Making paste and powder of unripe unshu mandarin whole orange by micro wet milling and spray drying

Unripe Unshu mandarin oranges are so hard that they are discarded. However, these whole oranges are richer in polyphenols than ripe ones and other citrus fruits. Micro wet milling (MWM) and spray drying (SD) are inexpensive processing methods that preserve nutrients. In this study, MWM and SD were used to produce unripe mandarin orange powder. In MWM, adjustment of the total solid ratio (TS) of unripe mandarin oranges to 10 % and 12 % yielded pastes with homogenous particle size after three to four MWM repeats. In SD, increasing the ratio of wall material and adjusting the TS to 15 % increased the powder yield to about 50 %. The properties of the powders were affected by the SD operating conditions such as air pressure, SD inlet temperature, and content of feed sample.