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The identification of preservative compounds from pumpkin fruit peel for the development of a fruit pulp product

Publication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Dias, Maria Inês; Vassilou, Charikleia; Petropoulos, Spyridon Α.; Oliveira, Beatriz; Barros, Lillian

The food industry is facing a growing demand for ready-to-use or ready-to-cook products with a long shelf life and increased nutritional value to meet consumers’ needs. However, there is also a growing concern about the widespread use of synthetic additives, which have been alarmingly correlated with adverse health effects. In this context, the opportunity to use the by-products generated during the industrial processing of pumpkin fruit to obtain a natural extract with preservative properties and to incorporate it in a fruit pulp product is being explored. In a preliminary study where pumpkin peels, seeds, and fibers were assessed, the peels showed the strongest bioactive properties, being thus selected to obtain the preservative extract in this work. To identify the bioactive molecules of the pumpkin peels, HPLC-DAD-ESI/MS was applied to the extracts of four genotypes. One to five different phenolic compounds were found in the tested samples, with (-)-epicatechin ([M-H]- at m/z 289) as the major compound detected in all of the extracts. These results suggest the possibility of using a natural preservative obtained from this fruit by-product in a new pumpkin pulp formulation.

2022Conference object

Open access

Egyptian pumpkin by-product extracts as natural food preservatives

Publication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Mohamed, Mustafa H.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, Lillian

The correlation between synthetic food additives and their adverse health effects has aroused the concern of consumers, which increasingly prefer natural food alternatives. On the other hand, industries have faced the challenge of meeting consumers’ expectations with ready-to-use healthy products with a long shelf life. The present work aimed to investigate the by-products of pumpkin industrial processing as cheap sources of preservative compounds for food application. For that purpose, the seeds, peels, and fibers of five pumpkin genotypes cultivated in Egypt, namely ‘Butternut Squash’, ‘Golden Cushaw’, ‘Dickinson’, ‘Halloween’, and ‘Honey Delite’, were evaluated regarding their preservative potential. The hydroethanolic extracts of these by-products were assessed for their antioxidant activity, by TBARS in porcine brain homogenates, antimicrobial activity, against eight bacterial and two fungal strains with relevance in food contamination, and cytotoxicity in a primary culture of non-tumor hepatic cells (PLP2). Regarding the antioxidant activity, it was tested using a cell-based assay that has the advantage of evaluating oxidizable biological targets. In general, all the samples presented great capacity of lipid peroxidation inhibition. The seeds showed the best results in four of the five evaluated genotypes, with IC50 values ranging from three to almost thirteen times higher than the positive control Trolox. In addition, all samples were able to protect against at least one of the eight tested bacterial strains. The seeds of ‘Honew Delite’ stood out, inhibiting six bacteria and the two tested fungi, followed by the peel of ‘Butternut Squash’, which inhibited five bacterial and two fungal strains. Actually, all the peel samples protected against at least three bacteria and one fungus. Furthermore, none of the tested samples showed cytotoxic activity against the non-tumor porcine liver cells up to the maximum tested concentration of 400 μg/mL, which is a first validation of their safe application in food. Through these results, it is possible to point out the potential of pumpkin by-products as sources of preservative compounds, contributing to the gradual reduction of synthetic additives in food. On the other hand, it also promotes more sustainable industrial processes, by reusing pumpkin by-products.

2022Conference object

Open access

Integrative and sustainable strategy for the valorization of pumpkin by-products

Publication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pires, Tânia C.S.P.; Pereira, Carla; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, Lillian

The food industry has sought to meet consumers’ demand for practical, ready-to-eatfoods capable of meeting daily nutritional needs and providing pleasure and satiety. However, the industry still relies on artificial additives to preserve and improve food properties, due to the lack of effective natural analogues, which face stability and availability limitations [1]. Aiming at the objectives of the circular economy and the promotion of more sustainable agro-industrial processes, the ambition of this project is to develop a new pumpkin fruit pulp formulation functionalised with a biobased preservative extracted from pumpkin by-products. For that purpose, production protocols will be established to ensure high agronomic performance and high-quality pumpkins. Meanwhile, pumpkin pulps will be evaluated in terms of nutritional value and the by-products, as seeds, peels, and fibers, will be assessed for their content in preservative compounds. The recovered, refined, and stabilized preservative compounds will further be incorporated in the pumpkin product formulated with the pumpkin elite cultivars. In addition, the quality assessment of pumpkin fruit pulp during shelf-life and the waste and wastewater management are targeted. The proposed project involves multidisciplinary research groups (IPB/PT, MORE/PT, UTH/GR, GFV/GR, CBBC/TN, ATB/DE, CRAPC/DZ, BU/EG) with various expertise in the food and farming sector, and the company DECORGEL/PT, which will further process the pumpkin pulp to be “market ready”, within the consortium PRIMA Section 2 - Multi-topic 2019: PulpIng (PRIMA/0007/2019). The described aims are in line with the EU Biodiversity Strategy of 2020 and 2030 Agenda for Sustainable Development, and intend to address food safety/security issues and promote circular food systems in Mediterranean regions.

2023Conference object

Open access

Application of an anthocyanin-based colorant in a pastry product

Publication . Backes, Emanueli; Leichtweis, Maria Gabriela; Molina, Adriana K.; Palmeira, Luís; Pereira, Carla; Ferreira, Isabel C.F.R.; Barros, Lillian

The fig (Ficus carica L.) peel is an agro-industrial by-product that is not applied in any field of industry. Due to its colour, it can be considered as an important source of anthocyanins that can be used in the preparation of food colorants [1]. In the present study, an anthocyanin-based food colorant was obtained from fig peel and was applied in a food product, a doughnut icing, in order to analyse the variations induced in its nutritional, chemical, and physical composition during storage (24 hours). The anthocyanin-rich extract was obtained by ultrasound assisted extraction, its composition was determined by HPLC-DAD-ESI/MS, and the cytotoxicity was tested against a primary culture of non-tumour porcine liver cells, PLP2. The nutritional properties of the prepared icing were evaluated following official food analysis methods [2] and free sugars and fatty acids profiles were obtained by HPLC-RI and GC-FID, respectively. The pH was measured with a pH-meter and the colour (L*, a*, and b*) and texture (firmness, consistency, cohesiveness, and viscosity) parameters were measured using a colorimeter and a texture analyser.The main colouring compound found in the fig peel extract was cyanidin-3-rutinoside and the extract did not reveal cytotoxic properties, being safe for food application. Comparing with a control formulation (Figure 1), the extract addition did not cause significant changes in the icing nutritional, free sugars, and fatty acids profiles. After storage, there was a slight decrease in the moisture content, probably due to absorption from the environment. For this reason, nutritional and chemical parameters tended to increase after 24 hours. The addition of the extract did not change the pH of the icing. However, significant differences were observed for all the texture parameters both between the control and the coloured icing and between both icings regarding the day of preparation and 24 hours after. Moreover, the differences after storage were much lower in the coloured icing, which is an additional advantage of its application.The results obtained corroborate the possibility of recovering colouring molecules from agro-food industry residues to be used as food colorants.

2021Conference object

Open access

Uso sustentável da abóbora: extratos de subprodutos de abóbora egípcia como conservantes natural