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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.
- Quality assessment of Cantaloupe melon juice under ozone processingPublication . 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.
- 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.
- Impact of ozonisation on quality parameters, nutritional aspects and inactivation of Listeria innocua in beansPublication . Alexandre, A. P .S.; Fundo, J.; Miller, F.; Calori-Domingues, M. A.; Silva, C. L. M.; Augusto, P. E. D.Beans are one of the most consumed legumes, due to their high content of proteins, complex carbohydrates, fibers, vitamins and also antioxidant substances, such as polyphenols. Antioxidants are substances that can slow down or inhibit oxidative damage by playing a role in preventing chronic diseases. However, the bean quality can be affected by microbial contamination or the methods used to avoid it. Ozone (O3) is a gas with high oxidizing potential, considered a “green chemical process” and recognized as GRAS (Generally Recognized As Safe). It can be used for microbial inactivation in different agricultural products, as well as for mycotoxins degradation in grains and derivate. However, it can also negatively impact the product quality due to oxidative processes. Consequently, the objective of this study was to evaluate the effect of processing beans with ozone on their phenolic compounds and antioxidant capacity, as well as their impact on the physical properties (water activity, color) and inactivation of Listeria innocua, as a target microorganism. Three different beans were evaluated: black, red and catarino beans with 10 and 40% moisture content. The samples were processed, in a reactor using a gas flow of 5 g/h with ozone concentration of37.06g/L, for up to 240min. The total phenolic content was evaluated through the method of Folin–Ciocalteu, while the antioxidant capacity was evaluated through the method of ABTS. The results demonstrates that it was possible to reduce 2.0Logcycles of Listeria innocua after 240 min of processing. The catarino bean was affected in the phenolic content when moistened. On the other hand, the ozone processing did not affected (p≤0.05) the total phenolic content, antioxidant capacity, and color of the beans. Therefore, the present study demonstrated that the ozonation can reduce the microbiology content in beans, without impact its nutritional quality.