Free Amino Acids and Other Nitrogenous Fractions in Wine Grapes

Abstract

SUMMARY: The concentration of eight free amino acids, total nitrogen, amino‐acid fraction nitrogen, and nonamino‐acid‐fraction nitrogen in the juices of 26 red‐ and 23 white‐wine varieties of grapes was determined at early and late stages of fruit maturity. Proline was the most prominent amino acid in 31 of the varieties at early harvest and in 45 of the varieties at late harvest while arginine was the main amino acid in 16 and 3 varieties at early and late harvest, respectively. “Salvador” and “Scarlet” were the only varieties in which α‐alanine was the predominant amino acid. The concentration of total nitrogen in the juices of the various varieties ranged from 44 to 256 mg/100 ml and the amino‐acid fraction nitrogen ranged from 26 to 171 mg/100 ml juice. The amino acid fraction and nonamino acid fraction nitrogen in the juices ranged from 53 to 76% and 23 to 56% of total Kjeldahl nitrogen respectively. Alanine, γ‐aminobutyric acid, arginine, aspartic acid, glutamic acid, proline, serine and theronine accounted for 29 to 72% of the total nitrogen and 47 to 96% of the amino acid fraction nitrogen. Arginine contributed the most nitrogen of the amino acids, accounting for 6 to 44% of the total nitrogen in the juices of the various fruits.

Juice and Wine Quality Responses of Vitis vinifera L. cvs. Sauvignon blanc and Chenin blanc to Timing of Irrigation during Berry Ripening in the Coastal Region of South Africa

“…Water stress significantly increased proline in juice of grapevines compared with juice from continually irrigated grapevines (Matthews & Anderson, 1988). Hence, where grapevines of the I00 and II0 treatments were subjected to high levels of available water depletion during ripening (Myburgh, 2005), water stress could have increased proline, which is one of the predominating amino acids in Sauvignon blanc and Chenin blanc grapes (Kliewer, 1970). This could also explain the high juice N content in Sauvignon blanc grapes of the II31 treatment, where grapevines were subjected to the same levels of water stress as the II0 treatment for most of the duration of ripening (Myburgh, 2005).…”

Three descriptors for sugars to evaluate grape germplasm

“…As shown in Table 3, the mean ° Brix of cultivated species (V vinifera : Lott & Barrett, 1967 ;Kliewer, 1970;V labrusca : Caldwell,1925 ; hybrids between V labrusca and V vinifera : Caldwell, 1925 ;Lott & Barrett, 1967) were generally high (17 to 20%), while that of V rotundifolia (Carroll et al ., 1971) and wild species (Nakagawa et al ., 1980) were low (13% and 12%, respectively) except V coignetiae (16%) . In this study, the mean ° Brix of cultivated species were higher (varieties : 17% ; bred lines : 18%) than that of rootstocks (11%) and wild species (13%), which is in agreement with previous reports, but it needs further research on wild species and rootstocks because of the lack of information .…”

Amino Acids Profile of Two Galician White Grapevine Cultivars (Godello and Treixadura)

“…Grape variety is the most important determinant of the type and concentrations of amino acids that accumulate in the grape berry (Kliewer, 1970;Stines et al, 2000). When other factors are held comparatively constant, climate is the dominant factor that influences berry and wine quality (Storchmann, 2005;Makra et al, 2009).…”