Maturity determination of fresh dates by near infrared spectrometry

In Israel, fresh dates are normally harvested unripe and stored in a controlled environment until marketed. Proper ripening depends on maturity at harvest time. Sugar and water contents of the dates are considered important maturity attributes. Decision-making on the harvesting schedule for each section in a plantation of fresh dates (variety Hayani) is one of the major problems for the growers. In order to estimate the optimum harvest time, conventional laboratory methods have been used to assess the maturity of samples of dates; methods which by nature are destructive, manual and time consuming. A semi-automatic system for maturity determination of fresh dates has been developed, tested and operated. It combines a near infrared (NIR) spectrometer with a step-wise cell conveyor, both of which are controlled by a PC. The NIR models were based on measuring the water and total soluble solids (TSS) contents. The calibration models and the prediction results had a standard error of prediction (SEP) of 1% for TSS and water contents. The correlation coefficient R between TSS and water contents as predicted by NIR models and as measured in routine laboratory destructive tests was 0.9. The system was capable of testing 100 dates in 3 min. © 1999 Society of Chemical Industry