GASEOUS OZONE AS A POTENTIAL ALTERNATIVE DISINFECTION METHOD FOR MODIFIED ATMOSPHERE PACKAGING FRESH-CUT PRODUCE WITH HIGH QUALITY AND SAFETY STANDARDS

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Impact of ozone processing on microbiological, physicochemical, and bioactive characteristics of refrigerated stored Cantaloupe melon juice

Publication . Sroy, Sengly; Fundo, Joana F.; Miller, Fátima A.; Brandão, Teresa R. S.; Silva, Cristina L. M.

The objective of this study was to evaluate the impact of ozone treatment on microbiological decontamination (intrinsic microflora and inoculated Listeria innocua) and some physicochemical characteristics and bioactive compounds of Cantaloupe melon juice, also during refrigerated storage. To determine adequate ozone exposure, the survival curve of L. innocua was previously assessed. A thermal treatment was also performed seeking comparison with ozone treatment impact. After ozone exposure, L. innocua was not detected in juice samples, while thermal pasteurization allowed a reduction of 5.2 ± 0.2 log cycles. Although ozone reduced the intrinsic microflora loads, this reduction was higher for heat‐treated samples. Vitamin C was highly retained in ozone‐treated juices (68%), when compared with the pasteurized ones (39%). After 13 days of storage, ozone allowed the retention of the most quality parameters analyzed and, therefore, it can be considered as a promising alternative to traditional pasteurization of Cantaloupe melon juice. Practical applications The actual consumers' demand for high‐quality food standards has launched research to alternative and milder nonthermal processes, which have gained increasing attention and importance in the fruit juice industries. Ideally, preservation and/or processing of foods should involve technologies that prevent undesirable microbial survival and minimize quality attributes changes and nutrient losses. Thermal treatments are conventionally used to attain such targets; however, the content and the biological activity of the most health‐related compounds are dramatically reduced. In this context, and particularly in the beverages industries, ozone has been exploited due to its potential for inactivating spoilage and pathogenic microorganisms, while being effective in overall quality retention of the products.

2019Journal article

Open access

Mathematical models for prediction of temperature effects on kinetic parameters of microorganisms’ inactivation: tools for model comparison and adequacy in data fitting

Publication . Gil, Maria M.; Miller, Fátima A.; Brandão, Teresa R. S.; Silva, Cristina L. M.

Microbial inactivation often follows a sigmoidal kinetic behaviour, with an initial lag phase, followed by a maximum inactivation rate period and tending to a final asymptotic value. Mathematically, such tendencies may be described by using primary kinetic models (Gompertz based model is one example) that describe microbial survival throughout processing time when stressing conditions are applied. The parameters of kinetic models are directly affected by temperature. Despite the number of mathematical equations used to describe the dependence of the kinetic parameters on temperature (so-called secondary models), there is a lack of studies regarding model comparison and adequacy in data fitting. This work provides a review of mathematical models that describe the temperature dependence of kinetic parameters related to microbial thermal inactivation. Regression analysis schemes and tests seeking model comparison are presented. A case study is included to provide guidance for the assessment of secondary model adequacy and regression analyses procedures. When modelling temperature effects on sigmoidal inactivation kinetics of microorganisms, one should be aware about the regression methodology applied. The most adequate models according to the two-step regression methodology may not be the best selection if a global fit is applied.

2017Journal article

Open access

Quality assessment of Cantaloupe melon juice under ozone processing

Publication . Fundo, Joana F.; Miller, Fátima A.; Tremarin, Andréia; Garcia, Ester; Brandão, Teresa R.S.; Silva, Cristina L.M.

Ozone treatment is a non-thermal technology with promising applications in food processing. The objective of this study was to evaluate the effect of gaseous ozone at a concentration of 7.0 ± 2.4 g/L for 30 and 60 min of exposure, on some physicochemical characteristics (soluble solids content, pH, titratable acidity and color), bioactive compounds (vitamin C, total phenolics and carotenoids) and total antioxidant activity of Cantaloupe melon juice. The effectiveness of the ozone treatments in microbial survival was also assessed using Alicyclobacillus acidoterrestris spores as target spoilers of the juice (artificially inoculated). Some quality parameters were significantly affected by ozone treatments. The most relevant alterations were observed for color, vitamin C, carotenoids and total antioxidant activity. However, total phenolics content increased significantly in ozonized juices. Even though A. acidoterrestris spores reduced 2.22 ± 0.04 log cycles after 60 min of exposure, other quality related characteristics of the juice were modified. Industrial relevance The actual consumers demand for high-quality food standards have launched research to alternative and milder non-thermal processes, which have gained increasing attention and importance in the fruit juice industries. Ideally, preservation and/or processing of foods should involve technologies that prevent undesirable microbial survival and minimize quality attributes changes and nutrient losses. Thermal treatments are conventionally used to attain such targets, however, the content and the biological activity of the most health-related compounds are dramatically reduced. In this context, and particularly for the beverages industries, ozone has been exploited due to their potential for inactivating spoilage and pathogenic microorganisms while being effective in overall quality retention of the products.

2018Journal article

Restricted access

Ozonation of Adzuki beans (Vigna angularis): Effect on the hydration kinetics, phenolic compounds and antioxidant capacity

Publication . Alexandre, Allana Patrícia Santos; Miano, Alberto Claudio; Brandão, Teresa Ribeiro Silva; Miller, Fátima Alves; Fundo, Joana Freitas; Calori-Domingues, Maria Antonia; Silva, Cristina Luisa Miranda; Augusto, Pedro Esteves Duarte

Ozone is used in grains to guarantee mycotoxin degradation, microbial inactivation, and insect disinfestation. However, its oxidizing properties can promote changes in the grain constituents, affecting both product properties and process behavior. Even so, the effect of ozone processing on quality properties of grains and their process, was rarely studied. Consequently, this work studied the impact of ozonation processing on the hydration kinetics and selected nutritional properties of Adzuki beans (Vigna angularis). As the ozone reactiveness increases at high moistures, three different levels of grain moisture were evaluated. The bean nutritional quality was evaluated considering the total phenolic content and antioxidant capacity (both radicals ABTS and DPPH). The results showed that there was neither significant difference in the hydration kinetics nor in the phenolic compounds and antioxidant capacity after the processing with ozone. Consequently, ozonation is proposed as an alternative in the control of grain contaminants without affecting its quality.

2018Journal article

Restricted access

A review on ozone-based treatments for fruit and vegetables preservation

Publication . Miller, Fátima A.; Silva, Cristina L. M.; Brandão, Teresa R. S.

The development and application of efficient methods for the preservation of food products have always been industrial concerns. The search for new technologies that assure safety and quality of the products is an ever-growing challenge. In this context, ozone has emerged, presenting a set of characteristics that makes it highly suitable for fruits and vegetables. Ozone properties and ozone applications to fruits and vegetables industries are included in this work. Due to the potential of ozone-based treatments for obtaining safe products with extended shelf life, several researchers have been focusing on this topic. A compilation of those works is presented in this review, with emphasis on the ozone impact on microbial inactivation and quality aspects of processed fruits and vegetables, and fruit juices as well. This review can be a helpful tool for finding process conditions of ozone-based treatments and subsequent impacts on quality and safety attributes of already studied products, opening further areas of research.

2013Journal article

Restricted access