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- Extraction of Phenolic Compounds from Cherry Seeds: A Preliminary StudyPublication . Dulyanska, Yuliya; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Lima, Maria João; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Barroca, Maria João; Moreira da Silva, Aida; Guiné, Raquel P. F.Agri-food waste has proved to be a valuable bioresource that can be used to obtain a variety of valuable materials, ingredients and chemicals. The optimum conditions for extracting bioactive compounds from sweet cherry seeds (SCS) with different solvents and temperatures were tested in this work. The choice criteria were based on the most efficient extracting capacity while looking for cleaner techniques with lower health or environmental impacts. Some extracting solvents (methanol, ethanol and water) were tested in different combinations and temperatures. The obtained extracts were evaluated for total phenolic compounds and some families of phenolics as well, using spectrophotometric methods. The results obtained showed that the highest extraction of total phenolic compounds was at 70 °C with 60:40 ratio water:ethanol (2.65 mg GAE/g), while maximum flavonoids were obtained at 80 °C and 50% ethanolic aqueous solution (7.26 mg QE/g). The highest value for ortho-diphenols was 21.47 mg GAE/g for 50 °C and water:ethanol 50:50 solution. The highest proanthocyanidins and flavonols were obtained for 50:50 solution at 70 °C (6.43 mg CE/g and 3.88 mg QE/g, respectively), while the same solution at 80 °C allowed obtaining maximum phenolic acids (1.68 mg CAE/g). The extraction of anthocyanins was found to vary significantly with concentration and temperature, being highest in the range 35–40 °C, when using an 80:20 water:ethanol solution. Hierarchical clustering showed three clusters, while factor analysis resulted in two factors and four groups of samples. In conclusion, it was found that extracts obtained from sweet cherry seeds have relevant bioactive compounds with applications in the food, pharmaceutical or cosmetic industries.
- The impact of extraction temperature and solution concentration on the antioxidant activity of sweet cherry seeds’ extractsPublication . Dulyanska, Y.; Cunha, Margarida; Lima, M. J.; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Barroca, Maria João; Silva, A.; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Guiné, Raquel P. F.Sweet cherry seeds, a valuable lignin-cellulose raw material for the production of polyurethane foams 1, are also a significant source of different phenolic compounds 2 and can be a good source of natural antioxidants, which can play an important role in preventing the formation of free radicals and protection against degenerative diseases. Considering sustainability, the main objective of this project was the use of cherry by-products (seeds) to produce extracts rich in antioxidant compounds. In this work, the seed extracts were obtained with the addition of different combinations of ethanolic solution (water:ethanol ratios - 50:50; 60:40; 80:20; 100:0 v:v) and at different temperatures (35, 50, 70 and 80 °C), all under magnetic stirring for 40 minutes. Then, the antioxidant activity of the extracts was evaluated through spectrophotometric methods, using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid)) radicals, and also the Ferric Reducing Antioxidant Power Assay (FRAP). All measurements were replicated at least in triplicates and were expressed as mg Trolox equivalents per gram (mg TE/g). Statistical analysis was performed using the JAVA software. ANOVA tests show that there is a statistically significant effect of temperature, water percentage and temperature on the antioxidant activity evaluated by the three methods used (p> 0.001 in all tests). The percentage of water is the variable that most contributes to this effect. Individual Post Hoc comparisons show, for all tests, that in general the temperatures induce differences in antioxidant activity, except 70 °C and 80 °C in DPPH and FRAP, and 80 °C and 50 °C in ABTS. Regarding the percentage of water, it was found that all samples are different from each other, except the FRAP, in which no significant differences between 50 and 60% of water were found. In conclusion, no major differences between the ABTS, DPPH and FRAP methods were found. Temperature and percentage of water have a significant effect on the concentration of antioxidant activity in all methods. In that way, the cherry pit is a good by-product to produce extracts with high content of antioxidant activity, being that the 70° C with 50:50 and 60:40 water:ethanol solutions are the most favorable conditions to potentiate the antioxidant activity.
- Evaluation of the antioxidant activity of extracts obtained form cherry seeds.Publication . Dulyanska, Y.; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Lima, M. J. Reis; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Barroca, Maria João; Silva, A. M.; Guiné, Raquel P. F.Annual cherry production in Portugal is around 19,000 tonnes, in an area of about 6,450 ha and covering about 11,100 farms, concentrated in some northern and central interior territories. It is also in these regions that in recent decades there has been a significant increase in farms specialized in the production of cherry, using new cultivars and new technologies in a business production model. Apart from being consumed in fresh form, cherries are used for many food preparations, like sweets, jellies or confectionary. In the plants that transform cherries, a significant amount of cherry seeds (also called cherry pits) is generated as residue or waste. The possible usage of these residues as raw material for extraction of compounds with antioxidant properties is beneficial in term of economic value as well as environmental impact. Hence, the objective of this work was to obtain extract rich in compounds with antioxidant activity from cherry seeds. The cherry seeds were obtained from a local waste management company, Nutrofertil, located in Tondela, in the district of Viseu (Portugal). They were grinded and then submitted to extraction procedures testing different operating conditions: magnetic stirrer versus ultrasound, different solvents (methanol, ethanol, water) and temperatures (from 35 ºC to 80 ºC). For the obtained extracts antioxidant activity was evaluated through spectrophotometric methods, using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid)) radicals, and also the Ferric Reducing Antioxidant Power Assay (FRAP). All measurements were replicated at least trice, and were expressed as mg Trolox equivalents per gram (mg TE/g). The results obtained for the different experimental conditions indicated that least efficient extractions at ambient temperature were obtained with methanol using magnetic stirrer and with water using ultrasounds, for which the antioxidant activities measured by the DPPH method were 0.26 and 0.33 mg TE/g and by the ABTS method were 0.82 and 0.86 mg TE/g, respectively. Most efficient methods were water:ethanol (at 50% concentration) and water (100%), using magnetic stirrer in both cases. Highest antioxidant activity was obtained for water:ethanol by the DPPH method (0.72 mg TE/g) and for water (100%) by the ABTS method (1.25 mg TE/g). Tests with different concentrations for the aqueous solutions of ethanol and at different temperatures revealed that with increasing concentration of water the antioxidant diminished, from 0.62 to 0.27 mg TE/g at 35 ºC using the DPPH method. Additionally, the variation in temperature allowed reaching a maximum extraction of compounds with antioxidant activity at 70 ºC and decreasing thereafter. The maximum values obtained were registered at 70 ºC for all cases and were 0.74 mg TE/g for the water:ethanol 50:50 (v/v) by the DPPH method, 2.16 mg TE/g for the water:ethanol 60:40 (v/v) by the ABTS method and 3.43 mg TE/g for the water:ethanol 60:40 (v/v) by the FRAP method. The results obtained by the different methods were concordant in terms of the observed trends but giving different values of the measured antioxidant activity, which is a common characteristic observed in these types of evaluation techniques. This research allowed establishing some operational conditions that should be selected in order to maximize the extraction of compounds with antioxidant activity from cherry seeds. The use of ultrasounds was not found beneficial and the magnetic stirrer technique revealed to be more useful. Also the use of methanol was not found suitable, which is a good point given that this solvent is more pollutant and has more problems of toxicity. With respect to temperature, it was found that temperatures higher than 70 ºC are not beneficial because they induce the degradation of some bioactive compounds thus reducing the antioxidant activity of thee extracts.
- Extração de compostos fenólicos de caroço de cerejaPublication . Dulyanska, Yuliya; Guiné, Raquel P. F.; valente, Luisa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Barroca, Maria João; Silva, Aida Moreira; Lima, M. J.Os resíduos agroalimentares provaram ser um biorecurso que pode ser usado para obter uma variedade de materiais, ingredientes e produtos químicos valiosos. Neste trabalho foram testadas as condições ótimas para extração de compostos bioativos dos caroços de cereja com diferentes solventes e temperaturas. Os critérios escolhidos basearam-se na capacidade de extração mais eficiente, buscando técnicas mais limpas e com menor impacto no meio ambiente. Alguns solventes de extração foram testados em diferentes combinações e temperaturas. Os extratos obtidos foram avaliados utilizando métodos espectrofotométricos quanto a compostos fenólicos totais, bem como algumas famílias de compostos fenólicos. Os resultados obtidos mostraram que a maior extração de compostos fenólicos totais foi a 70°C com razão água:etanol de 60:40 (% v/v) (2,65 mg GAE/g), enquanto os máximos resultados para flavonoides foram obtidos a 80°C e solução aquosa etanólica 50% (7,26 mg QE/g). O maior valor para orto-difenóis foi de 21,47 mg GAE/g para 50°C e solução água:etanol 50:50. As maiores quantidades de proantocianidinas e flavonóis foram obtidas para solução 50:50 a 70 °C (6,43 mg CE/g e 3,88 mg QE/g, respetivamente), enquanto a mesma solução a 80 °C permitiu obter o máximo de ácidos fenólicos (1,68 mg CAE/ g). A extração de antocianinas varia significativamente com a concentração e temperatura, sendo mais alta na faixa de 35-40 °C, quando se utiliza uma solução de água:etanol 80:20. Em conclusão, verificou-se que os extratos de caroços de cereja obtidos possuem compostos bioativos relevantes com aplicações nas indústrias alimentícia, farmacêutica ou cosmética.
- Análise agroecológica de caroços de cereja liquefeitos utilizando FTIR-ATRPublication . Dulyanska, Y.; Esteves, Bruno; Guiné, Raquel; Ferreira, José; Domingos, Idalina; Lopes, Rogério; Lima, Maria; Correia, Paula; Fragata, Anabela; Ferreira, Manuela; Barroca, Maria João; Silva, Aida; Lopes, Luísa P. CruzA agroecologia, combina princípios ecológicos com práticas agrícolas, tem ganho crescente relevância no desenvolvimento de práticas sustentáveis. Esta área valoriza não apenas a produção eficiente de alimentos, mas também a utilização responsável e inovadora dos resíduos agrícolas. Neste contexto, a análise de produtos derivados de cultivos frutícolas, como a caroço de cereja (Prunus avium L.), mostra ser uma área promissora para a identificação de novas estratégias de valor acrescentado. O presente trabalho teve como objetivo analisar o material liquefeito de caroço de cereja doce (Prunus avium L.) e apresentar novas estratégias de valor acrescentado para as possíveis transformações deste produto. Utilizando a espectroscopia FTIR-ATR, foram investigados tanto o material liquefeito quanto os resíduos sólidos resultantes destas liquefações, além do material original de Prunus avium L. Os resultados obtidos demonstram que o material original e o resíduo sólido liquefeito apresentam espectros semelhantes, enquanto as principais diferenças foram observadas entre o material original e o material liquefeito. Estas diferenças indicam potenciais caminhos para o aproveitamento eficiente e sustentável dos resíduos, promovendo a valorização de subprodutos agrícolas e contribuindo para um modelo de produção mais ecológico e economicamente viável. Desta forma, este estudo insere-se na linha de pesquisas que visam fortalecer a sustentabilidade na agricultura, através da inovação e da otimização dos resíduos agrícolas.
- Evaluating phenolic compounds in ethanolic extracts of cherry pitPublication . Dulyanska, Y.; Lima, M. J. Reis; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Barroca, Maria João; Silva, A.; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Guiné, Raquel P. F.The climatic conditions in Portugal favoured the adaptation of the cherry tree allowing its cultivation in several regions of the country. Studies made by the Portuguese Bureau of Statistics – INE 1, showed that the Portuguese sweet cherry production has an implemented area of 6,387 ha, producing 9,241 tons of this fruit. Its production extends mainly to two regions: the North (area of 3,099 ha and production of 6,586 tons) and the Centre (3,177 ha and 2,510 tons), while the rest of the country and islands accounts for only 1.6% of the cherry production. There are several varieties of cherry in Portugal, and the most important traditionally cultivated are: “Saco da Cova da Beira”, “Saco do Douro”, “Lisboeta”, “São Julião”, Big Burlat, Maring, Napoleon-big-foot and Big Windsor, being the first four varieties native from Portugal. Cova da Beira is the most important cherry production area in Portugal, either in terms of production volume, or also in area. Additionally, the evolution of technological indicators associated with culture reveals a high degree of specialization of the “new” farms, almost always associated with other fruit crops, which coexist in a very significant number of smaller farms, of a family type, that constitute the historical legacy of cherry production on the hillside north of the Serra da Gardunha. Sweet cherry seeds result from processing sweet cherry for sweets, juices and jams’ production. Generally, seeds are considered a production waste, which gains a strong interest due to the environmental aspects related to waste disposal 2. Additionally, it is well documented that production waste, such as peels, seeds, and pomace, contain high-value bioactive compounds 3. Hence, the present work investigated the extraction of some bioactive compounds from cherry pits that originate from food manufacturing industries. The waste management company Nutrofertil, located in Portugal, namely in the district of Viseu (Tondela), provided the Seeds of Sweet Cherry (SSC) for this study. The seeds were milled and dried for stability and then used for extraction with ethanolic solutions at different percentages (from 50 to 100% water v/v). Variable temperatures were also tested and the extracts were used for quantification of phenolic compounds through spectrophotometric techniques. The material was analysed to verify that it was exempt of hydrocyanic acid. Statistical techniques were used to treat the data: (a) Hierarchical cluster analysis using squared Euclidean distance and average linkage between groups method; (b) Principal component factor analysis with Varimax rotation. The results indicated that extraction at 40 ºC with magnetic stirring and using aqueous solutions of ethanol (water:ethanol ratio = 80:20, % v/v) constitute a separate cluster. Also, extracts obtained with similar conditions but for the temperature of 35 ºC constitute another isolated cluster. Factor analysis revealed a grouping structure with four clearly distinct clusters (Figure 1). Group G1 accounts for the samples with water:ethanol 80:20 (% v/v) and a temperature of 35 ºC, corresponding to the extraction of higher amounts of anthocyanins. Group G3 includes the extractions with 100% water at 70 ºC (G3), with lowest contents of anthocyanins and flavonols. The remaining groups are divergent according to the values of total phenolic compounds. In group G4 are included samples in which were quantified high values for total phenolic compounds, flavonoids, proanthocyanidins, ortho-diphenols and phenolic acids, while G2 corresponds to samples with smaller amounts of those compounds. In conclusion, investigating the extraction potential of different conditions it was allowed to optimize the experimental conditions more favourable to maximize the recovery of certain bioactive compounds, which can have multiple applications as antioxidant substances after rigorous quality control regarding possible concentrations of hydrocyanic acid.