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Coconut Proteins: Alternative Source of Protein for Retention of Phenolics

The aim of this study was to prepare different protein-polyphenol complexes, and to determine whether coconut protein can be as efficient as soy protein or whey protein as adsorbent (carrier) for phenolic compounds. Protein-polyphenol complexes were prepared by complexing soy protein, whey protein or coconut protein with water extracts of blueberry pomace, cranberry pomace or muscadine grape pomace. Prepared complexes were investigated for total phenolics, proanthocyanidins, anthocyanins and antioxidant capacity. Three different amounts of each protein was used depending on dispersibility of proteins in water extracts: 5, 10 and 15% for coconut protein, 10, 20 and 30% for soy protein and 10, 20 and 40% for whey protein. The amounts of bonded phenolics were calculated as mgcompounds/gprotein. The increase in protein amounts resulted in a decrease in the amount of total phenolics, proanthocyanidins and anthocyanins. Common amount for all three protein complexes was 10%. Whey protein bonded the lowest amount of proanthocyanidins from blueberry and cranberry extracts. Other two proteins bonded higher amount of this compounds but there was no difference between them. Total phenolics of blueberry and muscadine grape extracts were bonded in the highest amount by soy proteins, while there was no difference between coconut and whey proteins. Cranberry phenolics were bonded in the same extent by all three proteins. Blueberry pomace extract contained considerable amount of anthocyanins and they were bonded in the highest amount by soy protein. In addition, correlation between protein amount and total phenolics was conducted and linear dependence was observed. Extrapolation of phenolics retention for soy proteins and whey proteins at 5% was conducted using obtained equations in order to compare results with coconut protein. Through extrapolation, for blueberry and cranberry extracts the highest amount of bonded phenolics and proanthocyanidins were obtained by coconut protein. Results of this research showed that there is potential of coconut protein as adsorbent for phenolics if it is used in lower amount. Obtained complexes can be used as food additives for enrichment of different foods with bioactive phenolics.

coconut protein ; soy protein ; whey protein ; phenolics

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