Sulfite residues on litchi fruit treated with sulfur dioxide

Abstract

Hot water treatment of litchi at 49°C for 20 min proposed as insect disinfestation treatment results in peel damage. When combined with a sulfur dioxide treatment, this damage was prevented with residue in the edible aril on a fresh mass basis of less than 5 mg kg −1 . The non-edible peel sulfite residues were 388 mg kg −1 immediately after treatment declining to 125 mg kg −1 after 2 days at 22°C and 5 days at 1°C. Hot air treated fruit had significantly lower aril sulfite residue than hot water treated fruit. Fumigation load factor significantly influenced peel and aril sulfite residues; at 53 kg m −3 , aril sulfite residue were 1 mg kg −1 . It was therefore possible to protect litchi pericarp color and not increase the edible aril sulfite residues above background.