Agriculture Reference
In-Depth Information
is used on other countries: (1) U.S. Mature (minimum
maturity), (2) Well-Mature and (3) Tree Ripe. Measurement
of fruit firmness is recommended in cultivars where skin
ground colour is masked by full red colour development,
especially nectarines, before maturation. In these cases, a
maximum maturity index can be applied. Maximum matu-
rity is defined as the minimum flesh firmness (measured
with a penetrometre with an 8 mm tip) at which fruit can be
handled without bruising damage. Bruising susceptibility
varies widely among cultivars. The optimum maturity for
stone fruit harvest must be defined for each cultivar. The
highest maturity at which a cultivar can be successfully
harvested is influenced by post-harvest handling and
temperature management procedures. Maturity selection is
more critical for distant markets than for local markets,
but does not necessarily mean lower maturity. Because of
the availability of new cultivars that adapt well to harvesting
more mature (softer), the increase in popularity of high-
quality, less firm fruit (more mature) and the use of more
sophisticated packinghouse equipment, a large proportion
of stone fruits are being picked at a more advanced matu-
rity stage.
lack of flavours has been associated with early-season fruit
or mid-late CI damaged fruit. These early cultivars have
low flavour quality potential and generally are consumed
mature and 'not ripe'. However, lately a group of new cul-
tivars that ripen early in our season (late April-mid-June) is
becoming available. The ones that have been tested had
high SSC, moderate to low acidity levels, were aromatic
and had a high consumer acceptance when consumed at the
'ready to eat' stage. As production of new cultivars with
diverse flesh colours, flavours, soluble solids concentra-
tions (SSC), and titratable acidities (TA) is increasing in
California and the rest of the world, we tested the concept
of cultivar segregation according to the sensory perception
of organoleptic characteristics. We were able to consist-
ently segregate peach and nectarine cultivars into groups
(balanced, tart, sweet, peach or nectarine aroma and/or
peach or nectarine flavour) with similar sensory attributes.
Based on this information, we suggest that cultivars should
be clustered in organoleptic groups and development of a
minimum quality index should be attempted within each
organoleptic group rather than proposing a generic mini-
mum quality index based on ripe SSC. This organoleptic
cultivar classification may help to match consumer or eth-
nic preferences and enhance the current promotion and
marketing programs.
Quality characteristics and criteria
In California the minimum ripe soluble solids concentration
(RSSC) needed to reach high consumer acceptance for
peach and nectarine was determined by using 'in-store'
consumer tests of low and high ripe titratable acidity (RTA)
melting flesh cultivars as a part of our program to develop
minimum quality indexes (Crisosto and Crisosto, 2005).
There is high consumer acceptance of peaches with high
soluble solids content (SSC). Titratable acidity (TA) and
SSC:TA are currently used as an important predictor of
consumer acceptance but it is accepted that volatile, fla-
vour and texture are also important components of flavour.
For these moderate/low-acid and high-acid cultivars, con-
sumer acceptance was closely related to RSSC, but maxi-
mum consumer acceptance was attained at different RSCC
levels depending on the cultivar. The fact that these culti-
vars reached high consumer acceptance with different
RSSC levels indicates that a single generic RSSC quality
index would not be reliable to assure consumer satisfaction
across all cultivars. For most of the midseason peaches, a
minimum of 11% SSC with a TA ≤ 0.7% is required to sat-
isfy about 80% of consumers. Our 'in-store' consumer
tests indicated that high consumer acceptance is attained
with mid- and late-season cultivars when peaches are free
of chilling injury and 'ready to eat' prior to consumption.
Within these cultivars, a large population of the fruit will
be highly accepted by the consumers. Traditionally, the
Harvesting and packaging handling
Fruit are hand-picked using bags, plastic baskets or totes.
Fruit are dumped in bins that are on the top of trailers
between rows in the orchard. If fruit are picked into totes,
the totes are usually placed directly inside the bins. Baskets
are placed on racks within modified trailers. Fruit picked at
advanced maturity stages and white flesh peaches or nec-
tarines are most commonly picked and placed into baskets
or totes. Fruit can be hauled for short distances by these
trailers, but they are designed principally for transport
within orchards. If the transport distance is longer than
5-10 km, bins are loaded on a truck or semi-truck and
trailer for transportation to packinghouses. Harvest crews
usually consist of 15 to 25 labourers including a foreman,
who is responsible for ensuring uniformity of harvest,
adherence to maturity and fruit size criteria and general
supervision. Depending on the cultivar and orchard, a
labourer can usually harvest 1½ to 3 bins (400-450 kg per bin)
of fruit per day. Early-season cultivars are usually picked
every 2-3 days, and by mid- to late season the interval can
stretch to as much as 7 days between harvests. Tree heights
are commonly 3.7-4.7 m, and workers require ladders to
reach the uppermost fruits. Ladders are made of aluminium
and are 3.7-4.0 m in length. Either four or six rows
