Coffee Science

URI permanente desta seção${dspace.url}/handle/123456789/3355

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2020 - 20242

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Assunto: search.filters.subject.Principal component analysis

Resultados da Pesquisa

Agora exibindo 1 - 2 de 2
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    Diversity pattern on phytochemical traits of coffee bean skin from various species and harvesting methods
    (Editora UFLA, 2024-11-12) Maxiselly, Yudithia; Bakti, Citra; Renaldi, Gerry; Sari, Dwi Novanda; Nusifera, Sosiawan; Maulana, Haris
    Coffee is a well-known beverage consumed widely all around the globe. During its processing, a vast amount of waste was generated that can be utilized due to its bioactive compounds beneficial for human health. This study aimed to investigate the diversity pattern of three coffee pulp species based on phytochemical properties (total phenolic content (TPC), caffeine content, and antioxidant activity using the DPPH assay) exhibited by the skin of three coffee bean species: Coffea arabica (Arabica), Coffea canephora (Robusta), and Coffea liberica (Liberica) harvested with different technique (selective and strip picking). This study revealed that species and harvesting techniques significantly influenced the phytochemical properties of the coffee bean skin (CBS). The diversity pattern is shown by Principal Component Analysis (PCA), which has a correlation between Robusta and TPC and Arabica with Caffeine content. The findings from this study show the possibility of utilizing the waste from the coffee industry, especially the skin, to be used further in the development of products with considerable amounts of bioactive compounds.
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    Comparison of sensory attributes and chemical markers of the infrared spectrum between defective and non-defective Colombian coffee samples
    (Editora UFLA, 2020) Rodriguez, Yeison Fernando Barrios; Calderon, Karen Tatiana Salas; Hernández, Joel Girón
    Defects in coffee affect the sensory quality of finished drink. To avoid this, defective beans are usually removed after threshing, as, once the green beans have been roasted, it becomes difficult to identify the defects. Procedures have been developed to evaluate coffee samples using infrared spectroscopy to detect such defects. As such, this study evaluated infrared spectra and sensory attributes of 39 coffee samples in: commercial ground and instant coffees, medium and high roast quality coffees, and defects present in the coffee. The sensory analysis was performed by 10 judges, semi-trained by a Q-grader, and eleven attributes were assessed using a semi-structured hedonic scale. The spectra obtained from the coffee samples were processed by mean centering, normalization (probabilistic quotient normalization), area normalization, first derivative and second derivative, later followed by principal component analyses. The sensory results showed differences in the evaluated attributes, differentiating between the samples of high quality medium roasted coffee from the other samples. After processing IR spectra of the samples by area normalization, PCA results exhibited four different groups: a) medium, high roasted quality coffee, with broken and chipped defects; b) commercial ground coffee and defects of sour, insect damaged, and faded; c) black defects, and d) instant coffee. Using the chemical descriptors obtained from the infrared spectra, it was possible to separate between high quality, commercial and instant coffee.