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。     

大米凝胶质构特性评价模型建立

采用物性仪对大米凝胶特性进行测试,对质构仪测定结果与感官评价之间的相关性进行分析,采用多元逐步回归建立了凝胶特性评价模型.结果表明,质构仪测定结果与感官评价指标具有较好的相关性,并建立了感官评定指标以压缩、剪切探头测试指标为变量的数学预测模型.采用质构仪TPA模式,以压缩和剪切探头结合的方法建立的数学预测模型可预测大米凝胶特性各指标特征值.     

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。     

大米理化特性与米饭口感品质的相关性研究

本试验以8种原料大米为试验材料,测定了包括水分、脂肪、直链淀粉和蛋白质含量的4项成分指标,采用质构仪对米饭的质构特性进行测定,通过感官评价对米饭的口感品质进行了评定,分析了各成分指标对米饭口感的影响,就米饭的质构特性与米饭的口感品质进行了相关性分析。得出结论：水分、直链淀粉与蛋白质含量对蒸煮质构特性有显著影响;质构指标总体上可以反映人们对米饭口感的评判。     

大米理化指标与米饭品质相关性的研究

测定了七种大米基本理化指标及加工成米饭后的感官指标和质构特性,探讨原料大米特性与米饭的感官品质、质构特性之间的相关性.结果表明:原料大米水分含量与米饭的弹性呈显著的负相关;蛋白质干基含量与米饭的咀嚼性呈显著的负相关,而脂肪干基含量则与米饭的回复性呈显著的正相关.通过感官评价得出:大米的直链淀粉含量与米饭的冷饭质地呈显著...     

基于模糊感官评价对大米感官品质分析

以7种不同品种的大米为研究对象,运用模糊综合评判法评价大米感官品质,用质构仪及色差仪对米饭品质进行评定。结果表明:大粒香米饭感官品质最佳,内优5H25最差,米饭质构特性中内优5H25米饭弹性和咀嚼性最大,大粒溪香、大粒香、金麻粘3种米饭在粘硬度比、粘性、弹性均无显著差异,且大粒香3项指标值均最大,说明大粒香质构特性最佳。不同品种米饭色差值存在显著差异。结合感官评价中对米饭色泽要求综合分析色差值,大粒香和金麻粘色泽最佳。模糊感官评价与外观品质特性和质构特性结果相一致,综合分析表明:大粒香米饭感官品质最佳,说明模糊感官评价能有效的评价米饭感官品质。     

米饭质构特性测定方法的研究(Ⅲ)——米饭质构测试的最佳条件探讨

用天津小站米(粳米)和南充顺心大米(籼型杂交稻米),参照GB/T 15682-2008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,主要通过单因素试验考察了压缩程度和压缩速度对米饭硬度测定值的影响,并通过正交试验探讨了米饭质构测定的最佳测试条件.结果表明:在压缩程度为50％条件下,不同压缩速度的米饭硬度测定值的变异系数为2.8％～7.7％;压缩程度、压缩速度、米饭样品制作与测试温度、放置时间对硬度测定值都有高度显著(P＜0.01)的影响,各因素对米饭硬度测定值的变异幅度大小无影响.以米饭硬度测定值变异幅度为指标的米饭质构测定的最佳条件为:米饭放置时间90 min、米饭样品制作与测试温度20℃、压缩程度50％、压缩速度50 mm/min.     

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。     

不同品种大米口感品质分析

以不同品种大米为研究对象,采用模糊感官评价结合质构仪分析及电子舌技术,对大米米饭口感品质 进行比较分析,建立一种米饭口感品质评价的方法。结果表明：模糊感官评价和质构特性分析中大粒香米饭口 感最佳,内优5H25米饭口感最差,大粒香、大粒溪香、金麻粘3 种米饭感官评分较接近且质构特性基本无显著差 异（P＞0.05）。通过主成分分析,电子舌能很好地区分不同品种大米原料及米饭,其结果与模糊感官评价一致。 通过偏最小二乘回归分析建立米饭滋味评价模型,相关系数达到0.954 06,能很好地预测不同品种米饭的滋味。因 此,在大米口感品质评价中,感官评定结合电子舌的分析方法更易获得准确、可靠的结论。     

不同品种大米理化性质及其淀粉结构对米饭食用品质的影响

米饭食味值和质构特性是评价大米食用品质的重要指标,为了探究不同品种大米的食味值、质构特性与其理化性质及淀粉结构的关系,以12种大米为研究样本,测定其食味值、质构特性、理化性质及淀粉结构特性,并分析内在相关性。结果表明,直链淀粉含量（质量分数）与米饭的硬度呈极显著正相关（P<0.01）,与米饭的凝聚性呈极显著负相关（P<0.01）;米饭食味值、质构特性与大米淀粉的糊化特性、热特性之间存在显著相关性,与结晶特性、淀粉颗粒表面有序度无显著相关性,表明淀粉的糊化特性决定了米饭的食味值、硬度、凝聚性和回复性。该研究可为后期优质稻米筛选培育以及大米适宜性加工提供理论基础。     

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。     

TEXTURE MEASUREMENT OF COOKED RICE KERNELS USING THE MULTIPLE-POINT MENSURATION METHOD 1

A new modification of Texture Profile Analysis, a two-point mensuration method, was shown to give better differentiation between different types of cooked rice. The method involves compressing single rice kernels 50% and 90% at 240 mm/mm. Ratios of values obtained at the two compression depths were better reflectors of the texture of rice as affected by the amount of water used in cooking and by rice variety (glutinous versus non-glutinous). Data are also presented showing how hardness, cohesiveness, adhesiveness and springiness of rice vary with compression or biting depths and with the position of the kernel in the cooker. The ratio of adhesiveness to hardness at 50% compression and the ratio of adhesiveness to hardness between the two compressions were the most useful indices.; in final form February 18, 1981     

TEXTURE CHANGES AND STORAGE OF RICE

Monthly texture assessments of seven milled rices, differing in amylose content and stored at 28–30°C, verified that three months was the minimum storage period for major changes to occur in hardness of cooked rice, gel consistency, and amylograph viscosity values. Therefore, texture measurements should be done on samples aged at least three months after harvest. Texture changes tend to be greatest for high-amylose rice with hard gel consistency and least for waxy rice. Free fatty acids were highest in stored, waxy, milled rice. Storage under nitrogen instead of air had a slight retarding effect on storage changes of five rices in another study. Surface defatting with petroleum ether had little effect on storage change in cooked rice hardness and stickiness, but reduced the changes in gel consistency and amylograph setback and consistency.     

不同烹煮方式对米饭食味品质的影响

以4种市售大米为研究对象,利用质构仪、气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)及感官评价等检测和评价手段,对不同烹煮方式的米饭进行基本蒸煮品质、质构特性以及风味物质等食味品质的评价,并探究其与感官评价的相关性。旨在探究不同大米品种(粳米和籼米),以及不同蒸煮工艺(高压烹煮、电饭锅烹煮、微波烹煮和电蒸锅烹煮)对米饭食味品质的影响,寻找一种能够综合评价米饭食味品质的方法,为米饭的制作及米饭食味品质的改善提供理论参考。结果表明:经高压烹煮后的米饭吸水率、膨胀率、碘蓝值均高于其他方式,且米饭硬度小,弹性和黏性较大,感官品质评价最优,而微波烹煮米饭食味品质最差。米饭膨胀率与感官评价中米饭的滋味和形态呈显著正相关(P0.05,P0.01),硬度与口感呈极显著负相关(P0.01),弹性与米饭形态呈极显著正相关(P0.01)。此外,米饭风味物质分析表明经高压烹煮和电饭锅烹煮的米饭,醛、醇、酮等主要的米饭风味物质含量和种类均高于其他烹煮方式,且因品种不同大米的香气有所差异。     

TEXTURE MEASUREMENT OF COOKED RICE AND ITS RELATIONSHIP TO THE EATING QUALITY

A method has been developed for quantifying hardness, stickiness and cohesiveness of rice. It utilizes the Texturometer and requires only a small quantity of cooked kernels. The portability of rice in Japan is governed by its hardness and the ratio of stickiness to hardness. A texturogram has been constructed showing zones of acceptability as a function of hardness and stickiness. For the non-glutinous rice to be of high acceptability, the ratio of stickiness to hardness should be between 0.15 and 0.20. The developed testing method and the constructed texturogram were used to demonstrate factors affecting the texture of cooked commodity rice, to describe the textural characteristics of convenience rices and to develop some principles on combining different rice varieties for optimum blend texture.     

Effects of cooking, drying and pretreatment methods on texture and starch digestibility of instant rice

Instant rice produced from a conventional process consisting of the cooking, washing and drying steps possesses poorer eating quality compared with that of freshly cooked rice. The objective of this work was therefore to study the effects of cooking, pretreatment and drying methods on microstructure, textural properties and starch digestability of instant rice after rehydration; jasmine white rice was chosen as a test material. Conventional boiling method and electric rice cooking were selected as the methods to prepare cooked rice. In the case of boiling, cooked rice was frozen at −20 °C or cooled at 4 °C for 24 h prior to drying, while the cooked rice from an electric rice cooker was washed with ambient or cool water for 30 s prior to drying. After pretreatment the cooked rice was dried either by freeze drying or hot air drying at 80 °C. Based on the scanning electron microscopic results it was found that the cooking, pretreatment and drying methods all affected the rice morphology. The hardness and stickiness of instant rice after rehydration were lower for samples prepared from the rice cooker than those of freshly cooked rice, while both textural properties appeared to be improved significantly for the samples from boiling. The texture of the freeze-dried products was not different from that of the air-dried one. The freezing pretreatment provided the texture and glycemic index of instant rice after rehydration similar to those of the freshly cooked rice. On the other hand, the cooling pretreatment resulted in the harder texture and higher glycemic index of the samples.     

蛋白酶改善方便米饭品质的研究

研究了方便米饭浸泡过程中蛋白酶作用条件对米饭品质的影响。选择酶用量、酶处理温度、酶作用时间、pH值做单因素实验,研究其对米饭品质影响变化规律;采用响应面分析方法,研究各自变量及其交互作用对米饭复水率的影响,优化出的酶处理工艺最佳条件为：加酶量0.12%,温度62.37℃,处理时间60.90 min,pH值6.42。在此条件下浸泡的方便米饭复水率为2.37,复水时间为4.62 min。感官评价和物性仪测定结果表明：用酶处理的方便米饭复水后外观、口感、滋味等都优于未用酶处理的方便米饭。