Orange peel (Citrus sinensis)
Orange peel comprises the flavedo (colored outer layer rich in essential oils) and the albedo (white inner layer rich in fiber and pectin). In food supply chains it appears as fresh or dried zest, candied peel (sometimes chocolate-coated), pastry pastes, and expressed essential oils/oleoresins from the flavedo.
Commercial forms
Fresh or grated zest; dried and milled peel; candied peel strips or cubes (in syrup or glazed); pastry pastes; sweet orange essential oil for flavoring.
Caloric value (100 g)
Fresh peel: about 90–110 kcal/100 g (typical ≈ 97 kcal/100 g; moisture dependent).
Dried peel: about 250–320 kcal/100 g (concentration of solids).
Candied peel: about 300–380 kcal/100 g (depends on syrup °Brix and any glazing).
Average composition (indicative)
Water (fresh): ~70–75 g.
Total carbohydrates: ~20–28 g (fresh; added sugars dominate in candied products).
Dietary fiber: ~10–12 g (pectin and insoluble fiber; higher in the albedo).
Protein: ~1–2 g.
Fat: ~0.2–0.5 g (mostly from flavedo).
Micronutrients: vitamin C, folates; minerals (K, Ca).
Phytochemicals: flavanones (hesperidin, narirutin), polymethoxyflavones (tangeretin, nobiletin), carotenoids; essential oil dominated by d-limonene with myrcene, linalool, and aliphatic aldehydes (e.g., decanal).
Sensory and technological properties
Flavedo delivers a bright, floral–citrus aroma; albedo contributes body and mild bitterness. Essential oil rich in monoterpenes is volatile and light/oxygen sensitive; drying and storage should limit loss. In candied peel, osmotic sugar infusion lowers aw and stabilizes the product; pre-blanching moderates bitterness and astringency.
Processing and controls
Zest production: Remove only the flavedo to avoid excess albedo bitterness.
Drying: Use gentle convective air or freeze-drying to reach low moisture while preserving color and aroma.
Candying: Apply stepwise osmotic cycles to target °Brix (typically medium–high), then glaze/dry as needed.
Essential oil: Obtain by cold pressing or distillation, then filter and standardize for food use.
Hygiene and safety: Operate under GMP and HACCP (cleaning, foreign-body prevention, temperature/time control).
Food applications
Bakery and pastry (panettone/colomba, cakes, biscuits), gelato and semifreddi, jams and marmalades, cereals and bars, savory sauces and light marinades, salads, and infusions/teas. Candied peel serves as inclusions or décor; fresh zest elevates emulsions and dressings.
Nutrition and health
Orange peel supplies fiber and polyphenols; flavanones and pectin contribute prebiotic and viscosifying functionality. Candied versions carry significant added sugar and should be portioned sensibly. Compared with grapefruit, sweet orange peel generally contains fewer furanocoumarins; drug–food interaction potential is considered lower, though individual sensitivity varies.
Quality and specification themes
Appearance: vivid color, uniform cut, no browning.
Aroma: fresh and clean, free from oxidized/terpenic “tired” notes.
Moisture/aw: low for dried and candied forms to ensure stability and anticaking.
°Brix: compliant with candying specification (texture and sweetness).
Contaminants: post-harvest residues on whole fruit and heavy metals within legal limits.
Microbiology: counts appropriate to category; manage osmophilic yeasts in candied products.
Storage and shelf life
Fresh zest: Refrigerate in airtight containers and use promptly to preserve aroma.
Dried peel: Store cool and dry, protected from light/oxygen; control ambient RH to prevent caking and volatile loss.
Candied peel: Hold at 10–18 °C in barrier packaging; avoid condensation that promotes sugar bloom.
Allergens and safety
Sulfites may be present in candied peel as preservatives (label when above thresholds). Manage potential residues from post-harvest fruit treatments via sourcing and washing. Essential oil can cause dermal sensitization in predisposed individuals; culinary use levels are typically low.
Troubleshooting
Excess bitterness: Too much albedo or insufficient blanching → increase blanch/rinse cycles.
Sticky or “wet” candied cubes: Final °Brix too low or drying incomplete → extend osmotic steps and optimize drying.
Sugar bloom or surface crystals: Moisture diffusion/thermal swings → improve packaging barrier and control RH and cooling.
Aroma loss in dried peel: Exposure to light/air/heat → upgrade barrier packaging and apply FIFO rotation.
Sustainability and supply chain
Orange peel valorizes a by-product of juice processing. Peels can be routed to pectin and essential-oil extraction, reducing waste and BOD/COD in effluents. Traceable sourcing and compliant post-harvest practices improve safety and environmental profile.
Conclusion
Orange peel combines intense citrus aroma, useful technological functions (pectin/fiber, color), and wide culinary versatility. Careful control of bitterness, moisture, aw, and packaging maximizes sensory quality, stability, and safety across applications.
Mini-glossary
aw — Water activity: Fraction of “free” water available for reactions and microbial growth; lower aw improves stability.
RH — Relative humidity: Percentage of water vapor in air; high RH promotes caking, condensation, and sugar bloom.
°Brix — Degrees Brix: Percentage by mass of soluble solids (sucrose equivalents) in a syrup; proxy for sweetness/consistency.
GMP — Good Manufacturing Practice: Procedures and controls ensuring hygiene, consistency, traceability, and quality.
HACCP — Hazard Analysis and Critical Control Points: Preventive food-safety system identifying hazards and defining CCPs, limits, monitoring, corrective actions, and verification.
CCPs — Critical control points: Steps where control prevents, eliminates, or reduces a food-safety hazard to acceptable levels.
FIFO — First in, first out: Inventory rotation principle—use the oldest lots first to preserve quality and aroma.
BOD/COD — Biochemical oxygen demand / Chemical oxygen demand: Indicators of organic load in effluents; higher values signal greater pollution potential.
Health
A normal intake of sugar in the body is important for human health, particularly for the brain (1).
Excessive or reiterated sugar or refined sugars consumption is primarily associated with the risk of:
- type 2 diabetes mellitus,
- weight gain with consequent risk of obesity,
- increase in cholesterol LDL
- hepatic steatosis
- caries
- hypertension.
To counteract this trend, sugar levels in the blood must be lowered.
Flavonoids are phenolic compounds found in fruits and vegetables and have properties that prevent diabetes and its complications. This could improve blood sugar levels (2).
A reduction in the consumption of sugar-based sweetened beverages is recommended. The consumption of this type of beverage in early childhood is associated with increased risks of adiposity and risk of overweight/obesity (3).
