AVOCADO - Tropical Fruits - page 183

relative humidity is occasionally used to delay softening and reduce respiration
and ethylene production.
Fruit can be ripened at 25°C or by exposure to 10-100 ppm ethylene at
17-20°C for 12-72 h, depending upon fruit maturity, and then transported
to markets. Following ethylene treatment fruit will ripen in 3-6 days. The
ethylene-treated fruits are marketed locally, as the current market strategy is
to provide ripe fruit for immediate consumption.
UTILIZATION
The avocado is considered a nutrient-dense food (Rainey et al. , 1994). It has
the highest fi bre content of any fruit and is a source of food antioxidants
(Bergh, 1990a). Avocado has a high oil content, although Florida cultivars are
lower in oil content compared with cultivars from California. Major fatty acids
are the mono-unsaturated oleic acid, followed by palmitic and linoleic acids.
Palmitoleic acid is found to approximate percentages of linoleic acid, and
values are slightly higher or lower depending upon the cultivar analysed. The
nutrient values of the dif erent ecological races also vary, but, in general, it is
a fair to good source of P, provitamin A, ribofl avin and niacin (Table 7.7). The
protein content of 1-2% is considered to be greater than in any other fresh
fruit (Bergh, 1990b). Avocado also increases the diet's content of antioxidants,
foliates, K and fi bre (Rainey et al. , 1994).
Avocado is mainly used fresh in salads, its high fat content combining well
with acid fruit and vegetables, such as pineapple, citrus and tomatoes, or with
acid dressings. A major commercial avocado product is guacamole, used as a
favourite dip with potato chips, tortilla chips and similar products. Avocado
may be used to supply the fat content of frozen desserts, such as ice cream
and sorbets. Miller et al. (1965) provide numerous recipes for various types of
salads, cocktails and desserts. In some places, avocado is eaten as a dessert,
adding sugar to it instead of salt. Shakes and ice creams are also made of the
pulp. Recently there is a growing industry of producing avocado oil, which is a
very healthy product, using subtropical varieties.
Deterioration of fl avour and enzymatic discoloration are serious problems
in the commercial processing of avocado (Ahmed and Barmore, 1980).
Avocado is not conducive to heat processing as it results in an of -fl avour.
High polyphenoloxidase and total phenol contents contribute to the processed
product's browning potential, with dif erences in browning potential occurring
among cultivars. Enzymatic browning of avocado products can be minimized
by processing a cultivar with low polyphenolase activity into an acidifi ed
product containing an antioxidant (e.g. ascorbic acid), packing under N or a
vacuum and storing at low temperatures.