Meat emulsion formation under vacuum was studied in a model system and in a sausage emulsion. Sarcoplasmic and myofibrillar extracts from beef and pork infraspinatus muscle were used to compare emulsification of vegetable oil with or without vacuum. Vacuum treatment permitted more oil to be emulsified by all protein extracts. The proportional increase was greater for water-soluble than for salt-soluble extracts. Sausage emulsion was evaluated using frankfurters prepared in a vacuum chopper with or without vacuum. Product stability was improved by application of vacuum only for the entire chopping procedure. Cured color development was more rapid and more complete in the vacuum treatment. Without vacuum chopping, frankfurters showed more obvious cavitation and less density, confirming presence of air within the emulsion.