Grape/grapes Niagara

The range of pH and total acid values found in commercial musts of five native and two hybrid varieties for a six-year period (18) are given in Table III. Total acidity and pH were determined in filtered must samples representative of each day s total production, first noting pH then titrating to pH 8.2 using a Beckman Zeromatic pH meter (27). Only the Niagara grape consistently had a total acid content below 1.000... 

Data from GC/O run shown in Figure Gl.8.4 (Niagara grapes OV-101 index). The odor descriptors were the most frequent descriptors used by the sniffer over several GC/O runs of the same sample. RI, retention index. 

Figure G1.8.4 An FID chromatogram of concentrated extract of Niagara grape juice drawn to display the data on a linear retention index scale where the y axis is flame ionization response (upper trace). Below it is the charm chromatogram, where the / axis is dilution value. By simply comparing the index of a peak with the data listed in the Flavornet (see Internet Resource), it is possible to determine which odorants have similar retention indices. Notice how large the methyl anthranilate peak is, whereas there is no convincing peak for p-damascenone in the FID chromatogram, even though both compounds have the same potency in the charm chromatogram.

Figure 11.3.1 HPLC chromatogram of acidic polyphenolics isolated from Niagara grapes and detected at 320 nm. Retention time 8.647 min, frans-caftaric acid 13.789 min, c/s-coutaric acid 14.944, frans-coutaric acid. Reproduced from Lee and Jaworski (1987) with permission from the American Society for Enology and Viticulture.

Retention times of the peaks are subject to the particular type of column. The acidic fraction from solid-phase extraction consists of phenolic acids such as cis-coutaric, trans-coutaric, and trans-caftaric acids. Isocratic elution is suitable because of the limited number of compounds found in the acidic fraction. Analysis of the acidic fraction is completed within 30 min. See Figure 11.3.1 for an HPLC chromatogram of the acidic polyphenolics isolated from Niagara grapes. 

So far our attempts to isolate a pure chemical component from labrusca or muscadine grapes with a clear foxy odor have been unsucessful. There is however one component trans-2-hexen-l-o1. apparently present in all grape species that has an odor very similar to the foxy odor component of Niagara grapes. Possibly this compound is present in foxy-smelling... 

Some representative compounds from the family of 4>phenethylaminoquinolines were examined under field conditions to determine their level of control against grape downy mildew of Niagara grapes and compared to the initial lead, compound 1. As can be seen in Table V, a number of these compounds gave good-to-excellent control at levels of 100-500 ppm, much lower than the comparable activity shown by the parent compound, compound 1. 

FIELD EFFICACY OF SELECTED COMPOUNDS AGAINST GRAPE DOWNY MILDEW (NIAGARA GRAPES)... 

Holloway, P., R.E. Subden, and M.A. Lachance. 1990. The yeasts in a Riesling must from the Niagara grape-growing region of Ontario Ganada. Can. Inst. 

Until the middle of the 1900s, Brazilian viticulture was restricted to the cultivation of American grapes under temperate and subtropical climates in the South and Southeast. After the spread of Isabella from 1830 to 1840, other American cultivars became popular, such as Herbemont, Concord, Ives, Seibel 2, White Niagara, Rose Niagara and Jacquez. In the 1970s, the Brazilian white wine market was supported by Seyve Villard 5276 and Couderc 13, while the red wines were mainly made from Ives (synonym Bordo) and Concord (Camargo et al., 2012c). 

V50154 (Seibel 5455xSeibel 14664). V50154 is blue grape selection with wine possibilities. It is vigorous and very productive. Clusters are medium in size and very compact. It may not be sufficiently hardy above the Niagara Escarpment. 

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