In over 190 countries all over the world, hundreds of thousands of Memmert products have been permanently in use for decades. This is why Memmert is one of the leading suppliers of temperature control appliances worldwide.
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.
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.
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.
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
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
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.
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.
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
