Biodegradable coatings on the postharvest of blackberry stored under refrigeration

Abstract

-Blackberry is a notable fruit due to bioactive compounds. However it has a fragile structure, which reduces the consumption in natura. The aim of this study was to evaluate the physical and chemical quality of the cv. Tupy blackberry fruits, produced in an organic system, and coated with emulsions based on cassava starch and water kefir grains stored under refrigeration. The fruits were divided into three groups: a control (T1) and two treatments with coatings. The coatings used were: cassava starch solution 2.5% (T2); water kefir grains at 20% (T3). The fruits of the three treatments were stored at 10 ± 2 °C and RH 85 ± 3%, and were evaluated every three days for 12 days period. It was determined: weight loss, firmness, pH, titratable acid, soluble solids, ratio, anthocyanins and decay incidence. The results for the chemical features showed statistical differences (p>0.05) except for the pH value at the end of the storage. There were differences between crop for all parameters. During the storage period, the anthocyanin content increased on the 2008 crop and reduced on the fruits of 2009. To reduce the decay incidence it is recommended to use the coating with kefir grains. These fruits can be consumed until the third day of storage at 10 °C.

Recent advances in postharvest technologies to extend the shelf life of blueberries (Vaccinium sp.), raspberries (Rubus idaeus L.) and blackberries (Rubus sp.)

“…Chitosan (poly ␤-(1-4)-N-acetyl-Dglucosamine) is a polysaccharide derived from chitins that has been extensively studied to extend the shelf life of fresh produce [91]. In the context of berries, fruit weights were maintained, and large reductions of fungal decay were observed in various blueberry cultivars (5-30%) [92][93][94][95], 'Tupy' blackberries (45%) [96] and 'Tullmeen' raspberries (93%) [97]. However, while improving firmness of blueberries [92][93][94][95] and blackberries [96], chitosan coatings resulted in greater loss of firmness in 'Tullmeen' raspberries [52].…”

“…In the context of berries, fruit weights were maintained, and large reductions of fungal decay were observed in various blueberry cultivars (5-30%) [92][93][94][95], 'Tupy' blackberries (45%) [96] and 'Tullmeen' raspberries (93%) [97]. However, while improving firmness of blueberries [92][93][94][95] and blackberries [96], chitosan coatings resulted in greater loss of firmness in 'Tullmeen' raspberries [52]. Additional technical concerns that need to be addressed before edible coatings have wide commercial applications include the maintenance of the natural wax bloom which affects the desirable perceived colour of blueberries [98,99] and overcoming the difficulty in completely drying out any residual coating materials accumulating inside the fruit hollow of picked raspberries [97].…”

Postharvest Handling of Berries

“…Low temperatures slow down fungal growth and, at the same time, reduce respiration rate and water loss and, therefore, delay ripening and senescence processes [30]. As these berries are insensitive to chilling injury, extending the shelf-life of berry fruit is often achieved through low temperature with optimum storage conditions for strawberries, raspberries, and blackberries being 0°C and 90-95% relative humidity [31].…”

Nanocellulose Coating Associated with Lemongrass Essential Oil at Postharvest of Blackberry Fruits

“…Although blackberry has bioactives that directly attracts the consumer, the fruit has a fragile structure, which reduces its consumption in natura (Cia et al, 2007;Oliveira et al, 2013). Its lifespan is relatively short after harvesting, because of the high content of water, its metabolism and the occurrence of diseases demanding care with storage (Bischoff et al, 2013;Palharini et al, 2015).…”