Postharvest Biology and Technology of Fruits, Vegetables, and Flowers

POSTHARVEST TREATMENTS AFFECTING SENSORY QUALITY 303
management decision in crop production (Hampson and McKenzie, 2006). Cultivar and
planting site are two factors that often receive minimal attention, but can have a significant
impact on the quality and flavor of many fruits and vegetables (Barritt, 2001). Miller et al.
(2005a) reported that apple fruit quality and sensory variables measured were affected in
20 different cultivars. Similar findings have been reported in a study conducted in 13 apple
varieties (Young et al., 2004). Principal component analysis clustered the apples into three
groups according to skin color: red, green, and red green. Total ester contents were highest
with the red apples, and the green apples had the highest α-farnesene levels, thus affecting
the sensory attributes of the fruits (Young et al., 2004). Flavor was affected by the cultivar
× planting site interaction. Attractiveness and desirability were two other sensory attributes
that were affected by the apple cultivar × planting site interaction (Miller et al., 2005b).
The sensory evaluations of sweetness, taste, and aroma were well correlated with chemical
attributes of peach and nectarine quality in nine cultivars (Colaric et al., 2005). Cultivar
was more important than the harvest date in aroma volatile production by strawberries
(Pelayo-Zaldivar et al., 2005). Similar conclusions were reported for blackberries over three
growing seasons (Qian and Wang, 2005). Despite seasonal variations, cultivar variations
contributed more to the total amount of volatiles and therefore to the sensory attributes.
Three tomato cultivars differed in their contents of aroma flavor compounds and their
intensity of sensory attributes. Changes in most of the flavor compounds after harvest
phase were similar, despite the different levels of the aroma compounds in the different
cultivars at harvest. In all three cultivars, the intensity of the attribute “tomatolike” (odor,
flavor, and aftertaste) increased, but so did the intensity of the undesired attribute “moldy”
(odor, flavor, and aftertaste). Changes of flavor components and related sensory attributes
appeared to lead to an altered balance of potentially desirable and undesirable properties
when tomatoes were stored ripe (Krumbein et al., 2004). In a different study conducted
on different tomato cultivars, significant differences among very closely related tomato
cultivars could be detected for volatile aromas and sensory testes (Ruiz et al., 2005). The
texture and the sensory quality and acceptability of melon cultivars seem to be linked with
the genotype, which can be differentiated on the basis of retronasal odor (Hoberg et al.,
2003).
The effects of preharvest treatments on apple quality and sensory were studied over three
seasons using “Delicious” apple trees. The bioregulators aminoethoxyvinylglycine (AVG)
and ethephon (ETH) were applied alone or in combinations at various time intervals before
harvest. Fruit response to bioregulators was evaluated at harvest and after storage. AVG
in all instances reduced the sensory scores for apples and apple juice. Sensory values for
whole apples were not influenced by ETH treatment, but ETH improved sensory preference
for apple taste, particularly at early harvest. Applying AVG before ETH enhanced soluble
solids and sensory scores for the fruit. Fruits treated with AVG followed by ETH had better
quality and sensory perceptions (Drake et al., 2005).
14.3 Harvest and stage of maturity
Stage of maturity at harvest is a very important factor in determining the quality of the fresh
harvested commodities. Immature fruits are more subject to shriveling, internal breakdown,
mechanical damage, and inferior quality when they finally ripen after harvest. Overmature
fruits are likely to become soft and mealy, and attain insipid flavor soon after harvest.