ISHS Acta Horticulturae 368: International Symposium on Postharvest Treatment of Horticultural Crops
STORAGE LOSSES IN FRESH ASPARAGUS (ASPARAGUS OFFICINALIS L.) |
| Author: | E. Fehér |
| Abstract:
The asparagus is a native of Europe and Asia. In both continents it is mostly found along coasts and rivers. It was already consumed in Ancient Egypt. In Hungary it has been cultivated since the XVII century but plantations of importance were only established after 1950. Asparagus has always been considered a delicacy as it contains some very valuable substances (vitamins, carbohydrates, raw fat, proteins, etc.). The shoots (spears) of the white type and the closed heads of the green type are highly esteemed for their excellent flavour. In Hungary asparagus is generally harvested from early April till 15th June. In this season fresh vegetables are relatively scarce thus accounting for its demand on markets. On the other hand, its cultivation and preparation is very labour-intensive which explains its high price. Spears must be harvested once or twice a day due to their intensive growing (3–6 cm/24 h). Because the white spears cannot develop a protective cover during their growth their evaporation is high, resulting in rapid water loss and tenderness. Tarján and Lindner (1974) found 94.4 % water content in spears. The fresh stem contains 81 – 83 % water (Fehérné, 1985) and the fresh spear consists of 9.79 – 10.25 % solids (Fehérné, 1983). It is very important to preserve the water content of harvested spears as it affects their storability and tenderness considerably. Tenderness must be taken care of as early as harvest. In Hungary spears are cut in the early morning or in the late afternoon hours as cool temperatures and low light intensity hinder their drying up. After cutting, spears are washed, sorted, trimmed and kept in boxes lined with wet paper. These operations must be performed in cool rooms. Our trials indicated that spears can loose 2.0 – 2.2 % of their weight in 24 hours at 20 – 22 °C and 65 – 70 % relative humidity. Spears wrapped carefully in wet paper and transported in closed vehicles can have additive losses of 0.4 – 0.5 %. In Hungary 94–96 % of the asparagus (400–500 tons) is exported. Spears delivered by growers or purchased by exporting firms are kept in cold store. According to David and Koródi (1969) they can be stored for 3 – 4 weeks at 0.5–5.0°C and 85–95 % relative humidity as their respiration rate is slow. Voloszov (1969) reported 5 % respiration loss at 5.0°C without wrapping. Stenners (1966) and Kern (1966) stated that spears had a good shelf-life even partly packed in shrink wrap. Lill (1980) stored spears at 2–4 °C for 2–4 weeks in polyethylene bags. | |
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