A GIS Analysis of New Zealand Terroir

According to the Protected Designation of Origin (PDO), Cava is protected in the quality sparkling wines made by the traditional Champenoise method were the wine realize a second fermentation inside the own bottle1. Geographical and human peculiarities of each bottle are the main way for the final quality2. The aim of this study is to find correlations and which target compounds are the most representative of the quality of two different grape varieties, Pinot Noir and Xarel·lo. The quality of these two types of grapes is being studied for each variety by a previous classification of the vineyard made by the company who provided the samples (qualities A,B,C,D, being A the better one and D the worst one). The target compounds studied are organic acids and polyphenols. The methodology for the determination of organic acids is HPLC-UV/vis and for some of them the enzymatic methodology.

Hydroxytyrosol (HT) is well known for its potent antioxidant activity and anticarcinogenic, antimicrobial, cardioprotective and neuroprotective properties. One possible explanation to its origin in wines is the synthesis from tyrosol, which in turn is produced from the Ehrlich pathway by yeasts. This work aims to explore the factors that could increase the final content as the initial concentration of yeast assimilable nitrogen (YAN) and sugar. Two different concentrations of YAN were proved between 210mg/L and 300 mg/L. Additionally, two different concentrations of sugar were used: 100g/L and 240 g/L. Alcoholic fermentations in synthetic must were performed with the strain QA23.

When grapevine plants are transplanted into already established vineyards, they face multiple challenges, including adverse climate, heavy metal accumulation from agronomic practices [1], and pressure from highly adapted pathogens [2].

A lot of work has been done on the impact of Botrytis on the foam of sparkling wines. This work often concerns wines produced in cool regions, where Botrytis is the dominant fungal pathogen. However, in southern countries such as Spain, in particularly hot years such as 2022, the majority fungal pathogen is sometimes Rhizopus. Like Botrytis, Rhizopus is a fungus that produces an aspartic protease.

Mannoproteins (MPs) are proteoglycans from the outmost layer of yeast cell walls released into wine during alcoholic fermentation and ageing on lees processes. The use of commercial preparations of mannoproteins as additives to improve wine stability with regards to the crystallization of tartaric salts and to prevent protein haze in the case of white and rosé wines is authorized by the OIV.
Regarding red wines and polyphenols, mannoproteins are described as able to improve their colloidal stability and modulate the astringent effect of condensed tannins. The latter interact with salivary proteins forming insoluble aggregates that cause a loss of lubrication in the mouth and promote a drying and puckering sensation. However, neither the interaction mechanisms involved in mannoproteins capacity to impact astringency nor the structure-function relationships related to this property are fully understood.