| 摘要 |
The colour of green vegetables is preserved in canning by including in the canning medium a dibasic alkali metal or alkaline earth metal salt of glutamic acid, in concentration exemplified by 0.0015-0.02 moles per 100g. of the medium. The canning medium is preferably adjusted to pH 8.0-8.5 by adding alkali. An example is concerned with sterilizing, at 240-260 DEG F., green vegetables sealed in cans with an aqueous solution containing 4.5 per cent of sucrose, 2.5 per cent of sodium chloride, 0.3-0.8 per cent of disodium glutamate and sufficient sodium hydroxide to maintain pH 8.5 after the heat treatment. Replacement of a tenth to a third of the disodium glutamate by calcium or magnesium glutamate is referred to. The calcium glutamate is said to produce skin toughening. Further improvement is effected by including in the canning medium an alkali metal or alkaline earth metal salt of ascorbic or phosphorous acid as a reducing agent, e.g. 0.05-0.10 per cent of sodium ascorbate or calcium phosphite may be added to the sugar and glutamate-containing brine mentioned. |
