Rennet - Clotting properties and starter activity on milk acidified with carbon dioxide

The influence of acidification with C02 on starter activity, rennet clotting properties, and cheese yield have been studied. Results obtained with lactic acid-treated milk were compared with those obtained with C02-treated milks. C02-treated samples showed lower acidification by starter than lactic acid-treated samples. The higher final pH values found in C02-treated samples could be attributed to reduced starter metabolic activity. Heat treatments to 60 or 70°C for 30 min did not influence coagulation time by rennet. Acidification produced a decrease of coagulation time, which was more pronounced on samples treated with lactic acid. Cheese yield was influenced by the growth of psychrotrophic bacteria during storage of milk.The authors acknowledge financial support for the research project ALI91-0540 provided by the Comision Interministerial de Ciencia y Tecnologia.Peer Reviewe