Nutraceutical consumers go to green tea fo its catechins, soy for its isoflavones, grapes for its resveratrol and anthocyanins, and royal jelly for its complex matrix of proteins and polyphenols.
“The concentration of these compounds can change during their storage or thermal treatment,” the researchers from the University of Almeria, Spain, wrote in the report, citing a study published in the Journal of the Science of Food and Agriculture in 2000.
This current study, titled Influence of storage conditions in the evolution of phytochemicals in nutraceutical products applying high resolution mass spectrometry, researchers observed the bioactive components of grape, tea, royal jelly, and soy stored at 5 degrees Celsius, monitoring them for one year “to check the evolution of the detected compounds asa result of possible transformations occurred during storage conditions.”
Purchased from local markets in Spain, the researchers studied samples from various, undisclosed brands of two green tea capsules, two soy capsules, one grape capsule, and royal jelly liquid nutraceuticals.
The compounds were analysed using a method developed by the same group of researchers last year. The samples were analysed throughout one year.
“To eliminate variations between single capsules, the content of 20 capsules was homogenized using a coffee grinder,” the report said. “All samples were stored at 5 degrees Celsius in a desiccant located in a refrigerator in a dark place.”
The scientists differentiated their study from similar ones out there by performing analysis “at low temperature in order to minimize potential degradation,” as most studies have done the analysis in room temperature.
“It was noted that [degradation] in products were detected after 3 months of storage in green tea and soy products, while 6 months were necessary to observe transformation in royal jelly,” the study said.
When it came to the grape-based products, they found no significant loss of original bioactive compounds during the storage time.
“It was observed that the kind of matrix is really important, observing that royal jelly is more ‘stable’ than green tea or soy based products, although different results were obtained for the same type of matrix, indicating the difficulty of the problem faced in this study,” the scientists said.
Despite this, they said that “the evaluation of the influence of storage conditions is important since storage properties need to be carefully controlled in order to preserve the quality and efficacy of this kind of product.”
Source: Food Chemistry
First published online, doi:10.1016/j.foodchem.2016.01.067
Influence of storage conditions in the evolution of phytochemicals in nutraceutical products applying high resolution mass spectrometry
Authors: Noelia López-Gutiérrez, Roberto Romero-González, José Luis Martínez Vidal, Antonia Garrido Frenich