Undetected browning, spots, blemishes and other flaws can affect fruit quality, damage brand reputation and result in lost business.
Optical sensing techniques including spectroscopy are among the tools available to fruit and vegetable producers to assess quality parameters such as internal and surface color, sugar content and acid level.
Optical sensing technologies are very versatile, making possible rapid, non-destructive measurements at the surface of the fruit or under the skin or peel. Setups can be deployed in-line, at-line or in the lab.
In addition, sensing tools like spectrometers can be integrated into food sorting machines at the component or sub-assembly level or used as turnkey systems. Systems can be combined with advanced machine learning to create smart sensors for grading samples.
Since 2010, Ocean Optics has worked with a leading European supplier of fruit and vegetable sorting solutions on a system that sorts apples using reflectance spectroscopy. By measuring the apples and then applying chemometric modeling to the results, the sorting supplier can predict fruit quality characteristics. These include internal browning, which consumers associate with poor quality; and acid level, which is especially relevant for fruits used in soft drinks.
Along the way, technical challenges were tackled as a partnership between Ocean Optics and the customer. These challenges included the speed of the sorting line, which is why a spectrometer with rapid scanning capabilities was selected; the need for a custom optical setup to illuminate the samples, which was integrated with our collimating lens to view the reflected light; and the use of chemometrics methods to predict apple parameters such as sugar level, internal browning and acid level.
Reflection spectroscopy has the benefit of being non-contact and noninvasive and can be configured for various samples. When combined with chemometrics modeling, reflection spectroscopy is a powerful tool for extracting information about chemical composition that would otherwise require laboratory analysis. It can be used to address a range of issues related to food quality and safety and can be applied at all points in the supply chain, from producer to consumer.