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Extraction of lutein from marigold petals

Petals of the marigold contain valuable lutein. You can read in this article how the lutein can be extracted with the help of a vacuum oven.

The Chemistry Study Program and Research Center for Photosynthetic Pigments from Universitas Ma Chung published a study in May 2019 on the Integrated solvent-free extraction and encapsulation of lutein from marigold petals and its application by using a laboratory vacuum drying oven from Memmertvacuum oven VO.

This article is a compilation of the report and the role played by the vacuum oven VO in it.

Detailed information is now available in the vacuum oven whitepaper. For further information on drying ovens, its technology, uses, versatility and more, read this explainer blog.

This images visualizes the space-filling model of the lutein molecule, a compound used by plants to protect themselves from intense light.
Space-filling model of the lutein molecule, a compound used by plants to protect themselves from intense light. Courtesy of Jynto.

Background

Resources of lutein are point of great interest and experiments. Its benefit for eye care is well documented. As a popular resource of lutein – the scientific community has focused on the vivid orange petals of marigold.

Lutein displays potential to be used a food grade ingredient with extraction methods via marigold – which brings this report into being.

This study aims to show lutein extraction from marigold petals with vegetable oil and ultimately finished as milk tea beverage. The results show that this extraction capacity was 1.9 times greater than acetone. The milk tea containing lutein was found to be quite flavorful by panelists in the study.

Source of marigold

Bali, Indonesia, is home to flower gardens where marigold grows in abundance. In addition to lutein, the flower petals are a useful source of β-carotene, lycopene, and zeaxanthin.

Studies found that lutein:

Image of marigold flower.

Figure 2: Marigold flower (Tagetes erecta L.). Courtesy of Mauricio Mercadante.

Background on lutein extraction from marigold

Marigold lutein as food product instead of dietary supplement

Arguments can be made about the lutein extracted from marigold be served better as an ordinary food product as opposed to being used a diet supplement.

This brings forth the objective of deciding on a food product for the purposes of this study. Functional food product has a higher acceptance amongst consumers. The carrier product must meet certain criteria:

  • The food product must incorporate lutein properties
  • Be heat-labile
  • pH sensitivity
  • Dissolving and absorption qualities in oil-based substance
  • Appeal to the 13–40-year-old demographic who are health conscious, have prolonged exposure to television, computers and other displays

Thus, the food item chosen was milk-tea beverage that appeals to a broad demographic, its brown color blends in the yellow-colored lutein whilst not giving consumers misconceptions of other yellow colored beverages with citrus, for example, and the milk-tea also possesses fat-based ingredients.

Objectives

  • Solvent-free extraction of marigold petals using vegetable oil
  • Encapsulation procedure to produce lutein powder
  • Use lutein powder in milk tea
  • Check for sensory reaction to the final product - “marimilktea” beverage

Materials and methods

Preparing marigold petals with Memmert vacuum oven VO

  • The marigold flower, Tagetes erecta L. var. Mega Orange, was sourced from a cultivation garden in Bali, Indonesia
  • Freeze drying was used to separate the petals from the stalk
  • Drying treatment is applied using a Memmert laboratory vacuum drying oven at 40°C, until moisture content was valued at under 10%
  • Now this dried flower is grounded and sieved via 180-μm sieve and afterwards kept in low humidity & light

Continue reading for more information on how a vacuum oven works, its features and applications, or reach out for expert consultation. Latest information on vacuum ovens and other heating and drying ovens can be found here.  The blog also contains other vacuum oven applications for a better impression of its versatility.

Determination of pigment composition

  • 1mm acetone is added to 0.01 g of marigold powder
  • The mixture is vortexed and centrifuged
  • Liquid chromatography analysis is applied to crude extract
  • Reversed phase C30 (VP-ODS) column is eluted with gradient solvent in high performance liquid chromatography apparatus. This is combined with a diode array detector consisting of an aliquot (20 μL) of crude pigment extract
  • Successful identification of pigments in extract

Optimization and encapsulation of lutein

  • 0.01g of marigold powder is suspended in 1 mL canola oil
  • Vortexed for 3 minutes
  • Sonicated for 1 minute
  • Centrifuged at 10,000 rpm for 2-minute time period
  • Extracted repeatedly until color of residue was pale
  • Individual supernatant diluted hundred times in hexane and subsequently measured spectrophotometrically at 350–600 nm
  • Quantity of marigold powder raised, i.e., 0.03, 0.07, 0.1, 0.2, and 0.3 g/mL oil and above processed repeated
  • Quantification of the lutein ester is made possible as acetonic solution
  • Optimum ratio (0.2 g dried flower per milliliter oil) is scaled and encapsulated for the making of lutein powder
This graph shows the correlation plot between concentration of dried marigold powder in oil and its absorbance (diluted hundred-fold and measured in n-hexane).

Correlation plot between concentration of dried marigold powder in oil and its absorbance (diluted hundred-fold and measured in n-hexane). Courtesy of Taylor & Francis Online.

Milk tea preparation and lutein powder

It began as a blend of black tea extract and evaporated full cream milk. For the purposes of the topping, liquid whipping cream is whisked. Lutein incorporation is possible by either as emulsified in milk tea or mixed in whipping cream, and can be adjusted for sweetness and calories at the end

Focus group testing

The beverage was offered in 3 ways:

  • milk-tea
  • milk-tea with cream topping
  • milk-tea with cream topping and lutein powder

Focus group members evaluated the color, aroma, flavor, mouthfeel, sweetness, and overall preference between them.

This image shows the mean scores for sensory attributes of different serving recipes of milk tea beverage.

Spider web diagram representing the mean scores for sensory attributes of different serving ways, i.e. milk-tea base (a), milk-tea with lutein-enriched cream topping (b), and milk-tea with lutein-enriched and ornamented cream topping (c). Lutein powder has incorporated into the whipped cream (10 g/L). Courtesy of Taylor & Francis Online.
A graph showing hedonic scores for the sensory attributes of “marimilktea”.

Hedonic scores for the sensory attributes of “marimilktea”. Courtesy of Taylor & Francis Online.

About Memmert vacuum oven

Memmert GmbH + Co.KG, operating out of Schwabach and manufacturing from Büchenbach, produces the vacuum oven VO as part of its diverse heating and drying oven range.

It offers features such as:

  • Temperature range up to +200 °C
  • Vacuum control range: 5 to 1100 mbar
  • 3 model sizes (29 to 101 litres volume)
  • 1 model variant: TwinDISPLAY
  • Anti-splinter; VDE-tested door construction for all models
  • Pump control: Optimised rinsing of the pump membrane as well as signal output for switching the pump ON/OFF according to requirements.
  • Optional: Pump base cabinet and energy-efficient vacuum pump
  • Nearly exclusive use of high-quality, rust-resistant and easy to clean stainless steel for interior and exterior housing
  • Precise and homogenous temperature control thanks to a product-specific heating concept
  • A wide range of options for programming and documentation using interfaces, integrated data loggers and the AtmoCONTROL software
  • 3 years guarantee worldwide
This device is a Memmert vacuum oven VO.
Memmert vacuum oven VO.

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