INSTRUMENTAL TEXTURE PROFILE ANALYSIS OF PECANS OF VARIOUS OIL AND MOISTURE CONTENTS AFTER FREEZING TREATMENTS

Freezing of pecans is done to maintain flavor but has a lesser-known effect on other quality factors such as texture. Pecans were frozen by various methods, thawed and tested for texture by 50% compression of 3-mm dia. × 5-mm long cylinders. The Texture Profile Analysis (TPA) parameters, which were, affected most were fracturability, hardness and Area 1. The most extreme, slowest and fastest, freezing rates produced similar TPA values and were different from intermediate freezing rates that simulate commercial cold storage practices. The effect of the various freezing treatments on texture was similar for full-oil and reduced-oil pecans and for those sprayed or not sprayed with water.     

Moisture Content Adjustment to Modify Texture of Reduced-Oil Pecans

Reducing oil content has produced pecans with extended shelf-life and less calories, but poor texture. Adjusting final moisture content may restore texture of reduced-oil pecans. Texture Profile Analysis (TPA) was performed using an Instron on cylinders taken from full-oil and reduced-oil pecans sprayed with water or with a water-based flavoring, then dried to 15 final moisture contents ranging from 2.43 to 19.85%. Wetting and partial drying increased hardness to 87%, Area 1 to 89%, and fracturability to 79% of the value for full-oil pecans. Springiness and Area 2 were practically fully restored after redrying to 5% MC.     

Texture of Pecans Measured by Sensory and Instrumental Means

The texture of pecans (Carya illinoensis) from four cuhivars (Barton, Mahan, Western and Wichita) was analyzed using sensory and instrumental methods. Sensory hardness, flexibility and crispness were rated by trained panelists. Ranking of hardness and crispness was also carried out. A Texture Analyser TAXT2 was used for 50% compression, texture profile analysis (TPA), puncture and bending. Puncture and 50% compression gave best reproducibility, least variability and agreement with sensory data. The most relevant TPA parameters were cohesiveness, elasticity and fracturabihty. Parameters from the bending test did not indicate texture of the pecans suitably.     

Pecan Texture as Affected by Freezing Rates, Storage Temperature, and Thawing Rates

Pecan texture was measured by texture profile analysis (TPA) at 80% compression before and after being frozen at 6 controlled rates, to 3 minimum temperatures and thawed at 2 rates. Freezing and thawing rates had more influence than storage temperature on pecan texture. Certain TPA parameters (i.e., hardness, area 1, fracturability and slope of linear segment of force vs. deformation curve) were more affected than others by freezing and thawing rates. Freezing and thawing at high rates had the least effect on pecan texture.     

磷酸盐对西式蒸煮火腿质构影响研究

研究了不同添加量的磷酸三钠、六偏磷酸钠和焦磷酸钠3种磷酸盐对西式蒸煮火腿TPA特性（硬度、弹性、咀嚼性、凝聚性、回复性）的影响变化规律：随着磷酸盐添加量的增加，TPA特性（凝聚性除外）优化。3种磷酸盐对西式火腿质构影响的大小顺序：焦磷酸钠〉磷酸三钠〉六偏磷酸钠。通过感官评定与机械测试TPA特性之间的相关分析，结果表明感官评定和TPA特性间有较好的相关性。     

Chemical, physical, and sensorial characteristics of "Terrincho" ewe cheese: changes during ripening and intravarietal comparison

The objectives of this study were to monitor the changes in chemical [moisture, acidity, pH, and water activity (a(w))] and physical (color and texture) parameters of "Terrincho" ewe cheese during 60 d of ripening, and to determine the correlations between the changes in instrumental texture and color parameters and the ripening time of the product. Intravarietal comparison of Terrincho ewe cheese from 5 different dairy plants was performed by evaluation of mechanical parameters from texture profile analysis (TPA) and color parameters in terms of CIELAB color space (L*, a*, and b*). In addition to mechanical and color tests, composition analyses and sensory tests were performed. The results were evaluated with statistical methods (single valued and multivariate analysis). During the first 20 d of ripening, an increase in hardness, fracturability, gumminess, chewiness, and yellowness occurred. Simultaneously, adhesiveness, resilience, L* (inside cheese, "i" and external "e"), and cohesiveness decreased. After 20 d of ripening hardness, fracturability, gumminess, and chewiness decreased and cohesiveness increased. The ripening time of Terrincho cheeses can be estimated with 6 variables: L* (external, e), L* (i), b* (inside cheese, i), hardness, a* (i), chewiness, and a constant. The estimation error was 4.2 d. Evaluation of composition, pH, texture profile analyses, color, and related sensory characteristics of Terrincho cheeses from 5 different dairy plants (with 30 d of ripening) revealed correlations between these parameters.     

凝胶软糖质构特性的感官评定与仪器分析研究

针对目前广州市场上不同品牌的凝胶软糖的质地特性进行感官评定与仪器分析的相关性研究。选用9种市售凝胶软糖,采用质地剖面检验法进行感官评定,质构仪(TPA模式)进行仪器分析,对感官评定与质构仪测定结果进行相关性分析。研究表明,凝胶软糖的仪器分析能很好地反映感官质构,其中质构仪测定出的硬度、弹性、咀嚼性与对应的感官指标有显著的相关性。选取主要仪器分析指标为自变量,感官评定指标为因变量,进行逐步回归分析,得到具有统计意义的感官硬度和感官弹性的预测方程。表明TPA质构分析和感官质构评价均能较准确地测定和反映目前市售凝胶软糖的质构。为利用质构仪测定定量表达凝胶软糖的感官质构提供理论依据。     

酸菜自然发酵过程中的质地变化

以自然发酵酸菜为研究对象,应用质构仪质地多面分析(Texture Profile Analysis,TPA)法对自然发酵过程中酸菜质地变化进行分析,探讨了质构仪各项参数之间的相关性及自然发酵过程中各参数的变化规律。结果表明,大多数的质构参数之间呈现显著相关性,酸菜的硬度1、脆度、回复性、凝聚性及咀嚼性随着发酵时间的延长整体呈现下降的趋势,且发酵40～60 d时是食用酸菜品质最佳的时期。     

Effect of rice ageing and freeze‐thaw cycle on textural properties of cooked rice (Oryza sativa L.) cv. Khao Dawk Mali 105

This study investigated the effect of rice grain ageing (0.7–12 months) and freeze‐thaw 1–5 cycles on the textural properties of cooked rice. The cooked rice from aged rice grains was freezing and thawing up to five cycles. Ageing of the rice grain increased the hardness and decreased the stickiness of the cooked rice. Repeated freeze‐thaw cycles caused an increase in hardness and a decrease in stickiness of aged cooked rice. Scanning electron micrographs showed a rough surface on the cooked rice after repeated freeze‐thaw cycles, especially for cooked rice from rice aged for 12 months. Differential scanning calorimetry and X‐ray diffraction showed increased starch retrogradation with increased freeze‐thaw cycles. The gelatinisation temperature and gelatinisation enthalpy increased when rice was aged for longer periods. Thus, ageing of rice and the number of freeze‐thaw cycles influence the textural properties of cooked rice.     

RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY PARAMETERS OF COOKED SWEETPOTATO TEXTURE1

This study compared two instrumental methods, namely uniaxial compression and texture profile analysis (TPA), with sensory evaluation in describing the textural properties of cooked sweetpotatoes. The steamed cooked samples (1.35 × 2.2 cm cylinder) of four cultivars and six selections were subjected to a trained texture profile panel for sensory ratings and the two instrumental methods for determination of the mechanical properties. Factor analysis indicated that the 15 sensory variables were grouped into 3 main factors, namely moistness-firmness (factor 1), particles (factor 2), and fiber (factor 3). Among the instrumental parameters, shear stress of compression and fracturability, hardness, and gumminess of TPA correlated highly (R = 0.73–0.95) with both the mouthfeel and mechanical-type sensory notes. These parameters of the two instrumental methods were linearly related (R²≥ 0.95) and could be converted from one to another with a high degree of reliability. Regression equations based on shear stress significantly explained (R²= 0.71–0.91) eight of the sensory notes. These instrumental parameters can be good predictors of cooked sweetpotato texture.     

Dried Soy Tofu Powder Effects on Frankfurters and Pork Sausage Patties

Regular frankfurters treated with tofu powder had decreased fat with no significant differences in color, texture, or overall acceptability compared to a control by sensory analysis. Lean frankfurters with tofu powder had lower moisture and color, better texture, and overall acceptability with no flavor differences from controls. Except for fracturability, there were no differences in texture-related parameters by Texture Profile Analysis (TPA) between regular and control frankfurters but treated lean frankfurters had improved texture. Lean pork sausages treated with tofu powder were lower in fat, higher in protein, and moisture with no differences in sensory attributes compared to controls.     

奶糖质构性能评价方法的研究

对上海市售不同品牌奶糖的感官评定指标和质构仪测定指标进行相关性研究。研究表明,质构仪测定出的奶糖弹性、黏聚性、胶着性、咀嚼性、回复性、硬度指标与其感官评价的硬度、黏度、咀嚼性、弹性及综合评分密切相关。为利用质构仪定量表达奶糖的感官品质提供理论依据。     

五种苹果质构测定方法的比较及与感官评价的相关性分析

为比较5种苹果质构不同测定方法,采用剪切法、穿刺法和TPA压缩法测定了辽宁地区5种主栽苹果的质构特征,同时研究了不同测试条件对测定指标的影响,并分析了仪器测定与感官评价结果的相关性。结果表明剪切、穿刺和TPA压缩均能测得苹果的硬度特征,并区分不同品种间的差异,去皮果肉硬度大小依次为王林 > 红富士 > 国光 > 乔纳金 > 黄元帅;穿刺法检测显示果皮对苹果质构有显著影响(P<0.05),且不同穿刺部位的质构差异显著(P<0.05),其中果顶部位穿刺硬度值最大,其次为果肩和赤道;与感官评价相关性分析显示最大穿刺模量与感官脆性极显著相关(r=0.638,P<0.01),可作为苹果脆性的表征指标;对TPA法,随着压缩形变量增加,苹果硬度测定值显著增加(P<0.05),而内聚性显著减小(P<0.05),且形变量为25%时与感官评价相关性最好。本研究表明穿刺法和TPA法均适用于苹果质构的测定,果皮及穿刺位点对穿刺影响显著,最大穿刺模量可用于表征苹果脆性指标;压缩形变量为25%时TPA法所测得质构参数与感官评价结果相关性最好。     

不同发酵剂生产的酸奶感官评定和TPA质构分析

质构剖面分析法(Texture Profile Analysis,TPA)是食品质构分析的重要方法。该文通过质构剖面分析法研究了不同发酵剂对酸奶质构的影响,并和感观评价方法进行了比较。结果表明,不同发酵剂对酸奶的硬度和胶粘性影响很大,单一保加利亚乳杆菌和嗜热链球菌生产的酸奶硬度和胶粘性最高。两菌混合硬度和胶粘性明显降低,但内聚性最高。嗜热链球菌可明显增加产品粘度。TPA分析和感观评价中硬度参数值非常吻合,TPA分析中的胶粘性和感观评价中的喉咙口滞留度有较好的关联性。两菌混合后提高杆菌比例生产的酸奶综合感观评价值最高。     

潮汕脆性肉丸的感官评定与质构评价相关性分析

目的:探索一种综合评价潮汕脆肉丸脆性品质的方法。方法:采用质构剖面法（texture profile analysis,TPA）和穿刺实验测定肉丸的质构特性,同时进行感官评定实验,并对感官和质构指标之间进行相关性分析。结果:TPA实验的硬度、咀嚼性与感官评定指标硬度、弹性、脆性、咀嚼性之间存在显著相关性（r=0.554~0.793,P<0.05）,TPA实验的回复性与感官评定的脆性、组织状态之间存在显著相关性（r=0.556,0.625,P<0.05）。穿刺实验的破裂力与感官评定指标之间均存在显著相关性（r=0.595~0.709,P<0.05）。运用主成分分析从仪器质构指标数据中提取出2个最主要的独立成分,这2个主成分的方差贡献率累计达74.5%。结论:潮汕肉丸的脆性可以采用TPA实验的硬度、咀嚼性和穿刺破裂力的定量评价结合感官评定进行综合评价,为构建客观、精确、便捷的潮汕脆性肉丸感官性状评价体系奠定基础。     

抗冻蛋白对预发酵冷冻面团发酵流变特性和馒头品质的影响

运用F4发酵流变仪、质构仪等研究冻藏和冻融循环下抗冻蛋白对预醒发冷冻面团发酵流变学特性和馒头品质的影响。结果表明:随着冻藏时间的延长和冻融循环次数的增加,冷冻面团馒头的比容减小,硬度和咀嚼性明显增大,弹性和回复性下降。冷冻面团的最大发酵高度、气体总释放量和气体释放最大高度均明显下降。说明冻藏和冻融循环严重影响了酵母的产气能力和面团的持气性,与冻藏和冻融循环过程中重结晶和大冰晶的形成有关。添加抗冻蛋白的冷冻面团馒头品质得到明显改善,说明抗冻蛋白能够减缓冷冻面团馒头冻藏和冻融循环过程中品质下降。     

熏煮香肠中脂肪、食盐、淀粉和水分含量对其质构的影响

质构是熏煮香肠的重要品质特征之一,脂肪、食盐、淀粉和水分含量是影响其质构的主要原辅料组成。文中应用质构剖面分析方法(textureprofileanalysis,TPA)对脂肪、食盐、淀粉和水分含量四因素的交互效应对熏煮香肠质构的影响进行了研究。结果显示,脂肪含量对熏煮香肠的硬度、粘聚性和咀嚼影响最大(调整R分别为129·34、0·051和33·14),而水分添加量对熏煮香肠的弹性影响最大(调整R为0·20)。通过感官评定与机械测定之间的相关分析,发现感官评定指标与机械测定的相应指标硬度、弹性、粘聚性和咀嚼性相关性较好(特别是硬度r=0·94和弹性r=0·89)。     

Comparison of Sensory and Instrumental Texture Profile Techniques for the Evaluation of Beef and Beef-Soy Loaves

Relationships among sensory texture profile parameters, among values for textural parameters obtained through different methods of interpreting instrumental texture profile analysis (TPA) curves obtained with an Instron, and between sensory and instrumental TPA values were examined for beef and beef-soy loaves. The only singificant relationship among sensory parameters was between cohesiveness and springiness. Although a number of significant relationships existed between the various methods of interpreting instrumental parameters, a number of these were associated with secondary parameters having common primary parameters. A strong relationship was found between sensory springiness and adjusted downstroke cohesiveness. Sensory cohesiveness was related both to this instrumental parameter and to downstroke cohesiveness. Chewiness values calculated for these two methods for obtaining cohesiveness values showed strong negative associations with sensory fracturability scores.     

枣泥馅料质构参数与感官品质的相关性

针对目前枣泥馅料品质缺乏客观性评价标准的问题,通过分析测试条件对枣泥馅料TPA参数的影响,确定枣泥馅料质构仪质地分析法(Texture Profile Analysis,TPA)在探头的测试速度5 mm/s,对枣泥表面的压缩程度为50%,测试停留时间为5 s,探头对枣泥馅料的触发力为5g时,此时得到的TPA参数对枣泥馅料的测验条件最佳;通过采用感官评定中的质地多面剖析方法,制定了枣泥馅料评分细则。结合对感官评分之间的相关性进行皮尔逊分析结果得知感官评定指标的粗糙度与易碎性、硬度、紧密性之间具有不同程度的影响(皮尔逊系数r在0.9～1之间,p0.01);对TPA参数与感官评分的相关性分析得出,质构仪(TPA)分析参数中硬度、黏附性、凝聚性、咀嚼性和回复性与感官评分都在0.01水平上显著相关。由此提出以硬度、黏附性、凝聚性、咀嚼性和回复性5个TPA参数作为客观评价馅料品质的指标。