Exploitation of bioactive and nutritive compounds from waste parts of fruits, seeking development of new strategies for adding value to fruit waste

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Publications

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

Evaluation of drying and storage conditions on nutritional and sensory properties of dried galega kale (Brassica oleracea L. var. Acephala)

Publication . Araújo, Ana C.; Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Monteiro, Maria J.; Silva, Cristina L. M.

This work evaluated the effect of the air-drying temperature and vacuum packaging on quality and nutritional compounds of dehydrated galega kale, previously steam blanched, during 5 months of storage. When compared with the vacuum packaged kale, the packaging without vacuum yielded improved nutritional features, in general. This approach combined with a drying temperature of 40°C resulted in retention percentages of 62, 38, 92, and 48% for vitamin C, total phenolic content, total antioxidant capacity, and chlorophylls, respectively. The acceptance of the dried product by the consumer was assessed through a focus group. The participants classified the product as a practical and convenient alternative to cook healthier dishes. The appearance of dried galega kale was described as being fragile and being with nice smell, natural colour, and flavour similar to the fresh product. In conclusion, the herein presented product was addressed as an innovation with multiple possible applications in several recipes.

2017Journal 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

Modeling the soluble solids rolids and storage temperature effects on byssochlamys fulva growth in apple juices

Publication . Tremarin, Andréia; Aragão, Gláucia M. F.; Salomão, Beatriz C. M.; Brandão, Teresa R. S.; Silva, Cristina L. M.

Byssochlamys fulva is an ascospore producer fungus known to be heat resistant and commonly found in fruit juices. This work aims at studying the influence of soluble solid content and storage temperature on the growth of B. fulva in apple juices. Agar-added apple juices, adjusted to different levels of soluble solids (12, 20, 25, 35, 45, 55, 70 degrees Bx) were artificially inoculated with B. fulva spores and incubated at different temperatures (10, 15, 20, 25, 30 degrees C). Microorganisms' growth was assessed every day for a total of 3 months. A Gompertz-based model was used in experimental data fit for each soluble solid and temperature condition applied. Kinetic parameters were estimated by nonlinear regression procedures. The soluble solids and temperature effects were thereafter included in the primary Gompertz-based model. The predictive ability of this expression in terms of B. fulva growth was successfully proven for the range of conditions tested.

2017Journal article

Restricted access