Pitaya fruit processing as Economic Opportunity

Pitaya Fruit Processing As Economic Opportunity
For Central-American Farmers and Industry
RALF M. SCHWEIGGERT1, GABRIELA VILLALOBOS2, CAROLINA RAMÍREZ2, PATRICIA ESQUIVEL2,
REINHOLD CARLE1
1
Institute of Food Science and Biotechnology, Hohenheim University, D-70599 Stuttgart, Germany
2
School of Food Technology, University of Costa Rica, 10101 San José, Costa Rica
Introduction
Originating in Central America, red-purple pitaya (Hylocereus sp.) is commercially grown
from northern Costa Rica to Nicaragua (LeBellec et al., 2006), where approximately 3000
tons of pitaya (Hylocereus sp.) are annually produced on 420 ha (Vaillant et al., 2005).
The red-skinned and red-fleshed genotypes are commonly consumed as fresh fruit or juice.
Belonging to the Cactaceae family with their typical crassulacean acid metabolism, pitaya
cultivation is feasible in dry areas including high atmospheric sulphur concentrations. Hence,
the crop is grown mostly on the volcanic hillsides of Nicaragua and Costa Rica, areas having
very high poverty indices. Offering a developmental perspective for agriculture and
processing industry, this crop has high social importance in these regions (Vaillant et al.,
2005).
Since the plant consists of ribbed stems which climb on any natural or artificial support
(figure 1 A-C), cultivation is mostly carried out best with dead or living supports (LeBellec et
al., 2006). The fruit genotypes are distinguished by scales, shape, size and colour (Esquivel et
al., 2007). Figure 2 shows a typical fruit of the common Hylocereus polyrhizus genotype
„Rosa“. The intensive colour of pitaya is caused by betalains, water-soluble nitrogencontaining pigments, divided in two mayor structural groups which comprised red-purple
betacyanins and yellow betaxanthins (Wybraniec & Mizrahi, 2002).
As customers worldwide continuously demand more natural products, the development of
new plant-derived colorants like betalain containing foodstuff has been forced (Wissgott &
Bortlik, 1996), especially since several synthetic azo-dyes have been recently associated with
hyperactivity in preschool children (McCann et al., 2007). Annual growth rates of 10-15% on
European markets for colouring fruit and vegetable extracts are therefore not unexpected
besides their promising health benefits accompanying their colouring potential (Pszczola,
2003, Stintzing & Carle, 2004).
Betalain containing foodstuff is quite suitable for colouring low acid food like dairy products
or beverages, as anthocyanin extracts loose their tinctorial strength and colour shade at pH 3
to 7 (Stinzting & Carle, 2004). The most common betalain source is red beet (Beta vulgaris L.
ssp. vulgaris) despite its high nitrate levels (Santamaria, 2006) and its earthy smell caused by
geosmin and pyrazine derivatives (Lu et al., 2003, Acree et al., 1976). Searching for new
betalain-containing plants being devoid of those disadvantages, several studies described the
processing of cactus pears (Opuntia sp.) and purple pitaya (Hylocereus sp.) into fruit juices
and related products (Herbach et al., 2007, Mosshammer, Stintzing & Carle, 2005,
Mosshammer, Stintzing & Carle, 2006, Essa et al., 2002, Sáenz et al., 1993).
Nevertheless, particularly pitaya processing remained difficult due to its high content of
mucilaginous material, resulting in low yields during juice or pulp extraction (Esquivel et al.,
2007, Stintzing & Carle, 2007)). Therefore, pitaya juice concentration and spray drying has
not been described. Moreover, stability studies of those products, the application on food
systems and the processing of possible by-products like seeds and peels has not been assessed
so far. Therefore, the know-how for efficient processing of whole pitaya fruits and the
application of there from derived colouring foodstuff should be established in this study in
cooperation with the University of Costa Rica.
Results / Expected Results
After characterizing pitaya genotypes found in Central America, several studies were
conducted with special reference to technological purposes like juice production,
concentration or spray drying. An enzyme screening was carried out in order to degrade
pitaya mucilage more efficiently. Finally, a new enzyme-assisted liquefaction process was
developed enabling a high-yield pitaya juice production. Furthermore, feasibility of juice
concentration was already shown and fruit powder production will be assessed in a current
study. Moreover, the use of seeds and peels as by-products will be evaluated. Pitaya peel
mucilage was characterized and a process for the effective separation from the peels and
subsequent purification will be developed. Pitaya hydrocolloids could be used in food,
cosmetic and pharmaceutical industry as water-binding agents. Chemical characterization of
pitaya seeds and technological extraction of the seeds’ oil will be carried out in upcoming
studies since this oil could be interesting for health beneficial or advertising purposes in
cosmetic and food industry. Figure 3 shows the proposed scheme for whole pitaya fruit
processing.
Since first results in pitaya mucilage degradation and juice concentration were successful, the
project will provide sufficient knowledge for the establishment of a local pitaya processing
industry. The production of high quality betalain containing colouring foodstuff from pitaya
must be carried out locally in Central America as the fruit is highly perishable and, moreover,
mucilage contents are lower and pigment contents are higher in fully ripe fruits. Especially
Nicaraguan and Costa Rican farmers will benefit directly from selling their fruits not only to
local markets but also to industrial processors. Subsequently, new jobs will be created in
processing facilities and a French enterprise was already found to be interested. As mentioned
above, natural colorants will be demanded more and more on future markets, whereby
colouring foodstuff from pitaya will be a real alternative to red beet, which carries negative
connotations due to its high nitrate and geosmin levels. Processing the by-products like seeds
and peels will not only enhance the profitability, but also provide new products for food,
cosmetic and pharmaceutical industry. Summarized, both industrial and developing countries
will considerably profit by effective pitaya processing.
Literature:
Acree, T.E., Lee, C.Y., Butts, R.M., Barnard, J. (1976) Geosmin, the earthy component of table beet odour.
Journal of Agricultural and Food Chemistry, 24, 430-431.
Esquivel, P., Stintzing, F.C., Carle, R. (2007) Comparison of morphological and chemical fruit traits from
different Pitaya genotypes (Hylocereus sp.) grown in Costa Rica. Journal of Applied Botany and Food
Quality, 81, 7-14.
Essa, H.A., Salama, M.F. (2002) Effect of macerate enzymes on the yield, quality, volatile compounds and
rheological property of prickly pear juice. Nahrung/Food, 46, 245-250.
Herbach, K. M., Maier, C., Stintzing, F.C., Carle, R. (2007) Effects of processing and storage on juice color and
betacyanin stability of purple pitaya (Hylocereus polyrhizus) juice. European Food Research and Technology,
224, 649-658.
LeBellec, F., Vaillant, F., Imbert, E. (2006) Pitahaya (Hylocereus sp.): a new fruit crop, a market with a future.
Fruits 61 237-250.
Lu, G., Edwards, G., Fellmann, J.K., Mattinson, D.S., Navazio, J. (2003) Biosynthetic origin of geosmin in red
beets (Beta vulgaris L.). Journal of Agricultural and Food Chemistry, 51, 1026-1027.
McCann, D., Barrett, A., Cooper, A., Crumpler, D., Dalen, L., Grimshaw, K., Kitchin, E., Lok, K., Porteous, L.,
Prince, E., Sonuga-Barke, E., Warner, J. O., Stevenson, J. (2007) Food additives and hyperactive behaviour
in 3-year-old and 8/9-year-old children in the community: a randomized, double-blinded, placebo-controlled
trial. The Lancet, 370, 1560-1567.
Mosshammer, M., Stintzing, F.C., Carle, R. (2005) Development of a process for the production of a betalainbased coloring foodstuff from cactus pear. Innovative Food Science and Emerging Technologies, 6, 221-231.
Mosshammer, M., Stintzing, F.C., Carle, R. (2006) Evaluation of different methods for the production of juice
concentrates and fruit powders from cactus pear. Innovative Food Science and Emerging Technologies, 7, 275287.
Pszczola, D.E. (2003) Getting more fruits and vegetables into food. Food Technology, 57, 52-63.
Santamaria, P. (2006) Nitrate in vegetables: toxicity, content, intake and EC regulation. Journal of the Science of
Food and Agriculture, 86, 10-17.
Sáenz, C., Sepúlveda, E., Araya, E., Calvo C. (1993) Colour changes in concentrated juices of prickly pear
(Opuntia ficus indica) during storage at different temperatures. Lebensmittelwissenschaft und Technologie, 26,
417-421.
Stintzing, F.C., Carle, R. (2004) Functional properties of anthocyanins and betalains in plants, food and in
human nutrition. Trends in Food Science and Technology, 15, 19-38.
Stintzing, F.C., Carle, R. (2007) Betalains – emerging prospects for food scientists. Trends in Food Science &
Technology, 18, 514-525.
Vaillant, F., Pérez, A., Dávila, I., Dornier, M., Reynes, M. (2005) Colorant and antioxidant properties of redpurple pitahaya (Hylocereus sp.). Fruits, 60, 1-10.
Wissgott, U., Bortlik, K. (1996) Prospects for new natural food colorants. Trends in Food Science & Technology,
7, 298-302.
Wybraniec, S., Mizrahi, Y. (2002) Fruit Flesh Betacyanin Pigments in Hylocereus Cacti. Journal of Agricultural
and Food Chemistry, 50, 6086-6089.
Figure 1: Pitaya (Hylocereus polyrhizus Britton & Rose) plantations in Nicaragua.
Figure 2: Hylocereus sp., „Rosa“ genotype halved fruit.