IMPROVE TECHNOLOGY IN COOLING AND COLD TRANSPORTING LITCHI TO MARKET IN SOUTH OF VIETNAM

1. IMPROVE TECHNOLOGY IN COOLING AND COLDTRANSPORTING LITCHI TO MARKET IN SOUTH OF VIETNAM Reported by Vietnamese group Nguyen ManhKhai, Dinh Thai Hoang, Huynh ThiThanhTuyen KhonKaen, 11/2011

2. I. Introduction • Litchi is one type of important tropical fruit with high nutrition value. • Litchi has high economic value with high competition and is exported with high foreign currency for many countries. • Recently, Vietnamese’s production of litchi increase incessantly with about 300,000 to 500,000 tons per year. • However, harvesting season of litchi is very short (only around 30 days) with only one season in year. Moreover, life of fruit after harvesting is very short, too (only about 3 days). These make many difficulties for consumption, therefore price of litchi fruit fell continuously, this cause no small damage about economic for producer.

3. To commercialize litchi, it is necessary to maintain quality until it is transported to consumer. However, the most difficult problem when managing quality of litchi after harvesting is that color of fruit’s cover change into brown after fruit cut from plant. This characteristic of litchi fruit is one no small restriction for ability extending consumption market. • Therefore, finding maintaining and transporting methods to maintain quality of fruit during commercial route, but conducting method must be simple and can deploying with large scale in practice with highest economic effect is extremely necessary. • One of effective method to ensure quality and to lengthen maintaining time is decreasing rapidly temperature of fruit after harvesting to appropriate maintaining temperature.

4. II. Objectives • General objective - To restrict lose after harvesting fruit - To determine cooling and cold transporting litchi fruit • Specific objective - To study on effect of pre-cooling method to quality of litchi fruit - To evaluate ability of replacing old method by new method

5. III. Materials and methods 3.1. Object and materials • Object: Thanh Ha cultivar is planted in Thanh Binh commune, Thanh Ha district, Hai Duong province, Vietnam • Materials: Fruits are harvested when 50 percent of cover area changing color to red in the early morning. Fruits are cut down leaf then bundling into bunches with average weight about 2.0 kilogram and transporting rapidly to packing house.

6. 3.2. Experiment design Bruches after being transported to packing house will be pre-cooled according to 2 methods below: • Experiment 1 (Exp. 1): Bruches is packed into foam containers lined by polyethylene (about 8 bunches per container), then transporting immediatly into cold storage with temperature about 2oC within 10 hours. • Experiment 2 (Exp. 2): Soaking each bunch into frozen water with temperature about 2 – 4oC within 3 minutes, lifting in a sieve within around 2 minutes, after that putting them into foam containers lined by polyethylen (about 8 bunches per container) then transporting immediatly into cold storage with temperature about 2oC within 3 hours.

7. Control: Bunches are treated and transported according to current process (Fresh fruits are transported to packing house, after classifying they are bundled into bruch with weight about 2.0 kilogram per bruch. Soaking them into frozen water with temperature about 5oC within 3 minutes, then putting into foam containers lined by polyethylene (about 8 bunch per container with about 8 kilogram of ice). • After storing in cold storage as above, the litchi fruits of 2 experiments and control are transfered to lorry with cold hold (temperature in cold hold about 0oC) to transport to Ho Chi Minh city within 48 hours. Immediatly after, litchi containers are transported to Can Tho city by ordinary lorry within 18 hours (including waiting and transporting time).

8. 3.3. Studied targets • Weight lose level (%) • Color change Determining change in color of fruit’s cover by NR 3000 machine. The result is reported by indexes including: L, a and b. Where; L: index showed light level of fruit’s cover, with values range from 0 to 100. a: index showed color range from green to red, corresponding with value from – 60 to + 60 b: index showed color range from sea blue to yellow, corresponding with value from – 60 to + 60.

9. Changing to brown index of fruit' cover Determining by method of Wrolstad (1982) with grades ranging from 1 to 5. Grade 1 with fruits having natural red and grade 5 with fruits having over 50 percent of fruit’s cover area changing to brown. • Damaged rate (%) • Total sugar content (%) • Temperature of fruit after transporting • Vitamin C content (mg%) • Evalutating quality by sence method • Conducting to evaluate quality of fruit basing on standard TCVN 32 – 1579 of Vietnamese’s Ministry of Agriculture and Rural Development with targets, including: color of fruit’s cover, color of fruit’s pulp, state of fruit, state of fruit’s pulp, tase of fruit.

11. IV. Results Table 1: Effect of cooling methods on temperature of litchi fruit after transporting Slow increase of temperature process after taking fruit out ordinary temperature condition will help maintain better quality of fresh litchi fruits

12. Table 2: Changing color of fruit after transporting • Effect of cooling method on color of fruit’s cover was determined by three indexes: L, a and b with only index: ΔEab= square of (ΔL2 + Δa2 + Δb2) which is easy to compare changing color of fruit in maintaining process between methods

13. Table 3: Effect of cooling method on natural weight lose level of litchi after transporting In the same packaging and transporting condition, treating fruit by frozen water delayed losing weight speed of fruit

14. Table 4: Effect of cooling method on total dissolved matter content of litchi fruit after transporting • Litchi fruit cooling by soaked into frozen water method has total dissolved matter level less than ordinary method

15. Table 5: Effect of cooling method on vitamin C content (mg %) of pulp after transporting • Treating fruit by method soaked into frozen water before pre-cooling by cold air has good effect restricting process of declining vitamin C content in pulp of fruit

16. Table 6: Effect of cooling method on sense quality of litchi fruit after transporting

17. V. Conclusion and suggestion 5.1. Conclusion • Treating fruit by method soaking into frozen water within 3 minutes, then putting into cold storage with temperature about 2oC within 3 hours, after that transporting in cold lorry with temperature about 0oC gained the best effect in comparison with method which was not cooling treated and control • Treating fruit by method soaking into frozen water and packaging by foam container lined polyethylene, then transporting in cool lorry maintained the most sense quality and nutrition quality of fresh litchi fruit in comparison with method which was not cooling treated and control.

18. 5.2. Suggestion • It is necessary to continue researching with more large scale to affirm effect of treating and transporting methods to quality of fruit during transporting and maintaining to can hand over quickly research results into reality production. • It is necessary to research more about combining using substance against fungus and methods to restrict changing brown of fruit’s cover to improve quality and to lengthen maintaining time with fresh litchi fruit, to restrict seasonal, to extend consumption market for this special fruit.

25. Thanks for your attention