SUGARCANE JUICE PROCESSING: A SEARCH FOR OPTIMAL PARAMETERS

Although sugarcane juice is a highly perishable beverage, its stabilization may be achieved by applying the proper heat treatment. This study was conducted in an attempt to optimize the binomial holding time (t) x temperature (T) for the whole juice (pH~5.3) pasteurization. Eleven runs were carried out according to a Central Composite Rotatable Design. The temperature, ranging from 78 to 92 ºC, and holding time, from 16 to 44 s, were tested. The evaluation of different combinations was guided by microbiological, enzymatic, sensory tests, and instrumental measurement of color. Coliforms counts at 45 °C were less than 10 CFU/mL in all pasteurized juice samples. Salmonella spp. was not detected, assuring the product´s safety. The impact of the binomials applied to the juice’s pasteurization widely varied. With respect to enzymatic inactivation and microorganism reduction, the treatment at 90 ºC/40 s was the most efficient. The treatment at 85 ºC/44 s was more effective in maintaining the original juice´s color. As to the sensory acceptability, the binomial 85 ºC/16 s had a better performance. The 1st order analysis shown that temperature had a significant effect (p ≤ 0.1) on the peroxidase reduction and lightness variation. The holding time had no significant effect on any response. The interaction between variables was significant in reducing both peroxidase activity and psychrotrophs. The 2nd order analysis demonstrated that temperature had a significant effect on the peroxidase reduction, lightnesss variation, psychrotrophs reduction and flavor. The holding time had a significant effect on mesophilic reduction and flavor. The interaction between variables was significant in psychrotrophs reduction and flavor. Hence, the findings of this study demonstrated that there is not one unique binomial able to achieve all requisites needed for cane juice stabilization; nevertheless, the data hereby presented may be useful to design a thermal processing for the juice.