Both these factors make problems of over-pressure more significant, with peaking or breakages the result. Over the years there has been a trend towards ever thinner-walled can packages, as well as reduced head space volumes. The practice of using nitrogen for purging containers and for fobbing produces a mixture of gases in the headspace that may increase the pressure rise. This is partly due to the rise in temperature acting on the CO 2 gas already in the headspace and partly due to the vibration, which encourages CO 2 to be released from supersaturated solution in the product. The Haffmans RPU-352 and Haffmans RPU-353 have two temperature channels to allow measurement of product and spray temperatures.ĭuring pasteurization the pressure in the container increases.
This is of interest when pasteurizing bottles, as too great a Delta T during the heating or cooling cycles would likely lead to breakages. the difference between the temperature inside the package and outside. As the bed is in constant motion a sample time of at least 10 seconds is required to determine an accurate location for a damaged head.ĭelta T (ΔT) can also be measured i.e. Monitoring the spray temperature is used to view the temperature of the individual temperature zones and to identify the location of any bent or clogged spray heads. Setting the optimal automated PU values avoids over-pasteurization (loss of aroma and taste) and reduces energy consumption. Sufficient heat treatment of bottles or cans determined by multiple temperature probes during the pasteurization process is ensured by reaching the minimum required PU’s (at the coldest spot). The juices processed under optimal processing conditions show a minimum shelf life of 21 d at a storage temperature of 4 ☌.Haffmans delivers equipment for reliable monitoring of tunnel pasteurizers in breweries and the soft drink industry. The optimization of the process condition thus results in a compromise between the reduction of the pressure value, due to the synergetic temperature action, and the achievement of quality of the final production. By coupling moderate heating to high pressure, the lethality of the process increases but thermal degradation of the products can be detected. Therefore the first pulse cycle is more effective than the following ones.
The efficacy of the single pulses decreases with the increase of the pulse number and pressure level. The pulsed high pressure cycles have no additive or synergetic effect on microbial count. According to our experimental results, the efficiency of pulsed high pressure processes depends on the combination of pulse holding time and number of pulses. The shelf life of the samples, processed at optimized conditions, was evaluated in terms of microbiological stability and quality retention. The aim of the article was the optimization of the process parameters in step-wise pressure treatment (pressure holding time of each pulse: 60 s, compression rate: 10.5 MPa/s, decompression time: 2 to 5s). The objective of this article was to investigate the effect of the main processing variables (pressure, temperature levels, and pulse number ) on the sanitation of nonpasteurized clear Annurca apple juice as well as freshly-squeezed clear orange juice. During treatments, orange juice maintained the same concentration of vitamin C.ĪBSTRACT: The use of pulsed high hydrostatic pressure was investigated as a possible approach to stabilize foodstuffs.
Moreover, an increase in condensed tannins compared to fresh orange juice was remarkably noted, especially for the thermal scale of 88☌/15s and 65☌/30 min. Also, a considerable decrease of the rate of the flavonoids was observed especially with 77☌/1min and 65☌/30min treatments. Furthermore, the contents of total polyphenols revealed significant increase with 88☌/15s treatment. However, the pH values increased considerably for all pasteurization treatments. The thermal effect on total acidity and soluble dry matter, or Brix analysis showed insignificant modifications due to all pasteurization treatments. The pH, soluble dry matter, total acidity, Vitamin C, total polyphenols, condensed tannins and flavonoids of fresh and treated juices were evaluated. Thus, freshly squeezed orange juice of Moroccan Valencia Late orange variety was processed by four thermal scales 65☌/30min, 77☌/1min, 88☌/15s, 92☌/30s. A better knowledge of the effect of pasteurization on the physiochemical stability and the nutritional quality of foods processed by emerging technologies with regard to thermal traditional technology is necessary.