Are Peach Seeds Dangerous? Cyanide and Color Change Near Pit

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Amygdalin can lead to the formation of HCN. Photo by Clara Piccirillo.

Peach Seeds: Is There Real Danger?

The quantity of cyanide contained in peach stones can be different, depending on the variety of the peach, its maturation, etc.

In a study published by Rezaul Hauqe et al. in Food Chemistry , it was reported that 1 kg of dried peach stones contained about the equivalent of 700 mg HCN. This quantity can hardly be dangerous for a human. As reported by the Integrated Risk Information System, a quantity of 10.8 mg a day per kg of weight of a person did not cause any evident adverse effect.

For instance, a person weighting 70 kg could ingest up to 760 mg of cyanide every day without being affected; this would correspond to about 1 kg of peach stones every day – that is a lot of peach seeds.
The ingestion of such high quantity of stones is not very likely for a person; care should be taken, however, for accidental ingestion by small pets.

Poison Leaching Into the Fruit?

It is possible that small amounts of amygdalin could leach into the pulp of the fruit from the pits. However, considering the concentration levels discussed above, there is no evidence that this can cause a real danger to human health.  The red/orange color of the pulp close to the pit is not due to the presence of amygdalin or cyanide, as these compounds are colorless.

This red/orange color happens only with some species of peach and it is normal, i.e. it is not due to the fruit becoming rotten. The color change is caused by the accumulation of water-soluble pigments called anthocyanines near to the pit; these are a class of compounds which can be red in color. The color change phenomenon is referred to as “pit bleeding.”

Peach Seed Safety

Peach seeds themselves do not offer an undue risk when eaten in reasonable quantities, using the calculation above based on body weight, and the red-orange coloration next to the seed in some peaches is even less dangerous. Set your mind at ease, there’s nothing wrong with eating a peach that’s got darker color next to the stone.

Sources

C.D. Dardick et al. Stone formation in peach fruit exhibits spatial coordination of the lignin and flavonoid pathways and similarity to Arabidopsis dehiscence. (2010). BMC Biology, 8(13), 2010 doi:10.1186/1741-7007-8-13. Accessed November 1, 2012.

Helsinki University of Technology. Chromophore in wood and hard pulp. Accessed November 1, 2012.

V. Mendu et al. Identification and thermochemical analysis of high-lignin feedstock for biofuel and biochemical production.” Biotechnology for Biofuels, 4(43), 2011 doi:10.1186/1754-6834-4-43.

M. Rezaul Hauqe et al.: “Total cyanide determination of plants and foods using the picrate and acid hydrolysis methods.” Food Chemistry, 77(107) 2002.

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