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  • Optimization studies to obtain colourant extracts from Curcuma longa Linnaeus
    Publication . Khadraoui, Mohamed Hamza; Pereira, Eliana; Barros, Lillian; Zaghdoudi, Khalil
    Colour is spread widely in nature in several matrices, namely in fruit, vegetables, seeds and roots. In daily diets, consumers ingest a large quantity of many natural pigments, especially anthocyanins, carotenoids, curcuminoids, chlorophylls and betacyanins. Over time, it has been visible that there has been a preference for natural and healthier products, leading to changes in the industrial sector, especially in the food industry. Colourants are one of the most important additives in terms of marketing, because their presence influences consumer’s perceptions; being used in juices, candies, cakes, jellies, yoghurts and many other products. Among the oldest cultivated species, Curcuma longa Linnaeus has been known for a very long time and widely used in Indian cuisine, being famous for its yellow-gold colour and its spicy flavour. In addition, its constituents - curcuminoids, are substances with important health properties, performing bioactive functions, mainly antioxidant and anti-inflammatory action. In this work, the extraction optimization studies of curcumin from Curcuma longa Linnaeus commercial powder was optimized through an ultra-sound assisted extraction (UAE), by applying a response surface methodology (RSM) combining different independent variables. The identification and concentration of curcumin was quantified by HPLC-DAD-ESI/MS. Moreover, the bioactive properties of the optimized extract rich in curcumin were also evaluated through in vitro tests of antioxidant, antimicrobial, toxicity, and cytotoxic activities. The antioxidant activity was evaluated by means of TBARS (Thiobarbituric Acid Reactive Species) and OxHLIA (oxidative hemolysis inhibition assay) methodologies; the antimicrobial activity was determined using the microdilution method in Gram-positive and Gram-negative bacteria; the cytotoxic properties were studied in four human tumor cell lines: MCF-7 (breast carcinoma), NCI-H460 (lung carcinoma), HeLa (cervical carcinoma), AGS (gastric adenocarcinoma) and CaCo (colorectal adenocarcinoma); and toxicity in a non-tumor cell line called hFOB (osteoblast). The results revealed that the UAE optimal conditions were established as t= 6.87 min, S= 57.50 % (ethanol) using 65 g/L of solid/liquid ratio and 27.5% of power, conducting to an extraction yield of 21%, with a total curcumins content of 30.2 mg per g of powder and 294.7 mg per g of extract (dried extracted residue-basis). Regarding the evaluation of bioactivities, the extract showed antioxidant capacity, as well as bacteriostatic and bactericidal activity in some of the tested strains. In addition, the extract also presented antiproliferative capacity in most of the tumour cell lines tested, a promising anti-inflammatory potential and absence of toxicity. In this sense, is possible to say that this study has a great interest for the food industry, because it highlights curcumin as colourant and as bioactive compound. Furthermore, it promotes the development of new solutions that allow the reduction of the number of artificial additives, namely colourants, used in the food sector, replacing them with natural equivalents.
    2020Dissertação de mestrado Acesso restrito Ver mais