Aromatization of olive oil with ginger and turmeric powder or extracts by the co-processing and maceration methods

Abstract

Aromatized olive oils were prepared by the addition of ginger and turmeric spices and their combination (ginger + turmeric) with two different forms: powder and extracts. The spices were incorporated to olive paste at kneading stage (co-processing) or directly to olive oil as infusion (maceration) (5% for powder, 3% for extract; w/w). Aromatization provided a lower peroxide value accompanied by a longer induction period, increased total phenolic content, and enhanced antioxidant activity. The use of turmeric as a powder may be advantageous for use in vegetable oils, especially because the bioactive antioxidant compounds it contains are hydrophobic. In another way, it was also the reason why the alcoholic extract of ginger gave more effective results than turmeric, which had a higher extraction yield than ginger. For both the co-processing and maceration methods, ginger powder and extract induced the strongest radical scavenging activity in oil. The pungent taste was more marked in turmeric-aromatized oils and spicy taste in ginger-aromatized oils. The use of these two spices together incorporated the bioactive components into the oil while balancing the burning effect of ginger, making it more possible to benefit from its high antioxidant effect.

Practical Applications: Aromatization of olive oil by maceration and co-processing not only enriched it with bioactive components but also improved oxidative stability with quality indices such as free acidity and peroxide. In terms of quality indices and oxidative stability, maceration had advantages over co-processing. However, co-processing was more effective in terms of total phenolic and radical scavenging activity. At the industrial level, the incorporation of an aromatic material at one step of the process, that is, co-processing or co-milling, can be advantageous in terms of application without requiring extra time for the aromatization.