Effect of process variables on the yield and quality of jerivá (<em>Syagrus romanzoffiana</em>) kernel oil from aqueous extraction

Abstract

The fruit from jerivá (Syagrus romanzoffiana) has a kernel which is rich in oil, and has a pleasant smell that reminds one of coconut. It is rich in monounsaturated and saturated fatty acids, in addition to bioactive compounds. In this work, the effect of process variables on the yield and quality of jerivá kernel oil from aqueous extraction was evaluated using response surface methodology. The variables pH, time and temperature influenced the yield and the quality of the oil. High pH and time, along with mild temperature were suitable conditions to extract jerivá kernel oil by aqueous extraction, but excessively high pH, temperature and time negatively impacted the oil's quality. pH was the only variable that significantly influenced free acidity, with a decrease in free acidity with the increase in pH. On the other hand, the increase in pH, time and temperature increased the peroxide value, which limited some conditions for obtaining jerivá kernel oil by aqueous extraction. The optimal conditions were found to be an extraction at pH 12, 25 °C and 60 minutes, which resulted in a yield of 39%, free acidity of 0.2% and a peroxide value of 5.8 meqO 2 ·kg −1 . Aqueous extraction yielded more unsaturated oil than that extracted with hexane, in addition to a higher proportion of caproic, oleic and linoleic acids, thus improving its nutritional characteristics and health benefits, despite decreasing its oxidative stability. RESUMEN: Efecto de las variables del proceso sobre el rendimiento y la calidad del aceite de almendra de yerivá (Syagrus romanzoffiana) mediante extracción acuosa. La fruta de yerivá (Syagrus romanzoffiana) tiene un grano rico en aceite, que tiene un olor agradable que recuerda al coco, es rico en ácidos grasos monoinsaturados y saturados, además de compuestos bioactivos. En este trabajo, se evaluó el efecto de las variables del proceso sobre el rendimiento y la calidad del aceite de grano de yerivá a partir de la extracción acuosa utilizando la metodología de superficie de respuesta. Las variables pH, tiempo y temperatura influyeron en el rendimiento y la calidad del aceite. pH alto, elevado tiempo y temperatura suave fueron las condiciones adecuadas para extraer el aceite de grano de yerivá mediante extracción acuosa. Sin embargo, el pH, la temperatura y el tiempo excesivamente altos impactaron negativamente en la calidad del aceite. El pH fue la única variable que influyó significativamente en la acidez libre, con una disminución de la acidez con el aumento del pH. Por otra parte, el aumento del pH, el tiempo y la temperatura aumentaron el valor del peróxido, lo que limitó algunas condiciones para obtener aceite de grano de yerivá por extracción acuosa. Se encontró que la condición óptima fue una extracción a pH 12, 25 °C y 60 minutos, lo que resultó en un rendimiento del 39%, una acidez libre del 0,2% y un valor de peróxido de 5,8 meqO 2 ·kg −1 . La extracción acuosa produjo más aceite insaturado que el extraído con hexano, además de una mayor proporción de caproico, oleico y linoleico, mejorand...

Thermal and chemical characterization of fractions from Syagrus romanzoffiana kernel oil

“…Therefore, these natural fats have a short melting range, which makes them suitable for the manufacture of a variety of fatty foods. In this respect, the low melting points and the low solid contents at room temperature are favorable for the production of some products, such as confectionery coatings and couvertures; although it is a drawback that can be alleviated by the fractional crystallization and separation of harder and softer fractions (Gunstone, 2010;Magalhães et al, 2020b;Rossell, 1985). In this sense, fractional crystallization, or simply fractionation, refers to a separation process in which fatty material is crystallized at a suitable temperature, after which a low melting phase (olein) is separated from a high melting phase (stearin) (Kellens et al, 2007;Sonwai et al, 2017).…”

“…In this sense, fractional crystallization, or simply fractionation, refers to a separation process in which fatty material is crystallized at a suitable temperature, after which a low melting phase (olein) is separated from a high melting phase (stearin) (Kellens et al, 2007;Sonwai et al, 2017). Nowadays, where trans fatty acids in food are questioned, fractionation oil modification stands out as an alternative for the industry because it is a physical process that does not promote changes in fat at the molecular level (Kellens et al, 2007;Magalhães et al, 2020b;Sonwai et al, 2017).…”

“…They are used in the food industry to produce spreads, specialty fats, ice cream, chocolate, and others, where most of them are specially derived from palm kernel oil. In addition, the increasing use of cocoa butter substitutes by the chocolate industry drives a growing demand for lauric oils (Calliauw et al, 2007;Chaleepa et al, 2010;Kellens et al, 2007;Magalhães et al, 2020b;Rossell 1985;Sonwai et al, 2017). Therefore, there is still room to explore other lauric oils, as well as their fractions, to obtain products with distinct characteristics from or equivalent to those derived from palm or coconut oil.…”

“…The almond (kernel) oil has a pleasant coconut-like smell, with about 33% lauric acid and 28% oleic acid. The oil also contains bioactive compounds, such as phenolics, carotenoids, and tocopherols (Coimbra and Jorge, 2011;Coimbra and Jorge, 2012;Pierezan et al, 2015;Magalhães et al, 2020b). Jerivá kernel oil has interesting characteristics for biofuel production, such as low acidity, a high oxidative stability and transesterification reaction with an ester conversion rate above the minimum percentage required (Falasca et al, 2012;Moreira et al, 2013), but also has potential for human consumption (Lescano et al, 2018;Magalhães et al, 2020a).…”