E230 (a biphenyl, diphenyl)

E230 is biphenyl, also called diphenyl. Historically it was used as an antifungal preservative for the surface treatment of citrus fruit such as oranges, lemons, grapefruits, and similar produce that needed to survive storage and transport without mold. This is different from additives mixed into the food itself. E230 is mainly about peel, packaging, and post-harvest treatment rather than the nutritional value of the fruit pulp.

Why it is not an ordinary recipe preservative

Biphenyl belongs to substances used to protect the surface of fruit from fungal spoilage during storage and transport. The technological reason is understandable: citrus fruit travels long distances, sits in warehouses, and faces changes in temperature and humidity. Mold on the peel can spoil a shipment quickly. Post-harvest peel treatment therefore became a separate issue in food safety and fruit trade.

For someone reading labels, the practical meaning is simple: E230 should not be judged as a normal ingredient in a dish. The real question is whether the peel, zest, peel-on slices, infusions, marmalades, or drinks containing citrus peel are meant to be eaten. If the fruit is peeled and only the flesh is consumed, contact with surface treatment is lower, but washing before peeling still matters so residues are not transferred by hands or a knife.

Regulatory and practical context

In the modern European context, E230 is not treated as an ordinary approved food additive for free use in foods. Questions about citrus treatment are now discussed more through post-harvest substances, pesticide residues, labeling, and whether the peel is edible. Older additive tables that simply list E230 as a citrus preservative may therefore be too simplified. Current assessment should always be tied to country, product, and labeling.

For keto and LCHF, E230 is not a carbohydrate problem. It is not sugar, starch, or a sweetener. However, citrus zest is often used in low-carb cooking: sauces, fish dishes, flourless baking, desserts, infusions, marinades, and flavoring. That is where peel treatment becomes practical. If zest is eaten, it is better to choose fruit labeled as having edible peel, reliable organic options where appropriate, or products specifically intended for peel use.

What to do with citrus at home

Washing reduces dirt and some surface contamination, but it does not automatically make every treated peel suitable for eating. If packaging says the peel is not intended for consumption, zest should not be used. For juice or pulp, the fruit can be washed, peeled, and used without the peel. For zest in recipes, the better choice is fruit where the producer or seller clearly allows peel use.

This matters in low-carb cooking because a small amount of zest can improve flavor without sugar. Lemon zest in sauce, orange zest in a keto dessert, or grapefruit zest in a marinade adds aroma, but it also makes the peel part of the food. The issue with E230 is therefore not ketosis or carbohydrates, but raw material quality and caution around surface treatment.

Practical conclusion

E230 is best understood as a historical and technological marker of citrus peel treatment against mold. It does not make fruit flesh high in carbohydrates and it has no nutritional value. But it reminds us that zest is not a neutral detail: its safety depends on what the fruit was treated with, how it is labeled, and whether it was intended for peel consumption.

If zest is needed, choose fruit with clear labeling, wash it carefully, and avoid peel from uncertain sources. If citrus is needed only for juice or pulp, surface treatment is less relevant, but careful hygiene before peeling still makes sense. This is more accurate than mechanically fearing the E230 code or assuming that every citrus peel is suitable for eating.