Effect of Plastic and Paper Packaging on Tomato Fruits Stored at Different Temperatures and High Relative Humidity I.

1. Effect of Plastic and Paper Packaging on Tomato Fruits Stored at Different Temperatures and High Relative Humidity I. Chemical Properties, Quality Attributes and Shelf Life

2. By: Abdullah A. Alsadon1, Abdullah M. Alhamdan2 Mahmoud A. Obied1 1 Department of Plant Production and 2 Dept. of Agric. Engn., College of Agric., King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia

3. INTRODUCTION Hydroponic vegetable production is expanding in Saudi Arabia. Tomato is among the most important vegetable crops worldwide including Saudi Arabia. Availability of tomato in the market year round - by green houses- is important for farmers as well as for consumers. Storage temperature, relative humidity and packaging influence fruit quality and shelf life.

4. Objectives:

5. Materials: Cultivar: Red Gold (De Ruiter, Holland) Seed were sown in JV7 pots. Three weeks old seedlings were transferred to the greenhouse. Materials and Methods

6. Hydroponic growing system has been used in the Agricultural Research and Experiment Station at Dirab, near Riyadh, Saudi Arabia. All cultural treatments were carried out as recommended.

9. Average size tomato fruits were harvested at stage 2 (Breaker stage). Two plastic packaging were used: - Low Density Poly Ethylene (LDPE), 50 ?m, - High Density Poly Ethylene (HDPE), 22 ?m,. Paper packaging (Brown paper bags, 0.11mm thick) were also used.

10. Three growth champers were set at three storage temperatures (5, 15, and 25°C). Relative humidity were set at 97% in each champer using humidification and dehumidification system.

12. Methods: Fifteen tomato fruits were harvested at breaker stage and placed inside each type of packaging. Control treatment consisted of un-packaged fruits. Fruits were labeled and divided into three replicates. Another group of fruits were stored for six weeks for chemical analysis. Plastic bags were sealed using thermal sealer. Paper bags were sealed using stapler. Fruit characteristics were evaluated weekly.

13. Measured parameters: Weight loss, %. Fungal infection, %. Coloring Chemical analysis (TSS, PH). Storage period (shelf life).

14. RESULTS AND DISCUSSION Influence of storage conditions and packaging on: Weight loss, %. Fungal infection, %. Coloring.. Chemical analysis (TSS, PH).

15. (1) Weight Loss:

17. Best storage temperature was 15°C since weight loss was less and chilling injury was avoided. Highest weight loss was in unpacked fruits. Lowest weight loss was in LDPE and HDPE packed fruits at all storage periods.

19. Alternaria spp., Fusarium spp., Rhizopus spp., Stemphylius spp.

21. The highest and significant fungal infection occurred on fruits stored at 25°C. Fungal infection were the same for fruits stored at 5 or 15°C except at the fifth and six week of storage. Fungal infection increased as storage period increased. Best storage temperature were 15°C since no significant difference in fungal infection with 5°C and it did expose fruits to chilling injury as 5°C.

23. Highest infection occurred in fruits packed in both plastic packaging. Unpacked fruits were less infected with fungal diseases followed by paper packed at all storage periods. Generally, fungal infection intensity correlated with fruit color change as fruit mature. As fruits mature, the rate of infection increase.

25. (3) Fruit Coloring: Storage at 15°C accelerated fruit color change compared to storage at 5 or 25°C. Storage at both 5°C and 25°C delayed fruit color change. No significant differences between plastic packaging. They both resulted in slowing fruit color change. Unpacked fruits and paper packed fruits had a speedy color change.

28. (4) Chemical Analysis (PH and TSS) No significant influence of storage temperature or type of packaging on TSS at all storage periods. TSS ranged from 5.33 to 7.00

30. Similarly, No significant influence of storage temperature or type of packaging on PH. Generally, PH increased as temperature increased and as storage period increased. Highest PH recorded in HDPE packed fruits stored at 15°C.

32. Conclusion Highest weight loss occurred in unpacked fruits stored at 25 or 15 °C. Although storage at 15 °C resulted in speeding of fruit coloring, it is generally recommended for storing tomato fruit to avoid chilling injury, maintain fruit weight, maintain longer shelf life and minimize fungal infection.

33. No significant differences between the two plastic packaging on fruit traits. They both resulted in slowing of fruit color. Unpacked and paper packed fruits resulted in speeding color change and reducing shelf life. Storage at 5°C and use of both plastic packaging resulted in significant delay in fruit color. Conclusion..

34. Generally, TSS was highest in fruits stored at 5 or 15 °C with no significant differences between packaging materials. Under the conditions of this study, it is recommended to use both plastic packages for short term storage (2 weeks) and paper packaging for longer periods (up to 5 weeks). It is important to consider the influence of temperature and type of packaging when storing tomato fruits. Conclusion..

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