HORTSCIENCE 40(7):2091–2095. 2005.

Influence of Mealiness on the Firmnessof Apples after Harvest
Hiroshi Iwanami, Shigeki Moriya, Nobuhiro Kotoda, Sae Takahashi,
and Kazuyuki Abe
Department of Apple Research, National Institute of Fruit Tree Science,
Morioka 020-0123, Japan
Additional index words. Malus ×domestica, breeding, softening, mealy, air space
Abstract. Changes in flesh firmness and mealiness during storage were investigated in 24
apple [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] cultivars and selections(genotypes) up to 40 days after harvest under 20 ± 2 °C and 85% ± 5% relative humidity
storage conditions. Flesh firmness was measured using a penetrometer, while mealiness
was quantified by measuring the degree of cell separation in tissue induced by shaking
discs of tissue in a sucrose solution. According to the relationship between the change infirmness and mealiness, the genotypes can be divided into four groups: those that did not
soften and remained hard and nonmealy during storage; those that softened without mealiness; those that softened with slight mealiness; and those that softened with mealiness.
Firmness decreased below 30 N in fruit that softened with mealiness, and the minimum
firmness during storage was correlated with the degree of mealiness at 30 days of storage.
The rate of softening was the highest in fruit that softened with mealiness. Therefore, it
was concluded that, by measuring the firmness and changes in firmness that take place
during storage, the genotypes resulting in softening with mealiness and those that resultin softening without mealiness could be identified.
Consumers are much more sensitive tosubtle differences in texture than in taste andtend to use texture as the primary limiting factor
for acceptability (Shewfelt, 1999). Crispness
and juiciness were found to be positively
associated with consumer preference (AllanWojtas, 2003; Daillant-Spinnler et al., 1996)
in apple [Malus ×sylvestris (L.) Mill. var.
domestica (Borkh.) Mansf.]. On the contrary,
mealiness was found to be negative attribute(Jaeger et al., 1998), which is associated witha soft and dry texture and sharp increase inmealiness was observed during cold storage
in some cultivars (Watada et al., 1980).
The differences between a mealy and a nonmealy texture can be described at the cellularlevel. When mechanical forces are applied toan apple, a structural failure is caused by thecells in nonmealy flesh, however, in mealy
flesh, failure occurs between cells (Lapsley etal., 1992). To measure the degree of failure between cells, a tensile test is widely used (Glennand Poovaiah, 1990; Harker and Hallett, 1992;
Stow, 1989; Tu et al., 2000). Higher tensile
strength indicates strong connections between
cells, and lower strength indicates weak cellconnections. Thus, the tensile strength is regarded as an indicator of the appearance of amealy texture (Tu et al., 2000). However, thetensile test requires time for cutting and shaping the tissue samples. In addition, the tissue
can be damaged as the samples are prepared(Harker et al., 2002). On the other hand, many
researchers have tried to estimate mealinessby instrumental measurements and concluded
that at least two or three measurements werenecessary to estimate mealy texture (Abbott
et al., 1984; Andani et al., 1999; Barreiro etal., 1998; Mehinagic et al., 2004). Therefore,
Received for publication 16 May 2005. Acceptedfor publication 2 Sept. 2005.

HORTSCIENCE VOL. 40(7) DECEMBER 2005

in many studies concerning storage, only thefirmness and changes in firmness rather thanmealiness have been measured to evaluate
the deterioration of fruit quality because an
objective and convenient method for evaluating
mealiness has not been developed.
In Japan, strains of ‘Delicious’ apples,
mainly ‘Starking Delicious’, were grownextensively in the 1970s because of their
good eating quality. The largest productionof these cultivars was recorded in 1977, and it
amounted to 37.7% of the total apple production in Japan (MAFF, 2005). However, theproduction of these cultivars has gradually

decreased since the 1980s; the production ofstrains of ‘Delicious’ apples was <1% of thetotal apple production in 2001. One of themain reasons for the decrease in the production was that fruit of these cultivars became
mealy after harvest under the cultural, climatic,
and storage conditions in Japan. As a result,Japanese consumers became very sensitive
to the mealy texture of apples, which madea nonmealy texture essential for new apple
varieties. In Europe, it has been estimated thatup to 30% of apples from northern Europe
may be affected by mealiness, and the findings
from cross-cultural comparisons of the perception of mealiness and consumer preference
for texture attributes have been investigated(Andani et al., 2001; De Smedt, 2000; Jaeger
et al., 1998). However, a limited number ofcultivars have been examined and it is still
unknown whether there are large variations
among apple genotypes regarding the degrees
of mealiness during storage.
Recently, Motomura et al. (2000) proposed
a quantitative method for the measurement of
mealiness, in which the degree of cell separation was assessed by shaking tissue discs in a
sucrose solution. Mealiness was determinedby the difference between the weights of thediscs before and after shaking, and it was
highly and significantly correlated (r = 0.86)
with the degree of mealiness evaluated by
sensory analysis in fruit stored at 20 °C for 4
or 8 weeks. Nara et al. (2001) confirmed thatcells separated from the shaken discs in thismethod were not ruptured and remained mostly
intact. The advantages of this method are thatmany samples can be handled at one cycle ofmeasurement and that the air space in the flesh
tissue can be measured in the same cycle ofmeasurement. The relationship between the
air space in the flesh tissue and fruit softening has been observed and discussed in manystudies (Harker and Ferguson, 1988; Harker

Table 1. Twenty-four apple cultivars and selections and rootstock, tree age, and harvest date evaluated inthis study.
Abbreviation
Tree
Harvest date
Genotypein Figure
Rootstock
agez
1st
2nd
3rd
American Summer Pearmain
ASP
M.9
10
19 Aug. 26 Aug.
2 Sept.
Sansa
SNS
M.26 EMLA
18
2 Sept. 9 Sept.
15Sept.
Akane
AKN Jonathan/Marubakaido (6)9 Sept. 15 Sept. 24 Sept.
Tsugaru
TGR
JM7
89 Sept. 15 Sept. 24 Sept.
McIntoshMC
Marubakaido
44
9 Sept. 15 Sept. 24 Sept.
SilkenSLK
M.9
1415 Sept. 24 Sept. 30Sept.
Santaro
STR
Morioka #9
14
30 Sept.
Hatsuaki
HTA Jonathan/Marubakaido (6)24 Sept. 30 Sept.
8 Oct.
Redgold
RG
M.9
1030 Sept. 8 Oct.
14 Oct.
Akagi
AKG
M.26 EMLA
Unknown
8 Oct.
SenshuSSU
JM7
11
8 Oct.
Morioka 57
M57
M.26 EMLA
Unknown
8 Oct.
KitaroKIT
M.9 EMLA
14
8 Oct. 14 Oct.
21 Oct.
JonathanJT
Marubakaido
46
8 Oct. 14 Oct.
21 Oct.
Starking DeliciousSD
MM.10632
14 Oct.
JonagoldJG
JM7
814 Oct. 21 Oct.
28 Oct.
Shinsekai
SSK
M.26 EMLA
Unknown
21 Oct.
Golden Delicious
GD
M.9
10
21 Oct.
MegumiMG
Unknown
Unknown
21 Oct.
KotaroKOT
JM2
14
21 Oct. 28 Oct.
4 Nov.
Shinano GoldSG
Unknown
Unknown
28 Oct.
Orin
OR
M.9
10
28 Oct. 4 Nov.
11 Nov.
Fuji
FJ
JM1
23
4 Nov. 11 Nov. 18 Nov.
Ralls Janet
RJ
M.9
10
11 Nov. 19 Nov. 26 Nov.
z
Numeral in parenthesis indicates years since top-grafting on intermediate stock.

2091

and Hallett, 1992; Hatfield and Knee, 1988;
Saftner et al., 1998; Vincent, 1989; Volz etal., 2003, 2004).
Mealiness developed faster in fruit of ‘Delicious’ stored at high temperature (15 °C) thanat low temperature (0 °C) (Fisher, 1943). In a
European project on mealiness of fruit, apple
fruit were stored and examined under 20 °C
and high relative humidity (>90%) conditions
to create several levels of mealiness, by whichfruit were successfully classified into threegroups: nonmealy, midpoint and mealy (DeSmedt, 2000). Then, the objectives of this study
were to 1) measure the degrees of mealiness infruit of cultivars by shaking tissue discs in asolution and 2) reveal the relationship between
the degrees of mealiness and changes in fruit
firmness under high temperature (20 °C) storage conditions.
Materials and Methods
Fruit materials. Twenty-four apple cultivars
and selections (genotypes) from the orchard at
the Department of Apple Research, National
Institute of Fruit Tree Science (NIFTS) in Japan
were selected on the basis of the diversity of
the harvest date (Table 1). The genotypes wereused as parents in the NIFTS apple-breeding
programs. The genotypes consist of 15 cultivars
and selections that originated in Japan and nine
cultivars that originated in North America. Depending on the number of fruit on a tree, one
to three trees for each genotype were used, and25 to 40 fruit samples were randomly harvested
from the trees at three times weekly during thematurity period in 2004. The harvests were,
however, conducted at one time in nine cultivarsof the 24 genotypes because of experimental
circumstances. Fruit of similar size (within
15% of average fruit weight) was picked fromeach genotype.
Measurement of flesh firmness, air space,and mealiness. Flesh firmness was measured
using a penetrometer (FT327; McCormick Fruit
Technology, Wash.) mounted on a drill press
and fitted with an 11.1-mm probe on the paredsurfaces of the sunny and shady sides of eachfruit. The air space in the flesh tissue and mealiness were measured as described in Motomura
et al. (2000) with some modifications. In brief,
10 discs (10 mm in diameter, 5 mm thick) weretaken from just below the skin of the equatorial
region of each fruit with a cork borer and immediately weighed. The discs were infiltrated
in a 12% sucrose solution for 45 min under avacuum at 11 kPa generated by a water aspirator(A-3S; EYELA, Tokyo) and reweighed. The
volume of the air space was calculated by d =(Wi – Wo)/Va, where d = density of the solution,
Wo and Wi = weight of discs before and after
infiltration, respectively, and Va = volume of the
air space expressed as mL·g–1 (Yamaki and Ino,
1992). The discs were then transferred to a test
tube (diameter 30 mm) containing 10 mL of thesucrose solution and shaken for 8 h (20 °C, 180
rpm, 3-cm-wide shake; PLUS SHAKER EP-1,
TAITEC, Tokyo). The degree of mealiness wascalculated as (Wi – Ws)/Wi ×100 (%), where
Wi and Ws = weight of discs before and after
shaking, respectively.
Storage conditions. Three to five fruit fromeach harvested sample were used for the measurement at harvest and until 40 d after harvest
at 5 or 10 d intervals. The remaining pieces werestored in 25-L containers arranged on racks in achamber controlled at 20 ± 2 °C and 85% ± 5%
relative humidity (RH). Fruit with decay wereimmediately removed from the containers during storage, reducing overall fruit numbers andtherefore measurement could not be continued
until 40 d after harvest in some genotypes.
Results
Changes in firmness and degree of mealiness in the flesh during storage varied among
genotypes (Fig. 1). The changes showed thesame trend among fruit harvested three times
during the maturity periods. Harvest data fromeach genotype that are representative of thetrends are shown in Fig. 1. According to therelationship between change in firmness andmealiness, the genotypes can be divided into
four groups: fruit that softened with mealiness,
which occurred after 5 d of storage and continued
to develop throughout storage (Fig. 1A); fruitthat softened with slight mealiness, which occurred after 5 d of storage and did not develop
during storage (Fig. 1B); fruit that softened
without mealiness (Fig. 1C); and fruit that did
not soften and remained hard and nonmealy
during storage (Fig. 1D).
Firmness in most genotypes decreased
rapidly after harvest, and the rapid reduction
stopped within 20 d of storage (Fig. 1A–C).
Few changes in firmness were observed after
20 d of storage in the genotypes.
The volume of the air space increased intissue just below the skin of the fruit in all
genotypes during storage (Fig. 2). The increases
in the volume of the air space were very slow in
the genotypes in which the firmness of flesh did
not decrease significantly during storage (Fig.

Fig. 1. Changes in flesh firmness and degree of mealiness in 24 apple cultivars and selections during 20 ± 2 °C, 85% ± 5% RH storage. (A) Firmness decreased,
and mealiness developed during storage; (B) firmness decreased, and some mealiness occurred but did not continue to develop; (C) firmness decreased, andmealiness did not occur; (D) firmness did not change significantly, and mealiness did not occur. Vertical bars represent SE of three to five fruit replications.

2092

HORTSCIENCE VOL. 40(7) DECEMBER 2005

Fig. 2. Changes in volume of air space in flesh tissue in 24 apple cultivars and selections during 20 ± 2 °C, 85% ± 5% RH storage. (A) Firmness decreased, andmealiness developed during storage; (B) firmness decreased, and some mealiness occurred but did not continue to develop; (C) firmness decreased, andmealiness did not occur; (D) firmness did not change significantly, and mealiness did not occur. Vertical bars represent SE of three to five fruit replications.

2D). In the other genotypes, the increases wererelatively fast until 10 d of storage and gradually became slow (Fig. 2A–C). The volume of
the air space at 40 d of storage was around 0.4
mL·g–1 in almost all genotypes, including thosein which the fruit softened with mealiness (Fig.
2A) and those in which the fruit softened without
mealiness (Fig. 2C).
The minimum firmness of flesh during storage was significantly correlated with the degreeof mealiness at 30 d of storage (r2 = 0.561) (Fig.
3A). The correlation coefficient was calculatedusing data of the genotypes in which the fruit
softened during storage and including the dataobtained at three harvest dates. This result indicated that the larger the degree of mealiness,the larger the decrease in firmness.
Genotypic differences in softening can beevaluated by comparing the softening rate,
which is obtained by applying a linear regression, with a 20% reduction in firmness fromthe harvest date, as described by Iwanami
et al. (2004). In this study, we examined therelationship between the softening rate and theoccurrence or the degree of mealiness. The result
was that the softening rates varied almost from0 to 2 N·d–1 in genotypes in which the fruit did
not show mealiness (Fig. 3B). In genotypes inwhich the fruit softened with just slight mealiness, the softening rates varied almost from 1
to 3 N·d–1, and the average of the softening rates
was slightly higher than that of the softening
rates in the genotypes in which the fruit softened without mealiness. On the other hand, inthe genotypes in which the fruit softened withmealiness, the softening rates were around 2.8
N·d–1 and not very different from each other,although the degrees of mealiness at 30 d ofstorage in the genotypes differed widely from
10% to 60%. This indicated that the softening
rate of 2.8 N·d–1 was almost the upper limit under
the storage conditions used in this study.
Since the volume of the air space increased
HORTSCIENCE VOL. 40(7) DECEMBER 2005

during storage, we also applied the linear regression to the change in the volume of the air spacefrom the harvest date until the date that firmness
decreased by 20%; this was done in the same
way as for the calculation of the softening rate.
The regression coefficient can be defined as therate of increase in the air space (mL·g–1·d–1).
The softening rates were closely correlatedwith the rates of increase in the air space in the
genotypes in which mealiness did not occur orin which only slight mealiness occurred (Fig.
4). However, the rate of increase in the air spacevaried widely in the genotypes inwhich mealiness developed during storage, although the softening
rates of all of them reached theupper limit.
Discussion
Instrumental firmness (penetrometer measurement) is agood predictor of the texturalcharacteristics of crispness,hardness, and juiciness (Harker
et al., 2002; Konopacka et al.,2003). Thus, the puncture test
(penetrometer or firmness tester) is the most widely used test
in quality standards (Harker etal., 1997). Since mealiness isthe opposite of hardness andjuiciness, a low measurement ofFig. 3. Relationship between the
degree of mealiness at 30 d of storageand (A): minimum firmness during 40
d of storage, (B): the softening rateduring storage. All harvest samples
described in Table 1 are included, except for those in which fruit displayedrot during storage and left insufficientamounts to continue the experimentfor 30 d of storage. Each sample
was categorized by genotype anddivided into four groups, as shownin Fig. 1. The solid line represents theregression equation calculated using
all data except the data of hard andnonmealy fruit.

2093

Fig. 4. Relationship between the rate of increase of the air space in flesh tissue and the softening rate during storage. Data include all harvest samples described in Table 1. The letters on each symbol are an
abbreviation for the genotype and harvest time. Each fruit sample was categorized by genotype anddivided into four groups, as shown in Fig. 1. The solid line represents the regression equation calculatedusing all data except the data of fruit softening with mealiness.

firmness may reflect mealiness. However, tothe best of our knowledge, no study has ever
elucidated whether a measurement of firmness
can discriminate between genotype-dependent
mealy and nonmealy fruit and whether changes
in firmness can predict the onset of mealinessduring storage. So far, qualitative differencesin physiology or microstructure between mealy
and nonmealy fruit have been well documented(Harker and Hallett, 1992; Lapsley et al., 1992),
but quantitative differences or genotypic differences in the development of mealiness duringstorage have not been determined. Some studies
have measured tensile strength constantly duringstorage (Johnston et al., 2001, 2002; Tu et al.,2000). However, measurements of the tensile
strength indicate the combined forces that are
required to fracture, rupture, and separate cells(Harker et al., 1997), and these forces continuously change during storage. The ratio of thecells that fracture, rupture, and separate also
depends on the tissue conditions (Harker et al.,2002). Thus, it is not certain that a measurementof the tensile strength will show the onset of
mealiness.
The method used in our study can detect
only the contribution of cell separation to tissue failure and indicated that mealiness, which
is defined as a structure failure caused by cell
separation, occurred when firmness decreased
to 40 N or after 10 d of storage in the genotypes
in which the fruit softened with mealiness (Fig.
1A). These observations were consistent withthose made by Harker et al. (2002), which indi-2094

cated that cell-to-cell debonding was the primarymode of tissue failure in apples softer than 39
N and that there was an abrupt increase in thepercentage of apples determined to be mealy
when the puncture force was below 50 N.
Our study also revealed that minimum firmness during storage depended on the degree of
mealiness in fruit that softens after harvest (Fig.
3A). The result also showed that the minimum
firmness in nonmealy fruit was never below
30 N during storage at 20 °C. Therefore it isprobable that, when firmness is below 30 N
during storage at 20 °C, the texture of the fruit
will be mealy. In other words, occurrence of
mealiness could be detected by only firmness
measurement.
Mealiness does not appear for all fruit at
the same time and nondestructive techniques
for assessment of mealiness have been developed to classify fruit individually as suitable
or unsuitable for market according to their
mealiness rate (Arana, et al., 2004). Several
parameters that highly correlated with mealiness have been derived from nondestructive
techniques (Arana, et al., 2004; Barreiro, et al.,
1999; Mehinagic, et al., 2004). However, themeasurement of firmness, which is destructive,
could be still useful in breeding situations
because genotypes can be classified as mealy
ones or nonmealy ones by measuring firmness
at only one time at 30 or 40 d after harvest witha few fruit stored at 20 °C.
The softening rate was higher in fruit thatsoftened with mealiness than in the other fruit(Fig. 3B). The softening rates in fruit thatsoftened with mealiness,
however, did not correlate with the degrees
of mealiness and were
almost the same (around
2.8 N·d–1), although thedegrees of mealiness at
30 d of storage widely
varied from 10% to60%. This observationsuggests that the softening rate is determinedby the occurrence of
mealiness, which was
at least over 15% at 30 dof storage, rather than by
the degree of mealiness.
Therefore, comparing
the softening rate could
be useful for evaluating
genotypic differences instorage ability because
the mealy genotypes
were all judged to havethe highest softeningrate.
A decrease in fruit
firmness and a simultaneous increase in air
space were observed during storage in apple(Harker and Hallett, 1992; Mohr, 1979; Tu etal., 2000). On the other hand, ultrastructural
studies showed that cell separation resulting
from degradation of the cell wall and middle
lamella was taking place during storage (Glennand Poovaiah, 1990; Lapsley et al., 1992; Mohr,
1979). Therefore, the increase in the air spaceis likely related to the degradation of cell wallcomponents during storage (Harker and Hallett,1992; Mohr, 1979). Since mealiness is assumed
to result from cell separation after degradation of
the middle lamella, a large air space is suggested
to be symptomatic of mealiness (Harker and Hallett, 1992). However, in our studies, the volumesof the air space at 40 d of storage in the mealy
genotypes were not always larger than those in
the genotypes in which the fruit softened without
mealiness (Fig. 2A–C). Moreover, the rates ofincrease in the air space in fruit that softenedwith mealiness varied relatively widely and were
not always larger than those in fruit that softened
without or with just slight mealiness (Fig. 4).
These results indicated that the increase in the
air space in flesh tissue did not result from thedevelopment of cell separation. Tu et al. (2000)
reported that higher relative humidity (RH)
tended to promote the development of mealy
texture more than lower RH at 20 °C, while
lower RH tended to increase the internal air
space more than higher RH. Harker and Hallett(1992) also indicated that the development ininternal air space during storage was smaller inthe fruit that changed from nonmealy at harvest
to mealy after storage than in the fruit that did
not change to mealy. Our study showed that cell
separation was rare, even in mealy genotypes,
until 10 d of storage, although a fast increase in
the air space was observed until 10 d of storage.
Therefore, the rate of increase in the air space
HORTSCIENCE VOL. 40(7) DECEMBER 2005

appears to represent the degree of degradationof the cell wall rather than the cell separationinduced by the degradation of the middle
lamella. In fact, the rate of increase in the air
space was highly correlated with the softening
rate in fruit in which no cell separation or just aslight amount of cell separation occurred (Fig.
4). Since tissue failure is predominantly caused
by cell rupture in nonmealy fruit (Harker andHallett, 1992), the rate of increase in the air
space also seems to indicate the easiness withwhich cells rupture rather than the easiness withwhich cells separate. Therefore, the decreasein the firmness of mealy fruit in which thesoftening rate was at the upper limit in spite of
the low increase rate of the air space may beevidence of softening induced by cell separation. Moreover, cell separation may occur evenin fruit in which cell rupture occurred because
mealy fruit in some genotypes showed a highrate of increase in the air space.
In conclusion, flesh firmness never decreased below 30 N during storage at 20 °C
in fruit that softened without mealiness. On
the other hand, firmness decreased below 30
N in fruit that softened with mealiness. The
minimum firmness during storage in fruit thatsoftened with mealiness was correlated withthe degree of mealiness at 30 d of storage.
The softening rate was the highest (around
2.8 N·d–1) in fruit that softened with mealinessunder storage conditions of 20 ± 2 °C and 85%± 5% RH. These results suggest that the measurement of firmness and changes in firmness
under shelf life conditions could be useful todiscriminate genotypes that soften with mealiness from those that soften without mealiness.
Furthermore, a large air space in flesh tissue,
which has been suggested to be symptomaticof mealiness (Harker and Hallett, 1992), was
not always observed during storage in mealy
fruit. It is likely that changes in the air space
during storage are related to softening without
rather than with mealiness.
Literature Cited
Abbott, J.A., A.E. Watada, and D.R. Massie. 1984.
Sensory and instrument measurement of apple
texture. J. Amer. Soc. Hort. Sci. 109:221–228.
Allan-Wojtas, P., K.A. Sanford, K.B. McRae, and
S. Carbyn. 2003. An integrated microstructuraland sensory approach to describe apple texture.
J. Amer. Soc. Hort. Sci. 128:381–390.
Andani, Z., V. De Smedt, and B. Nicolai. 1999.
Development of mealiness in apples undershelf-life conditions. Food Sci. Technol. Today
13:203–204.
Andani, Z., S.R. Jaeger, I. Wakeling, and H.J.H.
Macfie. 2001. Mealiness in apples: Towards a

HORTSCIENCE VOL. 40(7) DECEMBER 2005

multilingual consumer vocabulary. J. Food Sci.
66:872–879.
Arana, I., C. Jaren, and S. Arazuri. 2004. Apple
mealiness detection by nondestructive mechanical impact. J. Food Eng. 62:399–408.
Barreiro, P., C. Ortiz, M. Ruiz-Altisent, V. De
Smedt, S. Schotte, Z. Andani, I. Wakeling, andP.K. Beyts. 1998. Comparison between sensory
and instrumental measurements for mealinessassessment in apples: A collaborative test. J.
Texture Studies 29:509–525.
Barreiro, P., J. Ruiz-Cabello, M.E. Fernandez-Valle,
C. Ortiz, and M. Ruiz-Altisent. 1999. Mealinessassessment in apples using MRI techniques.
Magnetic Resonance Imaging 17:275–281.
Daillant-Spinnler, B., H.J.H. MacFie, P.K. Beyts,
and D. Hedderley. 1996. Relationships between
perceived sensory properties and major preference directions of 12 varieties of apples fromsouthern hemisphere. Food Qual. Preference
7:113–126.
De Smedt, V. 2000. Measurement and modeling of
mealiness in apples. PhD diss. Catholic Univ.
Leuven.
Fisher, D.V. 1943. Mealiness and quality of Delicious apples as affected by growing conditions,maturity and storage techniques. Sci. Agr.
23:569–588.
Glenn, G.M. and B.W. Poovaiah. 1990. Caluciummediated postharvest changes in texuture andcell wall structure and composition in ‘Golden
Delicious’ apples. J. Amer. Soc. Hort. Sci.
115:962–968.
Harker, F.R. and I.B. Ferguson. 1988. Calcium ion
transport across discs of the cortical flesh of apple
fruit in relation to fruit development. Physiol.
Plant. 74:695–700.
Harker, F.R. and I.C. Hallett. 1992. Physiologicalchanges associated with development of mealiness of apple fruit during storage. HortScience
27:1291–1294.
Harker, F.R., R.J. Redgwell, I.C. Hallett, S.H. Murray., and G. Carter. 1997. Texture of fresh fruit.
Hort. Rev. 20:121–224.
Harker, F.R., J. Maindonald, S.H. Murray, F.A.
Gunson, I.C. Hallett, and S.B. Walker. 2002.
Sensory interpretation of instrumental measurements. I. texture of apple fruit. Postharvest Biol.
Technol. 24:225–239.
Hatfield, S.G.S. and M. Knee. 1988. Effects ofwater loss on apples in storage. Intl. J. Food Sci.
Technol. 23:575–583.
Iwanami, H., M. Ishiguro, N. Kotoda, S. Takahashi,
and J. Soejima. 2004. Evaluation of differencesin softening of apple genotypes by linear regression. HortScience 39:1185–1188.
Jaeger, S.R., Z. Andani, I.N. Wakeling, and H.J.H.
Macfie. 1998. Consumer preferences for freshand aged apples: A cross-cultural comparison.
Food Qual. Preference 9:355–366.
Johnston, J.W., E.W. Hewett, N.H. Banks, F.R.
Harker, and M.L.A.T.M. Hertog. 2001. Physicalchange in apple texture with fruit temperature:effects of cultivar and time in storage. Postharvest

Biol. Technol. 23:13–21.
Johnston, J.W., E.W. Hewett, M.L.A.T.M. Hertog,
and F.R. Harker. 2002. Temperature and ethylene
affect induction of rapid softening in ‘Granny
Smith’ and ‘Pacific Rose’ apple cultivars. Postharvest Biol. Technol. 25:257–264.
Konopacka, D., W.J. Plocharski, and J. Zwierz. 2003.
Perception of apple quality in relation to texture
attributes. Acta Hort. 604:443–448.
Lapsley, K.G., F.E. Escher, and E. Hoehn. 1992.
The cellular structure of selected apple varieties.
Food Structure 11:339–349.
The Ministry of Agriculture, Forestry and Fisheries
of Japan. 2005. Statistics. MAFF home page(in Japanese). 6 Feb. 2005 http://www.maff.
go.jp/www/info/index. html.
Mehinagic, E., G. Royer, R. Symoneaux, D. Bertrand,
and F. Jourjon. 2004. Prediction of the sensory
quality of apples by physical measurements.
Postharvest Biol. Technol. 34:257–269.
Mohr, W.P. 1979. Silver proteinate staining of
neutral polysaccharides in apple cell walls:
implications relative to fruit firmness. J. Food
Technol. 14:521–526.
Motomura, Y., J. Takahashi, and K. Nara. 2000.
Quantitative measurement of mealiness inapple flesh. Bul. Fac. Agr. Life Sci. Hirosaki
Univ. 3:23–28.
Nara, K., Y. Kato, and Y. Motomura. 2001. Involvement of terminal-arabinose and –galactose
pectic compounds in mealiness of apple fruit
during storage. Postharvest Biol. Technol.
22:141–150.
Saftner, R., W.S. Conway, and C.E. Sams. 1998.
Effect of postharvest calcium chloride treatments
on tissue water relations, cell wall calcium levels
and postharvest life of ‘Golden Delicious’ apples.
J. Amer. Soc. Hort. Sci. 123:893–897.
Shewfelt, R.L. 1999. What is quality? Postharvest
Biol. Technol. 15:197–200.
Stow, J. 1989. The involvement of calcium ions inmaintenance of apple fruit tissue structure. J.
Expt. Bot. 40:1053–1057.
Tu, K., B. Nicolai, and J. De Baerdemaeker. 2000.
Effects of relative humidity on apple quality
under simulated shelf temperature storage.
Scientia Hort. 85:217–229.
Vincent, J.F.V. 1989. Relationship between density
and stiffness of apple flesh. J. Sci. Food Agr.
47:443–462.
Volz, R.K., F.R. Harker, and S. Lang. 2003. Firmness
decline in ‘Gala’ apple during fruit development.
J. Amer. Soc. Hort. Sci. 128:797–802.
Volz, R.K., F.R. Harker, I.C. Hallet, and A.
Lang. 2004. Development of texture in apple
fruit—A biophysical perspective. Acta Hort.
636:473–479.
Watada, A.E., J.A. Abbott, and R.E. Hardenburg.
1980. Sensory characteristics of apple fruit. J.
Amer. Soc. Hort. Sci. 105:371–375.
Yamaki, S. and M. Ino. 1992. Alteration of cellularcompartmentation and membrane permeability
to sugars in immature and mature apple fruit. J.
Amer. Soc. Hort. Sci. 117:951–954.

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