ABSTRACT
The quality of a batch of fruit and vegetables is typically evaluated through subjective visual inspection and destructive measurements on a small number of samples. The fast and nondestructive character of near-infrared (NIR) spectroscopy makes it an appealing alternative for use in horticulture. Within this group, apple and pear are the fruit for which most reports on the use of NIRS technology for nondestructive quality evaluation can be found. While the skin of citrus fruit is thicker and more turbid than that of pome fruit, its flesh is more translucent. Transmittance measurements are, thus, more feasible for citrus fruit such as mandarins and oranges. The flesh, which is the only part that is consumed, is also highly turbid, which makes the transmittance approach applied in citrus fruit quite challenging. As root vegetables are storage structures that have developed under the ground, they have higher dry matter content than leafy greens, ranging from 12% for carrots to 30% for sweet potatoes.
