Postharvest Biology and Technology of Fruits, Vegetables, and Flowers

312 POSTHARVEST BIOLOGY & TECHNOLOGY OF FRUITS, VEGETABLES, & FLOWERS
14.6 Future aspects and conclusions
While it is relatively straightforward to assess the economic benefits associated with reducing
storage costs, and eliminating disorders that develop during storage of products, it is
more difficult to assess the benefits associated by improving overall quality. Sensory quality
is usually defined as all those characteristics of a food that lead a consumer to be satisfied
with the product (Harker et al., 2003). However, it was concluded that taste, aroma, and
freshness were most frequently chosen as decisive attributes for selecting fresh produce by
consumers (Peneau et al., 2006), although quality may also be used to describe subjective
attributes such as crispness, juiciness, flavor, or attractiveness (Barritt, 2001). Yet, problem
exists in most agricultural crops, and has resulted in often legitimate consumer complaints
concerning the lack of sensory quality (mainly aroma) in agricultural produce.
Fresh produce sensory quality is the sum of the interaction between sugars, acids, and
a set of volatile compounds synthesized from a diverse set of precursors, including amino
acids, lipids, and carotenoids. Some of these volatiles impart desirable qualities, while
others are negatively perceived. Based on the data above, preharvest and postharvest factors
were found to determine the overall external and internal quality if the fresh harvested
and fresh-cut product. Moreover, sensory quality is also based on the manner in which the
product is typically consumed and the means by which of the aroma compounds with the
aromatic character impact are generated (Beaudry, 2000). However, it is impossible to point
out which practices contribute more to the overall quality (Forney et al., 2000). Cultivar
and site are two factors that affect fruit sensory quality where a grower’s opportunity to
influence that quality may be limited. A single decision made before the orchard is even
planted regarding site and cultivar may have a profound affect on fruit quality throughout
the life of the planting. This could be solved, in part, by getting the best possible cultivar
using a breeding program. Crop breeding is used to improve plant variety and productivity
in intensive agriculture.
Traditionally, most of the effort in breeding plants has been directed toward the inclusion
of desirable agronomical traits, such as high yields, ease of mechanization, perfect visual
appeal, plant resistance to pests and pathogens, enhanced shelf life, and other commercially
important characteristics. It is unfortunate that with the development of these excellent
crop varieties, traits that affect the aroma and flavor of fruit and vegetables have often
been lost. Carbonell-Barrachina et al. (2006) suggested a different tool for breeding better
fresh produce. A system specifically designed for the nondestructive analysis of volatile
organic compounds in fresh tomatoes, based on a dynamic headspace technique, was used
to quantify the volatile aroma constituents of the fruits. This system reduced the high
variability associated to sample selection in postharvest studies. Volatile compounds with
a major contribution to aroma are quantitatively determined in traditional cultivars and
one commercial F1 hybrid, thus allowing the use of volatile determination as a possible
tool in fresh fruit and vegetable breeding programs. Moreover, metabolic engineering can
provide assistance in conventional breeding programs (marker-assisted breeding), or by
the implementation of genetic engineering. Although the specific major flavor and aroma
compounds have been identified in many fruits, the genes and enzymes involved are not
yet fully understood. Thus, to implement the novel biotechnological advances in restoring
the “lost” aromas of fruits, it is imperative to identify the genes that affect flavor and aroma
production, and to understand their regulation and limitations. As a first step to identify the