改進臺灣蘆筍品質及產量之研究 (II) 影響蘆筍嫩莖水冷效果因子之研究

Abstract

筍農使用之小型水冷容器質料宜選擇質輕，保溫性強之普利龍保溫箱，大小以25×32×36cm爲適。冰塊重，冰塊表面積與相對熱傳導有關係，水冷時冰塊愈小，增加之表面積愈大，熱交換亦愈速。8塊2.5kg/8及16塊2.5kg/16大小之冰塊在75分鍾後將水溫降至4℃，與蘆筍最適之貯運溫度5℃相近，且可維持將近5小時之久。冰塊加量對於水冷效果有影響，相當冰塊重二倍之水量，不僅水冷效果佳，且可維持4~5℃達6小時之久。食鹽用量對於冰融解速率及溫度朋影響但不實用。展著劑如Triton 1991對熱之傳導有阻礙，對於提高水冷效果似無多大裨益。規模大之蘆筍檢收站宜設計一套噴洒式水冷槽供嫩莖預冷處理之用，並宜製繪水冷圖標，供水冷作業人員實際操作之參考。 Hydrocooling can be an economical and effective protection against loss of eating quality in asparagus after harvest. And the factors affecting the effects of hydrocooling and applicable measures were studied to promote the asparagus quality of Taiwan. Asparagus growers should select 25×32×36cm^2 sized polylon box for hydrocooling asparagus spears. Since the weight of ice pieces and total surface area exposed to coolant water have relation to the relative heat transfer of such areas. The smaller piece of ice used, the larger the increase in surface area and the faster heat transfer and exchange, during hydrocooling 8 places of 2.5 kg/8 and 16 pieces of 2.5 kg/16 sized ice chunks can cool the water coolant to 4℃ in 75 minutes and keep at 3℃, the preferable temperature of asparagus for 5 hours The amounts of water added to ice pieces affected the effectiveness sod efficiency of hydrocooling. For example, addition of water which was 2 times weight of ice pieces had good effect of hydrocooling and kept cold water at 4-5℃ for 6 hours. The amounts of salt added to ice pieces showed the effect on the ice meltage and temperature. However, the addition of wetting agent ouch as Triton 1991 in the cooling water didn't show any good effect of hydrocooling. Large scale asparagus packing house or lot should equip a set of shower type hydrocooler and recirculate the cold water as much as possible to save the cost of hydrocooling asparagus. And also construct appropriate hydrocooling nomographs to predict unknown temperature or time for general on-the-job use and particular commercial operation.