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Andean blackberries (Rubus glaucus Benth) quality as affected by harvest maturity and storage conditions

Abstract:

Maturity stage at harvest and storage conditions are critical factors determining fruit postharvest quality. Physicochemical (fruit size, mass loss, color, firmness, pH, total soluble solids, titratable acidity), microbiological (total aerobic mesophiles, psychrotrophes, and yeasts and molds) and sensory quality of Andean blackberries harvested at two maturity stages and stored under room (18 ± 2 °C) and cold storage (8 ± 1 °C) was studied. Total phenolic compounds, anthocyanins and organic acids content, and antioxidant activity were also evaluated. The more mature fruit was classified as “big” according to the Ecuadorian Standard and showed lower acidity and higher total soluble solids, anthocyanins content and sensory scores compared with the fruit harvested earlier, whilst maturity at harvest did not affect the microbial counts of any of the groups studied. Cold storage was effective in delaying weight loss, softening and microbial growth and also in maintaining a better sensory quality of the blackberries. What's more, under refrigeration it was possible to extend the shelf-life of the fruit to up to 8 d. The main limiting factors for shelf-life were microbial growth and loss of firmness at room storage and cold storage, respectively. Based on these results, it would be advisable to harvest the fruit at maturity stage 5 in order to achieve an appropriate fruit size, a high anthocyanin concentration, a better sugars/acids equilibrium, and a better sensory quality and the fruit should be maintained under refrigerated storage.