Ingunn Øvsthus
Research Scientist
(+47) 482 07 250
ingunn.ovsthus@nibio.no
Place
Ullensvang
Visiting address
NIBIO Ullensvang, NO-5781 Lofthus
Authors
Jorunn Børve Theresa Weigl Emily Follett Ingunn Øvsthus H. Larsen Torbjørn Haukås E. Indergård S.F. Remberg Dalphy Ondine Camira Harteveld Arne StensvandAbstract
Evaluating the effect of different treatments after a simulated shelf life is common in postharvest industry experiments. As fungal fruit decay development is closely linked to preharvest factors, fruit quality, and postharvest treatments two other time points were added in recent experiments. When commercial packinghouses graded the different experimental units (from 1 to 4 bins) they made three different samples; 1) all the fruit manually discarded before size grading (mostly external symptoms of fungal fruit decay and physiological disorders), 2) a 100-fruit sample of the fruit not regarded as first class by the grading machine at size grading (fruit that could be used for industry purpose, processing fruit), and 3) packed fruit for shelf life testing. As expected, differences in pathogen presence were found varying with storage time, cultivar, season, treatments, etc., but overall, some important factors could be pointed at: up to 70% of the processing fruit had damages (caused by insects, weather or mechanical damage) that could be an entry point of fungal pathogens in storage. Apple scab was found on up to 60% of that fruit and up to 12% of the graded fruit in shelf-life tests, indicating a less effective fungicide strategy in some of the commercial orchards. The additional knowledge gained by having three sample types in the experiments is discussed.
Abstract
In Norway, plum fruit is sold for fresh consumption in a similar way as sweet cherry for a high price. Different treatments were tested to ensure high quality at the consumer end. The fruit is normally picked with a range in ripeness. At packaging grading the fruit in different maturity classes for intended sale in shorter (Ripe+) and longer channels (Ripe-) has been partially implemented in the industry. As a further improvement, application of 1-methylcyclopropene (1-MCP) was tested on fruit of the two ripeness categories of two cultivars. After a period of cold storage and simulated shelf-life for two days at 20°C fruits were tasted by a sensory panel. Fruit quality and fungal decay were assessed both after cold storage and simulated shelf-life. It was clear that taste of less ripe fruit was associated with firmer fruit, more acidity and greener taste, and quality of riper fruit was associated with sweetness, higher colour value, softer texture and a higher taste intensity. The panel found that treated Ripe- fruit had a greener taste and flavour and were less juicy and less sweet. In general, quality analysis of less ripe plum fruit of both cultivars showed that they had higher content of acids, were firmer, and had less cover colour after storage compared to riper fruits. Also, treatment with 1-MCP impacted firmness, colour, and acidity. However, the treatment effect was different depending on cultivars and years. In 2022, the effect of 1-MCP was seen for both ripeness categories of ‘Reeves’, but only for Ripe- fruit in 2023. There was no effect of 1-MCP treatments on ‘Mallard’ in 2022, however, there was a slight effect of 1-MCP on firmness, acids and cover colour after self-life test for less ripe plum fruit in 2023. The Ripe+ fruit developed 2-10 times more fungal fruit decay than less ripe fruit. 1-MCP had no effect on development of fungal fruit decay. Preliminary conclusion was that management of fruit maturation is more effective than 1-MCP application in securing consumer end quality.
Abstract
No abstract has been registered