![Photo by WUR](/upload_mm/7/f/c/4505413d-7b3f-4cef-8c55-12648208187d_Quality%20firmness%20%282%29%2020201207_110453_2fe79c09_320x800_1831x1416.jpg)
Doing quality measurements
Extensive quality evaluations are carried out at various points in the fruit and vegetable chain. Different markets require different quality criteria. Examples of these quality criteria are a specific colour, size, firmness and sugar content. Quality can be measured non-destructively (by looking, feeling, sizing, smelling) or destructively (by cutting, tasting, grinding). Quality measurements include both external and internal properties. External quality measurements are usually focused on size and shape, colour, physiological disorders and diseases. Examples of internal quality measurements are firmness, sugar content, acidity, flavour, and disorders and diseases.
![Example of destructive quality measurement. Photo by WUR](/upload_mm/2/c/e/7ad702d8-f0b7-4107-b394-dcd43a264ace_Quality%20destructive%2020190629_112548_1eab615c_320x240.jpg)
Destructive quality measurements
Different methods for analyses of fruit and vegetable quality exists. Well-known measurement methods are measurement of soluble solids content (SSC) after juicing and measurement of firmness with a penetrometer. These methods are easy to perform under the condition that the right protocol is followed.
Unfortunately these mentioned methods are destructive for the fresh product. Consequently only a sample of produce can be measured. It is therefore very important that the sample is representative of the whole batch.
![XRT image of an apple. Photo by WUR](/upload_mm/7/8/c/22a28b59-f0f3-47fc-a8dc-2686a6874853_XRT-Kanzi%20doorsnede%20sec_ecc2f9cc_320x240.png)
Non-destructive quality measurements
Non-destructive quality measurements of fruit and vegetables can be helpful to measure external and internal properties. It has the great advantage over destructive measurements that products can still be sold after inspection. In this way, it facilitates the grading of products based on their size, shape, maturity or ripeness.
Among the techniques used are vision systems and near infrared spectroscopy (NIR). In addition to NIR devices in sorting lines, several hand-held NIR devices are available. Handheld devices can also be used in the field to measure fruit maturity. A very interesting development is NIR hyperspectral imaging which provides spectral data as a set of images.
![At least 15 apples should be used in a sample. Photo by WUR](/upload_mm/4/f/9/8223a376-1434-4ff3-b675-ace8707e5b3c_20210604_125016_8e12e5e5_320x240.jpg)
Sample preparation
![Calibrated equipment for measuring the soluble solids content. Photo by WUR](/upload_mm/4/6/e/6b290cfd-e956-486a-ac3a-0333d3374bc2_Quality%20preparations%20ijkreeks_babadf3b_320x240.jpg)
Equipment preparation
![A colour chart is used to determine the colour of a product objectively. Photo by WUR](/upload_mm/c/d/7/fbcfb39c-579b-49bd-b020-ed93ec103e57_Quality%20colour_6f4cf4db_320x240.jpg)
Colour measurements
![Different tools can be used to measure the size of a product. Photo by WUR](/upload_mm/d/a/7/b3c6d9f5-5799-4934-9ddc-7958b9d675e5_Quality%20size%2020220214_131852_883effce_320x240.jpg)
Size and shape measurements
![Use of a penetrometer to determine the firmness of the fruit. Photo by WUR](/upload_mm/e/9/6/3a8616d9-8161-4566-9358-bb44d4f6e2e1_Quality%20firmness%20%281%29%2020201207_110435_257169d1_320x240.jpg)
Firmness measurements
![The measurement of soluble solids content is a destructive measurement. Photo by WUR](/upload_mm/8/f/9/cbd15fb1-cdb2-4ace-b2a5-ca713a9d708b_Quality%20soluble%20solids%20content%2020211208_135505_ad8fc947_320x240.jpg)
Measure Soluble Solids Content
![Apples dipped in lugol to measure the starch content. Photo by WUR](/upload_mm/d/0/6/1c253823-d028-4cc6-b1aa-22996fda38f7_Quality%20starch_d72df54b_320x240.jpg)
Measuring starch
![Setup to measure titratable acidity. Photo by WUR](/upload_mm/5/e/b/c36a9ccc-1fb8-48bd-a849-f7061de27d47_Quality%20titratable%20acidity%2020190628_144108_25fbb6f5_320x240.jpg)
Titratable acid measurements
![Drying samples in the oven as part of the %dry matter content determination. Photo by WUR](/upload_mm/1/9/6/a25e4393-36ac-4935-a639-62fe53ce83de_Quality%20droge%20stof%2020200908_125911_12c8002d_320x240.jpg)
Measure the % dry matter
![Tasting of fresh products by a trained panel is the best way to determine sensory quality. Photo by WUR](/upload_mm/9/9/2/de178abd-36b1-4ac5-88e1-6f1bb9fdef1e_Off%20taste_cbeae838_320x240.png)
Measuring the sensory quality
![Two examples of how disorders may appear in fresh products. Photo by WUR](/upload_mm/4/4/e/70265fe4-e1c9-461e-8589-c8f8e3902251_Quality%20disorders%2020220224_143532_002_29097698_320x240.jpg)