Evaluation of fatty acid and mineral profiles and bioaccessibility of diosgenin in different types of Peruvian maca ( Lepidium meyenii Walp )

The present work aimed to study the bioaccessibility of diosgenin, fatty acid and mineral profile in different types of Peruvian maca (Lepidium meyenii Walp). Analyzes of minerals, fatty acids, saponins and bioaccessibility of diosgenin were performed. For minerals the values were detected: commercial litter (MC) 490.65mg / 100g of Ca, 1472.65mg / 100g of K, in red litter (MV) 1478.25mg / 100g of K and 670.25mg / 100g of Ca, yellow yellow (MA) 875.65mg / 100g Ca, 1215.25mg / 100g K. The highest concentrations of fatty acids were related to the unsaturated portion. % oleic acid in the red stretcher. Regarding the saponin and diosgenin content, the commercial litter presented the highest contents 250.33mg / 100g for saponins, and 340.56μg / ml for diosgenin. These results emphasize the importance of the consumption of this nutrient-rich vegetable with effective action on human metabolism (p <0.05).


Chemical composition
Moisture, ash, and protein content was determined the protocol by the Association of Official Analytical Chemists (AOAC) (2016) using a 6.25 factor to convert nitrogen percentages into protein content. Total lipids were extracted and identified according to Bligh and Dyer (1959) as described above. Total carbohydrates were calculated using the following equation: c = 100−(Moisture+Lipid+Protein+Ash). Caloric value was determined by using an indirect method based on main product nutrient (carbohydrates, protein, and lipids) conversion factors.
The mineral content was determined in triplicates using atomic absorption spectrometry method recommended by Adolfo Lutz Institute (IAL, 2008), and according to Varian manual (2000). The digestion of samples was performed using microwave in MARS -Xpress CEM Corporation, MD -2591 digester followed by mineralization of organic matter using concentrated nitric acid, cooling and dilution with deionized water, and reading. Reading was performed directly using diluted atomic absorption spectrophotometer solutions (Spectra AA, model 220 FS, Varian, 2000), with specific lamps according to the manufacturer's manual. Research, Society and Development, v. 9, n. 6, e181963519, 2020 (CC BY 4. The quantified mineral elements were Ca, K, Na, Mg, Fe, Zn, Mn, and Cu. For controlling the analyses, recommendations according to Cornelis (1992) were used, having certified reference material Peach leaves (NIST-SRM 1547).

Extraction and quantification of total saponins
Sprayed drug was weighed and 0.2 g degreased with 30 mL hexane for 2 h then powder filtered and oven dried. Powder was refluxed with three 20 mL aliquots of methanolwater (4:1) for 30 min and the methanolic extract filtered and concentrated via extraction with three 20 mL volumes of water-saturated n-butanol. The butanolic fraction was collected and concentrated until dried then dissolved in 100 mL of water. Next, 1 mL 0.2% cobalt chloride and 1 mL concentrated sulfuric acid were added to 1 mL aliquot of resuspended butanolic solution. Absorbance of both processed methanolic and butanolic extracts was then measured at 284 nm (Vigo et al. 2003). A calibration curve consisting of six points was then constructed, producing a correlation coefficient R2 = 0.9904, confirming reading linearity and indicating that the technique was performed correctly. The saponin analysis was performed using a spectrophotometer and following recommendations from the literature. The standard curves of Merck saponins were generated at five concentrations: 0.08 mg/mL, 0.12 mg/mL, 0.16 mg/mL, 0.20 mg/mL, 0.28 mg/mL, 0.36 mg/mL, and 0.40 mg/mL. The chromogenic reagent used was 0.2% cobalt chloride with an optimal reaction time of 10 to 20 min. A wavelength of 284 nm was used for analysis.  Dini et. al., (1994) and Dufour & Loonis, (2005) studied the chemical composition and regional and stereo selective oxidation of serum albumin-linked linoleic acid in maca (Lepidium meyenii) and found fatty acid profiles in maca similar to those in our study. A lack of unsaturated fatty acids leads to skin problems like alopecia, a peeling epidermis, and eczema (Yang & Kallio, 2001). Additionally, according to Cozza & Costa, (2000), high blood cholesterol levels can lead to coronary heart disease and can be prevented through lower consumption of saturated fatty acids and increased consumption of polyunsaturated fatty acids (PUFAs). Figure 1 shows fatty acid concentrations in maca varieties (commercial MC, red MV, yellow MA, and black MP). arachidonic acid, which is also known as vitamin F and is necessary for skin growth and protection (Wannes & Marzouk, 2016). The chromatographic peaks shown above in Figure 1, for the fatty acid content, corroborate with the values described in table 1.
Higher potassium levels in maca compared to our study were detected by Dini et al., (1994), who found that maca (Lepidium meyenii) on average contains 2050 mg/100 g potassium.
Vegetables are generally the main mineral sources for humans and mineral availability is closely related to soil content.
Within vegetables, minerals are present in their natural organic complex forms, which are readily usable by the body (Food Ingredients Brazil, 2008). However, the quantity of these minerals is not always sufficient to meet nutritional requirements, requiring supplement consumption.

Saponin detection and diosgenin bioaccessibility
As presented in Table 2, MC contained the highest levels of saponins at 250.33 mg/100 g for saponins and showed comparable levels of diosgenin (340.56 µg/mL) to MA. Table 2 shows fatty saponin an diosgenin levels in maca varieties (commercial MC, red MV, yellow MA, and black MP).