C. Camps and C. Gilli
Agroscope, Research Division in Plant-Production Systems, Route des Eterpys 18, CH-1964 Conthey, Switzerland

SUMMARY Textural properties of fruit and vegetable remain a key information in postharvest supply chains. Indeed, the ability of a given fruit or vegetable to be transported, stored or appreciated by a given consumer segment is strongly related to texture. Today, textural characterization and measurement with aiming at deciding the post-harvest life of a fruit or vegetable is for far a current and future research topic. In the present study, local and global elasticity and SSC of two cherry tomato varieties and a grape tomato let in shelf-life for two weeks have been monitored. Local elasticity has been measured by using penetrometry while global elasticity has been assessed by analyzing uniaxial compression test. Fruit were subjected to non-destructive FT-NIR measurements and prediction models of texture have been performed by using a PLS regression and wavenumber selections. Promising results have been obtained for several parameters allowing to measure local or global textural properties. R2-values ranged from 0.70 to 0.97 and RPD-values from 1.8 to 6.1. The development of a non-destructive and rapid method for measuring fruit texture, with particular regard on fruit elasticity, is promising because it could be helpful to better understand the potential of tomato varieties shelf-life in post-harvest stages. Also, the texture parameters predicted by NIR spectroscopy can be related to skin or/and flesh properties, giving the possibility to non-destructively follow the texture changes at tissue level. However, further development is required to consolidate the chemometric models by adding more variability (genetic, cultural practices, post-harvest). Keywords near-infrared spectroscopy, partial least square regression, penetrometry, soluble solids, texture, uniaxial compression

Significance of this study What is already known on this subject? Texture is a key factor for tomato quality and consumers’ preferences. Firmness has been shown to be significant to evaluate tomato maturity and some studies showed the possibility to predict firmness values by Near-infrared spectroscopy and chemometrics. What are the new findings? The present study proposes a multi-parameter approach of texture analysis by using two mechanical tests giving orthogonal information. Such information allowed to differentiate texture at skin and flesh levels and variability due to variety or shelf-life exposure. Some of the described texture parameters can be predicted by non-destructive FT-NIR spectroscopy and chemometrics. What is the expected impact on horticulture? Since the FT-NIR measurements are non-destructive, the method could allow to measure larger batches of fruits compared to traditional methods of texture measurements. In this way, texture properties could be more easily implemented 1) in breeding programs aiming at creating new tomato varieties based on texture characteristics (thousands analyses); 2) in a postharvest research institute because the method gives the possibility to follow the texture of a single fruit over time; and 3) for quality control of fresh fruit and vegetables at any step of the supply chain.

E-mail: cedric.camps@agroscope.admin.ch  

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Received: 8 November 2016 | Accepted: 31 January 2017 | Published: 30 June 2017 | Available online: 30 June 2017