Can pine nuts go bad?

In this short article, we will provide an answer to the question “can pine nuts go bad?” and the effective methods of storing pine nuts.

Can pine nuts go bad?

Yes, pine nuts can go bad. Tree nuts have a high oil content and fatty acid composition that can render them susceptible to oxidative rancidity and rapid deterioration.

Storage conditions greatly influence the quality and shelf life of tree nuts. Tree nut species differ in their storage requirements because of their varying oil and fatty acid compositions.

In general, nuts with high levels of monounsaturated fatty acids are more stable and less susceptible to oxidative rancidity than nuts containing high levels of polyunsaturated fatty acids. (1)

 What is the shelf life of pine nuts?

The nuts can stay fresh in the pantry for up to 1 to 2 months, in the fridge for 3 to 4 months and in the freezer for 5 to 6 months. Optimal storage conditions and packing with special materials like high-density polyethylene have the potential to greatly increase the shelf life of pine nuts up to 3 years

The stability of tree nuts is affected by their fatty acid composition. Pine nuts possess a fatty acid profile in which polyunsaturated species are abundant, especially linoleic acid, with lesser amounts of α-linolenic acid. The major monounsaturated fatty acid is oleic acid.

The high levels of unsaturated fats limit the shelf-life of these nuts, making them prone to oxidation, which reduces their nutritional and organoleptic characteristics. 

During the storage and distribution steps, pine nuts are exposed to a wide range of environmental conditions that can trigger various chemical reactions that alter the product mainly due to oxidative processes (2)

What is the most effective way of preserving pine nuts?

In summary, low-moisture conditioning integrated with near freezing temperature storage effectively preserved the quality and extended the shelf-life of pine nuts.

Deterioration of pine nut quality in storage is caused by metabolism of nuts and microorganisms, which depends on storage conditions: temperature, moisture content, and gas composition. (3)

Can you put in the freezer pine nuts?

Yes. Pine nuts can be stored in the freezer to increase their shelf life. Overall, integration of low-moisture conditioning and near freezing temperature storage can be a promising non-chemical way for maintaining the postharvest quality and extending shelf-life of pine nuts (3)

What are the signs of pine nut spoilage?  

The sensory attributes that characterize pine nuts quality are color, odor, texture, and taste.

Unpleasant or rancid odors and flavors that affect the food quality, browning of the nut and the presence of mold are all signs of spoilage (2, 3)

What happens if you eat spoiled pine nuts?

You may experience symptoms like stomach pain, nausea, vomiting, and diarrhea all associated with light food poisoning. 

Eating pine nuts (spoiled or not) can also occasionally cause some people to experience a bitter or metallic taste lasting from a few days up to 2 weeks.

This taste disturbance has been referred to as ‘pine mouth’ or ‘pine nut syndrome’.

Not all people who consume pine nuts become afflicted with the taste disturbance. The pine nuts do not taste any different at the time, but after 1 to 3 days the bitter or metallic taste becomes apparent and is exacerbated by the consumption of food and drink.

The symptoms normally disappear after several days and there are no adverse health effects.(4)

Conclusion

In this short article, we provided an answer to the question “can pine nuts go bad?” and the effective methods of storing pine nuts.

Reference

  1. Gama, T., Wallace, H. M., Trueman, S. J., & Hosseini-Bai, S.  Quality and shelf life of tree nuts: A review. Scientia Horticulturae, 242, 116–126. 2018.
  2. Carolina Henríquez, Verónica Loewe, Jorge Saavedra, Andrés Córdova & Mariane Lutz  Effect of the type of packaging on the oxidative stability of pine nuts (Pinus pinea L.) grown in Chile, CyTA – Journal of Food, 16:1, 255-262, 2018.
  3. Cai, L., Liu, C., & Ying, T.  Changes in quality of low-moisture conditioned pine nut (Pinus gerardiana) under near freezing temperature storage. CyTA – Journal of Food, 11(3), 216–222. 2013.
  4. Risso DS, Howard L, VanWaes C, Drayna D. A potential trigger for pine mouth: a case of a homozygous phenylthiocarbamide taster. Nutr Res;35(12):1122-5.2015

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