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Browsing by Author "Jayanty, Sastry, advisor"

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    Assessment of methods to screen for carotenoids in yellow-fleshed potato germplasm
    (Colorado State University. Libraries, 2020) Logrono, Jeremy Brandon, author; Holm, David G., advisor; Jayanty, Sastry, advisor; Heuberger, Adam, committee member; Byrne, Patrick, committee member
    Rapid Evaporative Ionization Mass Spectrometry (REIMS) has the capability to rapidly perform tissue analysis without sample preparation, extractions or chromatography required. The study was conducted to evaluate REIMS as an efficient platform to identify carotenoids in yellow-fleshed potato germplasm (N = 60) from the Colorado Potato Breeding and Selection Program. The specific aim eventually is to improve selection efficiency and accelerate genetic gain in nutritional quality of potato cultivars. Phenotypic tuber flesh color (FC) rating (0 – 3), chroma values, and individual and total carotenoids data were collected, processed and combined with multivariate analyses to help in REIMS data interpretation. Results showed that orange-fleshed (FC 3) potato genotypes gave significantly higher overall carotenoid content (P <0.0001) compared to the white-fleshed (FC 0), yellow-fleshed (FC 1) and dark yellow-fleshed (FC 2) genotypes. Zeaxanthin was the major carotenoid detected among the 60 selections/cultivars evaluated. The association between tuber flesh chroma and carotenoid content was analyzed. Results from Pearson correlation analysis revealed positive correlations overall. The correlation coefficient values (r) for lutein vs. chroma (r = 0.56, P < 0.01), zeaxanthin vs. chroma (r = 0.60, P < 0.01) and total carotenoid vs. chroma (r = 0.63, P < 0.01) were considered moderate. A metabolite mass fingerprint for each replicated sample was collected via REIMS to build a data matrix and processed to test the fit with prediction models. Multivariate methods of analysis (MVA) of principal component analysis (PCA), partial least square (PLS) and orthogonal-PLS (OPLS) were created to determine any sample differentiation among the yellow germplasm. FC rating data (0 – 3) were integrated to MVA models as a covariate. Rep 3 samples were excluded in all MVA analyses due to high presence of noise in the raw data. PCA of Reps 1 and 2 (n = 95) showed a predictive power of 48.4% (Q2). No apparent trends or separations based on flesh color was observed in the PCA model. PLS and OPLS supervised models illustrated better differentiation among sample components. OPLS model (n = 71) of high carotenoids (FC 3) vs. low carotenoids (FC 1 & 0) with a predictive power of 56.1% (Q2) was considered the best model due to clear separations of high vs. low carotenoid samples. Loadings and variable importance score (VIP) data were also analyzed to rank metabolite masses that contributed to differentiation of samples, detecting mostly lipid class molecules. Precursor molecules of lutein and zeaxanthin were not detected from the REIMS analyses and carotenoid fragmentation products were most likely contributing to differentiation among samples. Further research is needed to verify identification of carotenoid fragmentation in REIMS as well as the use of more portable and cost-efficient devices.
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    Color, carotenoid content and sensory perceptions in potato germplasm from the Colorado Potato Breeding and Selection Program
    (Colorado State University. Libraries, 2014) Larson, Katie Mae, author; Holm, David, advisor; Jayanty, Sastry, advisor; Reddivari, Lavanya, committee member; Brick, Mark, committee member
    Field-grown potato tubers were evaluated for tuber flesh color, focusing on hue and chroma, total carotenoid content and identification and quantification of individual carotenoids. A total of 138 clones/cultivars from the Colorado Potato Breeding and Selection Program were evaluated to determine the chroma and hue of the tuber flesh. A subset of 100 entries, 65 tetraploids and 35 diploids, were analyzed for total carotenoid content and eight select entries for individual carotenoid content. Volatile flavor compounds were analyzed in 12 select entries, including two diploid entries with high carotenoid levels, using both microwaved and steamed cooking methods. Five entries from the volatile compound analysis were selected for a sensory evaluation. The relationship between tuber flesh chroma and carotenoid content was analyzed. Total carotenoid content was positively correlated (r = 0.72) with chroma for the subset of 100 entries. The range in total carotenoid content was 16 to 2741 μg/100 gfw (grams fresh weight). Diploid entries had a total carotenoid content three times higher than tetraploid entries. There was a significant entry by year interaction for total carotenoid content. Lutein was the major carotenoid detected among the eight entries analyzed. For the volatile flavor compounds, limonene was quantified and alpha-copaene, decanal, isovaleraldehyde, and 2-pentanone were detected in 12 select entries. The relationship between volatile compounds and sensory scores was analyzed. Limonene was not detected in the two diploid entries with high carotenoid levels. The sensory evaluation revealed higher sensory scores for the three tetraploid entries than the two diploid entries with high carotenoid levels. The recently named cultivar Masquerade received the highest score for overall acceptability for both steamed and microwaved cooking methods. The use of diploid potato entries will be a target for future breeding efforts in order to increase carotenoid levels. Further research is needed to identify entries with promising flavor characteristics in order to develop cultivars with greater carotenoid levels and enhanced flavor.
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    Development of methods to estimate or reduce pressure flattening of potatoes during storage
    (Colorado State University. Libraries, 2013) Castleberry, Henry C., author; Jayanty, Sastry, advisor; Wallner, Stephen, committee member; Barbarick, Ken, committee member; Holm, David, committee member
    To view the abstract, please see the full text of the document.
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    Profiling and putative aroma biomarker identification for flavor in potatoes using a trained sensory panel and HS-SPME GC-MS
    (Colorado State University. Libraries, 2017) Bough, Raven, author; Jayanty, Sastry, advisor; Holm, David G., advisor; Stone, Martha, committee member
    Flavor is the synthesis of taste and aroma sensations. The taste fraction of flavor, including salty, sweet, sour, bitter, and savory, refers to non-volatile chemical compounds that are detected by epithelial cells in the mouth. The aroma fraction encompasses volatile or semi-volatile chemical compounds that are sensed by nerve cells within the olfactory system, particularly during the chewing process, initiating a multitude of sensations such as earthy, floral, or fruity. Flavor may also be influenced by texture, sound, appearance, or personal preference, resulting in an inherently complex phenotypic trait that is difficult to assess. Cooked flavor profiling of fifteen fresh market potato clones (Solanum tuberosum, L.) using sensory analysis paired to aroma compound analysis reveals potential biomarkers for flavor phenotyping. Trained sensory panelists described extensive, significant sensory differences between potatoes including bitter, buttery, creamy, earthy, fruity, off-flavors other than bitter, potato-like flavor, sweet, woody, appearance, aroma intensity, mealy texture, and overall quality (mixed model ANOVA, α=0.05, n=17-38 ratings x 15 clones). Non-targeted volatile metabolomics with headspace solid-phase microextraction gas chromatography coupled to mass spectrometry (HS-SPME GC-MS) facilitated identification of 42 unique metabolites with significant variation across samples (ANOVA, α=0.05, n=5 technical replicates x 14-15 clones x 2 cooking methods). Based on Spearman's rank correlations, hierarchical clustering analysis (HCA), and principal component analysis (PCA), potential biomarkers for buttery, a positive flavor attribute, are aldehydes 1-nonanal, benzaldehyde, (E)-2-heptenal, pentanal, 2-phenylacetaldehyde, the alcohol (Z)-2-methyl-2-penten-1-ol, and 5-methyl-2-hexanone, a ketone. Other positive flavor attributes, sweet and potato-like flavor, are related to benzoate-3-methyl-2-buten-1-ol, 2-ethylfuran, and 3,4,5-trimethyl-2-cyclopenten-1-one. Potential biomarkers for negative flavor attributes are also implicated. Additionally, some sensory and aroma compound differences occur between baked versus boiled potatoes. Flavor biomarkers may play a key role in achieving flavor quality improvement through breeding and selection.
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    The influence of genotype, environment, and storage time on the ascorbic acid content and retention in potato germplasm from the Colorado Potato Breeding and Selection Program
    (Colorado State University. Libraries, 2023) Tikhonova, Olga, author; Holm, David G., advisor; Jayanty, Sastry, advisor; Heuberger, Adam, committee member; Weir, Tiffany, committee member
    Potato is a globally consumed vegetable crop known to contain vitamin C, with its active form, ascorbic acid (AsA), serving as a potent antioxidant involved in numerous physiological processes within the human body. The oxidized form, dehydroascorbic acid (DHA) was not measured in this study. Thus, the focus of this thesis was to investigate ascorbic acid in potato germplasm in the Colorado Potato Breeding and Selection Program. However, even if a potato genotype contains a sufficiently large amount of AsA, immediately after harvesting, its content may significantly decrease during storage. Therefore, it is so important to focus not only on the initial AsA content but also on its retention in storage. An investigation was conducted to enhance our understanding of the potential to increase AsA content in potato tubers through traditional breeding. This study examined the variations in AsA levels due to genetic factors (assaying multiple genotypes), environmental conditions (different growing locations), and AsA retention (sampling during storage). This study was divided into 2 parts. In Part 1 (Year 1, 2021), AsA initial level and its retention during storage was investigated in 34 genotypes grown in the San Luis Valley, CO, USA. The initial AsA content ranged from 8.5 to 37.7 mg/100 g FW. All genotypes experienced some level of AsA loss during storage, with the mean loss across all 34 genotypes being 34.8%. Notably, there was considerable variation in both initial AsA levels and retention among the genotypes, with some even exhibiting a temporary increase in AsA content during storage. In Part 2 (Year 2, 2022), six cultivars (selected from 34 from last year) were grown in three different locations to investigate the effect of environmental conditions on the initial content of AsA and retention. Among the genotypes examined, three showed evidence of variation between AsA retention and growing location (time:environment, TxE interaction), indicated by varying slopes. Four genotypes demonstrated variation in initial AsA content over three different locations, representing a genotype:environment, (GxE) interaction. In conclusion, this investigation emphasizes the potential for improving potato tuber AsA content through traditional breeding, while also underscoring the significance of considering both the initial content and retention during storage to maximize nutritional benefits. This research highlights the complex interactions between genetics (genotype), environment (growing location), and storage time that influence AsA retention in this widely consumed vegetable.