Storage methods of fresh longan for commercial dried flesh longan production

Appropiate for commercial, only three methods were selected as following: 1) storage whole longan in mixture of calcium chloride 1.5 percent, citric acid 0.25 percent, potassium sorbate 0.1 percent and potassium metabisulphate 0.15 percent at 25-30 deg C : 2) storage of fumigated longan in refrigerator at 2-5 deg C ; 3) storage at 30-35 percent moisture dried longan with silica gel at 25-30 deg C. Quanlity retention nearly equal to fresh longan was found only in fumigated longan stored in refrigerator. The development of process for suitable process for these storage longan had been studied as following : 1) Dried honey-longan product made from storage fumigated longan, had been developed by dipping longan in 5 percent honey 1.5 hrs and drying at 60 deg C 10 hrs. The products had 27.32 percent moisture, Aw 0.585 and got better color and texture significantly. 2) Dye and candying for longan glace and candied longan had been studied. The best dye proces was dipping longan in 70 ppm dye solution (1:1) hrs.:; heating at 70 deg C 10 min.; set aside 2 hrs. Candying was boiling longan in 40 deg brix syrup 7 min., set aside 48 hrs., adjust syrup to 40 deg brig, set aside 48 hrs., adjust to 45 deg brix, set aside 24 hrs and dry at 60 deg C 11 hrs. There were no difference significantly in taste, odor, texture and color intensity between longan glace and maraschino cherries. Only longan glace less gloss appearance. 3) Redrying of storage 30-35 percent dried longan had been done at 70 deg C 12 hrs for whole fruit and 60 deg C 4-6 hrs for longan meat. The keeping method for color retention of dried longan had been determined. It was found that keeping dried longan at 2-5 deg C could retain color while keeping at 25-30 deg C, color changed to be dark brown. The suitable package for storage at 25-30 deg C was AI/PE bag with oxygen scavenger which could retain color longer significantly.