Luís Filipe-Ribeiro

By Luís Filipe da Mota Ribeiro, Maria Fernanda Gil Cosme Martins and Fernando Hermínio Ferreira Milheiro Nunes

We recently proposed a simple methodology to improve cork powder waste adsorption properties through vacuum degassing and solvent impregnation, to use this abundant and cheap material as a new wine fining agent. Its applicability was first shown for red wine 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) reduction. Nowadays, the presence of 4-EP and 4-EG is a serious problem in the wine industry, known as “Brett character”, by the negative aroma imparted by these volatile phenols (VPs) to red wine. There are only some curative treatments to remove these compounds without impacting negatively on wine quality. Optimised cork powder was used successfully as a new treatment for the reduction of these negative VPs (41?75% for 4-EP and 40?69% for 4-EG) increasing at the same time wine sensory performance. Wine treated with cork powder reduced 6.9% phenolic acids and catechin and 2.3% monomeric anthocyanins without any significant change in colour intensity. In this chapter, the cork complex structure is discussed, besides the impact of its use in wine containing VPs on physicochemical composition and quality. This new application of this natural, abundant and cheap material has the potential of being a new wine fining agent with low environmental impact.

Part of the book: Advances in Grape and Wine Biotechnology

By Juliana Milheiro, Fernanda Cosme, Luís Filipe-Ribeiro and Fernando M. Nunes

Port wine is a traditional and worldwide renowned fortified wine produced in the Douro Demarcated Region (DDR) Northeast of Portugal by specific and traditional winemaking practices. The final quality and uniqueness of the different Port wine styles are highly dependent on the ageing process, namely time, temperature and oxygen levels that will ultimately dictate the type and extension of the chemical changes that occur during this process. These chemical changes occurring during the Port wine ageing process results in significant changes in colour and aroma according to the different ageing conditions employed for the different Port wine styles. This chapter intends to give a broad and generic overview of the known and potential chemical changes occurring during ageing of Port wine that are responsible for the changes in the sensory profile observed during the ageing process. Also, the known chromatic and aromatic characteristics of the different Port wine styles and the specific ageing processes, reductive or oxidative, are reviewed.

Part of the book: Chemistry and Biochemistry of Winemaking, Wine Stabilization and Aging

By Fernanda Cosme, Luís Filipe-Ribeiro and Fernando M. Nunes

Wine is widely consumed due to its distinctive sensory characteristics. However, during wine production and storage, several defects can appear. These can be the result of unwanted microbiological activity or due to the unbalanced levels of some compounds resulting from an unbalanced grape chemical composition or inadequate winemaking practices and storage conditions. The main purpose of wine stabilisation is the removal of wine defects, either visual, olfactive, gustative, or tactile, the increase in wine safety and stability by fining and filtration operations, avoiding the occurrence of some usual wine precipitations after bottling. Although the best strategy is to prevent the appearance of wine defects, when present, several fining agents or additives, and technologies are available today with different performances and impact on wine quality. By physicochemical and sensory analysis, the defect is detected, and if the objective is removing them, some laboratory trials are performed to achieve a better treatment approach. This review overviews the principal wine defects and treatments available today and in the near future. Generally, the future trend is the use of more sustainable and environmentally friendly fining agents and technologies, looking for treatments with better performance and specificity.

Part of the book: Chemistry and Biochemistry of Winemaking, Wine Stabilization and Aging

By Luís Filipe-Ribeiro, Fernanda Cosme and Fernando M. Nunes

White wine protein instability depends on several factors, where Vitis vinifera pathogenesis-related proteins (PRPs), namely chitinases and thaumatin-like proteins, present an important role. These proteins can be gradually denatured and aggregate during wine storage, developing a light-dispersing haze. At present, the most efficient process for avoiding this wine instability is through the removal of these unstable proteins from the wine before bottling. To remove unstable white wines proteins, the sodium bentonite fining is the most used treatment, however, many alternative techniques such as ultrafiltration, the application of proteolytic enzymes, flash pasteurisation, other adsorbents (silica gel, hydroxyapatite and alumina), zirconium oxide, natural zeolites, chitin and chitosan, carrageenan and the application of mannoproteins have been studied. This chapter overviews the factors that influenced the white wine protein instability and explored alternative treatments to bentonite to remove white wine unstable proteins.

Part of the book: Grapes and Wine