Fruits and vegetables such as watermelon (Citrullus lanatus) contain health-promoting bioactive compounds, but the levels of these compounds and other key quality parameters vary at different stages of fruit maturity. Establishing a relationship between optimum maturity and quality parameters including health-promoting compounds is critical to increase consumption and provide nutritional security. However, many chemical assays require destructive sampling of the fruit. Recently, non-destructive methods such as Raman and near-infrared spectroscopy (NIR) have attained increasing interest due to advances in instrumentation and chemometric applications. In the case of Raman spectroscopy, narrow and highly resolved bands allow non-destructive extraction of chemical and physical information from the samples. Similarly, NIR has been extensively used for non-destructive measurement of internal quality of fruits and vegetables. The presentation will focus on Raman and NIR and the application of different techniques to detect changes in quality parameters during the ripening of watermelon fruits. We evaluated the external maturity of watermelon using a non-invasive Raman spectroscopy. Spectral acquisition from the fruit surface was carried out at wavelength range 400–2000 cm-1 using a handheld Raman spectrometer equipped with 830 nm laser excitation source. The changes in the intensity of three Raman peaks (1002, 1156, and 1525 cm-1) assigned to the carotenoids were evaluated using chemometric analysis. The level of carotenoids decreased as the watermelons ripened, and the spectral signatures obtained from carotenoids can be used to evaluate the external maturity of watermelon. Furthermore, internal quality attributes (soluble solid contents) were predicted non-destructively using NIR and Soft Independent Modelling and Class of Analogy. Our results demonstrated that the developed model had good predictive power with high sensitivity. Therefore, these novel techniques have enormous potential to replace time-consuming, destructive and labor-intensive conventional techniques for monitoring quality indicators of fruits and vegetables.

Non-destructive methods to determine the maturity of specific fruits and vegetables

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.