{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T09:13:08Z","timestamp":1788340388466,"version":"build-2803163510"},"reference-count":30,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T00:00:00Z","timestamp":1788220800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Plants"],"abstract":"<jats:p>Replacing synthetic colorants with natural alternatives requires source-specific extraction strategies because pigment classes differ in polarity, pH response and thermal stability. This first-pass screening focused on six plant and agro-food matrices: red cabbage, Iris germanica petals, dragon fruit, orange peel, spent coffee grounds and pine bark. Each matrix was subjected to twelve extraction treatments combining water, ethanol, acetone 30%, acid\/base modifiers, boiling water, freezing and ultrasound assistance. Extracts were evaluated by visible transmittance spectroscopy from 360 to 740 nm, operationally transformed to apparent optical attenuation according to Aapp (\u03bb) = \u2212log10 [%T (\u03bb)\/100] only where measured %T exceeded 0.01; this signal may include both absorption and light scattering, and converted to CIELAB coordinates under D65\/10\u00b0 conditions. The combined spectral and colorimetric approach separated the extracts into red-purple and yellow-brown groups. Red cabbage and Iris showed anthocyanin-like behaviour, dragon fruit showed a betalain-compatible magenta response, orange peel showed carotenoid-compatible short-wavelength attenuation, and coffee grounds and pine bark generated broad brown-yellow profiles. Pigment-family assignments remain putative because chromatographic identification was not performed. This study is explicitly intended as a proof-of-concept descriptive mapping step rather than as a statistically validated extraction optimisation. Because every matrix\u2013treatment combination was prepared once, all comparisons in this article describe the observed screening preparations only; they do not estimate reproducible treatment effects, confidence intervals or statistical significance. The previous equal-weight low-L*\/high-C*ab intensity score has been removed from the revised analysis. No extraction yield, recovery percentage, mass balance, purity, pigment concentration or application performance was measured; accordingly, this study describes the optical appearance of the obtained extracts and does not quantify colorant recovery. Visible transmittance, apparent optical attenuation and CIELAB coordinates support only literature-informed class-level hypotheses and cannot identify a pigment family or individual compound.<\/jats:p>","DOI":"10.3390\/plants15172685","type":"journal-article","created":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T08:31:13Z","timestamp":1788251473000},"page":"2685","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Visible Spectral, CIELAB and Putative Chromophore-Class Screening of Plant and Agro-Food Residue Extracts"],"prefix":"10.3390","volume":"15","author":[{"given":"Joan","family":"Masanet Mart\u00ed","sequence":"first","affiliation":[{"name":"Faculty of Sciences, University of Alicante, 03690 San Vicente del Raspeig, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6782-4130","authenticated-orcid":false,"given":"Antonio","family":"Belda-Antol\u00ed","sequence":"additional","affiliation":[{"name":"Department of Earth and Environmental Sciences, Faculty of Sciences, University of Alicante, 03690 San Vicente del Raspeig, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2979-0179","authenticated-orcid":false,"given":"Daniel","family":"L\u00f3pez Rodr\u00edguez","sequence":"additional","affiliation":[{"name":"Department of Applied Mathematics, Universitat Polit\u00e8cnica de Val\u00e8ncia, Plaza Ferr\u00e1ndiz y Carbonell s\/n, 03801 Alcoy, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8178-9987","authenticated-orcid":false,"given":"Jorge","family":"Jord\u00e1n-N\u00fa\u00f1ez","sequence":"additional","affiliation":[{"name":"Department of Graphic Engineering, Universitat Polit\u00e8cnica de Val\u00e8ncia, Plaza Ferr\u00e1ndiz y Carbonell s\/n, 03801 Alcoy, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"validation","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2438-4961","authenticated-orcid":false,"given":"\u00c1lvaro-Francisco","family":"Morote","sequence":"additional","affiliation":[{"name":"Department of Experimental and Social Sciences Education, Faculty of Teacher Training, University of Valencia, Av. dels Tarongers 4, 46022 Valencia, Valencia, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8845-1495","authenticated-orcid":false,"given":"B\u00e0rbara","family":"Mic\u00f3-Vicent","sequence":"additional","affiliation":[{"name":"Department of Graphic Engineering, Universitat Polit\u00e8cnica de Val\u00e8ncia, Plaza Ferr\u00e1ndiz y Carbonell s\/n, 03801 Alcoy, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1146\/annurev-food-030216-025923","article-title":"Natural colorants: Food colorants from natural sources","volume":"8","author":"Sigurdson","year":"2017","journal-title":"Annu. 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