Arbutus unedo L. and Ocimum basilicum L. as sources of natural ingredients for bread functionalization

Mestrado com dupla diplomação com o High Institute of Biotechnology of Monastir (ISBM), TunisiaThe overwhelming growth of the world population is causing direct consequences on food demands, which has forced the food industry to apply synthetic additives in order to meet the needs of the consumer and ensuring the global quality of the food products including aspect, texture and flavor. However, due to the publication of some studies describing adverse effects associated with these synthetic additives, the natural ones have been gaining increasing interest. Arbutus unedo L. (strawberry tree) fruits and Ocimum basilicum L. (basil) leaves, are important sources of bioactive natural molecules. The aim of this work was to demonstrate the antioxidant potential (free radical scavenging effect, reducing power and inhibition of lipid peroxidation), antimicrobial (antibacterial using Gram-positive and Gram-negative strains and antifungal activity) and the absence of toxicity (porcine liver primary cells) of the ethanol extracts, obtained from the previously mentioned plants by using optimal conditions (23% of ethanol in A. unedo fruits; 80% of ethanol in O. basilicum leaves). Subsequently, the enriched extracts in catechin from A. unedo fruit and rosmarinic acid from O. basilicum leaves, were incorporated as natural ingredients in bread samples, with two objectives: to functionalize bread, introducing bioactive properties; and as natural ingredients with preservation capacity. Five groups of bread samples were prepared: i) control (without natural or synthetic additives); ii) bread incorporated with A. unedo fruit extract; iii) bread incorporated with O. basilicum leaves extract; iv) bread incorporated with ascorbic acid- E300 (natural additive); and v) bread incorporated with potassium sorbate - E202 (synthetic additive). Both extracts (A. unedo fruit and O. basilicum leaves) presented antioxidant activity (EC50 values lower the 595 and 351 μg/mL, respectively), without toxicity up to the maximal tested dose (400 μg/mL), and the main compounds present were catechin and rosmarinic acid, respectively. The breads enriched with the extracts obtained from O. basilicum leaves revealed the highest DPPH scavenging activity, showing to be more effective than ascorbic acid and potassium sorbate. Regarding reducing power all brad type’s revealed similar bioactivity. Some significant differences were observed for the color and nutritional parameters analyzed, and the bread with natural extracts showed lower values for color parameters (L* and a*) when compared to the breads with the chemical Abstract 11 additives. In relation to the nutritional parameters, higher values of water were observed in the breads with A. unedo fruits and ascorbic acid, whereas the higher values of fructose, energy and ash were attributed to the bread with O. basilicum leaves and potassium sorbate. Overall, the obtained results demonstrate that these extracts could be used in the development of new bread replacing the synthetic preservatives, without interfering with the physical and nutritional characteristics.The overwhelming growth of the world population is causing direct consequences on food demands, which has forced the food industry to apply synthetic additives in order to meet the needs of the consumer and ensuring the global quality of the food products including aspect, texture and flavor. However, due to the publication of some studies describing adverse effects associated with these synthetic additives, the natural ones have been gaining increasing interest. Arbutus unedo L. (strawberry tree) fruits and Ocimum basilicum L. (basil) leaves, are important sources of bioactive natural molecules. The aim of this work was to demonstrate the antioxidant potential (free radical scavenging effect, reducing power and inhibition of lipid peroxidation), antimicrobial (antibacterial using Gram-positive and Gram-negative strains and antifungal activity) and the absence of toxicity (porcine liver primary cells) of the ethanol extracts, obtained from the previously mentioned plants by using optimal conditions (23% of ethanol in A. unedo fruits; 80% of ethanol in O. basilicum leaves). Subsequently, the enriched extracts in catechin from A. unedo fruit and rosmarinic acid from O. basilicum leaves, were incorporated as natural ingredients in bread samples, with two objectives: to functionalize bread, introducing bioactive properties; and as natural ingredients with preservation capacity. Five groups of bread samples were prepared: i) control (without natural or synthetic additives); ii) bread incorporated with A. unedo fruit extract; iii) bread incorporated with O. basilicum leaves extract; iv) bread incorporated with ascorbic acid- E300 (natural additive); and v) bread incorporated with potassium sorbate - E202 (synthetic additive). Both extracts (A. unedo fruit and O. basilicum leaves) presented antioxidant activity (EC50 values lower the 595 and 351 μg/mL, respectively), without toxicity up to the maximal tested dose (400 μg/mL), and the main compounds present were catechin and rosmarinic acid, respectively. The breads enriched with the extracts obtained from O. basilicum leaves revealed the highest DPPH scavenging activity, showing to be more effective than ascorbic acid and potassium sorbate. Regarding reducing power all brad type’s revealed similar bioactivity. Some significant differences were observed for the color and nutritional parameters analyzed, and the bread with natural extracts showed lower values for color parameters (L* and a*) when compared to the breads with the chemical Abstract 11 additives. In relation to the nutritional parameters, higher values of water were observed in the breads with A. unedo fruits and ascorbic acid, whereas the higher values of fructose, energy and ash were attributed to the bread with O. basilicum leaves and potassium sorbate. Overall, the obtained results demonstrate that these extracts could be used in the development of new bread replacing the synthetic preservatives, without interfering with the physical and nutritional characteristics