4th IASME/WSEAS International Conference on ENERGY, ENVIRONMENT, ECOSYSTEMS and SUSTAINABLE DEVELOPMENT (EEESD'08) Algarve, Portugal, June 11-13, 2008
Sustainable Postharvest Handling of Minimally Processed Melon Fruits DULCE ANTUNES, SUSANA NUNES, GRAÇA MIGUEL, SUSANA DUNDLEN, ANA CAVACO Universidade do Algarve, CDCTPV/FERN, Campus de Gambelas, 8005-139 Faro, PORTUGAL e-mail:
[email protected] Abstract: Minimally processed products (ready-to-eat) fruits and vegetables, have continuously increased in the past years due to consumer life style. Sustainable commercial horticultural success depends on satisfying consumer requirements. However, fresh fruits and vegetables are highly perishable and losses can be of great importance if postharvest correct measures are not provided. Quality of fresh horticultural products can not be improved by postharvest technologies, only can be maintained, what means those products must be of high quality at harvest. Moreover, ready to eat fresh-cut fruits and vegetables need more care to preserve their quality through shelf-life. Several studies have been conducted regarding the preservation of fresh-cut horticultural products and the respective quality, giving priority to methods that reduce decay avoiding negative effects to human health and environment. Melons are commercially important as fresh-cut, mainly for fruit salad. The objective of our research was to apply environmental and human health friendly techniques to preserve freshcut fruit quality through storage. Cylinders melon cv. ‘Omega F1’ were cut from the pulp of just harvested fruits and subjected to dipping for 1 minute on a solution of 1% or 1.5% CaCl2, then stored at 5ºC. Measurements of weight loss, firmness, soluble solids content (SSC) and titratable acidity were performed after 0, 4 and 6 days. It was observed a positive effect of dipping fresh-cut melon pulp cylinders in calcium chloride up to 1.5% on their quality preservation during storage. This effect was mainly on preserving flesh firmness and reducing weight loss. Key-words: Minimally processed fruits, storage, fresh-cut, sustainable horticulture, postharvest technologies. Sustainability of supply chains are also of major importance [16] . To ensure that the highest and appropriate quality of product is available for consumers, it is critically important that all parties involved in the production, packaging, storage, transport, distribution and marketing of fresh horticultural products do everything correct in the chain from farm to plate [9]. To have a high quality product at harvest, it is of major importance to ensure that preharvest conditions are optimised. Quality is characterised by intrinsic and extrinsic factors which vary depending on the expectations and memory of the consumers [11]. Intrinsic factors include external attributes, such as, color, shape, size and freedom from defects and internal attributes which are texture, sweetness, acidity, aroma, flavour, shelf-life and nutritional value [7]. Extrinsic factors refer to production and distribution systems which include cultural practices during production, package types and their recycling capacity, management and postharvest practices, being of major importance the sustainability of production and distribution in relation to energy utilization. Sustainable development integrates economic, social and environmental factors. Sustainability requires that standards of living and production capabilities do not decline over time and that the
1 Introduction Fresh fruits and vegetables are important components of human food, occupying the second place in the food pyramid. The increased market demand for food may exert pressure on the environment through intensive farming [13] and postharvest technologies. Losses in fresh horticultural products can be of great importance if postharvest correct measures are not provided, since they have a short natural shelflife. Losses include partial or total loss, loss of quality, water loss, rots and physical damage. There is an increasing demand for ready-to-eat products in the market. Moreover, when subjected to wounding, as fresh-cut horticultural products are, it is much more difficult to maintain their fresh-like quality during prolonged storage periods. High losses mean small margins and high prices, which in turn lead to lower consumption. Agriculture has economically challenged due to globalization of the markets, reduced returns and increased cost of inputs [2]. Profitable agriculture depends on adequate postharvest technologies which provide good quality products for as longer as possible in order to decrease price fluctuations. Sustained commercial horticultural success depends on satisfying consumer demands.
ISBN: 978-960-6766-71-8
521
ISSN: 1790-5095
4th IASME/WSEAS International Conference on ENERGY, ENVIRONMENT, ECOSYSTEMS and SUSTAINABLE DEVELOPMENT (EEESD'08) Algarve, Portugal, June 11-13, 2008
natural environment is not damaged or degraded [15]. The benefits of increased food supplies at reasonable prices are important, but there may also be social and environmental costs, such as for example health or safety risks [13]. As a consequence, individuals or society make responses to exploit positive or mitigate negative impacts. Fresh-cut fruits and vegetables have continuously increased in the past years due to consumer life style [18]. Quality of fresh horticultural products can not be improved by postharvest technologies, only can be maintained, what means horticultural products must be of high quality at harvest. Moreover, ready to eat fresh-cut horticultural products need more care to preserve their quality through shelf-life. Fresh-cut fruit and vegetables are highly perishable and not well suited for long distance chill chain distribution [6]. Many studies have been conducted regarding the preservation of those products without significant modification of their quality, giving priority to methods that avoid negative effects to human health and environment. Melon is commercially important as fresh-cut. However, the marketing of minimally processed products is limited by a short shelf-life and a rapid deterioration of their components due to tissue damage as result of processing [20]. The pre and postharvest application of calcium salts has been used successfully in many fresh fruits to reduce loss of firmness and to slow down the ripening process [2, 4, 19]. Calcium alters intracellular and extracellular processes which retard ripening exemplified by lower rates of colour change, softening, CO2 and ethylene production, increase in sugar, and a reduction in total acid content [5]. It is known that calcium deficiency can induce a range of postharvest disorders in many fruits and vegetables [8]. Calcium deficiency can be overcome by calcium salts spraying during fruit development and/or by postharvest dip or drench treatments after harvest [10]. Calcium incorporation by impregnation was studied in fresh-cut apples with good results [1]. Also the consciousness of consumers on the benefits of calcium is relatively high [14]. The objective of this work was to study the effect of dipping fresh-cut melon pulp cylinders in calcium on their quality preservation during shelflife. We attempted to use different calcium salts such as calcium carbonate, calcium lactate and calcium chloride. In this paper are presented results of calcium chloride application on fresh-cut melon.
ISBN: 978-960-6766-71-8
2 Materials and methods 2.1 Plant material and treatments Melons cv. ‘Omega F1’ where harvested with around 9.5% ºBrix, then selected for uniformity of size and freedom of defects to be used in the experiment. Cylinders of melon (1.9cm diameter and 3cm length) were cut from the pulp and subjected to dipping for 1 minute on a solution of 1% or 1.5% CaCl2. Then, they were placed in plastic trays and covered with perforated polyethylene film. After that, fruits were stored at 5ºC for 6 days. Fruit cilinders were analysed before treatments and after 4 and 6 days storage. Measurements of weight loss, firmness, SSC and titratable acidity were performed. Recommended handling practices were followed, to reduce decay through shelf-life. Those included careful handling of the fruits to avoid extra wounding, bruising, crushing, or damage from humans, equipment, or harvest containers; use of clean and sanitized tools, packing, cold storage or transport containers.
2.2 Measurements Weigh loss was calculated as percentage of initial weight. Flesh colour (a*) was determined with a Minolta Chroma meter CR-200 and soluble solids content (SSC) (ºBrix) with an Atago refractometer. Firmness was recorded by a Chatillon Force TCD200 (Digital Force Gauge Dfis50) as the force needed to press fruit cylinders 1cm deep, with a disc of 5cm diameter. Titrable acidity was measured by titration with NaOH 0.1N to pH 8.2.
2.3 Statistical analysis Statistical analyses were carried out with a SPSS statistical package. Two-way analyses of variance (ANOVA) tests and Duncan’s Multiple Range Tests at (P
