Comparative Nutritional and Phytochemical Evaluation of Cold-Pressed Versus Refined Coconut Oil: A Laboratory Study

Abstract

Background: Coconut oil is a dietary and cultural staple across the South Indian coconut belt spanning Kerala, Tamil Nadu, and Karnataka. Cold-pressed (virgin) and industrially refined coconut oils are both widely marketed, yet consumers in South India have limited comparative information on how processing influences the retention of bioactive micronutrients, antioxidant capacity, and oxidative stability while preserving basic food-grade quality. Objective: To compare the physicochemical quality, nutritional and phytochemical composition, fatty-acid profile, and antioxidant properties of cold-pressed and refined coconut oil using standard laboratory methods. Methods: In this laboratory-based comparative study, six analytical batches each of cold-pressed and refined coconut oil (n = 12 total) were evaluated for moisture, free fatty acid (FFA), peroxide value, iodine value, and saponification value; for vitamin E, total carotenoids, total phenolics (Folin-Ciocalteu), DPPH radical-scavenging activity, and oxidative stability (Rancimat); and for fatty-acid composition by gas chromatography. Data are expressed as mean ± standard deviation and compared using independent-samples t-tests (df = 10) with Cohen's d effect sizes; p < 0.05 was significant. Results: Cold-pressed oil retained markedly higher vitamin E (48.31 ± 2.81 vs 20.06 ± 3.35 mg/kg), total carotenoids (2.757 ± 0.480 vs 0.768 ± 0.176 mg/kg), and total phenolics (75.42 ± 8.10 vs 26.99 ± 5.03 mg GAE/kg; mean difference 48.43), with correspondingly greater DPPH inhibition (58.93 ± 3.37 vs 22.73 ± 1.90 %) and oxidative stability (18.83 ± 0.63 vs 12.02 ± 0.81 h); all p < 0.001 with very large effect sizes. Refined oil showed lower moisture, FFA, and peroxide value, consistent with purification. Fatty-acid composition was essentially equivalent between oils (both lauric-dominant, ~90-92 % saturated). Conclusion: Cold-pressed coconut oil is nutritionally and antioxidant-superior, whereas refined oil is more purified; fatty-acid composition is equivalent. These low-cost quality indicators are relevant to consumers and the coconut industry across South India.