化,淀粉结晶区降低。挤压后的碎米淀粉变化较大,颗粒形状为片状,凝沉性强,1.0 h后体积仅为3 mL,糊化温度明显降低至55.0 ℃,直链淀粉含量增长为30.75%,溶解度强,为0.59%,酶解力达到45%,X-射线主要衍射峰的强度降低。     

COOKING WATER UPTAKE AND STARCH DIGESTIBLE VALUE OF SELECTED SPANISH RICES

The cooking water uptake and the starch digestible values (rapidly digestible, slowly digestible and resistant starch and starch digestible index) of eight selected Spanish rice were measured after cooking for 15, 20 and 25 min in limited boiling water. White short grain rices varieties, Bomba and Balilla x Sollana, showed the highest water uptake at all times studied. The relation between water uptake and amylose content was dependent on cooking time and type of rice and was negative for white rices (r= -0.83, P<0.05) at 15 min. Water uptake showed a positive correlation with rapidly digestible starch and negative with resistant starch. Brown short grain and parboiled long grain rices had the highest content of slowly digestible and resistant starch, predicting a low starch digestible index, adequate for nutritional disorders with high postprandial glucose.     

糙米复配粉中淀粉直/支比对挤压速食粥品质与结构的影响

糙米是一种营养丰富的全谷物食品,但较差的适口性、蒸煮性和消化性制约着其成为主流餐桌食品。为改善其食用品质,本文通过分析不同淀粉直/支比(0.176、0.196、0.216、0.236、0.256、0.276)糙米复配粉的原料特性以及其对挤压速食粥糊化特性、复水品质、质构特性与结构的影响,探究制作糙米挤压速食粥原料复配粉最优的淀粉直/支比。结果表明:随着淀粉直/支比的增加,糙米复配粉的糊化温度和峰值温度增加,挤压速食粥米粒横截面的光滑度及紧密度增加。当淀粉直/支比为0.256时,挤压速食粥米粒横截面的结构最均一、最紧密,复水时间达到12.6 min,米汤固形物损失率和径向膨胀率最小(0.153 g和2.282%),此时的硬度、胶着度和耐咀性明显高于淀粉直/支比0.276,达到3323.85 g、1242.76 g·s和744.73 g。可见,糙米复配粉中淀粉直/支比0.256为制作挤压速食粥的较佳比例。     

Studies on parboiled rice—Part 3: Characteristics of parboiled rice on recooking

The apparent solubility and cookwater loss of samples of parboiled rice, subjected to various steam treatments, were measured after recooking the rice in boiling water. Both parameters were reduced according to the severity of treatment received, the reduction of apparent solubility being the most marked.The results showed a highly significant, negative linear correlation (r = 0.972) between apparent solubility and the relative amount of complexed amylose in the starch. This confirmed the suggestion made in Part 1 of this paper that complexed amylose was responsible for the resistance of the starch towards solubilisation.Estimation of the amylose and amylopectin released into the cooking water and solubilised inside the kernel revealed that both fractions were insolubilised to a similar extent. It was proposed that amylose was insolubilised by complexing with free fatty acids and the amylopectin insolubilised by interaction with the complexed amylose.     

挤出处理对玉米粉流变及其成膜特性的影响

采用高温高压挤出改性技术对玉米粉进行质构优化及稳定化处理,通过研究玉米粉粒度、挤出温度和水分质量分数对玉米粉流变特性和成膜特性的影响,确定挤出改性玉米粉的制备工艺参数,并通过分析玉米粉分子间相互作用以及玉米粉膜结晶结构探究玉米粉的成膜机理。结果表明,高温高压挤出改性处理能够使玉米粉膜结构致密、膜表面较平整光滑、孔洞明显减少。当玉米粉粒度为120 目、挤出温度为165 ℃、水分质量分数为34%时制备的玉米粉膜具有良好的机械性能、阻水性以及较低的溶解度,并且此条件下制备的玉米粉成膜液具有较高的黏弹性和较大的触变环面积,体系内部分子之间的相互作用较强。此外,挤出改性处理使玉米淀粉由A晶型转变为V晶型,淀粉结晶度下降,部分支链淀粉发生降解生成直链淀粉以及小分子质量支链淀粉,易形成有序性较高的分子链排布状态,改善玉米粉的凝沉性和成膜特性。挤出改性处理还使玉米粉中淀粉、蛋白质、纤维等分子之间的相互作用增强,并且形成强烈而稳定的氢键,有利于分子间形成致密的结构网络。     

INTERNATIONAL COOPERATIVE COMPARISON OF INSTRUMENT METHODS FOR COOKED RICE TEXTURE

The texture of 10 milled rices cooked by a standardized method in excess water was measured in 11 laboratories using various instrument methods that had been developed specifically for national samples. The samples selected represented a wide range of rice textures. Instrument indexes for hardness and stickiness of cooked rice generally were more sensitive than the corresponding taste panel scores in discriminating among the 10 cooked rice samples. Instrument indexes for hardness correlated positively among each other as did those for stickiness. Most hardness indexes showed significant negative correlation with stickiness indexes. Most hardness indexes were positively correlated with amylose content whereas stickiness indexes were negatively correlated with amylose content. The continued use of amylose content as an index of eating quality in a rice breeding program is justified.