Identification of carotenoids and phenolic compounds in bacteriabased protein isolates using LC and MS techniques
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Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
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Global food demand is predicted to increase significantly in the future. Therefore,
discovering new protein sources of sustainable origin is important. One of these is
bacteria-based protein, which has minimal environmental impact compared to traditional
animal agriculture. These novel proteins can hold a variety of color pigments and phenolic
compounds that may impact their appearance and flavor. By identifying these compounds
and their possible contributions to sensory quality, more development can be done to
make them more attractive to consumers. In this study we aim to identify the carotenoid
and phenolic compound profile of five bacteria protein isolate samples from different
cultivations to identify key color pigments and possible off-flavor compounds as well as
observe the differences between different samples. The samples were received from
Aistila Oy, where the same samples had undergone sensory analyses.
The qualitative analysis of carotenoids and phenolics was done using HPLC-DAD and
UHPLC-ESI-MS/MS. Carotenoids and phenolic compounds were extracted using solid-liquid
extraction, using acetone for carotenoid extraction, and ethyl acetate, methanol,
and water for phenolic compound extraction. Identification and characterization of
compounds was carried out by combination of available reference standards, mass
spectrometry data, including both positive and negative ion modes as well as MS and
MS/MS data, retention time, UV/Vis spectral information and literature data of similar
HPLC-MS experiments.
A total of eight carotenoids and 16 phenolic compounds were observed; seven out of eight
and eight out of 16 of which were tentatively identified. Zeaxanthin (m/z 568 [M+H]+.)
and its glucosides zeaxanthin dirhamnoside (m/z 860 [M+H]+) and zeaxanthin
monorhamnoside (m/z 715 [M+H]+) were observed as major carotenoids in all five
samples; approximately 90-100% of observed carotenoid concentrations were identified
as zeaxanthin derivatives. Furthermore, beta-carotene was observed in four out of five
samples, accounting for roughly 1-5% of observed concentrations. Phenolic acid
derivatives were observed to be the most common compound type in all samples.
Hydroxybenxoic acid, benzoic acid, coumaric acid derivatives, phenylalanine, and
dihydroxyphenyllactic acid derivatives were tentatively identified from all samples.
Hydroxybenzoic acid or its derivatives were found to account for 20-50% of observed
phenolic concentrations.
Future studies are needed for a thorough quantification and identification of all
carotenoids and phenolic compounds in the protein isolate, as well as to discover their
influence on the product’s appearance, flavor, and odor.