Physicochemical and enzimatic transformations of "eva" apples stored under modified atmosphere

The need for a permanent market supply of fresh fruit has generated great interest in postharvest techniques that can promote useful life and quality of the fruit. The aim of this study was to evaluate the efficiency of atmospheric modification using different polymeric films in maintaining postharvest quality and prolonging the shelf life of Eva (Mallus sp) apples. For this, fruits from the city of Barbacena - MG, selected and sanitized were packed in plastic trays and wrapped in the corresponding films. The films used were: polypropylene - 20 µm, low-density polyethylene - 14 µm and high-density polyethylene - 7 µm. Another group of fruits (control) was not submitted to a modified atmosphere. Subsequently, all the the packages were stored under refrigeration (0 ° C ± 0.5) for 210 days and the evaluations of the following variables were performed every 30 days of storage: hydrogen potential (pH), titratable acidity, soluble solids, weight loss, firmness, total pectin, soluble pectin, pectin methyl esterase and polygalacturonase. The work was conducted in a completely randomized design (4x8), with 4 treatments and 8 experimental times. Each treatment consisted of three replicates and each experimental unit consisted of six fruits. The results were submitted to variance analysis and means were compared by the Tukey test at 5% probability and regression analysis. The low density polyethylene (14 µm) packaging provided the best conservation of the Eva cultivar apple textural characteristics

Cassava starch edible coating incorporated with propolis on bioactive compounds in strawberries

ABSTRACT Strawberry is a fruit appreciated throughout the world due to its attractive quality attributes and stands out due to its high phenolic compound content, which positively contribute to biological properties of nutritional interest. The objective of this study was to evaluate the effect of cassava starch coatings incorporated with propolis combinations on the phytochemical content and the maintenance and increase of the strawberry antioxidant activity. The treatments were 3% cassava starch (CS), 3% cassava starch + 33% ethanolic propolis extract (CS + P33%), 3% cassava starch + 66% ethanolic propolis extract (CS + P66%) and control (C). The fruits were stored at 4 °C ± 0.5 ºC and 90%RH for 16 days, making up a completely randomized design with 4 treatments and 5 time evaluations. Vitamin C, phenolic compound, anthocyanin, and antioxidant activity levels were evaluated through two methods. The coating with 66% of propolis promoted higher Vitamin C content than fruits submitted to the other treatments at 8 and 12 days of storage. For antioxidant activity, fruits treated with CS maintained a higher FRS percentage (free radical scavenging) at all time evaluations. Control fruits presented higher anthocyanin content at the last evaluation time when the highest antioxidant capacity, by the ABTS method (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)), was observed in fruits with CS and CS + P66% treatments. There was an increase tendency of the phenolic content during storage in all evaluated fruits. The propolis concentrations used, however, were not sufficient to increase or maintain the antioxidant capacity and phenolic contents of strawberries