The V C retention rate of haw jam by vacuum concentrating was notably higher than that by air concentrating. If the vacuum keep at 93.33kPa in vacuum pan, the V C retention rate of haw jam was 100% by vacuum concentrating.

• 真空浓缩比常压浓缩的酱体V－C保存率高得多，真空浓缩的V－C保存率与真空度密切相关，保持93.；33kPa真空度浓缩可使酱体V－C保存率达100%25；