卤煮鸡肉质构测定条件的研究

采用TA-XT2i质构仪,通过比较样品摆放方向、测前速度、测试速度、测后速度、压缩比及样品厚度等因素对TPA特征参数的影响,探讨卤煮鸡肉质构特性的测定条件,以期获得最佳测定条件。结果表明:卤煮鸡肉肌纤维方向呈水平摆放时TPA测定的硬度值显著大于竖直摆放的硬度值;随着测前速度、测试速度的增加,回复性无明显变化,其余特征参数均先增大后减小;测后速度对测定结果无显著影响;随着压缩比的增大,硬度、胶着性和咀嚼性呈总体上升趋势,弹性呈下降趋势;随着样品厚度的增加,各特征参数值均显著降低。最终确定在此工艺基础上卤煮鸡肉质构最佳测定条件为:肌纤维呈水平方向、测前速度2.0mm/s、测试速度1.5mm/s、测后速度1.0mm/s、压缩比70%、样品厚度1.0cm。     

速冻方便米饭的品质特性及最佳品质评价指标的确立

本实验分析了15种籼米的品质特性,并选择四种感官评价较好的品种加工成速冻方便米饭,分析其感官评分指标和质构指标的相关性。结果表明,采用TPA模式通过质构分析仪测定的硬度、黏着性和胶粘性与感官指标有显著相关性,可以用质构仪测定的质构指标来表示感官评分相关指标;理化特性中直链淀粉含量和胶稠度与感官评分呈极显著负相关,碱消度与感官评分呈极显著正相关。     

利用米饭质构特性评价大米食用品质的方法研究

文章针对不同品种的大米,利用质构仪对米饭样品的质构特性进行测定,通过分析其与大米蒸煮食用品质感官评价指标之间相关性,寻找一条有效的利用米饭质构特性评价大米食用品质的方法。米饭质构特性测定与感官评价进行相关性研究得出：质构特性测试硬度、弹性、适口性与米饭感官评价同一指标和综合评分具有显著相关性。结果还表明：直接测试法在Ф25．4cm圆柱型压缩探头,50％的压缩比和30mm／min的压缩速率等测试条件下,米饭质构特性测定结果与米饭蒸煮感官评价相关性显著,重现性较好。     

压榨型干米粉专用米关键指标的研究

为确定压榨型干米粉专用米的特征指标,文章以17种籼米为原料,运用相关分析、主成分分析、聚类分析以及逐步回归分析法探讨大米原料品质和糊化特性对干米粉食用品质和质构品质的影响。结果表明:大米原料中的直链淀粉含量、淀粉含量、脂肪含量、脂肪酸值,糊化特性中的最低黏度、最终黏度、崩解值、回生值、胶稠度,与干米粉的蒸煮品质和质构品质存在显著(P<0.05)相关性;其中影响米粉综合品质的关键性指标为直链淀粉含量、最终黏度和胶稠度;聚类分析得出的适宜加工压榨型干米粉的原料大米的直链淀粉含量应大于22%,淀粉的最终黏度应大于3963 cP,胶稠度应小于46 mm。     

混合实验仪法对大米食用品质评价的探索研究

目的探索大米食用品质的混合实验仪(Mixolab)表征点。方法利用混合实验仪测定70种大米的相关参数,用国标法测定大米品质理化指标(蛋白质、直链淀粉含量和胶稠度),并用描述性分析法对大米进行感官评定,分析Mixolab图谱特征值与大米的理化指标以及感官评定指标之间的相关关系。结果蛋白质含量与淀粉糊化特性、淀粉热糊化胶的稳定性以及冷却阶段糊化淀粉的回生特性呈显著负相关,直链淀粉含量与吸水率呈显著负相关,与蛋白质弱化、淀粉糊化特性、淀粉热糊化胶的稳定性、冷却阶段糊化淀粉的回生特性、淀粉糊化的速度、淀粉酶的水解速度和淀粉的崩解值呈显著正相关,胶稠度与吸水率和冷却阶段糊化淀粉的回生特性呈显著正相关;感官评定质地方面的粘性、硬度和凝聚性均和Mixolab的冷却阶段糊化淀粉的回生特性值有显著相关性。结论混合试验仪法应用于大米食用品质的评价是可行的,其中冷却阶段糊化淀粉的回生特性可以作为大米食用品质评价的参考表征点。     

测试条件对大米凝胶质构特性测定结果的影响

采用物性仪对大米凝胶特性进行测试,研究凝胶试样尺寸和测定参数对大米凝胶特性各指标测定结果及其重现性的影响。结果表明,大米凝胶TPA测定过程中,任何一个测试参数条件的改变都会对测定结果产生一定影响。根据各指标测试结果稳定性,对测试条件进行了对比优化,建议选用凝胶的样品尺寸为高度15mm,直径25mm,测试参数为压缩程度50%,压缩速度1.0mm/s,两次压缩间隔时间3s为物性仪测定凝胶特性较好的测定条件。     

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。     

再生季稻米蒸煮食味品质与糊化特性、淀粉晶体结构研究

以衡阳实验点种植的8个不同品种再生季稻米为研究材料,对其蒸煮食味品质、糊化特性及淀粉的晶体结构进行了测定和相关性分析。结果表明：供试品种中和两优1号和晶两优1468的再生季稻米直链淀粉含量适中,胶稠度长,糊化温度低,其中和两优1号的结晶度低,晶两优1468淀粉内部有序程度高,RVA谱特征值表明这两个品种均具有较好的蒸煮食味品质。相关性分析发现不同品种再生季稻米的直链淀粉含量与相对结晶度显著负相关,同时,相对结晶度与碱消值呈显著负相关,与胶稠度呈显著正相关;1047/1022 cm-1值与峰值时间、最低黏度呈显著负相关。表明再生季稻米中直链淀粉含量变化会影响淀粉的晶体结构,改变其糊化特性,导致稻米蒸煮食味品质的差异。     

香蕉果酱质构测试条件研究

为质构仪应用于果酱型产品特性的测定提供理论参考,探讨不同测试探头及测试速度对香蕉酱硬度、粘聚力、黏着性等测试结果的影响,通过对测试结果重复性、粘度变化响应曲线等的分析,优选出最佳测试条件。结果表明,相同测试速度下,锥形探头、刀形探头、球形探头、柱形探头四种探头测得的香蕉酱硬度、粘聚力、黏着性均呈依次增大趋势,柱形探头各指标均显著高于其他探头。柱形探头硬度、粘聚力、黏着性随测试速度的增大都呈现增加趋势。各探头对硬度、粘聚力、黏着性测试结果的总离散程度为柱形探头 < 刀形探头 < 球形探头 < 锥形探头,柱形探头1 mm/s可获得最佳的重复性曲线,但柱形探头5 mm/s对黄原胶梯度增加的香蕉酱响应较好,粘聚力变化趋势与粘度计所测粘度具有较高的一致性。综合比较后,认为柱形探头5 mm/s为最优测试条件。     

大米理化特性与食味品质的相关性分析

选取粳米、籼米共20种,测定大米的化学特性、蒸煮特性、食味值等对食味品质有主要影响的因素,通过感官评价对米饭的口感品质进行测定,经相关性分析结果表明:粳米的水分、蛋白质、脂肪对食味品质均有显著影响,其中蛋白质与食味品质呈极显著负相关(p≤0.01);而籼米水分与米饭外观、冷饭质地呈显著正相关(p≤0.05),其中蛋白质与食味品质呈极显著负相关(p≤0.01)。蒸煮特性中,粳米的吸水率、膨胀率对米饭的光泽、黏弹性影响显著,均呈显著负相关(p≤0.05),而籼米的膨胀率与米饭光泽、冷饭质地呈显著正相关(p≤0.05);粳米的干物质、碘蓝值与食味品质呈显著正相关(p≤0.05),而籼米的碘蓝值与软硬度呈显著负相关(p≤0.05)。     

基于物性仪评价大米食用品质的方法研究

为了建立国产物性仪评价大米食用品质的方法,探索了米饭摆放方式及压缩参数对大米物性测试结果的影响,并研究了米饭物性仪测试结果与感官评价指标间的相关关系。结果表明：米饭粒在辐射状摆放、圆柱型压缩探头、压缩比70％和压缩速率0．5mm／s的条件下,其物性测定结果重现性较好。物性测试的硬度、弹性和黏硬比与米饭感官评价中软硬发、弹性及综合评分值具有显著的相关性。可见硬度、弹性和黏硬比是米饭物性仪评价米饭食味的关键指标,物性测试仪能代替部分感官评价来快速、准确地测量米饭物性。     

基于原位观测的糙米籽粒力学特性研究

采用原位观测结合质构仪手段,研究稻谷加工过程中糙米籽粒受挤压力时的力学-结构特性,分析了压距等因素下糙米籽粒的挤压作用过程。结果表明：糙米所受的挤压力随压距的增大而增大,在外力冲击下,籽粒内部产生抗压应力,随之产生裂纹。粳米籽粒存在脆性,先产生裂纹,在挤压力增大之后,裂纹扩展,最后籽粒断裂;籼米和连糯籽粒脆性更明显,在产生裂纹后,短时间裂纹扩展,籽粒迅速断裂;速率对粳米所受挤压峰值力无明显影响;粳米所受的挤压峰值力随籽粒含水率的上升而减小,随温度的上升而减小,裂纹数量随浸泡时间的上升而增加,籽粒破坏程度随温度的上升而增大;3种米型在相同压距和压缩速度下的受挤压峰值力为：籼米>粳米>连糯。     

Eating quality indicators for waxy rices

A study of the properties of raw and cooked waxy milled rices from the Republic of Korea, the Philippines and Thailand verified that the hardness and stickiness values of cooked rices, as measured by an Instron food tester, tended to be related to final gelatinisation or birefringence end-point temperature (BEPT), neutral gel consistency or both properties of raw rices. Actual texture determination of cooked rice is required among the low final BEPT rices that have similar gel consistency and alkali test values. Intermediate final BEPT waxy rices as cooked rice had hardness and stickiness properties similar to those of high final BEPT rices.     

米饭质构特性测定方法的研究(Ⅱ)——米饭样品放置时间、环境温度对硬度值的影响

用不同品质的大米,参照GB/T 15682—2008的米饭样品制备方法制作米饭样品,并利用质构测试仪采用TPA模式对米饭样品的质构特性进行测定试验,探讨了米饭质构测定值的分散特征及米饭样品放置时间与测试环境温度对测定值的影响。用电饭煲炊饭和米饭样品预压8 mm方法制作米饭样品并用Φ25.4mm圆球探头进行的多次重复试验结果表明:硬度值的稳定性和精确性明显优于黏着性值,适宜将硬度值作为米饭质构特性测定的主要考察指标。结果还表明:随着米饭放置时间的延长,籼米米饭硬度值逐渐减小的趋势明显,粳米米饭在放置时间12 h范围内有硬度值缓慢增大的总体趋势;米饭制作、放置和测定过程的温度对米饭硬度值有较大影响,建议在进行米饭质构(硬度)测定时应当保持米饭制作、放置和测定全过程的温度恒定。     

THE EFFECT OF EXTRUDED FLOUR AND FERMENTATION TIME ON SOME QUALITY PARAMETERS OF IDLI

The effects on idli characteristics of fermentation time and substituting rice with differing proportions of rice flour extrusion‐cooked under different conditions were studied. The specific gravity, pH and viscosity of batter and idli characteristics such as expansion, compression force and sensory attributes were measured and described using regression to fit a response surface analysis. Fermentation time showed the most pronounced effect on specific gravity, pH and aqueous dispersion viscosity of batter and taste scores of idli. Substituting rice flour with extruded rice flour at different levels were observed to have significant effect on expansion and appearance scores of idlis. The textural scores and compression force was significantly affected by extrusion temperature. The formulation containing rice substituted by 30% extruded rice flour extruded at 175C and fermented for 24 h produced idlis with highest expansion and overall acceptability.     

米饭质构特性测定方法的研究(Ⅰ)

用不同品质的大米,参照GB/T 15682—2008的米饭样品制备方法制作米饭样品,并利用质构测试仪采用TPA模式对米饭样品的质构特性进行测定,通过试验考察米饭样品制作方法及米饭质构测试条件对测定值及其稳定性的影响。结果表明:在本研究的炊饭和米饭样品制作条件下,探头尺寸大小(形式)对质构测定值是否反映大米食味品质特征差异有较大的影响,电饭煲炊饭和铝盒炊饭方法用Φ25.4 mm圆球探头进行质构测定时,其硬度和黏着性测定值都能够较好地反映不同品质大米的差异程度,适合作为米饭质构测定方法采用。其中硬度值的变异系数较小,精确性较好。     

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.     

Indicators of eating quality for non-waxy rices

Although amylose content is the major determinant of the eating quality of milled rice, varieties of similar amylose content may differ in eating quality. Stickiness of cooked rice, as measured with an Instron food tester, gave a better correlation with amylose content than did hardness. Among rices of similar amylose content (high, intermediate or low) differences in hardness of cooked rice were shown to be generally related to differences in gel, and amylograph consistency, final gelatinisation temperature, or both. A higher rice concentration improved the differentiation among low-amylose samples for gel and amylograph consistency.     

OBJECTIVE TESTS FOR THE STICKINESS OF COOKED RICE

The suitability of a sieve test and an adhesion test as objective tests for determining the stickiness of cooked rice was examined. Six rice varieties, two each from dwarf incica, tall indica and japonica classes, and stored for 1 and 2 years at three different temperatures, were used. The consistency of the cooked rices was also determined by the Haake consistometer. The sieve test gave a very good indication of the stickiness of cooked rice. The adhesion test also gave a fair indication, but the correlation was less sharp and the test needs improvement. Consistency of cooked rice was negatively correlated with its stickiness. The water-insoluble amylose content of rice seemed to be importantly related to its stickiness and consistency after cooking.     

挤压碎米制备富锌强化大米

以粳米加工副产品碎米为原料,使用乳酸锌作为锌强化剂,通过挤压法制备富锌强化大米。将碎米粉碎成100?目,乳酸锌添加量2.0%,采用响应面法考察含水量、螺杆转速及机筒温度对富锌强化大米质构特性的影响。优化条件为含水量20%、螺杆转速80?r/min、机筒温度100?℃,制得富锌强化大米硬度为1?339.05?g,黏着性为0.75?mJ,弹性为0.79?mm,咀嚼性为967.42?mJ,锌含量为450.0?mg/kg。经X-射线衍射分析表明强化米中淀粉颗粒的结晶度较粳米明显减少,通过扫描电镜表征发现强化米淀粉颗粒外表面呈现不规则类似鳞片形状,并产生聚集现象,淀粉糊化温度由77.9?℃降低到56.2?℃,酶解反应完成后还原糖增加23.0%以上,有利于强化米淀粉颗粒的酶解作用。将其按1∶10的比例添加到粳米中,米饭口感、外观良好,锌含量为48.0?mg/kg。