Protein extracts of the Andean pseudocereals quinoa and kiwicha as alternatives for the fining of wine phenolics.

Abstract

INTRODUCTION: Lately, there has been an increasing interest in using plant-derived proteins for wine phenolic fining. Proteins extracted from cereals, potatoes, and legumes have been proposed as effective fining agents, but only those from pea and potatoes have been approved for their use in wine. This work aimed at determining the fining ability of the Andean pseudocereals quinoa (Chenopodium quinoa Willd.) and kiwicha (Amaranthus caudatus L.) protein extracts (QP and KP respectively), compared to commercial fining agents, on red wines.

METHODOLOGY: The trials compared the performance of QP and KP, two potato protein extracts and gelatin, at two different contact times (48 and 96 h), on Cabernet Sauvignon wine. The turbidity was measured with a Hanna HI 83749 turbidimeter and results were expressed as NTU. Total phenolics (1), precipitable tannins (2), catechins (3), polymeric pigments (4), and CIELab parameters were determined spectrophotometrically. Low molecular weight phenolics were analyzed by HPLC (5).

RESULTS: QP and KP were effective in reducing the turbidity of the studied wine in a similar way than commercial fining agents. Treatments with QP and KP reduced total phenolics and total tannins similarly than commercial fining agents. Most of the treatments did not affect the flavan-3-ol content of wines. Our results allow us to hypothesize that the fining agents used are more likely to bind high molecular weight tannins than to those of low molecular weight or monomers. In some cases, treatments with QP and KP slightly decreased the color intensity similarly to other vegetable proteins.

CONCLUSIONS:

The fining ability of quinoa and kiwicha protein extracts has been studied for the first time. Results showed that QP and KP could be used as effective fining agents for
red wines as alternatives to animal proteins such as gelatin. The use of QP and KP as fining agents has the advantage of being non-allergenic products.

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