Browsing by Author "Bejaoui, Ghada"
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- Development of a natural food colorant from Passiflora edulis Sims epicarpPublication . Bejaoui, Ghada; Barros, Lillian; Ferreira, Isabel C.F.R.; Zaghdoudi, KhalilFood industry is dedicated in the continuous improvement of products safety and quality, satisfying the consumer’s requirements. Thus, this sector has invested in the development of new solutions to decrease the amount of used artificial additives and whenever possible, replacing them by more innocuous natural counterparts. Colorants are one of the most important additives in terms of marketing, since their presence influences consumer’s perceptions, choices and preferences, interfering in market success or failure of food products. In this context, there are many fruits in which their bio-residue can be used to extract colorant ingredientes. Passiflora edulis, known as passion fruit, is native from Brazil and much appreciated by the cosumers. The purple passion fruit variety (Passiflora edulis Sims) is the most common variety and is cultivated for juice and pulp production. However, the largest portion of the fruit is constituted by the epicarp, resulting in a high quantity of bio-waste production. This part of the fruit has a dark purple colour, being a rich source of pigmented compounds, namely anthocyanins, which could be used as a source of natural ingredients with colourant potential. In this work, the extraction methodology of anthocyanins from passion fruit epicarp was optimized through a heat assisted extraction (HAE), by applying a response surface methodology combining different independent variables of the process. Furthermore, the bioactive properties (antioxidant, antimicrobial and cytotoxic activities) of the optimized extract and also of the extract obtained by a conventional extraction method (maceration using 80:20 v/v of acidified ethanol/water at room temperature) were compared. The anthocyanins profile was determined by HPLC-DAD-ESI/MS, using 520 nm as the preference wavelength and operating in positive mode. The antioxidant activity was evaluated by means of TBARS and OxHLIA methodologies; the antimicrobial activity was determined using the microdilution method in Gram-positive and Gram-negative bacteria, and in fungi; and finally, the cytotoxic properties were studied in four human tumor cell lines: HeLa (cervical carcinoma), HepG2 (hepatocellular carcinoma), MCF-7 (breast adenocarcinoma) and NCI-H460 (lung carcinoma); and in a non-tumor cell line: PLP2 (primary culture of pig liver cells). The HAE optimal conditions were established as t= 37.5 min, T= 20 ºC, S= 0 % (ethanol) using 50 g/L of solid/liquid ratio, conducting to an extraction yield of 37%, with a total anthocyanins’ content of 9.02 mg of anthocyanins (A) per g of extract (dried extracted residue-basis) and 3.35 mg of A per g of dried epicarp basis. Regarding the bioactive properties, the optimized extract rich in anthocyanin compounds was highlighted with higher antioxidant, antimicrobial and cytotoxic potential in comparison to the extract obtained by the conventional method. Overall, this study has a great interest in the food sector, because it highlights the colorant and bioactive potential of this natural ingredient, while enhancing the valorization of a specific bio-residue, widely produced by the food sector.