Files
Abstract
This research focused on developing a lipid ingredient with ω-3 rich algal oil from Schizochytrium sp. which could be used to formulate shelf-stable food products. Gelation, microencapsulation, and antioxidants were used to develop yogurts with comparable physicochemical properties to in-store products. Initially, antioxidant efficacies were assessed with model systems using bulk soybean oil and oil-in-water (O/W) emulsion. Oxidative stability of bulk oil had the highest improvement using 1-o-galloylglycerol (GG) as antioxidant with a final TOTOX value of 206.82 compared to bulk oil at 232.09. A mixture of δ, β, γ, and δ tocopherols (TOC) used with O/W emulsion exhibited similar results with a TOTOX value of 196.72 compared to O/W emulsion at 352.88. Gelation was used to modify ω-3 fatty acid rich algal oil to develop desirable physical properties while also improving its oxidative stability to produce an oxidatively stable ω- 3 fatty acid (FA) source. FA analysis over an accelerated oxidation study showed 12% (w/w) monolaurin oleogel (12% M) outperformed other gels in oxidative stability, preventing oxidation of approximately 17.96% and 20.43% of EPA and DHA, respectively, compared to algal oil alone. Solid fat content (SFC) and thermal properties of 12% M indicate that it could replace saturated fat sources, with an average SFC of approximately 4.5% at 30 °C, similar to butterfat, and a melting completion temperature of 59.38 °C. Antioxidants were combined with gelation and microencapsulation processing techniques to produce ingredients to formulate yogurt products. Combinations of gelation, microencapsulation, and antioxidants were produced, including a microencapsulated oleogel (MEOG) with GG as antioxidant (MEOG-GG) which exhibited significantly slower lipid oxidation than bulk oil alone as it prevented an average of 18.13 % of EPA and 12.55 % of DHA oxidation. Yogurt with MEOG-GG ingredient maintained a rheological profile and viscosity similar to store-bought yogurt and yogurt developed with butterfat. It also exhibited a significantly similar oxidative stability to both store-bought yogurt and yogurt made with butterfat. Yogurt made with MEOG-GG exhibited an average PV and p-AV of 7.17 ± 0.76 mmol O2/kg of oil and 118.85 ± 0.98 abs/g, respectively. Yogurt with butterfat had values of 8.17 ± 0.29 mmol O2/kg of oil and 149.71 ± 2.34 abs/g, for PV and p-AV, respectively.