Textural Determination of 'Montmorency' Cherries Using Shear/Compression and Stone Removal Forces

Selection of firm tart cherry cultivars has traditionally been limited by instrumental limitations when measuring cherry texture. Current methods estimate cherry texture by evaluating skin strength and/or turgor pressure rather than pericarp firmness. An attachment to a Kramer Shear Press was designed and built to determine the force required for stone removal. Pericarp strength was measured by placing pitted cherries in a shear/compression cell and measuring shear, compression, and extrusion forces. Preliminary testing indicated stone removal force with shear/compression force may be useful for determining texture of tart cherries in cultivar screening studies.     

EVALUATION OF THE TEXTURAL PROPERTIES OF JAPANESE PEAR

The texture of Japanese pear (Pyrus serotina Rehder var. culta 'Housui') during fruit enlargement and ripening was evaluated. From the plate compression test, only the deformation ratio, modulus of elasticity, and relaxation were the interpretable textural indices for the Japanese pear. From the puncture test, interpretable textural indices were the rupture force, deformation at the rupture point, toughness, average firmness, initial firmness, apparent modulus of elasticity, bioyield force, penetrating force and penetrating energy in the flesh. The skin of the Japanese pear contributed 70–80% of the firmness of the fruit. As the fruits enlarged, the strain decreased, the elasticity increased, the fruit skin was more prone to mechanical damage, the fruit flesh became softer, and firmness and rigidity of the whole fruit was reduced.     

YOUNG'S MODULUS,POISSON'S RATIO,AND LAME'S COEFFICIENTS OF GOLDEN DELICIOUS APPLE

ABSTRACT

Three measurement methods (falling impact, resonance impulse method and puncture test) are applied to determine some mechanical properties of Golden Delicious apple. Hertz' theory modified by Kozma and Cunningham for impact between two elastic bodies are applied in this work. This allows Young's modulus E, Poisson's ratio ν and Lame's coefficients µ and λ calculation from elasticity coefficients measured by puncture test and acoustic impulse method. Young's modulus and Lame's coefficients decreased with storage time and with degree of fruit ripening. Variation of Poisson's ratio during ripening appears to occurred into three steps: a moderate increase at the beginning of storage, a virtually constant value close to 0.170 up to the fourth storage month and an increase close to 25% up to 186 days cold storage. At the beginning of storage, increasing of Poisson's ratio linked to the decrease of percent contribution of the flesh to the overall firmness. Relationship between Young's modulus and Lame's coefficient µ is linear. Lame's coefficient µ and percent contribution of the flesh to the overall firmness decreased in the same extent (about 43%) during a 186 days cold storage.     

QUALITY OF APPLE FRUIT IN RIGID FILM CONTAINERS

The storage quality of‘Delicious’ apples individually packaged in rigid film containers was investigated. Objective quality attributes (internal and external color, firmness, soluble solids and titratable acidity) were measured as a function of storage time with and without packaging in a rigid container. Overall firmness, acidity and soluble solids content decreased over a 70-day storage period. Significant effects of rigid film packaging and storage included: superior skin color, decreased weight loss, slight decrease in soluble solids content and increased firmness loss during ripening when compared to control fruit. Upon examination of the atmosphere surrounding individual fruit in these containers, increased levels of carbon dioxide and ethylene were found. Conversely, packaged fruit contained significantly less internal carbon dioxide than control samples. It was concluded that the atmosphere modified by the rigid film container hastened ripening of‘Delicious’ apples, thus deteriorating eating quality. An adequately ventilated packaged would probably alleviate this condition.     

Evaluation of tomato textural mechanical properties

The texture of fresh tomatoes (Lycopersicum esculentum Mill., ‘Momotaro’) at three different stage of ripeness (mature green, pink, and red) was intensively evaluated. The double-cycle load plate compression test showed that initial firmness, average firmness, energy absorption, deformation ratio, and relaxation ratio were sensitive textural parameters for identifying the maturity stages. From a puncture test, initial firmness, average firmness, apparent modulus of elasticity, rupture force, toughness, and deformation at the rupture point were sensitive to the maturity stages. The mature unripe tomato deformed linearly as a function of force; hence, the firmness was constant. However, the fully ripe tomato firmness increased as a function of applied force. The fruit strain increased during ripening, and it was independent of fruit size. The unripe tomato was more elastic than the ripe one. The peel at the mature green stage contributed approximately 70% of the firmness of the fruit and approximately 90% at the pink stage and red stage. The rupture force by the puncture test (traditionally, peak force) was correlated well with other textural parameters, which indicated that it could be used as a firmness representative parameter, as has been used by many researchers. The degree of elasticity was a better indicator for elasticity than the relaxation ratio.     

Firmness and colour of the fruit of some tomato cultivars from various sources during storage

The firmness of fruit of tomato cultivars Sonato, Grenadier, Adagio, Extase and Exquise obtained from growers was significantly different at time of harvest and after storage for 7 and 14 days at 19-23°C. However, all fruit had firmness values above 1000 g force on day 7 and above 700 g force on day 14, which are postulated minima for sale of fruit at retail level and use in the home respectively. There is no evidence to downgrade fruit of Sonato from a firmness point of view. Variation in fruit firmness within a sample was considerable for most cultivars on each testing date, and coefficients of variation were calculated to quantify this. Correlation coefficients between Hunter a/b ratio and firmness for the different cultivars ranged from -0.91 to -0.97. Regression lines relating a/b ratios to firmness fell into two groups. Firmness tests on samples of tomato fruit purchased from retailers suggested that all samples were adequately firm and had a firmness shelf-life of at least 7 days.     

PEACH TEXTURE DURING RIPENING AFTER EXTENDED STORAGE1

Peach texture during storage is affected by temperature, humidity, and oxygen level. Four cultivars, ‘Sentinel’, ‘Topaz’, ‘Parade’, and ‘Fairtime’, were stored at 0C for 28 days after which time texture tests were done for the next four days during the peach's ripening at 25C. A cylindrical peach specimen was penetrated with a wire probe installed in an Instron universal testing machine. From the force-displacement response, firmness parameters were determined and a fast Fourier transform frequency analysis was performed to determine the jaggedness of the curves. Effegi firmness, Instron peak force, and spectrum area changed the most during ripening. The lowest frequency ratio (0 to 0.19 Hz) changed more than any other frequency ratio during ripening. Significant decreases in Effegi firmness and in Instron peak force, steady state force, and frequency ratios were observed between the first and the second day of ripening but the changes were not significant thereafter. After one day of ripening, late season cultivars ‘Fairtime’ and ‘Parade’ were significantly less firm than ‘Topaz’. Most parameters indicated that ‘Sentinel’ an early season cultivar, was firm like ‘Topaz’, a mid-season cultivar. After two days, differences in firmness parameters among the four cultivars were not significant.     

INFLUENCE OF THE SKIN ON PUNCTURE PROPERTIES OF CHILLED AND NONCHILLED TOMATO FRUIT

The puncture properties (firmness, toughness) of tomato skin and its influence on the overall puncture properties of mature-green fruit during ambient temperature (22C) ripening or chilled (5C) storage were estimated from the difference between whole fruit puncture force-deformation behaviour and that measured with the skin removed. Although the firmness of the skin of nonchilled fruit did not change significantly (p > 0.05) over 28 days of ripening, its contribution to overall puncture firmness increased from about 25 to 70%. Both skin toughness and its contribution to overall puncture toughness doubled within the first week of ripening of nonchilled fruit. The firmness of chilled fruit skin decreased (p > 0.05) only after 16 days of storage, but its contribution to overall puncture firmness remained constant at 25–30%. Both the toughness of the skin of chilled fruit and its contribution to overall puncture toughness remained constant during storage. Possible artifacts in the measurement of puncture properties of chilled fruit are discussed. The results are consistent with a toughening of tomato skin during early stages of ripening of nonchilled fruit that somewhat compensates for a rapid reduction in pericarp tissue integrity, and with an increase in firmness or rigidity of tomato skin and underlying tissue(s) during chilled storage of fruit.     

Texture variation in apricot: Intra-fruit heterogeneity, impact of thinning and relation with the texture after cooking

The rapid texture loss of apricot fruit during storage and transformation is a limiting factor for its commercialisation and use. Apricot flesh exhibits different tissue zones which differ in texture. To better understand texture in apricot fruit, we have studied (i) the intra-fruit heterogeneity of texture measured by puncture test (tissue firmness) (ii) the effect of thinning on whole fruit firmness (global firmness), measured by compression, and on tissue firmness and (iii) the evolution of texture upon steam cooking, on apricots of contrasted texture. Nine tissue zones were defined in fresh apricot fruits in order to study differences in texture from the peduncle to the pistil zones and from the external to the internal tissue. In the nine apricot varieties used, tissue firmness decreased gradually from the external to the internal tissue. However, from the peduncle to the pistil zone, the variation of texture seemed to be variety-dependent. Overall the textures measured for the nine tissue zones were highly correlated, indicative of the major differentiation between soft and firm fruits. However distinct heterogeneity patterns could be observed on axes 2 and 3 of a principal component analysis carried out on the textures of the nine zones. The effect of thinning on fruit firmness appeared variety-dependent. Tissue firmness of the raw apricots assessed by penetrometry explained about two-thirds of the variability of firmness of cooked apricots, versus only 40% for the compression test. High correlations between texture after cooking and prior to cooking were found for four (external equatorial, external pistil, median equatorial and median pistil) out of the nine tissue zones.     

Effects of Salt, Tripolyphosphate and Sodium Alginate on the Texture and Flavor of Fish Patties Prepared from Minced Sheepshead

An attempt was made to develop an acceptable fish patty using minced sheepshead flesh. Deboned and washed sheepshead flesh was mixed with varying proportions of sodium chloride (NaCl), sodium tripolyphosphate (TPP) and sodium alginate (NaAlg). The texture quality of cooked patties was determined by measuring breaking force and sensory acceptability. A regression analysis, performed to measure the effects of NaCl, TPP, and NaAlg as well as to try to determine the optimum combination of ingredients that produced the most acceptable product, showed that all texture responses were significantly influenced by the TPP level (α < 0.05). The breaking force and sensory firmness were strongly influenced by the NaAlg concentration (α < 0.01) which also influenced texture-preference (α < 0.05).     

METHYL BROMIDE, TIME and TEMPERATURE of EXPOSURE ON APPLE QUALITY

ABSTRACT. The use of methyl bromide (MeBr) as a fumigant to control codling moth in 'Delicious'apples resulted in a loss of firmness, internal color and therefore a reduction in the amount of acceptable fruit. Time and temperature of MeBr exposure were directly related to firmness and internal color loss. As the exposure time was increased beyond 2 h and exposure temperature above 6°C firmness and internal color loss were accelerated. an 8-day ambient storage period exacerbated firmness and internal color loss as time and temperature of MeBr exposure were increased. A fumigation regime of 56 g MeBr/m³ at 6°C for 2 h resulted in acceptable fruit during a 60 day refrigerated storage period. Increased exposure times or temperatures beyond 56 g MeBr/m³ at 6°C for 2 h resulted in unacceptable firmness and internal color loss, coupled with a major loss in acceptable fruit.     

TEXTURE OF SALT STOCK WHOLE CUCUMBER PICKLES: CORRELATION OF INSTRUMENTAL AND SENSORY MEASUREMENTS*

Correlations were determined between Texture Profile Analysis (TPA) parameters of brittleness, hardness or total work of compression obtained with the Instron testing machine and sensory responses of firmness or crispness in evaluating texture of fermented salt stock whole cucumbers (1-in. diam) of three ‘firm’ pickling cultivars (Explorer, Chipper, GY 3), two ‘soft’ pickling cultivars (Green F, Mincu) and a partheonocarpic slicer (MSU 6902 G). Correlations were also determined between the TPA parameters and Magness-Taylor fruit pressure test (FPT) firmness. Correlations were good between TPA parameters and FPT firmness. Correlations were poorer between instrumental and sensory methods due largely to inordinately high sensory scores assigned to salt stock of the slicer by all panelists. Mean textural values from the various methods were compared with those obtained in the same manner for raw cucumbers. TPA brittleness tended to disappear in salt stock. Processing reduced mean TPA values across the six varieties to 39-86% of raw fruit values. Mean FPT firmness was relatively unchanged at 99% that of raw fruit. Desalting from 16% down to 8 % or 4% NaCl reduced TPA values but increased FPT firmness.     

TEXTURE OF FRESH-PACK WHOLE CUCUMBER PICKLES: CORRELATION OF INSTRUMENTAL AND SENSORY MEASUREMENTS*

Correlations were determined between Texture Profile Analysis parameters of brittleness, hardness or total work of compression obtained with the Instron testing machine and sensory responses of firmness or crispness in evaluating texture of fresh-pack processed whole cucumbers (1-in. diam) of three ‘firm’ pickling cultivars (Explorer, Chipper, GY 3), two ‘soft’ pickling cultivars (Green F, Mincu) and a parthenocarpic slicer (MSU 6902 G). Further, correlations were determined between the TPA parameters and Magness-Taylor fruit pressure test (FPT) firmness. TPA hardness and total work correlated well with sensory responses; FPT firmness correlated satisfactorily with sensory firmness. Mean textural values from the various methods were compared with those obtained in the same manner for raw cucumbers. TPA brittleness tended to disappear in the processed fruit. Processing reduced mean TPA values across the six varieties to 35-58% of raw fruit values; it decreased mean FPT firmness to only 88%.     

橡胶果破壳力学特性试验与分析

为研究橡胶果在不同条件下静态压缩破壳力的变化规律,对橡胶果分别进行X、Y、Z 3个加载方向的剪切力、锥刺力、挤压力的静态压缩试验;运用有限元法建立橡胶果的力学模型,研究橡胶果在压缩载荷作用下应力应变情况及损伤规律。试验结果表明:橡胶果在剪切力、锥刺力、挤压力下的破壳力大小关系为F_(挤压力)F_(剪切力)F_(锥刺力);橡胶果较佳的加载方向为Y方向;试验中Ⅰ类、Ⅱ类、Ⅲ类橡胶果的挤压破壳力分别为0.548 0,0.564 5,0.715 1 kN,破壳力随着橡胶果尺寸的增加而增加;有限元分析出最佳加载方向为Y方向,与试验结果一致。     

Harvest parameters to optimise storage life of European plum 'Oullins Gage'

European plum ( Prunus domestica L.) cv. 'Oullins Gage' was harvested according to firmness on five harvest dates. Fruit was analysed at harvest and during storage for weight loss, firmness, total soluble solids (TSS), titratable acidity (TA) and skin colour before and after a 3-day shelf-life period at 20 °C. Significant differences were found among harvest dates in fruit mass, skin colour, firmness, TSS and TA. Fruit mass, TSS and colour b * increased, whereas firmness and TA decreased significantly during the harvesting period. Firmness parameter as a maximum maturity index and TSS:TA (or b * colour, a non-destructive measurement) as a minimum maturity index could be used to distinguish maturity at harvest. It is suggested that the best post-storage quality of 'Oullins Gage' plums would be obtained when fruit is harvested with TSS:TA >9 or b * colour >30, but with a firmness >20N to assure a long storage life.     

MECHANICAL PROPERTIES OF TOMATOES AS RELATED TO PUNCTURE INJURY SUSCEPTIBILITY

The relation between mechanical properties of tomato ( Lycopersicon esculentum Mill.) and puncture injury susceptibility was investigated using two cultivars: Tradiro, which is moderately resistant and Blitz, which is very susceptible. Mechanical properties were determined using a universal testing machine and an acoustic firmness sensor. The susceptibility to puncture injury was measured by a pendulum test. By means of Partial Least Squares analysis (PLS), a relationship with a coefficient of determination (R²) of 0.78 was found between the mechanical properties and the puncture injury susceptibility of the tomato cultivar. High loadings were found for the force required to puncture the tomato with and without skin, the elasticity of the fruit, the toughness of the skin and the acoustic firmness of the tomato fruit, indicating that these mechanical properties affect the susceptibility to puncture injury. The obtained results directly imply that these mechanical properties should be used to screen for genotypes with lower susceptibility to puncture injury.     

Postharvest Use of Sucrose Polyesters for Extending the Shelf-life of Stored 'Golden Delicious' Apples

The post-storage uses of a sucrose-fatty acid polyester (SPE) formulation, commercial fruit wax and a combination of both were investigated on ‘Golden Delicious’ apples after fruit were removed from both controlled atmosphere (CA) and refrigerated storage. Quality parameters measured included color (skin and internal), firmness, soluble solids and titratable acidity. Physiological parameters measured were carbon dioxide and ethylene concentrations both evolved and internal. Refrigerated stored apples, treated with SPE, displayed retarded color development, higher acid and greater firmness values compared to controls. CA stored, treated apples possessed similar attributes but no firmness retention. Ethylene evolution was reduced in SPE-coated apples. In comparison to control apples, an internal accumulation of carbon dioxide and a reduction in ethylene was observed.     

基于回归分析法预测湖景蜜露桃果实可溶性固形物含量

目的：建立一种科学预测桃果实可溶性固形物含量的方法。方法：以湖景蜜露水蜜桃为实验材料,利用多元回归、线性回归和二次多项式回归分析研究果皮色差、单果质量、带皮硬度、去皮硬度与可溶性固形物含量的关系。结果：1）以原始基础数据为依据,较难建立稳定的预测可溶性固形物含量的多元回归方程。2）通过将数据进行分组,以红色饱和度（a*）、色调角（h）、红色饱和度/黄色饱和度（a*/b*）不能建立稳定的回归方程;单果质量与可溶性固形物含量具有极显著的线性回归关系,但二者所建立的二次多项式预测可溶性固形物含量效果差;带皮硬度、去皮硬度与可溶性固形物含量的线性回归方程预测性差,而建立的二次多项式R2都较高,回归关系均达极显著水平,方程：可溶性固形物含量=－0.128 2×带皮硬度2＋1.403 5×带皮硬度＋11.418 0和可溶性固形物含量=－0.481 8×去皮硬度2＋1.975 0×去皮硬度＋13.290 0预测湖景蜜露果实可溶性固形物含量效果较好。结论：采用二次多项式回归法研究带皮硬度、去皮硬度与可溶性固形物含量的关系进而进行桃果实成熟度预测是可行的。     

6 个库尔勒香梨品种果实矿质元素与品质的相关性和通径分析

应用相关性分析和通径分析的方法分析6?个库尔勒香梨品种果实矿质营养元素和品质指标之间的相关性和通径系数,筛选影响果实品质指标的主要矿质元素因子,为合理施肥及果实提质增效提供理论依据。结果表明,不同梨品种的果实品质和矿质元素含量存在一定程度的差异,果实品质中石细胞含量变异系数较大,可溶性固形物含量变异系数较小;果实矿质元素中P含量变异系数较大,Mg含量变异系数较小。相关性分析表明,部分果实品质指标与部分矿质元素含量之间存在一定的相关性。通径分析进一步明确了Ca对单果质量、果实硬度和可溶性固形物具有最大的正直接作用,N对可溶性糖、可滴定酸和VC具有最大的正直接作用,P对糖酸比和石细胞具有最大的正直接作用;Cu对果实硬度、可溶性固形物和石细胞具有最大的负直接作用,Fe对可滴定酸和VC具有最大的负直接作用,Zn对可溶性糖具有最大的负直接作用,N对单果质量和糖酸比具有最大的负直接作用。生产中要合理调控各种矿质元素的施肥配比,从而实现梨果的优质生产。