Non-destructive prediction of ‘Valencia’ orange (Citrus sinensis) and ‘Star Ruby’ grapefruit (Citrus × paradisi Macfad) internal quality parameters using Vis/NIRS

Commercial maturity of citrus fruit is measured by sweetness and flavour parameters, which involve the use of destructive, inconsistent, time consuming and expensive techniques such as titrations and destructive refractometer-based juice analysis.
New approaches to substitute these techniques involve the application of non-destructive prediction of quality attributes.
The ability of visible to near infrared spectroscopy (Vis/NIRS) to non-destructively quantify total soluble solids (TSS), titratable acidity (TA), TSS:TA ratio and BrimA (balance between sugars and acids) of ‘Valencia’ orange and ‘Star Ruby’ grapefruit was evaluated.
BrimA is an organoleptic parameter considered highly correlated to citrus sweetness and flavour which better aligns with prediction of human perception of good taste.
The most accurate model for predicting BrimA was achieved on ‘Valencia’ orange (R²=0.9576; RMSEP=0.006; RPD=3.96) over ‘Star Ruby’ grapefruit (R²=0.858; RMSEP=0.429; RPD=2.45). Other parameters were also predicted with high accuracy.
This study demonstrated the ability of Vis/NIRS, combined with chemometrics, to non-destructively predict sweetness and flavour attributes of oranges and grapefruit.
Commercial application of NIRS models for predicting citrus fruit internal quality parameters prior to pricing of fruit was suggested as a tool for increasing reliability between suppliers and consumers.

VIII International Postharvest Symposium: Enhancing Supply Chain and Consumer Benefits – Ethical and Technological Issues

K. Ncama, S.Z. Tesfay, U.L. Opara, O.A. Fawole, L.S. Magwaza

BrimA, maturity index, citrus flavour, near infrared spectroscopy

https://doi.org/10.17660/ActaHortic.2018.1194.160