Response of raspberry cultivars and selections to controlled atmosphere storage
FORNEY, C. F., JAMIESON, A. R., PENNELL, K. D. M., JORDAN, M. A. & FILLMORE, S. A. E. 2016. Response of raspberry cultivars and selections to controlled atmosphere storage. Acta Horticulturae, 1120, 57-64.
Plain language summary
Fresh raspberry fruit are highly perishable and therefore have a short market life. New raspberry cultivars with superior quality and market life are needed to expand the availability of fresh raspberries to the consumer and ensure their satisfaction. Therefore, the quality and potential market-life of new cultivars and advanced selections from the Agriculture and Agri-Food Canada breeding program have been evaluated to help meet this goal. Following storage at 1 °C in air or a controlled atmosphere (CA) containing 12.5% carbon dioxide, fruit from nine cultivars and selections were assessed for decay and physiological breakdown. Fruit with the longest market-life when held in either air or CA included ‘ACC Eden’, K02-15, K03-9 and K06-5, those with the shortest market-life were ‘Encore’, K02-14, 'Nova' and K06-1, while ‘Glen Ample’ was intermediate. Fruit cultivars/selections with high firmness at harvest tended to have longer market-life than those with low firmness. Fruit decay of all cultivar/selections was strongly suppressed by CA storage. Depending on cultivar/selection, CA delayed the development of physiological breakdown by upto14 days longer than observed in fruit stored in air. However, fruit held in CA tended to soften more than air stored fruit, but the extent of softening varied significantly among cultivar/selections. Raspberry selections found to have superior market life potential and those that benefited from CA storage will be used for future improvement of new raspberry cultivars.
Nine red raspberry (Rubus idaeus L.) cultivars and advanced selections from the Agriculture and Agri-Food Canada breeding program were assessed for their potential market-life when held at 1°C in air or controlled atmosphere (CA, 12.5 kPA CO2/7.5 kPa O2) with 95% RH over two seasons. At harvest, fruit were assessed for firmness, soluble solids, titratable acids as well as sugar, acid and volatile composition. Fruit in 16-fruit samples were individually assessed every 2-3 days for decay and physiological breakdown (PB). Decay and PB development were determined as the number of days (lag) before the first sign of deterioration. The rate of fruit loss was calculated as a linear rate of deterioration following the lag period. Fruit decay of all genotypes was strongly suppressed by CA storage with the lag period extended to >45 days compared to 19-29 days for genotypes stored in air. The lag of PB, which was expressed as juice leakage, ranged from 6 to 28 days in air-stored fruit and was increased by -1.0 to 9.7 days in CA-stored fruit depending on genotype. Fruit sugar content averaged 51% fructose, 26% glucose and 23% sucrose and acids averaged 75% citric, 13% quinic, 6% succinic and 6% malic acids, but varied among genotypes. Volatile composition was dominated by C13 norisoprenoid, which comprised 65-93% and monoterpenes, which comprised 2.6-20.2% of total volatiles. Initial firmness strongly correlated with PB resistance during storage but no relationship between sugar and acid content and fruit storage-life was found. Fruit of genotypes with the longest market-life when held in air or CA included 'AAC Eden', 'K03-9', 'Glen Ample' and 'K02-15' and those with the shortest market-life were 'Encore', 'Nova', 'K02-14', and 'K06-1'.