In recent years, great interest has been focused on using natural antioxidants in food products, due to studies indicating possible adverse effects that may be related to the consumption of synthetic antioxidants. A variety of plant materials are known to be natural sources of antioxidants, such as herbs, spices, seeds, fruits and vegetables. The interest in these natural components is not only due to their biological value, but also to their economic impact, as most of them may be extracted from food by-products and under-exploited plant species. This article provides an overview of current knowledge on natural antioxidants: their sources, extraction methods and stabilization processes. In addition, recent studies on their applications in the food industry are also addressed; namely, as preservatives in different food products and in active films for packaging purposes and edible coatings.

Chitosan-based edible coatings were used to prolong the shelf-life of strawberries stored at 20 C and 35 e40% RH. Strawberries were coated with four different coating formulations (chitosan as monolayer, three layer coating consisting of separate beeswaxechitosanebeeswax layers, three layer coating where chitosan was crosslinked with sodium tripolyphosphate, TPP, and composite). The effectiveness of the coatings was evaluated by the changes of several parameters: fungal infection, weight loss, respiration rate, skin and flesh color, firmness, pH value, titratabale acidity, soluble solids content, reducing sugars content and sensory evaluation. The coatings, especially the three-layer coatings, significantly decreased the senescence and weight loss of the fruits. They modified the respiration rates of the strawberries and slowed down their metabolism as shown by the retention of the color and the texture of the tissue. Sensory evaluation of the coated strawberries showed that the chitosan and composite coatings gave better visual appearance and taste and were therefore more preferable by 90% of the judges than the three-layer coatings, even though the later had higher protective effect of the overall quality of the strawberries.

Watermelon rind offers quantitative interest as a natural source of citrulline, particularly Fashion, a dark-skinned, seedless cultivar. More research is required on the efficient extraction of citrulline from watermelon rind and its suitability as an additive to drinks, juices or others products to produce new functional food products with valid health claims.

a b s t r a c tAbiotic stresses such as heat shock and UV-C irradiation can be used to induce synthesis of bioactive compounds and to prevent decay in fresh-cut fruits and vegetables. This study aimed to evaluate the effects of heat shock and UV-C radiation stress treatments, applied in whole carrots, on the overall quality of fresh-cut carrot cv. Nantes during storage (5 C). Heat shock (HS, 100 C/45 s) and UV-C (0.78 AE 0.36 kJ/m 2 ) treated samples had higher phenolic content and exhibited reduced POD activities during storage when compared to control (Ctr) samples (200 mg/L free chlorine/1 min). All samples showed reduced carotenoid content considering raw material. Nonetheless, UV samples registered a three-fold increase in carotenoid content in subsequent storage. Fresh-cut carrot colour showed a continuous increase in whiteness index (WI) values during storage regardless of treatment without impairing visual quality. Respiratory metabolism was affected by both abiotic stress treatments since reduced O 2 /CO 2 rates were found, more significant in HS samples. The decontamination effect was more expressive in HS samples, where a 2.5 Log 10 cfu/g reduction in initial microbial load and reduced microbial growth were achieved.

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Natural bioactive compounds and living cells have been reported as promising products with beneficial properties to human health. The constant challenge regarding the use of these components is their easy degradation during processing and storage. However, their stability can be improved with the microencapsulation process, in which a compound sensitive to adverse environmental conditions is retained within a protective polymeric material. Microencapsulation is a widely used methodology for the preservation and stabilization of functional compounds for food, pharmaceutical, and cosmetic applications. The present review discusses advances in the production and application of microcapsules loaded with functional compounds in food products. The main methods for producing microcapsules, as well as the classes of functional compounds and wall materials used, are presented. Additionally, the release of compounds from loaded microcapsules in food matrices and in simulated gastrointestinal conditions is also assessed.

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