Los carotenoides son un grupo de pigmentos naturales presentes en frutas y hortalizas con alta capacidad antioxidante, y además son precursores de la formación de aromas específicos. El objetivo del trabajo fue evaluar la distribución de carotenoides y compuestos aromáticos del jugo de sandía durante operaciones secuenciales de microfiltración y diafiltración. Los ensayos de microfiltración se realizaron en jugo con tratamiento enzimático previo, empleando una membrana de 0,8 μm a una presión promedio de 0,1 MPa, temperatura de 50 ºC y velocidad de flujo de 6,0 m·s-1, con 2 L de volumen de alimentación constante. Seguidamente se realizó un proceso de diafiltración del retenido utilizando agua potable. Se determinó la concentración de β-caroteno, isómeros trans y cis licopeno, sólidos solubles totales (SST), pH, acidez titulable, materia seca total y componentes aromáticos en las corrientes derivadas del proceso. El flujo promedio obtenido en la etapa de microfiltración fue de 114 L·h-1·m-2 a un factor de reducción volumétrica (FRV) de 10. La concentración de licopeno en el retenido luego de la microfiltración fue de 657±40 mg·kg-1. La etapa de diafiltración redujo los SST hasta 11,1±0,3 g·kg-1. El tratamiento enzimático no influyó en la composición de los compuestos aromáticos del jugo, sin embargo del proceso de microfiltración y diafiltración se obtuvieron corrientes con una distribución de compuestos aromáticos diferentes al jugo fresco.

Carotenoids are a group of natural pigments of fruits and vegetables with high antioxidant capacity, and are also precursors to the formation of specific aromas. The objective of this work was to evaluate the distribution of carotenoids and aromatic compounds of watermelon juice during sequential microfiltration and diafiltration operations. The microfiltration tests were performed in juice with previous enzymatic treatment, using a membrane of 0.8 μm at an average pressure of 0.1 MPa, temperature of 50 °C and flow velocity of 6.0 m·s-1, with 2 L constant feed volume. A retention diafiltration process was then performed using potable water. The concentration of β-carotene, trans and cis-lycopene isomers, total soluble solids (SST), pH, titratable acidity, total dry matter and aromatic components were determined in all streams derived from the process. The average flow obtained in the microfiltration stage was 114 L·h-1·m-2 at a volumetric reduction factor of 10. The concentration of lycopene in the retentate after the microfiltration was 657±40 mg·kg-1. The diafiltration step reduced the SST to 11.1±0.3 g·kg-1. The enzymatic treatment did not influence the composition of the aromatic compounds of the juice; however, from the microfiltration and diafiltration processes currents were obtained with a distribution of aromatic compounds different from the fresh juice.

Resumo A variabilidade da composição físico-química e do teor de carotenoides e polifenóis, e a capacidade antioxidante hidrofílica da fruta fresca da pupunha (Bactris gasipaes) foram pesquisadas, a fim de avaliar o seu aproveitamento como uma fonte potencial de compostos bioativos. Estudou-se a variabilidade de cinco lotes de frutos da Costa Rica das regiões Tucurrique (T) e Pérez Zeledón (PZ). Foram encontradas diferenças significativas para a massa, o comprimento e a largura entre os lotes. Os teores de umidade, gordura e proteína dos frutos de Tucurrique foram significativamente menores do que os teores dos frutos de Pérez Zeledón. Não foi encontrada diferença significativa para o teor de amido entre todos os lotes de pupunheira estudados. Para os compostos antioxidantes, o teor de carotenoides totais variou entre 109 e 202 mg equivalentes β-caroteno / g de matéria seca (ms), enquanto o teor de polifenóis totais variou no intervalo de 54 a 106 mg de equivalentes de ácido gálico (GAE) / 100 g (ms). Ambos os compostos antioxidantes apresentaram variabilidade entre os cinco lotes. A capacidade antioxidante foi determinada pelo método ORAC e só a amostra PZ-3 foi significativamente diferente dos outros quatro lotes. A média da capacidade antioxidante hidrofílica foi de 37 ± 7 mmol de equivalentes de Trolox (TE) / g (ms). No geral, a fruta da pupunha apresenta potencial de utilização como ingrediente no desenvolvimento de alimentos funcionais, uma vez que a variabilidade da fruta da pupunha como matéria-prima, determinada pela aplicação de uma análise de componente principal, demonstrou que algumas das características dessa fruta não foram afetadas durante a época de colheita, e nenhuma diferença foi encontrada entre os lotes das duas áreas de estudo.

Summary The variability of the physicochemical composition, carotenoid and polyphenol contents and hydrophilic antioxidant capacity of fresh peach palm (Bactris gasipaes) fruit was studied with a view to its exploitation as a potential source of bioactive compounds. The variability present in five batches of peach palm fruit obtained from two regions in Costa Rica: Tucurrique (T) and Pérez Zeledón (PZ), was studied. Significant differences were found for fruit weight, length and width amongst the batches studied. The moisture, fat and protein contents of the Tucurrique fruit were significantly lower than those from Pérez Zeledón. No significant difference in starch content was found between any of the batches of peach palm fruit studied. In terms of antioxidant compounds, the total carotenoid content ranged between 109 and 202 µg β-carotene equivalents/g dry weight (dw), while the total polyphenol content varied from 54 to 106 mg gallic acid equivalents (GAE) /100 g (dw). Both these components presented variability amongst the five batches. The antioxidant capacity was determined by the ORAC method and only the PZ 3 sample presented significant differences from the other four batches. The average hydrophilic antioxidant capacity was 37 ± 7 µmol of Trolox equivalents (TE)/g (dw). Overall, the peach palm fruit showed potential to be used in the development of functional foods since the variability of the raw peach-palm fruit, determined by applying a principal component analysis, showed that some characteristics of this fruit were not affected by harvest time and showed no differences between the batches from the two areas.

La naranjilla (Solanum quitoense Lam.) es una fruta nativa de los Andes, cultivada y consumida principalmente en Ecuador, Colombia y América Central. Las principales características de frutas de naranjilla maduras cultivadas en Costa Rica fueron evaluadas, incluyendo contenido de azúcares, acidez titulable total, sólidos solubles totales, capacidad de absorbancia de radicales de oxígeno (H-ORAC) y contenido de polifenoles totales y ácido ascórbico. La identificación de carotenoides y compuestos volátiles fue también realizada. Las muestras presentaron contenidos de sacarosa, glucosa y fructosa de 1.6 ± 0.3, 0.68 ± 0.05 y 0.7 ± 0.1 g/100 g, respectivamente. La acidez titulable total fue 2.63 ± 0.07 g equivalentes de ácido cítrico / 100 g y los sólidos solubles totales fueron 9.1 ± 0.5 ºBrix. El valor de H-ORAC fue 17 ± 1 µmol equivalentes de Trolox / g, el contenido de polifenoles totales fue 48 ± 3 mg equivalentes de ácido gálico / 100 g y el contenido de ácido ascórbico fue 12.5 ± 0.0 mg/100 g. El contenido de carotenoides de la fruta completa y la pulpa fue 33.3 ± 0.6 y 7.2 ± 0.3 µg/g, respectivamente. El carotenoide predominante en los compuestos identificados en las frutas completas fue β-caroteno. Diez compuestos volátiles fueron identificados en la pulpa de naranjilla, siendo el predominante el butanoato de metilo. La composición química de naranjilla cultivada en Costa Rica aparenta no diferir de aquella reportada previamente en estudios realizados en lugares diferentes.

Naranjilla (Solanum quitoense Lam.) is a native fruit of the Andes, cultivated and consumed mainly in Ecuador, Colombia, and Central America. Because of its pleasant aroma and attractive color, it has high potential as an ingredient of products such as juices, nectars, and jams. The main characteristics of mature naranjilla fruits cultivated in Costa Rica were assessed, including sugar content, total titratable acidity, total soluble solids, oxygen radical absorbance capacity (H-ORAC), and total polyphenolic and ascorbic acid content. Carotenoid and volatile compound identification was also done. The samples showed sucrose, glucose, and fructose content of 1.6 ± 0.3, 0.68 ± 0.05, and 0.7 ± 0.1 g/100 g, respectively. Total titratable acidity was 2.63 ± 0.07 g citric acid equivalent / 100 g and total soluble solids amounted to 9.1 ± 0.5 ºBrix. H-ORAC value was 17 ± 1 µmol Trolox equivalent / g, total polyphenolic content was 48 ± 3 mg gallic acid equivalent / 100 g and ascorbic acid content was 12.5 ± 0.0 mg/100 g. Carotenoid content of the whole fruit and pulp was 33.3 ± 0.6 and 7.2 ± 0.3 µg/g, respectively. The predominant carotenoid among the compounds identified in the whole fruit was β-carotene. Ten volatile compounds were identified in naranjilla pulp, the predominant being methyl butanoate. The chemical composition of naranjilla cultivated in Costa Rica does not seem to differ from that previously reported in studies at different locations.