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%.     

INFLUENCE OF GROWING ENVIRONMENT AND STORAGE DURATION ON QUALITY OF FRESH-PACK CUCUMBER PICKLES3

Fruit of several pickling cucumbers (Cucumis sativus L.) grown in 1978 and 1979 in several environments under two soil nitrogen levels (high vs. normal) were stored for various time periods before fresh-pack processing. Firmness, color and general appearance as examined after equilibration were all highly affected by cultivar, growing environment, and storage duration but somewhat less by nitrogen level. Unexpectedly, color and appearance improved during the first 24 h after harvest. Acceptable firmness was maintained for at least 72 h after harvest. Fruit of genetically firm cultivars generally showed less change in firmness than did fruit of less firm cultivars.     

TEXTURE OF CULTURED GILTHEAD SEA BREAM (SPARUS AURATA): INSTRUMENTAL AND SENSORY MEASUREMENT

The texture of twelve samples of farmed gilthead sea bream (Sparus aurata) from experimental and commercial cultures, fresh and frozen, was determined by instrumental texture profile analysis (TPA) of whole raw fish and by sensory analysis of the corresponding cooked fish fillets. Average values of TPA hardness and chewiness were higher for fresh samples (78.0 N and 41.9 N, respectively) than for frozen and thawed samples (43.5 N and 21.5 N, respectively). The effect of freezing on springiness and cohesiveness values was different depending on the sample (a significant sample × freezing interaction). By sensory analysis, higher firmness, chewiness and fibrousness, and less juiciness were detected in frozen samples. Only one sample was perceived as less chewy, less fibrous and more juicy than the rest, and that corresponded to the smallest (less mature) fish. High percentages of the variability of sensory firmness (92%), chewiness (91%) or juiciness (85%) were explained by several of the TPA parameters measured on the raw whole fish using a fast nondestructive test.     

UNIAXIAL COMPRESSION OF UF-FETA CHEESE RELATED TO SENSORY TEXTURE ANALYSIS

Rheological characteristics of seven Feta cheeses with different textures and produced from ultrafiltered milk (UF-Feta cheeses) were evaluated by uniaxial compression and sensory texture analysis. The effect of uniaxial deformation rate (50–2500 mm/min) on four rheological parameters: Stress at fracture s?_f), Hencky strain at fracture (?_f), deformability modulus (E) and work to fracture (W_f) was examined. Three Principal Components (PC) described 76, 16 and 4% respectively, of the variation in the uniaxial compression data set (4 parameters at 12 deformation rates). Statistically α_f, E and W_f described the same type of information in the data set. Six sensory texture attributes of the UF-Feta cheeses were evaluated by a sensory texture panel: nonoral firmness, nonoral brittleness, nonoral spreadability, oral crumbliness, oral firmness and oral stickiness. One PC described 93% of the variation in the sensory texture data and grouped the sensory variables into two negatively correlated groups: nonoral firmness nonoral brittleness, oral firmness and oral crumbliness versus nonoral spreadability and oral stickiness. Correlations and Partial Least Squares regression (PLS) between instrumental and sensory texture variables showed that nonoral and oral firmness were the nonoral and oral sensory variables best predicted from instrumental measurements. α_f, E and W_f were all able to predict nonoral and oral firmness. Of the instrumental parameters, α_f generally gave the best correlation to nonoral firmness at all deformation rates. Above a deformation rate of 50 mm/min correlations between α_f and nonoral firmness were almost independent of deformation rate, and at any deformation rate correlations between α_f and oral firmness     

Quality evaluation of pickling cucumbers using hyperspectral reflectance and transmittance imaging—Part II. Performance of a prototype

This paper reports on the development and evaluation of methods and algorithms for detecting both external and internal quality of pickling cucumbers using the hyperspectral reflectance and transmittance images acquired by an online prototype described in a previous paper [1]. Experiments were performed in 2 years on ‘Journey’ pickling cucumbers, some of which were subjected to mechanical stress to induce internal defect in seed cavity. Hyperspectral images of the ‘Journey’ pickling cucumbers were collected under reflectance, transmittance, and their combination modes. Partial least squares analysis was performed on spectra extracted from the hyperspectral images to predict firmness, color, and the presence of internal defect. The system performed well on predicting skin color (chroma and hue) with the coefficient of determination (R ²) ranging between 0.75 and 0.77; however, it had poor prediction of fruit firmness. Transmittance data in the spectral region of 675–1,000 nm provided the best detection of internal defect for the test pickling cucumbers, with the detection accuracy up to 99%. Up to the best four wavelength combinations were identified using linear discriminant analysis for internal defect detection. The hyperspectral imaging technique can be used for simultaneous detection of color, size, and internal defect on pickling cucumbers.     

OBSERVATIONS ON TEXTURE MEASUREMENT OF RAW CUCUMBERS WITH THE FRUIT PRESSURE TESTER*

Raw fruit of a ‘firm’ (Explorer) and a ‘soft’ (Green F) cucumber cultivar were puncture tested with the Magness-Taylor fruit pressure tester (FPT) manually, and also with the FPT or only FPT tip mounted in the Instron. Puncture-values for flesh only were 70–75 % of those for intact fruit. Neither the cucumber size (1–2.5 in. diam) nor the test speed (5–50 cm min^-1) appreciably affected the puncture test values.     

Malic and Citric Acids in Pickling Cucumbers

The content of major organic acids in pickling cucumbers has been determined. Malic acid was found to be the major organic acid in commercial size pickling cucumbers. The concentration among a group of six cultivars ranged from 0.2–0.3% on a fresh weight basis. Malic acid was present in all parts of the fruit. The highest concentration was in the outer 3 mm of the mesocarp, followed by the endocarp, the inner mesocarp, and the exocarp. During enlargement and maturation of cucumbers, citric acid became the principal organic acid, reaching levels in excess of 1% on a wet weight basis in the endocarp. This large accumulation of citric acid is the probable cause of the decline in endocarp pH during fruit maturation.     

METHOD FOR DETERMINATION OF FIRMNESS IN CUCUMBER SLICES1

A punch and die assembly was adapted to the Instron UTM for deter-mination of firmness of mesocarp and endocarp tissues in cucumber slices. A cylindricalpunch 0.315 cm diameter (0.200 to 0.635 cm diameter tested) and a cucumber slice thickness of at least 0.48 cm were found to be suitable for the method developed. Penetration force was about five times greater for mesocarp than endocarp in 4 to 5 cm diameter cucumbers. Mesocarp and endocarp were firmer near the stem end than near the blossom end of cucumbers. Force readings also declined for both tissues with increase in fruit diameter from about 2 to 6 em. Single slices taken from the center of 20 cucumbers and punched once each at specified locations in the mesocarp and endocarp provided sufficient sampling to limit the coefficient of variation to about 5%. The correlation coefficient between sensory analysis for firmness and puncture force readings of fermented cucumber slices was 0.88.     

A COMPARISON OF FRUIT OF HIGHBUSH AND RABBITEYE BLUEBERRY CULTIVARS1

In 1986, 1988 and 1989, fruit from highbush blueberry (Vaccinium corymbosum L., cvs Collins, Bluecrop, and Herbert) and rabbiteye blueberry (V. ashei Reade, cvs Climax, Tifblue, and Menditoo) grown at the same location were compared for size, raw product quality, storage, and sensory attributes. Compared with rabbiteye blueberry fruit, fruit of highbush cvs were generally larger in size, volume, and surface area and higher in titratable acidity, higher Hunter color attributes of ‘L’, ‘a’, ‘b’, and chroma, protein, P, Ca, Mg, Mn, Fe, Cu, B (dry wt. basis), and higher in decay and water loss after 3 weeks storage at 7 C. Rabbiteye fruit, compared with highbush fruit, were generally higher in pulp pH, percent soluble solids, percent dry matter, seed weight per fruit, weight per seed, fruit height/width ratio, periderm dry weight per fruit, periderm wt. per surface area (in mg/cm²), sugar:acid ratio, firmness (as shear), and in sensory seediness. Fruit soluble solids, dry matter, hue, titratable acidity, pulp pH, and firmness of both species were influenced by weather (years).     

EFFECTS OF THE RATE OF HEATING ON APPLE AND PEAR FRUIT QUALITY

There is evidence that the rate of heating to meet quarantine security impacts fruit quality as well as insect mortality. Linear heating rates, of 4, 6, 8, 10, and 12C/h to treatment temperatures of 44 and 46C were used to treat 8 cultivars of apples (‘Delicious’, ‘Golden Delicious’, ‘Granny Smith’, ‘Fuji’, ‘Gala’, ‘Jonagold’, ‘Braeburn’, and ‘Cameo’) and two cultivars of winter pear (‘d'Anjou’ and ‘Bosc’). Fruit were stored, ripened, and tested for various quality parameters. Scald was controlled, firmness was higher in heat treated fruit, ripening was delayed but uniform in pears, decay organisms were suppressed, red fruit became redder and green fruit remained green, the Brix‐acid ratio (SS/TA) was either unchanged (‘Granny Smith’) or increased. Physiological disorders such as bitter pit were exacerbated by the heat treatment, requiring culling after treatment to avoid storage of fruit so affected.     

PHYSICOCHEMICAL AND SENSORY CHARACTERISTICS OF SELECTED MICHIGAN SWEET CHERRY (Prunus avium L.) CULTIVARS

Sweet cherry cultivars grown in Northern Michigan in 1992 were analyzed for sensory and physicochemical characteristics. ‘Emperor Francis’, a yellow/red blushed, light color cultivar had the highest Brix/acid ratio at the 4th harvest, and it scored higher in sensory tests for sweetness flavor and overall acceptability than the dark cultivars, ‘Sam’ and ‘Hedelfingen’. Harvest dates showed significant effect on titrable acidity, Brix, Brix/acid ratio, sugars, weight and diameter of fruits. Brix/acid ratio showed significant correlation with sweetness. Correlation coefficients between overall consumer acceptability and measured parameters for three sweet cherry cultivars indicate that firmness has potential as an objective overall index for acceptability.     

FIRMNESS EVALUATION OF SWEET CHERRIES BY A TRAINED AND CONSUMER SENSORY PANEL

The objective of this study was to examine cherry firmness and the ability of a trained and consumer panel to differentiate between cherries of different firmness values. For the trained panel ( n =  12) and consumer panel ( n =  100) evaluations, two late-maturing, commercially important cherry cultivars were evaluated, "Selah" and "Skeena." For trained panel evaluations, the analytical firmness value of each cherry was determined, although for the consumer panel, cherries were characterized into different firmness categories (low, intermediate and high), after which, a series of paired comparisons were made. "Selah" was the less-firm cultivar by approximately 20 g/mm and consumers could distinguish the more-firm cherry in all comparisons ( P <  0.05). For "Skeena," consumers could only distinguish soft versus firm. Trained panelists were able to distinguish between cherries of a minimum analytical firmness value of ∼40 g/mm. A model was developed to predict sensory firmness from analytical determinations of firmness ( r =  0.63).

PRACTICAL APPLICATIONS

Developing prediction models to estimate sensory response from analytical data will benefit the fruit industry by potentially allowing the use of analytical measurements as a proxy for sensory evaluation. In addition, understanding the importance of firmness on cherry acceptance and knowing the specific firmness values at which individuals can perceive a difference in sensory firmness is useful for cherry growers to produce a cherry with acceptable texture.     

Prediction of Sensory Profile of Mango Using Textural Attributes During Ripening

Mango is an important commercial fruit and is marketed based on their colour, firmness and taste. These sensory parameters vary with individual mango and person involved in testing. There is little or no information available on the instrumental estimation of these sensory attributes. The present study, therefore, was conducted to correlate sensory and instrumental textural attributes to explore the possibility of predicting them for seven major cultivars of mango influenced by harvesting dates and ripening period (10 days). In general, the textural property of peel, pulp and fruit decreased while sensory attributes increased during fruit ripening. Sensory qualities like taste, flavour and overall acceptability were significantly affected by harvesting date, cultivar and ripening period. Harvesting time and cultivars, however, did not influence the fruit appearance. Among textural attributes, peel firmness was closely associated with all the sensory parameters indicating that textural parameters could be useful to predict sensory profile of mango cultivars during their ripening. Cultivar-specific variations were observed while evaluating various equations (linear/polynomial/exponential/logarithmic/power) for correlating their textural and sensory attributes. Polynomial equation was found to be the best fit (highest coefficient of determination, R ²) for prediction of sensory quality using textural properties of majority of mango cultivars. All cultivars under study except Alphonso collected from Maharashtra showed R ² value above 0.911 which indicated potentiality of the fitted equations for the prediction of sensory attributes using textural characteristics of mango.     

POSTHARVEST QUALITY AND SENSORY ATTRIBUTES OF ‘BYRONGOLD’ AND ‘RUBYSWEET’ PLUMS1

Fruit from two new cultivars of plums, ‘Byrongold’ and ‘Rubysweet’ were harvested at three maturities. Maturity one and two were ripened for three and six days at 20C and 85% relative humidity to determine fruit quality characteristics during storage. Plums were separated into three maturity categories by delayed light emission. Fruit size, weight, hue angle, flesh firmness, soluble solids and concentration of sugars, organic acids and sensory attributes were determined to evaluate stroage quality of the fruit. Significant differences were found between cultivars for sucrose, glucose, fructose and sorbitol. Sugar concentrations varied within the same cultivar by maturity and storage times. In general, acid levels decreased as plums ripened. Panelists preferred “Byrongold” ripened for three days for tartness and juiciness and “Byrongold” ripened for six days for sweetness. “Rubysweet” ripened for three days was preferred for sweetness, tartness and juiciness. Significant differences were found in peel bitterness between cultivars and days ripened. Unripened maturity 2 ‘Byrongold’ and unripenedd maturity 3 ‘Rubysweet’ had the highest peel bitterness. Hedonic scores showed ‘Rubysweet’.     

Fermentation of Cucumbers Without Sodium Chloride

Cucumbers were successfully fermented and stored in the absence of sodium chloride (salt) under laboratory conditions, provided the fruit were blanched (3 min, 77°C) before brining in a calcium acetate buffer and the brine inoculated with Lactobacillus planturum. Bloater formation was prevented by blanching even when brines were not purged of CO₂. Firmness of cucumbers was similar in salt-free brines or those containing salt after 1 mo, but firmness of salt-free cucumbers was lower after storage for 12 mos. Under pilot-scale, commercial conditions, however, the cucumbers were severely bloated, and the firmness was unacceptable after storage for 7 mo, due apparently to Microbial recontamination after blanching.     

Comparison of the texture of fresh and preserved Agaricus bisporus and Boletus edulis mushrooms

This work compares changes during the production process and storage period in the texture of canned Agaricus bisporus and Boletus edulis mushrooms previously blanched in water, blanched or soaked and blanched in solutions containing citric, l ‐ascorbic and lactic acids. The texture was examined using instruments [textural profile analysis (TPA), Kramer shear cell (KSC)] and sensory analysis [five‐point, profiling (P)]. Canning B. edulis mushrooms reduced their hardness, chewiness and gumminess (TPA), the values for force and work (KC), and brittleness and crispiness (P), although increasing their cohesiveness (TPA). Canning A. bisporus mushrooms reduced their hardness (TPA) and the expenditure of work, but increased their cohesiveness, hardness, crispiness and firmness (P). Twelve‐month storage of both species of canned mushrooms led to a reduction in brittleness and crispiness (P). The type of pre‐treatment applied affected the texture only when determined using profile analysis, and significant differences in hardness, crispiness and firmness between blanched‐only and soaked and blanched products were mainly found in B. edulis.     

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。     

Effects of Fruit Size on Fresh Cucumber Composition and the Chemical and Physical Consequences of Fermentation

ABSTRACT: The composition of pickling cucumbers varied with fruit size, which affected buffer capacity, sugar utilization, terminal pH, and texture of the fermented fruit. We found that as cucumber size increased (from less than 27 to 51 mm in dia), malic acid, pH, buffer capacity, and dry matter content decreased, and glucose and fructose contents increased. Fruit firmness and bloater damage were greater in large than in small, fermented, whole cucumbers. Blanching (75 °C, 30 s) had little effect on the fermentation and prevention of bloater formation in finished products, regardless of fruit sizes. It was demonstrated that cucumber juice can serve as a model system for studying the metabolic, but not the physical (texture, bloater damage), consequences of lactic acid bacteria chosen as starter cultures for cucumber fermentation.     

保脆剂对腌制大头菜质构特性的影响研究

采用氯化钙、乳酸钙、丙酸钙3种保脆剂对腌制大头菜进行保脆处理,利用质构仪质地多面分析(TPA)方法定时测定大头菜腌制期间硬度、脆度、弹性、咀嚼性、黏附性和凝聚性6个质构参数的变化情况,并分析各质构参数之间的相关性。结果表明,在腌制期间,TPA测试反映了经保脆剂处理后的大头菜各项质地参数总体呈先上升后下降的趋势,且不同保脆剂间各质地参数下降规律有所差异。大头菜的黏附性和硬度、脆度、弹性、咀嚼性、凝聚性均呈负相关;硬度和脆度具有高度的正相关性(R=0.966);咀嚼性与弹性、凝聚性、硬度呈较好的相关性(R=0.876、R=0.964、R=0.923);凝聚性和硬度、脆度的相关性较好(R=0.934、R=0.919)。     

Mechanical behaviour and quality traits of highbush blueberry during postharvest storage

BACKGROUND: Berry firmness is one of the most important characteristics for fresh market consumption. Blueberry firmness is also an important attribute because it is considered to be a measure of its freshness. Berries lose their firmness by loss of water and by changes in their structure. RESULTS: The postharvest life of two highbush blueberry cultivars (Bluecrop and Coville) was investigated. Several parameters related to blueberry quality were evaluated during the postharvest storage period. To assess berry texture characteristics (firmness, hardness, cohesiveness, gumminess, chewiness, springiness, resilience), a rapid non‐destructive penetrometer test by Durofel^® and texture profile analysis (TPA) using a texture analyser were carried out. Low temperature inhibited the decrease of total soluble solids, total titratable acidity and increase of flesh pH value, thereby maintaining good taste quality. There was an increase in fruit firmness (Durofel index) and hardness and a decrease in chewiness and springiness during storage. CONCLUSION: There was a significant correlation among the TPA parameters and Durofel index. The Durofel index could therefore be used as a suitable indicator of fruit quality and storability, and low‐temperature storage is beneficial to maintain the taste quality of blueberry fruit after harvest. Copyright © 2009 Society of Chemical Industry