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This study focuses on optimizing the ultrasound-assisted extraction (UAE) of bioactive compounds from purple-fleshed sweet potatoes (PFSP) for potential use as natural colorants. Factors such as time, temperature, and solid-to-liquid ratio were varied using a Box-Behnken Design. The optimal conditions were determined as 75 min, 70 °C, and a 1:15 m/v solid-to-liquid ratio, resulting in 18.372 mg/100 g total anthocyanin (TA) and 151.160 mg GAE/100 g total phenolic content (TPC). The validation yielded 18.822 mg/100 g for total anthocyanin and 162.174 mg GAE/100 g for total phenolic content, showing a 7% difference from predictions. UAE significantly increased TA extraction by 81% and TPC by 93% compared with the conventional method, with a notable reduction in process time from 24 h to 75 min. Additionally, three kinetic models were tested to compare extraction mechanisms, confirming the efficiency of UAE for PFSP bioactive compound recovery. This study proposes the UAE technique as a highly effective means of extracting bioactive compounds from PFSP, offering promising applications across multiple industries.

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INTRODUCCIÓN: la especie Moringa oleifera Lam. conocida como Moringa, se ha introducido en Cuba principalmente con propósitos alimenticios. Sin embargo, no se han informado estudios de la composición de ácidos grasos del aceite obtenido de las semillas de esta especie en la región habanera. OBJETIVO: determinar la composición de ácidos grasos en el aceite de las semillas de las plantas de M. oleifera que crecen en La Habana, Cuba. MÉTODOS: las semillas se recolectaron, molieron y se extrajeron con hexano en un baño ultrasónico. Los extractos fueron filtrados y el disolvente fue evaporado. Los ácidos grasos obtenidos de los aceites fueron determinados como ésteres metílicos por cromatografía de gases con una columna capilar BPX-70. RESULTADOS: los principales ácidos grasos encontrados fueron el oleico (C18:1; 73,1 %), palmítico (C16:0; 7,4 %) y docosanoico (C22:0; 5,8 %), mientras que otros 19 ácidos grasos, entre estos los ácidos C12:0, C14:0, C15:0, C17:0,C18:1 (n-10), C18:2, C18:3, C20:0, C20:1, C21:0, C22:1, C23:0, C24:0, C25:0, C26:0 C27:0 y C28:0, se encontraron en menores proporciones. Este es el primer reporte de la presencia de los ácidos C15:0, C27:0 y C28:0 en esta especie, y el primero que identifica los ácidos C12:0, C14:0, C17:0, C18:3, C20:0, C23:0, C25:0 y C26:0 en la especie M. oleífera que crece en Cuba. CONCLUSIONES: la composición de ácidos grasos del aceite presente en las semillas de la especie M. oleífera que crece en La Habana muestra al ácido oleico como componente mayoritario. Se informa por primera vez la presencia de los ácidos C15:0, C27:0 y C28:0 en las semillas de esta especie, y de los ácidos C12:0, C14:0, C17:0, C18:3, C20:0, C23:0, C25:0 y C26:0 en la especie en Cuba. Estos resultados sobre la composición química del aceite de las semillas de la especie M. oleífera, pudieran contribuir a establecer su posible utilidad nutricional.

INTRODUCTION: the species Moringa oleifera Lam., known as Moringa, has been introduced in Cuba mainly for nutritional purposes. However, no study has been reported about the fatty acid composition of the seed oil obtained from this species in Havana. OBJECTIVE: determine the fatty acid composition of seed oil from M. oleifera plants growing in Havana, Cuba. METHODS: the seeds were collected, milled and extracted with hexane in an ultrasonic bath. Extracts were filtered and the solvent evaporated. Fatty acids obtained from the oils were determined as methyl esters by gas chromatography with a BPX-70 capillary column. RESULTS: the main fatty acids found were oleic (C18:1; 73.1%), palmitic (C16:0; 7.4%) and docosanoic (C22:0; 5.8%). Another 19 fatty acids, among them C12:0, C14:0, C15:0, C17:0, C18:1 (n-10), C18:2, C18:3, C20:0, C20:1, C21:0, C22:1, C23:0, C24:0, C25:0, C26:0 C27:0 and C28:0 were found in smaller proportions. This is the first report of the presence of acids C15:0, C27:0 and C28:0 in this species, and the first one to identify C12:0, C14:0, C17:0, C18:3, C20:0, C23:0, C25:0 and C26:0 acids in the species M. Oleifera growing in Cuba. CONCLUSIONS: oleic acid is the most abundant fatty acid component in seed oil from M. oleifera growing in Havana. This is the first report of the presence of acids C15:0, C27:0 and C28:0 in the seeds of this species, and of acids C12:0, C14:0, C17:0, C18:3, C20:0, C23:0, C25:0 and C26:0 in the species in Cuba. These results about the chemical composition of seed oil from the species M. oleifera could contribute to elucidate its potential nutritional usefulness.

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A fast and accurate method based on ultrasound-assisted extraction in a cup-horn sonoreactor was developed to determine the total content of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn in organic fertilizers by fast sequential flame atomic absorption spectrometry (FS FAAS). Multivariate optimization was used to establish the optimal conditions for the extraction procedure. An aliquot containing approximately 120 mg of the sample was added to a 500 µL volume of an acid mixture (HNO3/HCl/HF, 5:3:3, v/v/v). After a few minutes, 500 µL of deionized water was added and eight samples were simultaneously sonicated for 10 min at 50% amplitude, allowing a sample throughput of 32 extractions per hour. The performance of the method was evaluated with a certified reference material of sewage sludge (CRM 029). The precision, expressed as the relative standard deviation, ranged from 0.58% to 5.6%. The recoveries of analytes were found to 100%, 109%, 96%, 92%, 101%, 104% and 102% for Cd, Cr, Cu, Mn, Ni, Pb and Zn, respectively. The linearity, limit of detection and limit of quantification were calculated and the values obtained were adequate for the quality control of organic fertilizers. The method was applied to the analysis of several commercial organic fertilizers and organic wastes used as fertilizers, and the results were compared with those obtained using the microwave digestion procedure. A good agreement was found between the results obtained by microwave and ultrasound procedures with recoveries ranging from 80.4% to 117%. Two organic waste samples were not in accordance with the Brazilian legislation regarding the acceptable levels of contaminants.

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