Processing Methods, Storage Conditions, Quality, and Shelf Life of Sunflower (Helianthus Annuus L.) Seed Oil Marketed In Dodoma City, Tanzania

Abstract

The study assessed the processing methods, quality, storage, and shelf life of sunflower (Helianthus annuus L.) seed oil in Dodoma City, Tanzania, from May 2022 to November 2023. Twenty samples from cold-press extraction "(n=10)" and traditional refining "(n=10)" underwent analysis for various parameters at two time points, 12 and 18 months after manufacturing. Most brands met the Tanzania Bureau of Standards (TBS) limits, but some did not; Odour (1.8±0.20- 2.20±0.20, 1.00±0.00-2.20±0.20), taste (2.20±0.20-2.40±0.25, 1.20±0.20-2.40±0.25), colour yellow (38.60±0.40-38.60±0.40, 41.00±0.95-38.60±0.40), colourr red (3.88±0.04-4.18±0.07, 4.00±0.05-4.18±0.07 ), refractive index (1.44±0.00-1.44±0.01, 1.46±0.00 1.44±0.00), relative density (0.91±0.00-0.88±0.01, 0.88±0.01-9.48±0.08), acid value (0.33±0.01-0.41±0.02, 0.35±0.02- 0.41±0.03) mg KOH/g, peroxide value (9.32±0.06-9.48±0.08, 9.08±0.02-9.48±0.08) meq/kg, iodine value (136.6 ±0.98-130.00±2.43,140.20±0.86-130.00±2.43) g/g, and saponification value (174.60± 1.50-174.60± 1.50, 180.40±0.25-180.40±0.25-174.60±1.50) mg/g for crude cold-pressed and refined oils, respectively. There were no significant differences between refined and cold pressed oils (p > 0.01). Refined oils maintained superior quality over time, with most brands adhering to TBS labelling criteria, all brands had no additives and indicated best-before dates. Quality control measures should be strengthened to ensure all brands meet TBS standards by improving storage practices.