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| Author(s): |
Patrícia Maria Pinto
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2009-02-04 |
| Examining board members: |
Angelo Pedro Jacomino;
José Maria Monteiro Sigrist;
Marta Helena Fillet Spoto
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| Advisor: | Angelo Pedro Jacomino |
| Abstract | |
The guava is a healthy fruit, offer high levels of lycopene, vitamin C and fibers, being a good option to the minimal processing. However, the harvest point and senescence control are important for the processing success. The objective of this work was to define the best ripening stage for the minimal processing, in round slices, of Kumagai and Pedro Sato guavas, as well as means of controlling the senescence of theses fruits, as the 1-methylcyclopropene (1-MCP) and modified atmosphere. Firstly, the evaluation of the best ripening stages was conducted. The fruits of both varieties were harvested at 3 ripening stages defined by the skin color in green, light-green and yellowish-green. In the beginning of the experiment, physical-chemical and sensorial analyses took place every 3 days during 9 days. The green ones obtained low acceptability grades as to their appearance during evaluations. However, the yellowishgreen ones lost their firmness and gained a browning flesh. In the second experiment, the light-green and yellowish-green guavas were submitted, before the processing, to treatment with 1-MCP per 0, 3, 6 and 12 hours, in order to choose the best time of exposure of the fruit to the product. The physical-chemical analyses were equal to the previous experiment. The respiratory activity and ethylene production were achieved daily during 9 days. The respiratory peak and the increase of ethylene concentration were observed in the day of the processing in both varieties as well as in all treatments, probably due to injuries caused by the cuts. However, the treatment in which the guavas were exposed to 1-MCP for 12 hours had their respiratory activity and ethylene production reduced, thus keeping the physical-chemical qualities storage. In the third experiment, six packaging materials were studied, being selected according to the quality of the guavas. The physical-chemical analyses took place in the beginning and the end of the 9 days of storage. In this period the monitoring of gas composition was accomplished daily. The packagings of polypropylene and low density polyethylene films, under passive modified atmosphere, were efficient in keeping the quality of guavas. In the last experiment, the combination of the best results of the previous experiments was evaluated. The minimal processing of the two varieties was performed simultaneously, obtaining a mix of white and red guavas, thus achieving a more attractive look. Yellowish-green guavas treated with 1-MCP per 12 hours and packed with polypropylene film (52µm) the keeping the quality, thus enabling the combination of two techniques of senescence control. (AU) | |
| FAPESP's process: | 07/02157-3 - Minimal processing of guavas: ripening stage and senescence control |
| Grantee: | Patrícia Maria Pinto |
| Support Opportunities: | Scholarships in Brazil - Master |