The deterioration of freshly harvested horticultural crops prior to storage can be minimized by rapid pre-cooling. This deterioration occurs for two reasons: (i) the respiration rate is typically high due to high ambient temperatures at harvest, and (ii) physiological activity of the produce is at peak levels. Thus, precooling is essential. / Many precooling techniques are used in the horticulture industry today. Their main purpose is to rapidly extract heat from the produce by using a suitable fluid for the heat extraction/rejection process. / The efficiency of a cooling method depends on many factors: the cooling fluid used, the morphological characteristics of the product, the type and shape of packing, the system design, etc.. It is therefore relatively difficult to compare the efficiencies of cooling systems or to evaluate the effect of each parameter on system efficiency. A new method for assessing cooling system efficiency was therefore developed. The technique was based on the capacity of the system to maintain the product temperature at the surface as low as possible without affecting the morphological characteristics of the product. It was shown that this method of assessing efficiency was effective under field conditions. / A low cost liquid-ice system was designed and tested for broccoli precooling. It is based on ice particle injection into a water stream, the mixture then being pumped into the box of produce to be precooled. The effects of different ice particle sizes and ice-water ratios on the medium temperature of broccoli, the mass of ice remaining in the boxes of produce and the icing efficiency were analyzed. The results led to the establishment of optimum conditions for the parameters of the proposed system.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.68178 |
| Date | January 1994 |
| Creators | Goyette, Bernard |
| Contributors | Raghavan, G. S. V. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Agricultural Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001395970, proquestno: AAIMM94436, Theses scanned by UMI/ProQuest. |
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