Cooking Methods and Storage Treatments of Potato: Effects on Carotenoids, Antioxidant Activity, and Phenolics

Abstract

The influence of genotype, cooking method, and storage treatments on potato compounds associated with improved human health was analyzed. Antioxidant activity (AA), total phenolics (TP), and total carotenoids (xanthophyll carotenoids, CAR) were determined in eight genotypes using 2,2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu reagent, and spectrophotometric absorbance, respectively. Individual phenolic and carotenoid composition was analyzed using high performance liquid chromatography (HPLC) in three genotypes of potato. Samples were subjected to a combination of storage conditions for approximately 4 months (non-stored or stored for 110 days at either 4°C, 4°C with an additional 10 days of reconditioning at 20°C, or 20°C storage) and cooking methods (baking, boiling, frying, or microwaving); an uncooked sample was used as a control. The non-stored samples had lower amounts of CAR, AA, and TP along with the individual compounds compared to the various storage regimes, while the recondition storage treatment produced equal or higher levels of TP and individual phenolics than any other storage regime. No cooking and boiling resulted in significantly lower AA and TP, as compared to baking, frying and/or microwaving. Baking, frying and/or microwaving also increased the levels of chlorogenic acid, caffeic acid, (-) epicatechin, p-coumaric acid and vanillic acid, but decreased quercetin dihydrate when compared to uncooked samples. Most health promoting compounds were enhanced by one or both postharvest processing parameters (storage and cooking); however, t-cinnamic acid, and lutein were not affected.Resumen Se analizó la influencia del genotipo, del método de cocinado y de tratamientos en el almacén, sobre los compuestos de papa asociados con el mejoramiento de la salud humana. Se determinó la actividad antioxidante (AA), fenoles totales (TP), y carotenoides totales (carotenoides xantofílicos, CAR), en ocho genotipos, usando 2,2-difenil-1-picrilhidrazilo (DPPH), el reactivo de Folin-Ciocalteau, y la absorbancia espectrofotométrica, respectivamente. Se analizaron los fenoles individuales y la composición de los carotenoides usando cromatografía de líquidos de alta resolución (HPLC) en tres genotipos de papa. Las muestras estuvieron sujetas a una combinación de condiciones de almacenamiento por aproximadamente cuatro meses (sin almacenar, o almacenadas por 110 días ya fuera a 4°C, a 4°C con diez días adicionales de reacondicionamiento a 20°C, o a 20°C en el almacén), y métodos de cocinado (horneadas, hervidas, fritas, o en el horno de microondas); se usó una muestra sin cocinar como testigo. Las muestras sin almacenar tuvieron las cantidades más bajas de CAR, AA, y TP, junto con los compuestos individuales comparados a los diversos regímenes de almacenamiento, mientras que el tratamiento de reacondicionamiento en el almacén produjo niveles iguales o mayores de TP y de fenoles individuales que cualquier otro régimen de almacenamiento. Sin cocinar y hervidas resultaron en contenido más bajo de AA y TP, comparadas ...

Effect of the intensity of cooking methods on the nutritional and physical properties of potato tubers

“…Several authors have described a considerable reduction in the amount of TPC during cooking, depending on the cultivar and cooking methods (Blessington et al, 2010;Perla et al, 2012). We observed that the changes in the TPC of the potato flesh were more dependent on the genotype of each cultivar (Table 3).…”

“…Although the phenolic content has been extensively studied for raw potatoes (Rumbaoa, Cornago, & Geronimo, 2009;Stushnoff et al, 2008), there have been many discrepancies regarding the effect of heat treatments on the phenolics and antioxidant activity of potato samples, which could be due to the different processing conditions. Some literature has suggested that a shorter cooking time and lower temperature increased or did not change the total phenolic content and the antioxidant capacity (Blessington et al, 2010;Lachman et al, 2013;Mulinacci et al, 2008;Navarre, Shakya, Holden, & Kumar, 2010;Perla, Holm, & Jayanty, 2012).…”

Carotenoids in potatoes - a short overview

“…Following 9 months storage at 4°C the levels of zeaxanthin and antheraxanthin decreased, whereas the level of lutein increased; overall, however, there was only a small decrease in total carotenoid content. In non-stored potato tubers and in three storage conditions all storage treatments were higher in carotenoid content (expressed as lutein) in four cultivars and the interaction between genotype was significant for carotenoid content (Blessington et al 2010).…”

“…Carotenoid content was observed to be lower in boiled as compared to raw potatoes, however, no significant difference in other methods of cooking was observed (Blessington et al 2010). Isomerisation and oxidation reactions upon heating of carotenoids may cause small losses, which were later confirmed by Rautenbach et al (2010) when they observed an average decrease of 9.7% in boiling sweetpotato for 12 min.…”

“…A study that evaluated the effect of cooking on carotenoid concentration of three potato cultivars detected only lutein in the samples and reported that lutein concentration was not affected by cooking (Blessington et al 2010). A more recent study, that analysed the carotenoid concentration of raw and boiled tubers of four potato cultivars with violaxanthin and lutein as the main carotenoids and zeaxanthin present in very low concentration, reported that heat processing transformed all-trans carotenoids to 9-cis and 13-cis isomeric forms or degraded them (Burmeister et al 2011).…”