Predicting strawberry shelf life based on input quality : GreenCHAINge Fruit & Vegetables WP3 [report]

Bastiaan Brouwer, FBR Post Harvest Technology, Manon Mensink, Ernst Woltering, Fatima Pereira da Silva, PE&RC
2019 unpublished
The general objective in GreenCHAINge Fruit & Vegetables Work package 3 (GreenCHAINge), is to pave the way towards a supply chain with a high and constant strawberry quality. This report focuses on two main aspects: how initial quality at harvest influences strawberry quality and to what extent non-destructive measurement techniques can accurately determine and predict strawberry quality. At harvest, strawberries are picked at a certain level of ripeness, which is generally determined based on
more » ... etermined based on colour. The strawberry quality at the point of harvest is termed as its "initial quality". Initial strawberry quality is directly influenced by several issues related to growth, such as weather, picker and time of year. Other issues, such as order volume and market price, can also affect initial quality by changing the boundaries of harvest selection. The effect of variations in these issues on the initial quality and the shelf life in the chain is currently unknown. Beyond the harvest moment, strawberry quality changes over the course of its shelf life. While the ripening process will initially bring the fruits towards a ready-to-eat state, it will also make them more vulnerable to lose quality due to mechanical injury, decay, water loss and physiological deterioration. A well-established cold chain will strongly slow down these processes, but cannot prevent them altogether. As indicated, the aim of this study is to get insights in the effects of the ripening stage at harvest on the quality in the supply chain and in the use of non-destructive measuring methods to determine strawberry quality. To study the effects of initial quality, strawberries from the cultivars 'Elsanta' and 'Lusa' were harvested at different ripening levels during different times in their respective seasons and were stored for various times, after which their quality was assessed. Parallel to these experiments, different non-destructive techniques were tested to assess their capacity to determine and predict strawberry quality. After assessing the influences of strawberry cultivar, growth season, harvest ripeness and storage time and the use of PTR-ToF-MS and near infra-red spectroscopy, we can conclude that: -Growth season influences strawberry diameter -Harvest ripeness influences all quality parameters apart from calyx decay -Storage time strongly influences colour, firmness and fruit decay -Spectral analysis using VIS-NIR showed that firmness can be determined non-destructively -VIS-NIR shows promise for predicting firmness and fruit decay Netherlands), where the punnets were randomized per ripeness level, labelled and stored at 4°C and 80% RH. On days 1, 5 and 9 after harvest and labelling, respective samples were placed at 20°C and 80% RH for 6 hours prior to the measurements. Volatile analysis To determine volatile organic compound (VOC) production of the strawberries, the strawberries in a punnet were carefully transferred into an amber Duran GLS 80 wide mouth laboratory bottle of 2000 mL (DWK Life Sciences GmbH, Mainz, Germany) with septa mounted in the lids. After flushing with clean and filtered air for 1.5 min, the jars were closed, moved and after 1.2 h of headspace accumulation sampled using a PTR Qi-ToF-MS 8000 instrument (Ionicon Analytik GmbH, Innsbruck, Austria). The PTR-ToF-MS had a drift voltage of 900V at 60°C and 3.8 mbar, resulting in an E/N of 121 Td. Sampling flow rate was 60 mL/min and the mass range was 20 -512 m/z. Samples were taken from the jars by direct injection into the PTR-ToF-MS drift tube through a heated (110°C) peek inlet connected to a syringe needle. PTR-ToF-MS data was analysed using the program PTRwid (Holzinger, 2015), after which noise reduction was achieved by averaging over 20 consecutive and stable ToF Prod. 1 (yyyy-mm-dd) Prod. 2 (yyyy-mm-dd) Elsanta
doi:10.18174/503212 fatcat:li2iqxtid5efzkbx7sd3zqytge