Data Analysis of Penetrometric Force/Displacement Curves for the Characterization of 
 Whole Apple Fruits

Abstract

The objective of the present study was to compare two chemometric approaches for characterizing the rheological properties of fruits from puncture test force/displacement curves. The first approach (parameter approach) computed six texture parameters from the curves, which were supposed to be representative of skin hardness, fruit deformation before skin rupture, flesh firmness and mechanical work needed to penetrate the fruit. The second approach (whole curve approach) used the whole digitized curve (300 data points) in further data processing. Two experimental studies were compared: first, the variability of the rheological parameters of five apple cultivars; second, the rheological variability that was characterized as a function of storage conditions. For both approaches, factorial discriminant analysis was applied to discriminate the fruits based on the measured rheological properties. The qualitative groups in factorial discriminant analysis were either the apple cultivar or the storage conditions (days and temperatures of storage). The tests were carried out using cross-validation procedures, making it possible to compute the number of fruits correctly identified. Thus the percentage of correct identification was 92% and 87% for using the parameter and the whole curve approaches, respectively. The discrimination of storage duration was less accurate for both approaches giving about 50% correct identifications. Comparison of the percentage of correct classifications based on the whole curve 3 Corresponding author.Journal of Texture Studies 36 (2005) 387-401. All Rights Reserved. © Copyright 2005, Blackwell Publishing 387 and the parameter approaches showed that the six computed parameters gave a good summary of the information present in the curve. The whole curve approach showed that some additional information, not present in the six parameters, may be appropriate for a complete description of the fruit rheology. KEYWORDSApple, digitized curve, factorial discriminant analysis, penetrometry, puncture test, storage, texture 388 C. CAMPS ET AL. COMPARISON OF TWO CHEMOMETRIC APPROACHES

Texture analysis in an apple progeny through instrumental, sensory and histological phenotyping

“…According to the Fischer coefficient, the interaction of the two factors was generally lower than the individual effect. These results agreed with the reported evolution of apple texture during storage (Holt and Schoorl 1984;Kingston 1992;Harker et al 2002;Mehinagic et al 2004Mehinagic et al , 2003Iwanami et al 2005;Camps et al 2005;Billy et al 2008), which is known to be under genetic control (Iwanami et al 2008b;Kouassi et al 2009). These changes reflected the combination of the enzymatic cell wall disassembly (Goulao and Oliveira 2008) and the loss of cell turgor pressure (Johnston et al 2002;Iwanami et al 2008a) occurring during fruit ripening.…”

“…No such correlations were found with our progeny. Correlations between instrumental measures and sensory texture descriptors have been reported by several authors (Abbott et al 1984;Harker et al 2002;Mehinagic et al 2004;Camps et al 2005;Ioannides et al 2007), but besides FIRM and CRISP (Harker et al 2002), compression and penetrometry variables are known to be poor predictors of sensory descriptors, such as MEALI, MELT or JUIC (Harker et al 2002;Camps et al 2005). In support of King et al (2000) observations, the close genetic relatedness between individuals in our progeny likely led to absence of relation or to lower correlation values than those reported for genetically contrasted apple varieties (Barreiro et al 1998;Harker et al 2002;Mehinagic et al 2003Mehinagic et al , 2004Shmulevich et al 2003).…”

“…Penetrometry Penetrometry testing was performed on ten unpeeled apples per individual at dates 1, 2 and 3 according to Camps et al (2005) using the texture analyser TA.XT.PLUS (Stable Micro system) equipped with a 4 mm-diameter convex probe. Penetration speed was fixed at 3.3 mm s -1 .…”

Comprehensive ripeness-index for prediction of ripening level in mangoes by multivariate modelling of ripening behaviour

“…4 mm cylindrical probe (P/4) was used with 1 mm s -1 pre-test speed, 0.1 mm s -1 test speed, 1 mm s -1 post-test speed, and 10 mm penetration depth to obtain force displacement curve. Peel strength: PS (maximum force required to penetrate the peel in Newton), stiffness: S (slope of the force/displacement analysis, FDA, curve till peel strength in N mm -1 ) and flesh firmness: FF (mean force required to penetrate flesh in Newton) were extracted from FDA curve as proposed by Nambi et al (2015) and Camps et al (2005). Colour coordinates were recorded for both external peel colour (L e * ,a e * ,b e * ) and internal pulp colour (L i * ,a i * ,b i * ) of the mango using a HunterLAB colour meter (Hunter Associates Laboratory, Inc. USA) as proposed by Nambi et al (2016b).…”

tudy on Correlation between Electrical Parameters and Texture Parameters of Lingwu Long-Jujube during Storage Process

“…The average force value of anchor 3 and 4 was pulp firmness (g). The peak value of anchor 4 was the greatest degrees of hardness (Camps et al,2005) . Table 1 showed the variation value of long jujube texture parameters during storage.…”