Influence of churning and thawing temperatures on yield and quality of virgin coconut oil

Abstract

The churning and thawing temperatures affect the yield and quality of coconut oil in integrated wet process. The thesis reports on the selection of Cocos nucifera species that contributed the highest oil content, followed by the optimization of integrated wet process. The highest oil content from coconut varieties was rendered by Soxhlet extraction. The response surface methodology (RSM) was used to determine the effects of churning (Tc) and thawing (Tt) temperatures by using the central composite design (CCD). The experimental design was limited to Tc (0.5-17.5 oC ± 1.0) and Tt (25.0 - 67.2 oC ± 1.0). The chemical constituent of ferulic acid was used to represent the total phenolic content in virgin coconut oil. The ferulic acid was determined by using high performance liquid chromatography (HPLC) and its colour was analysed by colorimeter. The free fatty acid (FFA) was determined by Association of Analytical Communities (AOAC) 940.28 method. The highest oil content (p =0.05) was obtained from West African Tall (WAT), contributed 69.07 ± 0.06% compared to other species of Mawa, Matak, Rennel Island Tall, Maren and Tagnanan Tall comprising 64.62 ± 0.30%, 63.45 ± 0.37%, 63.42 ± 0.30%, 59.68 ± 0.01%, 58.12 ± 0.03% of oil, respectively. From the experiments, the oil yield and ferulic acid content showed the effects on the studied parameters. The equation of the responses were Oil Yield = 24.52 – 1.53A + 4.10B – 4.01A2 – 1.73B2 -3.79AB and Ferulic Acid = 7.17 – 0.042A + 0.22B – 0.28A - 0.59B2, respectively, where A (churning temperature) and B (thawing temperature). For FFA and colour implied the mean responses to the studied parameters corresponding with 0.11% and 0.55 yellowness. From the optimum point at Tc, 7.4 oC and Tt as 50.4 oC, the oil yield for WAT was 31.44 ± 0.24 % (w/w), 11.3x10-2 ± 0.11 ppm for ferulic acid, 0.10 ± 0.08 % for FFA and 0.04 yellowness for colour. The moisture content of the final oil 0.11 ± 0.15% was complied with the virgin coconut oil standards. The optimization process showed an increment of oil yield and ferulic acid content in virgin coconut oil using integrated wet process.