Formulation and validation of oil blends for enhanced nutritional quality and stability
Kumari, A. (2023). Formulation and validation of oil blends for enhanced nutritional quality and stability. PhD Thesis. Division of Biochemistry, ICAR-Indian Agricultural Research: New Delhi. 128 + i-xxix pp.
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Document type: Dissertation
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| Abstract |
Blending two or more oils is an effective and economical method to get optimized fatty acid composition and physicochemical properties. In blending, oil deficient in one component is mixed with the oil having the same component to get the desired composition. Rice bran oil (RBO) is deficient in omega-3 fatty acids but rich in antioxidants. However algal oil is a good source of omega-3 fatty acids particularly long-chain omega-3 fatty acids (EPA- eicosapentaenoic acid and DHA-docosahexaenoic acid) which is not found in other vegetarian sources. Due to the presence of polyunsaturated fatty acids (EPA and DHA), algal oil has low stability. In this study, the blending ratio for rice bran oil and algal oil was optimized to get superior physicochemical characteristics and omega-3 fatty acid content. The study was divided into three parts namely: screening and selection of microalgal culture producing EPA and DHA, optimization of blending ratio of RBO and algal oil for improved nutritional quality and stability and in-vivo validation of health benefits of the oil blend. Among the seven microalgal cultures viz. Chlorella minutissima, Chlorella sorokiniana, Haematococcus sp., Coelastrella sp., Nannochloropsis sp., Dunaliella sp., and Spirulina platensis, EPA and DHA were detected in Nannochloropsis sp. and Spirulina platensis (0.46 % and 0.50% respectively). The algal oils viz. oil extracted from Nannochloropsis sp. (NAO) and Spirulina platensis (SPO) and purified algal oil from Schizochytrium sp (SCO) were used for blending with RBO. Binary oil blends (RBO: SCO, RBO: NAO, RBO: SPO) were formed in six ratios viz. 90:10, 85:15, 80:20, 75:25, 70:30, and 65:35 and ternary oil blends (RBO: NAO: SPO) were formed in four ratios viz. 80:10:10, 80:05:15, 70:10:20 and 65:10:25. Among the formulated oil blends, RBO: SCO (80:20) was found superior in physicochemical parameters, fatty acid composition and omega-3 fatty acids content which was evaluated through chemometric approach viz. principle component analysis and cluster plot analysis. This oil blend has the lowest peroxide value (2.5 meq O2/kg), acid value (4.2 mg KOH/g), iodine value (118 g/100g) and a significant amount of total tocopherol (426 mg/kg) and total oryzanol (1.19 %). SFA: MUFA: PUFA (saturated: monounsaturated: polyunsaturated fatty acid) was 1.09: 1: 1.29 which is very near to the ideal fatty acid composition (1:1.5:1) as given by WHO. The total omega-3 fatty acids content was 20.71% compared to 0.79 % in RBO. This result showed improvement in omega-3 fatty acids content and oil stability-related parameters of oil blend (RBO: SCO, 80:20). The hypocholesterolemic, hepatoprotective and non-allergic properties of RBO: SCO (80:20) were validated in the hypercholesterolemic rats. This revealed the health benefit of formulated oil blends which could have promising applications in the fields of neutraceuticals, oil industry, feed and food industry. |
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