Soymilk treatments: UHPH, pasteurization and UHT
To obtain pasteurized soymilk, base product was homogenized at 18 MPa and subsequently pasteurized using a tubular heat exchanger at 95 C for 30 s. To obtain UHT soymilk, two step homogenization (18 MPa and 4 MPa) was performed in a homogenizer previous to the heat treatment (142 C for 6 s) with an indirect system equipment . UHPH treatments were conducted with a high pressure homogenizer . This device (flow rate of 120 L/h) is provided with a high pressure ceramic valve able to support 400 MPa. Inlet and outlet temperatures of soymilk were controlled by two heat exchangers located before the machine entrance and after the high pressure valve, respectively. During treatments, the inlet temperature, the temperature after the high pressure valve, and outlet temperature were monitored. Six UHPH treatments were performed by combining, 200 and 300 MPa with different inlet temperatures (55 C, 65 C and 75 C). Samples were collected in sterile bottles in a laminar flow cabin for this purpose.