Determination of a process time for a new product: canned low acid artichoke hearts

Abstract

In order to obtain a process time for canned low acid artichoke hearts, the heat resistance of Clostridium sporogenes PA 3679 in phosphate buffer (pH 7) and in artichoke puree (pH 5.2) was determined in the range of 100-118°C. DT values in artichoke puree were determined by the most probable number and plate count methods. D1210c values were deduced by extrapolation of the curves. An F f $ (see nomenclature section) target value of 1.8 min, equivalent to an Fo = 2.5 min, was established considering a Dlzlo~ value of 0.36 min for artichoke puree. The cold point for canned artichoke hearts in 1/2 kg (71.5~117 mm) cans was determined, a set of heat penetration and cooling curves were obtained and the values of the parameters 'j' and 'f' were found. A process time was deduced, 21.5 and 23 min of heating at 121"C, following the methods of Patashnik (1954) and Hayakawa (1970Hayakawa ( ,1974 respectively, in order to reach the Fo target of 2.5 min for this new canned food. This process was adequate, as the inoculated experimental pack test showed no altered cans out of 50 inoculated after 21.5 min of heating at 121°C.

Physical texture as an indicator of processing conditions for canning low‐acid artichoke hearts

“…This product was heated in batches of 29 cans at 100, 110, 115, and 121°C for various periods. In each batch, temperature was measured during heating and cooling in four cans by fine thermocouples located at the geometric centre (Rodrigo and Martinez, 1988). Immediately after sterilization the cans were cooled to 35-40°C as in industrial practice.…”

“…(Rodrigo & Martinez 1988) from the heat penetration curves obtained on four cans for each treatment. Similarly, values C:;, of 5 , 10,15,20, and 25min at each treatment temperature (100, 110, 115, and 121°C) were calculated.…”

“…This preserved some of the texture but the taste was poor (acid). To overcome this, Rodrigo & Martinez (1988) produced sterilization specifications for a product at pH = 5.2, a level which had given a more natural taste in a previous study (Martinez 1988) but required high temperatures to ensure the inactivation of Cfostridium botufinum, and as a result most of the texture was destroyed. This was a study optimizing product sterility with minimum loss of texture caused by the high temperature treatment.…”

“…for 15 min ensures microbiological stability of the product (Rodrigo & Martinez, 1988) and produces the least degradation of the texture over the range of temperatures studied.…”