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Mutation Research 523–524 (2003) 109–117
Review
Potential functional foods in the traditional Maori diet
Richard C. Cambie a , Lynnette R. Ferguson b,∗
a
b
Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand
Department of Nutrition, The University of Auckland, Private Bag 92019, Auckland, New Zealand
Received 8 January 2002; received in revised form 26 July 2002; accepted 23 August 2002
Abstract
The Maori people were early New Zealand settlers of Polynesian descent. The incidence of non-infectious diseases appears
to have been low in these people, perhaps in part due to the presence of protective chemical constituents within their food
plant supply. Three of the tropical crops they introduced are still eaten here today: the sweet potato or kumara (Ipomoea
batatas), the taro (Colocasia esculenta) and the cabbage tree or ti (Cordyline terminalis). Sporamins A and B, the major
storage proteins of kumara tubers, act as proteinase inhibitors, and may have other anti-cancer properties. The tubers also
contain the anti-coagulant coumarins, scopoletin, aesculetin, and umbelliferone. The corms of taro contain the anthocyanins,
cyanidin 3-glucoside, pelargonidin 3-glucoside and cyanidin 3-rhamnoside, reported to have antioxidant and anti-inflammatory
properties. Anthocyanins are also major components of a so-called “Maori potato”, a variety officially known as Ureniki,
which has a purple skin and flesh and was widely eaten in the early 1900s. Anthocyanins are also present in ripe berries
of the ramarama (Lophomyrtus bullata) and rohutu (Neomyrtus pedunculata). Both the leaves and seeds of the introduced
cabbage tree (Cordyline terminalis) and the native Cordyline spp., C. australis, C. indivisa, and C. pumilo, were eaten. The
seeds of C. australis, of some Astelia spp., and of hinau (Elaeocarpus dentatus) are good sources of various essential fatty
acids, generally regarded as protective against cardiovascular disease. Shoots and leaves from a wide range of native species
were traditionally eaten as greens, especially “sow thistle” or puha (Sonchus spp.), reportedly high in Vitamin C and various
phenolics. “New Zealand spinach” (Tetragonia tetragonioides or T. expansa) has anti-ulcerogenic activity that has been traced
to two cerebrosides and anti-inflammatory activity that has been traced to novel water-soluble polysaccharides, as well as
antioxidant phenylpropanoids including caffeic acid. Leaves of the “hen and chickens” fern (Asplenium bulbiferum) contain
antioxidant flavonoids such as kaempferol glucosides. Native seaweeds also have useful nutritive properties.
© 2003 Elsevier Science B.V. All rights reserved.
Keywords: New Zealand plants; Functional foods; Flavonoids; Polysaccharides; Antioxidants
1. Introduction
The first humans to settle in New Zealand were
Polynesians, later to be called Maori, who arrived
between 1000 and 2000 years ago. The exact date
is unknown but there is no hard evidence of settle∗ Corresponding author. Tel.: +64-9-373-7599x6372;
fax: +64-9-373-7502.
E-mail address: [email protected] (L.R. Ferguson).
ment before a.d. 800 and recently the period a.d.
1000–1200 has been suggested. Early Maori obtained
their food by hunting, fishing, shellfish gathering,
gardening, and gathering native and semi-cultivated
plants. However, in the temperate climate, gardening as practised elsewhere in Polynesia, was at best
marginal and at worst impossible. There is considerable evidence to suggest that even in regions most
amenable to horticulture, gardens contributed only
about 50% of the means of subsistence [1].
0027-5107/03/$ – see front matter © 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0027-5107(02)00344-5
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R.C. Cambie, L.R. Ferguson / Mutation Research 523–524 (2003) 109–117
Of the range of tropical crops that the Polynesian
settlers probably tried to introduce, only six species
survived until early European times, viz. the sweet
potato or kumara (Ipomoea batatas; Fig. 2A and B),
the taro (Colocasia esculenta; Fig. 2C and D), the
“bottle gourd” or hue (Lagenaria siceraria), the cabbage tree or ti (Cordyline terminalis; Fig. 2E), the
“paper mulberry” or aute (Broussonetia papyrifera),
and the yam or uhi (Dioscorea alata and D. esculenta). Captain Cook in his journey of exploration in
1769 identified all six, but the yam and paper mulberry
died out soon after [1]. The availability of food of
the prehistoric Maori has been summarized by Young
[2].
In this paper, our aim is to mention some of the
early food plants and where possible, attempt to identify chemical compounds within them that may have
contributed to their value as functional foods. The incidence of diabetes, cancer, and vascular-related diseases has been rising in Maori people over the last
30–40 years [3–6]. It may have been low in the early
Maori settlers, due in part to the presence of protective chemical constituents within the plants that were
eaten. Nevertheless, in prehistoric times the average
age of the Maori at death has been estimated to be
31–32 years [7]. It has been suggested [8] that the possible carcinogenic effects of eating the root of bracken
or aruhe (Pteridium esculentum) where the toxic principles have been identified as shikimic acid (1) and
the sesquiterpenoid ptaquiloside (2) [9], contributed
to this low age. However, the average age of death in
prehistoric times in Europe, Asia, and America was
also in the thirties [7,8], while cannibalism in New
Zealand was also a hazard to longevity.
2. Starch sources
Much has been written about the kumara which was
by far the most important vegetable and the achievement of the early Maori in adapting it to an annual
cycle in the temperate climate of New Zealand by storing the tubers in pits, is most impressive. Exactly how
the kumara, an American plant, reached New Zealand
or how its cultivation and storage in pits came about,
remains a subject of speculation [1]. The chemical literature on the constituents of the tubers is extensive
[10], and besides a series of stress metabolites (phy-
toalexins), produced as a result of infection, injury, or
fungicidal treatment, the major proteins which account
for more than 80% of the total protein are sporamins
A and B [11,12]. These are proteinase inhibitors and
may have some anti-cancer properties [11]. The tubers
also contain the coumarins scopoletin (3, R==H), aesculetin (3, R==OH), and umbelliferone (3, R==OMe),
(Fig. 1) compounds which have anti-coagulation properties and which are reputed to inhibit HIV replication
[13].
Taro roots are rich in starch (amylose, 28%, 4,
and amylopectin, 72%, 5) [14] and the corms contain
the anthocyanins, cyanidin 3-glucoside (6, R==OH),
pelargonidin 3-glucoside (6, R==H), and cyanidin
3-rhamnoside (7) [14]. In common with flavonoids,
the related anthocyanins are reputed to improve circulation by decreasing capillary fragility [15], to
improve eyesight, to act as potent antioxidants, to act
as anti-inflammatory agents, and to inhibit human
cancer cell growth [16–18]. The corms of taro also
contain calcium oxalate, an irritant, which prevents
them being eaten raw or incompletely cooked [19].
Little is recorded about the use of the gourd as a
food, its main use being the utilization of the shell
as a container [20], but the cabbage tree (Cordyline
terminalis) and the native Cordyline spp., C. australis
(Fig. 2F), C. indivisa, and C. pumilo, were exploited
for food. The inner blanched leaves and aerial stems
were the parts generally eaten, although the white
inner trunk and the fleshy taproot were also used [1].
The nutritive value of the edible portions have been
analysed by Fankhauser (Table 1) [21]. Hydrolysis
of the polysaccharides of the roots gives over 90%
of fructose, which is sweeter than any other common
sugar [8,22]. At its period of maximum polysaccharide production, C. australis contains more useable
carbohydrate on a fresh weight basis than either sugar
cane or sugar beet, and at one stage the cabbage tree
was proposed as a commercial source of fructose
[23].
With the arrival of the European, the potato
(Solanum tuberosum; Fig. 2G) became the major vegetable of cultivation. In the early 1900s, there was
interest in a so-called “Maori potato”, a variety officially known as Ureniki and which has small tubers
with a purple skin and flesh (Fig. 2H). The colour is
due to the presence of anthocyanins [24], the beneficial effects of which have been outlined above.
R.C. Cambie, L.R. Ferguson / Mutation Research 523–524 (2003) 109–117
111
Fig. 1. Structures of the chemicals identified in the text. Shikimic acid (1), ptaquiloside (2), scopoletin (3, R==H), aesculetin (3, R==OH),
umbelliferone (3, R==OMe), amylose (4), amylopectin (5), cyanidin 3-glucoside (6, R==OH), pelargonidin 3-glucoside (6, R==H), cyanidin
3-rhamnoside (7), ascorbic acid (8), cerebrosides (9, 10), caffeic acid (11), kaempferol glucosides (12), cinchophen (13), linoleic acid (14),
karakin (15), ␥-linolenic acid (16), pantothenic acid (17).
3. Green leafy vegetables
Andrew Crowe in his book “A Field Guide to the
Native Edible Plants of New Zealand” [25] maintains
that there are at least 190 edible native plants found
in New Zealand, and that the early Maori used most
of them. Shoots and leaves from a wide range of
species were used as greens and chief among them
was the “sow thistle” or puha (Sonchus asper). The
introduced S. oleraceus (Fig. 3A) is still used today.
The latter contains Vitamin C (ascorbic acid, 8) and
phenolics and was used by Cook as an antiscorbutic
[7]. Cook also collected boat-loads of “scurvy grass”
(Lepidium oleraceum; Fig. 3C) [26] which is related
botanically to water cress and which is a well-known
antiscorbutic due to its Vitamin C content. Cook also
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Fig. 2. (A) Flowers and leaves, (B) edible portion of the kumara (Ipomoea batatas), (C) edible portion, (D) vegetative parts of the taro
(Colocasia esculenta), (E) the introduced cabbage tree or ti (Cordyline terminalis), (F) the native cabbage tree (Cordyline australis), (G)
flowers and leaves of the potato (Solanum tuberosum), and (H) S. tuberosum variety Ureniki.
R.C. Cambie, L.R. Ferguson / Mutation Research 523–524 (2003) 109–117
113
Fig. 3. (I) puha (Sonchus oleraceus), (J) New Zealand spinach (Tetragonia tetragonioides), (K) scurvy grass (Lepidium oleraceum), (L)
hen and chickens fern (Asplenium bulbiferum), (M) berries from the karaka tree (Corynocarpus laevigatus), (N) (Elaeocarpus dentatus),
(O) Astelia trinerva, and (P) Porphyra columbina.
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Table 1
Food composition and nutritive value (%) of edible parts of Cordyline australis in relation to other starch sources commonly eaten in the
South Pacific
Food
Water
Ash
Fat
Carbohydrate
Fibre
Protein
kcal/100 g
kJ/100 g
Potato
Kumara
Taro
Yam
Wheat-cooked
Cordyline-root
Cordyline-stem
Cordyline-top
79.8
70.6
72.5
73.5
87.7
64.0
68.3
81.5
0.9
2.0
1.2
1.0
0.8
0.9
0.7
1.7
0.1
0.4
0.2
0.2
0.3
1.4
1.5
3.2
17.1
26.3
24.2
23.2
9.4
23.6
14.9
8.8
0.5
0.7
0.9
0.9
0.3
10.3
13.6
4.5
2.1
1.7
1.9
2.1
1.8
0.4
0.4
1.4
76
114
104
101
45
103
71
68
318
477
435
423
188
431
297
283
used the “New Zealand spinach” (Tetragonia tetragonioides or T. expansa; Fig. 3B), which has been shown
to be effective against ulcer formation by sedative
drugs [27]. It contains a number of compounds but the
anti-ulcerogenic activity has been traced to two cerebrosides (9, 10), which are glycolipids [27]. The leaves
also contain novel anti-inflammatory polysaccharides
[28], saponins and phenylpropanoids, e.g. caffeic acid
(11), which is an anti-hepatoxin [29].
Cook records [30] how he made a ‘Sour Kroutt’
from these plants and how he got his crew to eat it.
“The Sour Kroutt, the men at first would not eat it,
until I put it in practice—a method I never once knew
to fail with seamen—and this was to have some of it
dressed every day for the cabin table, and permitted all
the officers, without exception, to make use of it, and
left it to the option of the men either to take as much
as they pleased or none at all; but this practice was not
continued above a week before I found it necessary to
put every one on board on an allowance; for such are
the tempers and disposition of seamen. In general, that
whatever you give them out of the common way—
although it be ever so much for their good—it will not
go down, and you will hear nothing but murmurings
against the man who first invented it; but the moment
they see their superiors set a value upon it, it becomes
the finest stuff in the world and the inventor, an honest
fellow.”
The shoots and fiddleheads of the “hen and chickens
fern” (Asplenium bulbiferum; Fig. 3D) were also eaten
as a form of greens by the early Maori. The leaves
contain flavonoids such as kaempferol glucosides (12)
[31]. Several flavonoids show anti-inflammatory activity which is thought to be due to inhibition of some of
the enzyme systems involved in the inflammation pro-
cess. They also reduce the permeability and fragility
of capillary walls, cause dilation of coronary blood
vessels, have an anti-ulcer effect, have been used in
the treatment of diabetes-related cataracts of the eyes,
and exhibit both anti-viral and anti-cancer activity
[16,29].
The leaves of Cordyline terminalis, eaten as a leaf
vegetable commonly by the early Maori settlers, contain a compound closely related to cinchophen (13)
which has antipyretic and analgesic properties [10].
The leaves also contain saponins, glycosidic compounds, which generally have antibacterial activity
and various other beneficial properties [29].
4. Seeds and berries
The seeds of C. australis are one of the richest
sources of linoleic acid (14), an “essential” fatty acid
[32,33], the lack of which can give rise to skin complaints, and which is generally regarded to be a factor
in heart disease [34].
The berries of numerous trees were consumed by
the early Maori, but most have only a small amount
of flesh surrounding the kernel or seed and a number have an undesirable turpentine flavour [35]. One
exception is the berry from the karaka tree (Corynocarpus laevigatus; Fig. 3E) that, like the cabbage tree,
was semi-cultivated. The outer flesh of the ripe orange berries is tasty but the bulk of the value is in the
kernel, which is highly poisonous if eaten raw. The
toxic principles are karakin (15) and four other related
nitropropanoyl glucosides [36–38]. The kernels were
steamed in an earth oven (hangi), steeped in running
water, and then dried in the sun before use. This had
R.C. Cambie, L.R. Ferguson / Mutation Research 523–524 (2003) 109–117
the effect of hydrolyzing the glycoside, thereby providing a rich source of carbohydrate.
Ripe berries of the ramarama (Lophomyrtus bullata)
and rohutu (Neomyrtus pedunculata) each contain anthocyanins [39], which are dealt with above.
Colenso [40] rated hinau (Elaeocarpus dentatus;
Fig. 3F) berries as the third most valuable food of
the Maori. After separation of the stone, the flesh was
moulded into a cake and cooked in a hangi. The flesh
contains “essential” fatty acids [41] (see above).
The berries of Astelia spp., e.g. A. solandri and
A. trinerva (Fig. 3G), were eaten by the early Maori
but there is no evidence to suggest that they were
greatly valued. Up to 25% of the total seed oil is
␥-linolenic acid (GLA, 16) [42,43], which compares
favourably with ca. 9% in the seeds of the evening
primrose (Oenothera biennis), currently being actively
promoted as a potential medicament for a range of
medical conditions varying from pre-menstrual syndrome to multiple sclerosis [8]. GLA is an essential
fatty acid required by the body as a metabolic precursor of prostaglandins, compounds which have a variety
of beneficial functions. It is claimed that among other
things, small doses of ␥-linolenic acid can overcome
a deficiency caused by only using vegetable oils, can
alleviate diabetes, and can slow the process of ageing
[41,44].
The fatty acid profiles of the seeds and berries of a
number of New Zealand native plants, some of which
were eaten by the early Maori, is currently being examined in the Massey University Nutrition Laboratory, Institute of Food, Nutrition and Human Health.
Seeds of New Zealand flax (Phormium tenax), rengarenga (Arthropodium cirratum), miro (Prumnopitys
ferrugineus), and kohia (Tetrapthaea tetrandra) are reported to be good sources of linolenic acid while snowberry seeds (Gaultheria antipoda) are a rich source of
␣-linolenic acid [45].
5. Seaweeds
Seaweeds have received considerable attention in
the search for native foods with beneficial nutritive
properties. Their nutritional importance according to
Crowe [25] lies mainly in their mineral content, especially as a rich source of iodine; seaweeds contain
about 1000 times as much as any other food. Proteins
115
are usually about 10% of the dry weight although as
much as 28% is present in one species, viz. karengo
(Porphyra columbina; Fig. 3H) [25]. Seaweeds contain large amounts of carbohydrates, although only a
fraction of algal carbohydrate is digestable. They are
a good source of Vitamins A, B2 , B12 , and C, as well
as sodium, potassium, and magnesium. They also contain pantothenic acid (17), a member of the Vitamin B
complex, Vitamin D, and calcium. Early Maori made
extensive use of seaweeds as a food but only a few
species were eaten. Seaweed extracts such as agar, carrageen, furcellaran, and alginates are common ingredients of many foods [25]. The economic potential of
seaweeds as a source of functional foods is discussed
in “New Zealand’s Economic Native Plants” [8].
6. Conclusions
One fact that comes out of this survey is that few
native plants have been examined for their nutritive
value in any search for a useful food product. It is
of considerable interest that many of the plants described as having medicinal properties were also components of the normal Maori diet. There is current
concern about the rising incidence of degenerative
diseases such as diabetes and cardiovascular diseases
among Maori people. As indicated above, the prehistoric Maori was a hunter/gatherer. It is a widely held
view that hunters/gatherers with a stable diet have better health and a longer life span than agriculturists
[2,46]. Nevertheless, it is possible that with the rich
source of proteins, carbohydrates, fats, minerals and
vitamins from the New Zealand plants, the early Maori
possessed an adequate diet for survival.
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