New contact acoustic emission detector for texture evaluation of apples

A new contact acoustic emission detector (CAED) was developed for the instrumental texture evaluation of apples. The goal of this work was to determine the relations between instrumental parameters and sensory texture attributes, and to develop calibration models for prediction of the sensory texture of apples with CAED. Seven apple cultivars were used for the construction and validation of the models. CAED is particularly useful for evaluation of sensory crispness, crunchiness and hardness. There is also a significant correlation of acoustic emission counts with juiciness, mealiness and overall texture. Validation of the models indicates better prediction of these sensory attributes by total acoustic emission counts than prediction by puncture firmness in terms of variance explained, root-mean-square of a model prediction, and bias.     

Texture analysis of Red Delicious fruit: Towards multiple measurements on individual fruit

The sensory texture of Red Delicious apples was studied using single point and time–intensity (TI) methods together with penetrometers and in vivo techniques. Testing was performed in two trials on a per fruit basis, not with fruit batches. The standard penetrometer was significantly correlated (p < 0.05) to sensory hardness, juiciness, mealiness, crunchiness and degree of breakdown, but not to skin toughness. Facial muscle activity during chewing was collected with electromyography (EMG) together with spit outs for individuals. Parameters such as work done during chewing were extracted from the full EMG signals, and some were found to be related significantly (p < 0.05) to the penetrometer data and to sensory hardness. The aspect ratio of expectorated particles related significantly (p < 0.05) to sensory hardness and skin toughness.Principal component analysis shows that 76% of the variance in the combined data set was explained by seven components in Trial 1 and 73% by six components in Trial 2. The first component in both trials was described, principally by hardness, mealiness and the penetrometer value. The second component was described by the EMG signal parameters in Trial 1, and the apple skin properties in Trial 2. Sensory terms hardness, mealiness, crunchiness and juiciness were inter-correlated which may indicate that the texture of Red Delicious apples is perceived as mainly one-dimensional.     

Relationship between sensory analysis,penetrometry and visible–NIR spectroscopy of apples belonging to different cultivars

Nineteen French apple cultivars were characterised by sensory profiling, penetrometry and visible/near infrared (vis/NIR) spectroscopy. The main purpose was to investigate the relationships between sensory attributes, including apple texture and flavour, and destructive penetrometric measurements and non-destructive vis/NIR spectroscopy. Sensory crunchiness, touch resistance and crispness correlated well with total puncture force, flesh rupture breakdown force, and the work associated with that force. Juiciness and mealiness, two very important quality indices, were strongly correlated with the slope of force-deformation curves. A relationship was also found between different vis/NIR wavelengths and sensory attributes for apples (roughness, crunchiness, mealiness, sour and sweet taste). Subsequent studies will investigate the possible benefit of using vis/NIR spectroscopy to estimate certain sensory attributes measured by trained panellists.     

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。     

Influence of variety,site and storage on physical,sensory and compositional aspects of mashed potato

Over two seasons, eight potato varieties were grown locally and the three principal UK maincrop varieties at different sites. After periods of storage domestically prepared mashed potato was made from this material and assessed for back extrusion, adhesion, particle and cell size and distribution, ‘free’ starch, dry matter and cell wall polysaccharides in conjunction with sensory textural assessments for mealiness, moisture and structure. The results indicate that there are strong correlations between the physical measurements of work done during back extrusion (EWD) and the deformation to peak adhesion force (ADP) with both dry matter (DM) and the mean sensory scores for mealiness, moisture and structure. The sensory characteristics were also highly interdependent. The r value of these relationships declines after prolonged storage. No significant correlations were found between particle size or cell size and distribution and any of the physical, sensory or compositional data at any storage time. With the three principal UK maincrop varieties, site influenced DM and hence physical and sensory texture more strongly than variety.     

Textural and Rheological Properties of Cooked Potatoes

Cooked potato samples of different cultivars and specific gravities were analyzed for textural and rheological properties by sensory evaluation, texture profile analysis (TPA) and stress relaxation tests. Mealiness was correlated with the product of cohesiveness and adhesiveness, but not with other TPA parameters. Stress relaxation tests of cooked potatoes yielded a Maxwell model consisting of two viscous and three elastic elements. One of the elastic moduli was correlated with mealiness. Hardness by sensory evaluation correlated well with hardness and fracturability by TPA, and with the three elastic moduli in the relaxation model.     

Textural and physicochemical predictors of sensory texture and sweetness of boiled plantain

Boiled pulp is a major form of consumption for plantain. We assessed instrumental (puncture test and texture profile analysis) and sensory texture attributes of 13 plantain cultivars, two cooking hybrids and one dessert banana at different stages of ripeness after cooking in boiling water. Firmness, chewiness, stickiness, mealiness, sweetness and moistness described sensory variability, which was greater between stages of ripeness than between types of cultivars. Firmness and chewiness were well-predicted by instrumental force and hardness (r² > 0.72), and by soluble solid and dry matter content (r² > 0.85). Complementary sensitivity analysis revealed that a pulp puncture force or a hardness of at least 2.1 N or of 0.3 N/mm² was needed before a difference in firmness or chewiness could be perceived; a Brix of 3.7 was required to ensure a detectable difference in sweetness. Rheological and biochemical predictors can be useful for breeders for high-throughput phenotyping.     

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。     

Microstructural,cooking and textural characteristics of potato (Solanum tuberosum L) tubers in relation to physicochemical and functional properties of their flours

Potato tubers from six different cultivars were freeze‐dried, ground into flour and analyzed for thermal, pasting and textural characteristics (using differential scanning calorimetry, Rapid Visco analyzer and Instron universal testing machine, respectively) to study the relationship between flour characteristics and cooked potato mealiness. The potatoes with higher sensory mealiness scores resulted in flours having lower transition and pasting temperatures, higher amylose content, setback, peak and final viscosity. The flour gels from the mealier potatoes also exhibited higher values of textural parameters such as hardness, cohesiveness, chewiness and springiness. The microstructure of the tuber parenchyma (studied using scanning electron microscopy), cooking and sensory characteristics of potatoes were found to be related to the pasting and textural characteristics of their flours. Potato cultivars with lower mealiness scores, loosely packed cell arrangement, with comparatively large‐size cells and thinner cell walls showed lower values of textural parameters for both raw and cooked potatoes. This information may prove useful for the selection of potato cultivars with desirable textural and flour‐making properties for specific end‐uses. Copyright © 2005 Society of Chemical Industry     

梨质地变化规律与动力学模型

为了研究梨在采后贮藏过程中质地变化规律以对可食用期评估,实验测定了‘黄金’、‘玉冠’和‘丰水’3 个品种梨在贮藏过程中泰勒（Magness-Taylor,MT）硬度、果肉硬度、果肉弹性率和感官总体可接受度的变化,并建立了质地参数变化的动力学模型。结果表明：MT硬度、果肉硬度、果肉弹性率总体上均随贮藏时间延长逐渐降低,但果肉弹性率对贮藏时间变化的灵敏性优于MT硬度和果肉硬度,且果肉弹性率与感官总体可接受度的相关性更强;采用零级和一级动力学模型、Logistic模型和威布尔模型对各质地参数拟合,结果均是威布尔模型的拟合结果最佳;通过威布尔模型和感官评定,得到‘黄金’、‘玉冠’和‘丰水’梨的MT硬度分别低于14.762、10.411 N和7.255 N,果肉硬度分别低于8.215、7.438 N和5.181 N,果肉弹性率分别低于4.571、5.572 N/mm和3.609 N/mm后不具备商品价值,不建议食用。研究结果可为梨的贮藏和食用提供指导依据。     

Comparison of instrumental and sensory evaluation of texture of cured and cooked beef meat

The instrumental and sensory texture attributes of beef muscles (M. longissimus dorsi and M. semimembranosus) were compared after curing and thermal treatments. Shear, compression and puncture tests were carried out with an UTM Instron 4301 and the sensory evaluation was made with the score method. The force values obtained for puncture test gave a greater degree of correlation with the sensory tenderness, hardness and elasticity than the shear test forces. The shear test forces were found to significantly correlate with sensory tenderness only for muscles with perpendicular orientation of fibres to the direction of shear blade movement. The evaluation of beef texture with compression test was dependent on the level of sample deformation degree. The force values of compression were found to correlate significantly with elasticity and juiciness of meat up to 60% deformation levels, but at deformation levels higher than 60% appeared significant correlation with tenderness and hardness. The obtained results showed the usefulness of puncture test with proposed parameters for the instrumental measurements of beef texture.     

EMG assessment of chewing behaviour for food evaluation: Influence of personality characteristics

The aim of the present study was to evaluate the chewing behaviour stability over time and the influence of personality characteristics on chewing behaviour in order to assess the use of EMG for food assessment. From a set of eighty three subjects, thirty-two subjects were classified as personality type A or B (Jenkins Activity Survey questionnaire) and then recruited for the experimentation. Two types of assays were performed: Assay I: chewing gum for 10 chews and Assay II: chewing gum for 50 s. Only in two cases (6.3%) did the subject change his/her chewing behaviour; in the other cases, subjects’ chewing behaviour was stable over time (two months test). In both assays significant differences between the personality groups were found in terms of the EMG parameters. Discriminant and K-means cluster analysis confirmed the role of personality traits on the chewing behaviour of the subjects. Thus, personality traits should be considered for panel selection and/or data analysis.     

Comparison of electromyographic pattern of sensory experts and untrained subjects during chewing of Mahon cheese

Use of electromyography (EMG) to monitor mastication is a relatively new concept in assessing food physical and sensory properties. Although expert assessment of cheese characteristics is widely used, the effect of training in sensory analysis on mastication patterns, as assessed using EMG is not well known. Nine samples of the same Mahon cheese (60 days ripening) were given to 24 subjects (8 experts, 16 untrained) and EMG recorded for each chewing sequence. Three samples were tested in a single session by each subject, and three sessions carried out on different days. EMG was recorded from four masticatory muscles for each subject. From EMG records the following was extracted: number of chews, chewing time, mean and maximum voltage of EMG bursts (i.e. chews) across chewing sequence, chewing work and chewing rate. No gender bias was found for the EMG parameters considered, therefore, as regards gender, each group was considered to be homogeneous. Variability within-subjects across samples was greater for experts than untrained subjects. Significant differences in chewing time, chewing work and chewing rate were found between the expert and untrained groups. Data analysis of the three sessions showed an influence of cognitive constructs, mediating states, on the chewing process. The experts were found to be goal driven as to their mastication process. Experts showed no significant differences between sessions, untrained subjects were found to vary their EMG output in successive sessions for number of chews, chewing time, mean voltage, and chewing work.     

INSTRUMENTAL AND SENSORY CHARACTERIZATION OF COOKED POTATO TEXTURE

Uniaxial compression, Texture Profile Analysis (TPA) and chemical measurements were related to sensory texture evaluation of potato quality during storage. Principal component analysis grouped the varieties into three types of variation: mealiness versus firmness and springiness (PC1), moistness versus adhesiveness (PC2) and hardness versus adhesiveness and moistness (PC3). In uniaxial compression the variable 'stress', 'work up to fracture' and 'total work during compression' described the same type of information in the data. These uniaxial data and most of the TPA data were highly correlated. Uniaxial compression data (stress, strain, modulus of deformability), starch structural data (area, roundness, aspect ratio), specific gravity and pectin methyl esterase activity discriminated between the varieties and harvest times. Partial Least Squares Regression showed stress, strain, modulus of deformability and specific gravity to be the most important variables in distinguishing between two groups of sensory texture attributes explaining 65% of the total variance in the sensory data. Coefficients of correlation between predicted and measured sensory attributes were in the range 0.36–0.79. The TPA data were not found to be relevant substitutions for the sensory attributes.