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Postharvest Biology and Technology 16 (1999) 139 – 145

Ripening-related changes in ethylene production, respiration rate and cell-wall enzyme activity in goldenberry (Physalis peru6iana L.), a solanaceous species Gustavo D. Trinchero a, Gabriel O. Sozzi a,*, Ana M. Cerri b, Fernando Vilella b, Adela A. Fraschina a Departamento de Quımica, Facultad de Agronomıa, Uni6ersidad de Buenos Aires, A6da. San Martın 4453, ´ ´ ´ 1417 Buenos Aires, Argentina b Departamento de Produccion Vegetal, Facultad de Agronomıa, Uni6ersidad de Buenos Aires, A6da. San Martın 4453, ´ ´ ´ 1417 Buenos Aires, Argentina Received 22 July 1998; accepted 21 December 1998 a

Abstract The ripening of goldenberry (Physalis peru6iana) is associated with a conspicuous climacteric rise in carbon dioxide and ethylene production. Its respiration rate and ethylene biosynthesis can be classified as extremely high. Ethylene yields between 7 and 24 nmol h − 1 per g in the ripe/overripe stages thus compare favorably with production rates previously reported for tomato fruit. As the fruit color turns from green (chlorophyll) to yellowish orange (carotenoids) and a progressive softening occurs, several cell-wall enzyme changes arise. Pectinmethylesterase and aand b-galactosidase reach activity levels similar to those in tomato fruit. Pectinmethylesterase and a-galactosidase increase toward the ripe stage. a-Arabinofuranosidase and b-glucosidase show lower activities but with an increasing pattern during ripening. On the other hand, polygalacturonase and a-glucosidase activities are hardly noticeable. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Physalis peru6iana; Goldenberry; Ripening; Ethylene; Respiration; Firmness; Pigments; Cell-wall enzymes

1. Introduction Physalis peru6iana L., commonly known as goldenberry or cape gooseberry, is a solanaceous hairy plant native to tropical South America. This * Corresponding author. Tel.: + 54-11-45248087; fax: +5411-45148739. E-mail address: gsozzi@mail.agro.uba.ar (G.O. Sozzi)

perennial herb presents fuzzy, slender-pointed heart-shaped leaves and yellowish flowers. The orange edible fruit, pleasantly flavored (Berger et al., 1989) and containing high levels of vitamin A, B, C, carotene, phosphorus and iron (Hewett, 1993; Sarkar and Chattopadhyay, 1993), are globose seedy berries enclosed in an inflated, bladder-like calyx or husk. The conspicuous postfloral growth and enlargement of the calyx lends itself

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G.D. Trinchero et al. / Posthar6est Biology and Technology 16 (1999) 139–145

as one of the best-known examples of persistent sepals. The calyx takes over a certain defensive function: berries with an intact expanded calyx, containing air that reduces the specific weight, are less prone to handling damage and have longer storage life, probably due to both mechanical and chemical protection (Baumann and Meier, 1993). Goldenberry is a quick growing and high yielding minor horticultural crop. It has achieved increasing economic importance in the last two decades and has been introduced as a specialized culture in warm regions worldwide, particularly in some American countries (USA, Mexico, Colombia) as well as in specific areas of Oceania (Australia and New Zealand), Asia (India) and Central and South Africa (Klinac, 1986). The fruit may be eaten fresh, in salads or in cocktails, or may be used for preserves, sauces and pies (Klinac, 1986; Hewett, 1993). Nowadays, this species is considered among the most promising crops for cool subtropical areas of the USA (McCain, 1993). Despite the increasing demand for this berry, there is little or no information about its ripening and postharvest characteristics. Ripening of climacteric fruit such as tomato (Lycopersicon esculentum Mill.) is mainly coordinated by the biosynthesis of the gaseous phytohormone ethylene which...
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