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- Effect of ozone on the quality of fresh-cut green beans (Phaseolus vulgaris L.) and bell peppers (Capsicum annuum L.)Publication . Alexandre, Elisabete M. C.; Fundo, Joana; Santos, Dora M.; Brandão, Teresa R. S.; Silva, Cristina L. M.Ozone is a potent oxidant and disinfectant agent with multiple industrial applications. The efficacy of ozone treatments has been recognised in the sanitation of equipments and water disinfections. Recently, ozone started to be used as an innovative food processing technology that guarantees product safety. The objective of this work was to study the effect of ozone on the quality of fresh-cut green beans (Phaseolus vulgaris, L.) and green and red bell peppers (Capsicum annuum, L.). The quality factors analysed were enzyme (peroxidase) activity, colour and texture for green beans, and colour, texture and pH for bell peppers. Experiments were carried out in pilot equipment. An ozone generator was interconnected to a container filled with tap water. Ozone was continuously incorporated in water and its content was indirectly measured by potential difference. Green beans and bell peppers were cut in small portions. Samples were immersed in ozonated and non-ozonated water baths and removed after different times till a maximum of 180 minutes. Data from both treatments were compared by analysis of variance. For green beans, results showed that ozone treatment did not affect the colour, but significantly influenced texture (firmness) and peroxidase inactivation (at 7% significance level). After 40 minutes enzyme activity was reduced approximately 20%. This inactivation was verified for the rest of the sampling times. Ozone treatment affected pH and texture (fracturability) of red bell peppers (at 1% significance level). The other quality factors were not significantly influenced by ozone.
- Influence of disinfectant technologies on red bell peppers safetyPublication . Alexandre, Elisabete M. C.; Fundo, Joana F.; Santos Pedro, Dora M.; Brandão, Teresa R. S.; Silva, Cristina L. M.The development of innovative technologies, promoting fruits and vegetables safety to reduce the risk of related food-borne diseases, is an actual concern. Several sanitizing agents for washing fruits and vegetables may be used to reduce the risk of microbial contamination. Traditional washing technologies utilize chlorine and hydrogen peroxide as sanitizing agents for fresh produce. More recently, ozone is being used as an innovative food processing technology that guarantees product safety, also increasing shelf life of fruits and vegetables. Its main advantage, when compared to traditional disinfectant technologies, relies on its potent antimicrobial action and non-toxic products decomposition. The objective of this work was to study the effectiveness of three sanitizing agents (sodium hypochlorite - used in a commercial available solution AMUKINA, hydrogen peroxide and ozone in aqueous solutions), on the reduction of Listeria innocua inoculated on red bell peppers. Results showed that ozone treatment allowed bacteria reductions identical to the ones attained with the traditional disinfectant solutions. On average, aqueous ozone allowed a decimal reduction of 2 cycles in Listeria innocua counts.
- Physicochemical and bioactive compounds of ‘Cantaloupe’ Melon: effect of ozone processing on pulp and seedsPublication . Miller, Fátima A.; Fundo, Joana F.; Silva, Cristina L. M.; Brandão, Teresa R. S.Melon seeds are an important source of bioactive compounds, which are considered to be health beneficial. Therefore, the objective of this work was to assess the impact of gaseous ozone treatments (30 and 60 min) on melon seeds paste (nonedible part) and compare with the effect on pulp (edible part). Ozone treatments were evaluated in terms of physicochemical (color, pH, and soluble solids content) and nutritional profiles (total phenolics, total carotenoids, and total antioxidant capacity) of processed material. Results indicate that ozone has a different impact on the two fruit matrices, being seeds less affected by this preservation treatment.
- Effect of gaseous ozone process on cantaloupe melon peel: assessment of quality and antilisterial indicatorsPublication . Miller, Fátima A.; Fundo, Joana F.; Garcia, Ester; Silva, Cristina L. M.; Brandão, Teresa R. S.Fruit waste parts, particularly peel, are abundant sources of bioactive compounds. To be included in the formulation of value-added foods, peel needs to be transformed and subjected to a preservation process. Therefore, this study seeks to assess the effect of ozone on the quality and antilisterial indicators of cantaloupe melon peel paste, aiming at obtaining a product with the potential to be used as a food additive. Ozone was bubbled during 30 and 60 min, and some physicochemical characteristics (soluble solids content, pH and colour), bioactive compounds (total phenolics, chlorophylls and vitamin C) and antioxidant activity were analysed. Peel was also inoculated with Listeria innocua, used as a treatment efficiency indicator. The results indicated that, although ozone negatively affected antioxidant activity, it positively influenced all bioactive compounds analysed. An L. innocua reduction of 1.2 log cycle was achieved after ozone exposure. Ozone should be exploited as a promising technology to assure the quality/safety of cantaloupe melon peel. Indeed, if melon peel is conveniently converted into a suitable form that can be used as a food ingredient, this will promote the valorisation of waste materials with the consequent reduction of industrial by-products and new perspectives for market opportunities.