Near infrared (NIR) spectroscopy as a tool for monitoring blueberry osmo-air dehydration process |
| |
Authors: | Nicoletta Sinelli Ernestina CasiraghiStefania Barzaghi Ada BrambillaGabriella Giovanelli |
| |
Affiliation: | a Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano via Celoria 2, 20133 Milano, Italyb CRA-Centro di ricerca per le produzioni foraggere e lattiero-casearie, via Piacenza 29, 26900 Lodi, Italyc CRA-IAA, Unità di ricerca per i processi dell''industria agroalimentare, via Venezian 26, 20133 Milano, Italy |
| |
Abstract: | Osmo-air dehydration treatments are widely applied to fruits in order to prolong shelf-life, reduce packaging and logistic costs, and improve both sensory and nutritional quality of the end products. In this work osmo-air dehydration was applied to blueberries (Vaccinium corymbosum), a fruit that is gaining increasing attention due to its high content of dietary antioxidants. In particular, the aim of this study was to investigate the performance of near infrared (NIR) spectroscopy as a tool for monitoring blueberry osmo and air dehydration processes.Blanched blueberries were dipped in sucrose and fructose + glucose osmotic solutions for 24 h, and the osmotic exchanges were determined by mass balances (water loss, solid gain, sugar intake, changes in total phenolics and anthocyanins); NIR spectra were collected in order to study modifications due to the osmotic treatments. Untreated and infused berries were subsequently air-dried at 70 °C to final moisture content of 10-14%. During drying chemical, nutritional and structural changes were monitored and NIR spectra were acquired on whole berries, using an optic probe working in diffuse reflectance. Spectral data were standardized, transformed into first derivative and processed by Principal Component Analysis. Results show that NIR spectroscopy was able to follow the osmotic and the air-drying processes and to discriminate untreated and osmo-dehydrated berries. Spectral differences reflect the main molecular modifications associated with water absorption bands due to OH stretch + OH bending and sugar absorption bands due to CH stretch + CH bending and OH stretch + OH bending. In order to investigate the variation of main constituents (sugars and water) involved in the osmo-dehydration process, two-dimensional correlation analysis of spectral data was also carried out. |
| |
Keywords: | NIR spectroscopy Osmo-air dehydration processes Blueberries Two-dimension correlation analysis |
本文献已被 ScienceDirect 等数据库收录! |
|