AVALIAÇÃO QUÍMICA DE COUVE-MANTEIGA (Brassica oleracea) COM ADIÇÃO DE REVESTIMENTO À BASE DE AMIDO

Abstract

Kale (Brassica oleracea) is a very important crop among Brazilian farmers. Due to its high resistance to temperature fluctuations, it can be found on the country's market during all year. It is a very consumed vegetable, which has a high content of carotenoids, minerals, phenolic compounds, and antioxidant activity, in addition to vitamin C and fiber, and also has a low caloric value. However, kale has a short shelf life, which causes many losses due to inappropriate treatment, packaging, and storage. Starch-based biopolymers are being used and extensively studied in various types of food to increase shelf life, especially post-harvest, such as the edible coatings influence on preserving the post-harvest quality of strawberries, the application effect different edible coatings on the post-harvest conservation of guava. Furthermore, there are no studies that indicate the use of this biopolymer in kale. Thus, the objective of this work was to evaluate the post-harvest quality of fresh and minimally processed kale leaves, using a starch-based coating. The experimental design was carried out in blocks, which the leaves to be used were separated to the minimally processed ones, then submitted in the filmogenic solution after sanitization and stored under refrigeration (10 ± 2ºC) and evaluations at each three days for 12 days. A standard sample of fresh and minimally processed kale were used for comparison purposes. For the interaction between the media, the analysis of variance ANOVA was used and when significant, they were compared by Tukey's test, adopting a significance level of 5% of probability (p<0.05). Analyzes of moisture, ash, vitamin C, chlorophyll a, chlorophyll b, pH, phenolic compounds, and antioxidant capacity were performed. Based on the analysis of variance, it was observed that there was no significant difference between the samples, nor between their interaction in relation to the days, for the pH values. Therefore, it was not necessary to apply test of averages for this aspect. The results also indicated that the starch-based coating was efficient in maintaining the antioxidant properties of whole and minimally processed kale, and this maintenance takes place up to the 6th day of storage. The application of a starch-based coating on whole and minimally processed kale leaves proved to be efficient in terms of preserving their physicochemical and nutraceutical properties. Therefore, it showed to be an efficient alternative in terms of increasing the useful life of the studied hardwood, thus allowing it to be maintained for a longer time without losing its quality.