Antioxidants and Bioactive Compounds in Fruits - Fruit Ripening: Physiology, Signalling and Genomics - page 101

Terry, 2011). This chapter provides an
initial overview of the principal anti-
oxidants and bioactive compounds found
in ripening fruit, as well as the methods
employed for determination. A thorough
description of the diversity of phyto-
chemical compounds found in fruits and
factors affecting their content is provided.
Lastly, recent advances in the develop-
mental regulation of bioactive compound
accumulation are discussed.

fruits, but some are distributed only among
specifi c species. In addition, they are
considered non-nutrient constituents with
signifi cant biological activity, with each
fruit crop having a distinct profi le
(Schreiner and Huyskens-Keil, 2006). Fruit
phytochemicals have variable chemical
structures and functions and are cate-
gorized into phenolic compounds, caroten-
oids and vitamins (C and E). An overview
of the principal phytochemical compounds
is provided in Fig. 7.1. Details about the
structure of the antioxidant compounds are
specifi ed in a recent review by Vicente et
al. (2009).

7.2 The Main Antioxidants and Bioactive
Compounds in Ripening Fruits

Typical nutritional components of fl eshy
fruits are water, organic acids, proteins,
lipids and fatty acids, metabolizable
carbohydrates and dietary fi bre (reviewed
by Vicente et al. , 2009). Apart from the so-
called 'traditional' components, fruits are
rich sources of phytochemical compounds,
also referred to as bioactive compounds.
Antioxidant (polyphenols and carotenoids)
and non-antioxidant (phytosterols) bio-
active compounds are strongly linked to
high consumption of fruit having a
signifi cant health-promoting role (Saura-
Calixto and Goni, 2009). Many phyto-
chemicals are present in a wide range of

7.2.1 Phenolic compounds or polyphenols

This group encompasses a wide diversity
of compounds derived from the aromatic
amino acids phenylalanine and tyrosine,
having variable degrees of hydroxylation,
methoxylation and glycosidation. They
usually act as sunscreens, deterrents of
potential predators and antimicrobials, and
also contribute to fruit pigmentation,
astringency and the bitter taste of some
products (Mattila et al. , 2006). In general,
phenolic compounds accumulate more in
the peel than in the pulp of the fruits.

Phenolic
compounds

Carotenoids Vitamin E

• Phenolic acids

• Flavonoids
• Lignans, tannins,
coumarins

• Carotenes

• Oxygenated
derivatives

• Tocopherols

• Tocotrienols

Vitamin C Other compounds

• Ascorbic acid

• Dehydroascorbic
acid

• Terpenes

• ω -3 PUFA
•

Glucosinolates and
organosulfur
compounds

Fig. 7.1. The main antioxidants in ripening fruits. PUFA, polyunsaturated fatty acids.