Flush-dependent formation of industrial black tea liquor color: Integrating oxidation pigments with physicochemical quality indices through predictive modeling

Dönmez Akdağ G., Subaşı H., Alikoç D., Eminoğlu A.

FOOD RESEARCH INTERNATIONAL, cilt.245, sa.1202025, ss.1-15, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 245 Sayı: 1202025
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.foodres.2026.120225
  • Dergi Adı: FOOD RESEARCH INTERNATIONAL
  • Derginin Tarandığı İndeksler: Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Science Citation Index Expanded (SCI-EXPANDED), BIOSIS, Compendex, EMBASE, MEDLINE, DIALNET
  • Sayfa Sayıları: ss.1-15
  • Recep Tayyip Erdoğan Üniversitesi Adresli: Evet

Özet

Traditional assessment of industrial black tea liquor color has predominantly focused on oxidation pigments,

often overlooking the influence of routine physicochemical quality indices. This study fills this gap by, for the

first time, jointly quantifying the relative contributions of oxidation-derived pigments (TF, TR), caffeine, and

routine physicochemical quality indices (water extract, total ash, acid-insoluble ash (AIA), and moisture) within

a unified, flush-resolved analytical framework. Spearman analyses revealed strong negative associations between

color intensity and moisture, total ash, and acid-insoluble ash, and a strong positive association with water

extract, while brightness was positively linked to TF and the TF/TR. Regression models identified TF and AIA as

the principal predictors of liquor color, AIA and total ash as key determinants of brightness, and water extract as

the dominant driver of color intensity. Random forest analysis supported the multivariate structure of color

formation and confirmed the relative importance of both pigment and non-pigment quality indices. These

findings demonstrate that black tea liquor color is governed by integrated compositional interactions rather than

pigment concentration alone. This integration establishes a compositional basis for reinterpreting industrial

black tea liquor color beyond pigment-centric evaluation. This study also provides a flush-aware framework for

interpreting the formation mechanism of industrial black tea liquor color and advances objective, QC-oriented

modeling in industrial contexts.