quality out of store begins with fruit development is necessary. This ap-
preciation is consistent with the theme of this book.
It is well documented that the stage of maturity at harvest has a crit-
ical effect on storage life and quality. This is not surprising since the
rapid rise in ethylene production associated with the climacteric is con-
sidered to trigger softening in apple. In other fruits, such as tomatoes
and avocados, enzymes involved in ripening are induced at the onset of
the climacteric (Christoffersen et al., 1982; Grierson et al., 1985). Con-
siderable research has been undertaken to relate quality characteristics
of fruit after storage to direct indicators of maturity (e.g., proximity to
the climacteric and associated rise in ethylene production). Establishing
relationships between quality attributes of fruit after storage and “ma-
turity” indicators at harvest provides an opportunity to create harvest
maturity standards as a means of providing more consistent quality. For
example, Knee and Farman (1989) developed regression equations to
predict firmness of Cox apples after CA storage on the basis of harvest
firmness and ethylene concentration in the fruit. One of the complica-
tions in the development of picking date criteria is that the various qual-
ity attributes of stored fruit have different optima. Early harvested fruit
will tend to be firmer, more acid, less sweet and less aromatic than fruit
that are harvested later. The data in Table 4.3 show the effect of harvest
date on the average quality of Cox from 30 orchards stored under the
same CA conditions. Although fruit from the first harvest were high in
firmness, the sensory scores were low, particularly for aroma. It is dif-
ficult to establish a harvest date that is optimal in all respects. In this
situation, there has to be a decision on the priority of the various qual-
ity attributes and a compromise must be made to achieve the best all-
round quality.
To achieve consistent quality in fruit from store, it is not sufficient to
consider harvest maturity/quality criteria. For some quality attributes
such as firmness, much of the variation ex-store can be accounted for
by measurements carried out at harvest (Knee and Farman, 1989; Silsby,
1993). However, for some other quality attributes and for certain phys-
iological disorders that develop during storage, it is necessary to con-
sider the chemical composition of the fruit during development. Many
authors have reported the importance of mineral nutrition on the sus-
ceptibility of apples to storage disorders (Sharples, 1980; Bramlage et
al., 1980). Possibly the most researched disorder is bitter pit, which re-
lates predominantly to the inadequate supply of calcium to the devel-
oping fruit (Perring, 1986). Data are available that link the susceptibility
An Approach to Achieving Consistent Quality from Store 77