Use of edible alginate and limonene-liposome coatings for shelf-life improvement of blackberries

Abstract

Blackberries are an important seasonal fruit crop. However, their supply and market growth are negatively impacted by a short shelf-life. To address this problem, the shelf-life and quality characteristics of blackberries coated with edible alginate and limonene-liposomes were investigated. The weight loss, respiration rates (O2/CO2), physicochemical properties, and microbial loads of blackberries treated with edible coatings and stored under refrigeration (4 °C) were determined. The rate of weight loss in alginate-coated fruits was significantly lower (0.44 ± 0.02 g/day/100 g) compared to limonene-encapsulated liposome coated blackberries (0.50 ± 0.02 g/day/100 g) as well as uncoated blackberries (0.54 ± 0.02 g /day/100 g) after the first 10 days of storage. The alginate-coated fruits also had a lower rate of CO2 release (0.47 ± 0.03 mmol/h/100 g) compared to the uncoated blackberries (0.80 ± 0.27 mmol/h/100 g). Both alginate and limonene-liposome coated blackberries had a lower average respiratory quotient (RQ) compared to non-coated blackberries. The quality indices of total soluble solids, pH, total polyphenol content, and total anthocyanin content did not exhibit significant deviation from non-coated blackberries. The yeast and mold count on limonene-liposome coated blackberries was significantly lower than the control after 1, 7, and 12 days of storage. The results suggest that the alginate coating was more effective than the control in lowering respiration rates and weight loss. Similarly, the limonene-liposome coating was effective at lowering microbial growth on the berries.

Keywords

• Blackberries
• Edible coating
• Liposome
• Limonene
• Alginate