Effect of ozone processing conditions on stability of fungal pigments


Diederich Aguilar1, Lourdes Morales-Oyervides2, Juan Carlos Contreras-Esquivel1, Alejandro Méndez-Zavala2, Javier Raso3, Julio Montañez2,*

1 Department of Food Research, Universidad Autónoma de Coahuila, Mexico
2 Department of Chemical Engineering, Universidad Autónoma de Coahuila, Mexico
3 Department of Food Technology, University of Zaragoza, Zaragoza, Spain


The aim of the present study was to analyze the impact of ozone processing technology on the stability of fungal pigments produced by Talaromyces spp. suspended in a buffer of pH 6 and a beverage model system (BMS). Both samples were ozonated by different ozone levels (0.031 to 0.064 mg/min/mL) and processing times (0 to 10 min). The impact of these processing variables on color degradation parameters was studied. Significant changes in pigmented extract and pigmented beverage model system (BMS) were observed. Ozone concentration and treatment time demonstrated to be critical factors in the color degradation of fungal pigments. First-order kinetic models adequately described the degradation pattern of pigments during ozonation. Degradation rate constants ranged from 0.127 to 0.206 in the buffer and from 0.068 to 0.119 in the BMS. The CIE L*a*b* parameters also confirmed the degradation behavior during ozonation process. Results from this study indicated that color stability of microbial pigments is affected by ozone processing conditions, thus, this quality aspect should be considered before applying this type of colorants in food products processed with ozone. Industrial relevance: Natural colorants sources are required to meet the recent growing demands by the food industry due to consumers concerns of using synthetic pigments. Microbial pigments are of increasing interest as a result of the high yields that can be produced by microorganisms. Recently, Talaromyces spp. has gained attention as a good pigment producer strain. However, the application of these pigments in food manufacturing will depend on their stability to food processing (thermal and non-thermal). Accordingly, this work aimed to determinate if the colorants produced by Talaromyces spp. are applicable given their stability under ozone pasteurization. Results indicated that fungal pigments exposed to ozone could be considered as a potential natural ingredient to replace the color loss of some fruit juice processed under ozone technology. These results are promising for future applications in the food sector.

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