This weekend, I looked up "pistachio."
The pistachio (Pistacia vera L., Anacardiaceae ; sometimes placed in Pistaciaceae) is a small tree up to 10 m tall, native to mountainous regions of Iran, Turkmenistan and western Afghanistan. It has deciduous pinnate leaves 10-20 cm long
.I was specifically interested in why the pistachios people eat as a snack are sometimes covered with a dye.
The shell of the pistachio is naturally a beige colour, but it is sometimes dyed red or green in commercial pistachios. Originally the dye was applied by importers to hide stains on the shells caused when the nuts were picked by hand. However most pistachios are now picked by machine and the shells remain unstained, making dyeing unnecessary (except that some consumers have been led to expect coloured pistachios). Roasted pistachio nuts turn naturally red if they are marinated prior to roasting in a salt and strawberry marinade, or salt and citrus salts.
I'd hardly say that applying a marinade of salt and strawberries is natural, unless pistachios tend to naturally fall into such a bath.
I found it intriguing that pistachios may calm physical stress reactions. From Science Daily:
Posted by James at March 3, 2008 8:54 AM
"A ten-year follow-up study of young men showed that those who had larger cardiovascular responses to stress in the lab, were more likely to contract hypertension later in life," says Dr. Sheila G. West, associate professor of biobehavioral health. "Elevated reactions to stressors are partly genetic, but can be changed by diet and exercise. Lifestyle changes can make the biological reactions to stress smaller."