Studies on the Functional and Biochemical Properties of Kariya Seed Defatted Flour and Storage Stability Studies of its Oil.
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Date
2014
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Obafemi Awolowo University
Abstract
This study determined the physicochemical properties and storage stability of kariya oil, functional properties and in-vitro protein digestibility of the fermented and un-fermented kariya flours. It also evaluated the effect of processing on anti-nutrients and antioxidant properties of kariya seed flour with a view to increasing the utilization of kariya seed.
A portion of dried kariya pods obtained from ornamental kariya trees in Obafemi Awolowo University, Ile-Ife were sorted, shelled and some were allowed to ferment naturally for 96 hr. Samples were taken for analysis at 24 hr interval, milled and defatted (solvent cold extraction). Crude oil was extracted from another portion using soxhlet extraction method. Part of the extracted oil was refined by degumming, neutralization and bleaching. Portions of crude and refined oil were stored at ambient and refrigeration temperature (5 °C) with or without added butylatedhydroxyltoluene (BHT) for 90 days. Samples were taken at 15 days interval for analysis. Physicochemical (pH, bulk density), functional [water, swelling and oil absorption capacities (WAC, SC and OAC)], least gelling concentration (LGC), foam capacity and stability (FC and FS), emulsifying activity and emulsion stability index (EAI and ESI)], anti-nutrients (oxalate, saponin and tannin), in-vitro protein digestibility (IVPD) and antioxidant activitiy were evaluated using standard procedures. Data obtained were analysed using descriptive and inferential statistics.
The physicochemical result showed that all the samples were acidic in aqueous solution, the bulk density ranged between 0.53 g/ml for raw fermented kariya (RFK) to 0.59 g/ml for both cooked unfermented and raw unfermented kariya (CUK and RUK). Cooked fermented kariya (CFK) and RFK had the lowest and highest WAC (106.63, 137.47%) respectively, sample RFK and CUK had the lowest and highest OAC (47.73, 84.50%). The foam capacities for samples CFK, CUK, RFK and RUK, and were 14.29, 20.00, 26.32 and 33.33% respectively while the emulsifying activity index for samples RUK, CUK, CFK and RFK were 8.75, 24.19, 24.95 and 29.79 m2/g, respectively. All the processing treatment were found to increase the in-vitro protein digestibility and reduced the anti-nutrient level in the kariya seed. The kariya seed extracts exhibited high DPPH (2,2-diphenyl-2-picrylhydrazyl hydrate) radical scavenging activity (RFK, IC50 2.68 mg extract/ml; RUK, IC50 3.37 mg extract/ml; CUK, IC50 2.82 mg extract/ml; CFK, IC50 2.69 mg extract/ml), metal chelating (RFK, IC50 1.13 mg extract/ml; RUK, IC50 0.69 mg extract/ml; CUK, IC50 0.39 mg extract/ml; CFK, IC50 1.31 mg extract/ml), ferric reducing antioxidant power (RFK, 0.28 (AAE µg/g); RUK; 0.26 AAE µg/g; CUK; 0.09 AAE µg/g; CFK; 0.56 AAE µg/g), total phenol content (RFK, 1.21 (GAE µg/g); RUK, 0.47 GAE µg/g; CUK, 0.60 GAE µg/g; CFK, 0.90 GAE µg/g). The primary oxidation products formed were very low, but rose significantly as the storage period increased. Refractive index remained almost constant while other physical and chemical properties of the oils such as peroxide value and acid value increased wth an increase in the storage period
In conclusion, kariya seed flour could find application as food ingredients in the manufacture of confectionary foods owing to its high water absorption capacity and swelling capacity. The kariya extracts could be employed as natural antioxidant and the oil could be suitable for domestic and industrial applications.
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xix,165 P
Keywords
kariya oil, in-vitro protein,, kariya pods,, kariya trees, kariya seed, Obafemi Awolowo University
Citation
Fawale S.O(2014).Studies on the functional and biochemical properties of kariya seed defatted flour and storage stability studies of its oil.Obafemi Awolowo University.