Avaliação da tecnologia das barreiras no crescimento de Monascus ruber em conservas de azeitonas e a determinação da resistência térmica de seus ascósporos

Abstract

Brazil has great importance in addressing the world market of olives, the second largest importer and the ninth largest consumer of the world's table olives. Despite having prominent position, little is known about the fruit characteristics, as well as the methods of preparation and conservation of olives but preserved. Filamentous fungi are as potential fruit of contaminants, especially during its storage. In view of the growing increase in imports of fruits, knowledge about the quality of the raw material and mainly of microbial contaminants, it is essential to ensure the safety and quality of preserved table olives produced in the country. The fungus, identified as Monascus ruber, was isolated during storage of green olives of Arauco cultivar imported from Argentina in a factory located in Three Rivers - RJ. Its development leads to various impairments, such as softening of fruits, reddish pigmentation of mycelium developing in the brine surface and increasing the pH of the brine, causing economic losses and reduced microbiological stability of the product and may allow development of pathogens such as Clostridium botulinium, due to the increase of pH. Based on olives preserved conservation methods provided for by law (pasteurization or chemical preservatives), this study aims to assess the effect of each factor and determine the process parameters to establish the most efficient conditions in growth control and caused deterioration by the fungus. First, a study was conducted on the effect of applying the concept of the technology barriers for the growth of fungus, investigated by the aid of the experimental design (full factorial 24 and face-centered central composite), through the combined use of sodium chloride, sorbate potassium, sodium benzoate and temperature at different levels. From the results, it was observed that the fungus was tolerant to the concentration of 5.5% salt, showing the highest growth rate at lowest concentration tested (3.5% salt). The use of preservatives has proved effective in controlling fungal, and potassium sorbate effective as a preservative fungicide action having a minimum concentration of about 0.03%. The combined use showed no synergistic effect, resulting in fungiostatic against the fungus. From the results obtained in this study, it was possible to determine the composition of the brine in which there was a higher rate of growth of the fungus, which is used as a heating medium to evaluate the heat resistance of the fungus. The D values were D75 ºC = 26,92; D80 ºC = 5,72; D90 ºC = 1,57 and the value of z was 8,1 ºC. The result showed that the binomial time x temperature set by law is not able to kill the fungus. Therefore, the results obtained in both studies can help the industry to develop more efficient processes for disposal of Monascus ruber in olives preserved from the pasteurization or the addition of preservatives.