Grapefruit - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 357

Table 19.4. Nutrients in grapefruit.

% DV 1 Nutrient Amount/100g Nutrient Density World Healthiest Food Rating

Vitamin C 46.86 mg 78.1 38.1 Excellent

Dietary fiber 1.69 g 6.8 3.3 Good

Vitamin A 318.57 IU 6.4 3.1 Good

Potassuim 158.67 mg 4.5 2.2 Good

Folate 15.01 m μ g 3.8 1.8 Good

Vitamin B-5 (pantothenic acid) 0.35 mg 3.5 1.7 Good

1 Daily recommended value.
Source: GMF (2010).

percentage daily value (DV) calculated for 25-50 year old
healthy women and the nutrient density rating (GMF, 2010).
Some other values from literature for grapefruit in mg per
100 gm are as follows: vitamin C, 40; vitamin A, trace;
vitamin B, thiamine, 0.04; riboflavin, 0.02; niacin, 0.2; cal-
cium, 22; and iron, 0.2 (Hubpages, 2010).
Lu et al. (2006) compared their flavonoids result with
published data from the United States (114 citrus cultivars
grown in California), Japan (66 citrus species and near-
relatives), and Spain (6 citrus species) and observed that
grapefruit is an unchallenged naringin source for cultivars
grown in the United States ('Star Ruby,' 1.13% in albedo),
Japan (march grapefruit, 1.46% in edible parts), and Spain
(37.8% in whole immature fruit). They confirmed high lev-
els of naringin (3.25%) and neohesperidin (2.76%) in the
peel of huyou ( C. paradise cv. 'Changshanhuyou'), a rel-
ative to grapefruit, making them the best source of these
flavonoids.

and storage on the stability of organic acids and the func-
tional value of grapefruit juice (Igual et al., 2010b); com-
mon flavonoids in different brands of grapefruit juice (Ross
et al., 2000); influence of pre- and postharvest factors and
processing on the levels of furocoumarins in grapefruits
(Girennavar et al., 2008); postharvest quality of Florida
grapefruit after gamma irradiation (Miller and McDonald,
1996); and naringin and naringenin determination and
control in grapefruit juice by a validated HPLC method
(Ribeiro and Ribeiro, 2008).
Nonconventional or “nonthermal” processing methods
such as irradiation, high HP, ultrasound, and filtration
are attractive to the food industry because more fresh-
like, flavorful, colorful, and nutrient-rich preserved foods
(Gonzalez and Barrett, 2010) are obtained. It is believed
that many of the components responsible for the sensory
and nutritional quality of foods, such as flavor components
and vitamins, are relatively intact under HP processing con-
dition. However, some effects of HP on plant tissues include
changes in protein, polysaccharides, and lipids (Cano and
de Ancos, 2005) and pectic substance degradation.

Effect of processing on nutrients
Table 19.5 shows the nutrient composition of raw grapefruit
and its processed products. The values shown here are for
the fruit grown and processed in the United States; therefore
some differences can be anticipated in composition of raw
grapefruit and grapefruit products in other parts of the world
owing to different climatic and soil conditions, agricultural
practices, postharvest handling and processing techniques,
and so on. Additionally, varietal differences can also con-
tribute to variations in the composition of raw and finished
products.
The nutritional quality of grapefruit has been studied
by various authors: the influence of different postharvest
treatments on nutritional quality (Biolatto et al., 2005); ef-
fects of various heat treatments on the induction of cold
tolerance and on the postharvest qualities of 'Star Ruby'
grapefruit (Porat et al., 2000); effect of thermal treatment

Health-beneficial compounds
Grapefruit is rich in compounds that have noticeable health
benefits in both young and old. Some of these health-
beneficial compounds in grapefruit are lycopene, vitamin
C, limonoids, pectin, and naringenin.

Vitamin C
Grapefruit is a good source of vitamin C, which is known
for supporting the human immune system. It is also known
for its ability to reduce cold symptoms and reduction of
severity of inflammatory conditions in asthma, osteoarthri-
tis, and rheumatoid arthritis. It is very helpful in removing
or dissolving inorganic calcium, which may have formed
in the cartilage of the joints, as in arthritis, as a result of an