Olusola Lamikanra

Formation and occurrence of flavor components in Noble muscadine wine

Flavor development in Noble muscadine wine during fermentation and aging was determined with a combined gas chromatograph-mass spectrometer. The source of 2-phenylethanol, a major aroma component of the wine, is predominantly through biosynthesis during the vinification process, although the alcohol was also found to be present in fresh muscadine grape skin. The involvement of substituted benzene derivatives in the formation of phenyl ethanol during fermentation and aging of wines is proposed. The complexity of the volatile aroma extracts increased with time, especially after fermentable sugars were exhausted. Anaerobic formation of fatty acid esters also commenced after active fermentation had ceased. These compounds constitute major components of the aged muscadine wine. Effluent sniffing indicated that many odorous compounds including phenyl ethanol and methyl succinate contribute significantly to the muscadine wine aroma.

Specific Detection of Xylella fastidiosa Pierce's Disease Strains

Abstract. Pierces disease (PD, Xylella fastidiosa) of grapevine is the primary pathogen limiting vinifera grape production in Florida and other regions of the southeastern United States. Quick and accurate detection of PD strains is essential for PD studies and control. A unique random amplified polymorphic DNA (PD1-1-2) was isolated from a PD strain from Florida. Fragment PD1-1-2 was cloned, sequenced, and found to be 1005 bp in length. PCR primers were designed to utilize these sequence data for PD strain detection. One primer set (XF176f–XF954r) amplified a 779-bp DNA fragment from 34 PD strains including seven pathotypes of X. fastidiosa, but not from strains of Xanthomonas campestris pv. campestris, Xan. vesicatoria or Escherichia coli. A second primer set (XF176f and XF686r) amplified a 511-bp fragment specific to 98 PD strains, but not from strains of citrus variegated chlorosis, mulberry leaf scorch, oak leaf scorch, periwinkle wilt, phony peach, or plum leaf scald. Sequence analysis indicated that RAPD fragment PD1-1-2 contains a Ser-tRNA gene. The PD-specific region includes a TaqI restriction site (TCGA) and is 150 bp downstream of the Ser-tRNA gene.

Anthocyanins of Vitis rotundifolia hybrid grapes

Abstract The anthocyanins (Acy) of 14 black Vitis rotundifolia hybrid grapes were separated and quantified by reversed phase high performance liquid chromatography (HPLC) on a C 18 column. Twenty-five pigments were separated and 20 anthocyanins were identified. All the cultivars investigated contained mono and diglucosides of acylated and non-acylated anthocyanidins in varying quantities. Total Acy concentration in grapes ranged from 55 to 357 mg/berry. Most of the cultivars had no delphinidin 3,5-diglucoside and the relative amounts of the other non-acylated Acy, which are the pigments found on V. rotundifolia grapes, were very low. The relative malvidin content ranged from 0·0% of total grape Acy content in M4-83, to 25·5% in Conquistador. No correlation was found between the relative content of any type of Acy and either the lightness (L) or hue (θ) values of the grapes and their juices. The cultivars were ranked for their possible wine color characteristics and selection in breeding programs, based on their total delphinidin and malvidin content. CD12-72 was rated the best cultivar while AD2-75 was the least desirable cultivar used in the study.

Volatile aroma constituents of Noble muscadine grapes

Abstract The volatile components of Noble muscadine grapes were analysed with a combined gas chromatograph-mass spectrometer. Over twenty-five peaks were separated, of which fifteen were identified. A gas chromatogram of the grape extract is presented, along with a Table of compounds and their associated mass spectral data.

Randomly amplified polymorphic DNA analysis of Vitis species and Florida bunch grapes

Abstract Randomly amplified polymorphic DNA (RAPD) analysis was performed on 42 accessions of Vitis , representing 13 species. Inter- and intra-specific/varietal variation were observed. Principal component analysis of Nei and Lis similarity index separated V. rotundifolia from other bunch-grape species. Within the bunch-grape species, V. vinifera , the North American bunch grapes, and the East Asian bunch grapes formed three separate RAPD clusters. RAPD analysis also demonstrated its sensitivity by detecting the genetic diversity within Florida bunch-grape cultivars. RAPD analysis, together with the published morphological data, will lead to a more comprehensive understanding of Vitis genetic diversity.

Effects of grape skins and seeds on the composition and quality of muscadine wines

Abstract The contributions of grape skins and seeds to the composition and quality of muscadine wines, when these are present during a partial fermentation process, were determined. The presence of the grape components affected total and volatile acidity, total phenol and volatile ester concentrations, as well as wine color. The quality of white wine made from partially fermented must in the presence of grape skins and seeds was lower than that in which the seeds were absent during this process, as well as that which was produced from fresh grape juice. Grape seeds had no significant effect on the sensory scores for red wines.

Effect of the A-Type Linkage on the Pharmacokinetics and Intestinal Metabolism of Litchi Pericarp Oligomeric Procyanidins

The bioavailability of A-type procyanidins in vivo has been rarely investigated; as such, this study discusses the effect of A-type linkage and degree of polymerization on the metabolism of procyanidins extracted from litchi pericarp (LPOPC). Sprague-Dawley rats were gavaged with (-)-epicatechin (EC) and LPOPC and sacrificed at different time points after ingestion. A-type linkage procyanidin oligomers inhibited the absorption of EC. Analysis of urinary contents from rats administered with EC, A-type procyanidin dimer (A-2), and A-type procyanidin trimer (A-3) showed distinct native and metabolite profiles for each rat. Rats fed with A-2 and A-3 presented significantly higher levels of shikimic acid and less amount of m(p)-coumaric acid metabolites in vivo and provide insight into the quantitative structure-activity relationship of procyanidin oligomers during metabolism, indicating that procyanidins with A-type linkage could induce an altered metabolic pathway of oligomers in the gastrointestinal system.

Identification of grape cultivars from their seed polypeptide composition

Abstract Seed polypeptides from six Vitis vinifera and three V. rotundifolia cultivars were compared by means of 2D gel electrophoresis. The seed polypeptides were readily separated into several non-overlapping spots, with each cultivar having unique patterns and ca 300 spots. Isoelectric points for the seed polypeptides ranged between 4.3 and 7.3, while their Mr, range was 7000–55 000. The unique polypeptide patterns and their variability with cultivars demonstrates the potential of this method for cultivar identification and other types of varietal research.